To improve understanding of the pathophysiology of hypertension in adolescents and pave the way for risk stratification, studies have sought to determine the correlates of blood pressure (BP). Inconsistencies in dependent and independent variables have resulted in an elusive consensus. The aim of this report is to examine an inclusive array of correlates of BP, as a continuous (systolic and diastolic BP) and a dichotomous variable.z-score, waist circumference, waist-to-height ratio (WHtR), body surface area, fat mass , fat-free mass (FFM), percentage of body fat, and presence of overweight/obesity.Subjects were a school-based sample of 730 urban, mostly African American, non-referred 6th and 7th grade girls. To find independent correlates of SBP/DBP, we used a stepwise model selection method based on the Schwarz Bayesian Information Criterion, enabling selection of a parsimonious model among highly correlated covariates. Candidate variables were: age, stature, heart rate, pubertal development, BMI, BMI The best-fitting models for DBP and SBP (considered separately) included fat-free mass, heart rate and, in the case of SBP, stature. The best-fitting model for high-normal/elevated blood pressure (H-N/EBP) included WHtR with no independent relation of any other variable. The prevalence of H-N/EBP tripled between a WHtR of 0.5 and 0.7.The easily obtained and calculated WHtR is the strongest correlate of elevated blood pressure among available variables and is a prime candidate for longitudinal studies of predictors of the development of hypertension.NCT00746083ClinicalTrials.gov Identifier,  To better understand its pathophysiology and identify risk markers, i.e., variables that identify individuals at risk for developing HTN, an obvious starting point is to identify the cross-sectional correlates of HTN. Although several studies have been published in adolescents, a consensus is elusive because studies vary in their choice of dependent variable  increases with stature, BMI, and heart rate (HR) , 2. OtheAnother important question is whether age and pubertal stage, both of which are correlated with BP , 6, remaTo address this knowledge deficit, this study aims to evaluate, in a non-referred sample of adolescent girls, which subset of variables provides the best model to explain (1) inter-individual variation in BP (separately for SBP and DBP) and (2) the presence of pathologically high BP. Extending beyond the limited number of variables considered in other studies, we included BMI-for-age, other anthropometric indices, body composition, HR, stature, age, pubertal development, and race. Notably, we also included the variable fat-free mass (FFM), which is seldom considered by investigators. Because practically all the examined independent variables are correlated, we used a model selection method based on the Schwarz Bayesian Information Criterion . This meThe participants were primarily African American adolescent girls in a Mid-Atlantic, large, urban school district serving mostly low-income communities. The relative homogeneity of the sample confers a high degree of internal validity, i.e., findings are less likely to be explained by non-measured confounders than if the sample had been drawn from a broader geographical area and ethnic mix. Moreover, because obesity is related to socioeconomic factors  this groWe used baseline observations from a randomized, controlled trial of girls attending grades 6 and 7 in 22 Baltimore City schools. Girls were invited to participate through mailings and in person during lunch breaks and at school-sponsored events. The randomized element of the trial was assignment to either (1) nutrition and physical activity or (2) bullying prevention. Data were collected prior to randomization. Exclusion criteria were language barriers, competing time commitments, and medical conditions that would interfere with any of the 2 interventions or pose an increased risk. All participants provided informed assent and their primary caregivers provided informed consent. This study was approved by the U of Maryland, Professional Schools IRB and the Baltimore City Public Schools IRB.By self-report, participants selected among 5 racial categories with the option of selecting multiple categories as well as an “Other,” write-in category.Anthropometric measurements were taken by trained research staff. Height was measured to the nearest 0.1 centimeter with a portable stadiometer  in triplicate and averaged. Waist circumference (WC) was measured at the level of the umbilicus with a tape measure to the nearest 0.1 centimeter in triplicate and averaged. WHtR was calculated as waist circumference divided by height. Body weight, fat mass, fat-free mass , and percent body fat (to the nearest 0.1 %) were assessed using a body composition analyzer , which combines a traditional scale with bioelectrical impedance analysis (BIA). Participants removed socks, jewelry and pocket contents prior to stepping on the device. BIA measurements were performed twice; if weight or percent body fat differed, a third measurement was taken and the average calculated.2). BMI z-scores and percentiles were computed and participants were categorized as normal weight (<85th percentile) or overweight/obese (≥85th percentile) based on the Centers for Disease Control and Prevention growth charts [0.425 · height0.725.BMI was calculated for each participant as weight divided by height squared , were averaged into a single puberty score with a theoretical and observed range from 1-5.Pubertal status was assessed using a validated self-assessment questionnaire with drawings of the Tanner puberty stages . Illustrn = 16), BP measurements were repeated 4, 5, or 6 times. Average HR was calculated in a similar fashion.BP and HR were measured using a professional, digital oscillometric BP monitor , validated within ± 3 mmHg or 2 % for BP and within ± 5 % of the reading for HR. Cuff size was selected based on measured arm circumference. BP was measured after a 3-minute rest, with the participant in a seated position and her right arm in an extended position resting at heart level with palm facing up. After the first measurement, the participant was instructed to raise her arm in the air and to clench and release her hand three times and, approximately one minute later, a second measurement was taken. If the first two BP measurements differed by more than 10 %, a third measurement was taken. The two closest measurements were used for computation of an average SBP and average DBP. In rare cases  and b) high-normal/elevated BP  [Age-, gender-, and height- specific SBP and DBP  Program . Individcentile) .z-score, BMI category , WC, WHtR, BSA, body weight, percent body fat, fat mass, and FFM.Data were analyzed using SAS Version 9.2 . The first part of the analysis identified the correlates of DBP and SBP. A Pearson’s correlation matrix was calculated for all pairs of dependent and independent variables. To establish the correlates of DBP and SBP in the framework of general linear models, independent variable selection was performed in a stepwise manner according to the Schwarz Bayesian Information Criterion (SBC) as implemented in SAS PROC GLMSELECT . DecisioTo account for possible intra-school clustering, the selected models were examined further in SAS PROC GENMOD, which accounts for clustered data using the generalized estimating equation.t-tests for continuous and X2 tests for categorical variables. Initial variable selection was performed by stepwise logistic regression according to SAS PROC LOGISTIC. The selected variables were further examined in PROC GENMOD to account for possible intra-school clustering while specifying the appropriate distribution for logistic regression. Log odds ratio estimates were converted to odds ratios by exponential transformation. Prevalence was calculated as 1/(1 + odds ratio).The second part of the analysis focused on the statistical correlates of HTN. Subjects were characterized according to BP category. Group differences were examined by n = 13).Out of 1840 girls in grades 6 and 7 in the participating schools, 789 (43 %) were enrolled. Less than 5 % of girls seeking enrollment were excluded for any reason, including medical conditions, language barriers, and competing time commitments. By self-identified racial/ethnic category 701 girls (90.3 %) were African American/Black, including 29 girls who additionally selected one or more other categories, 29 were solely Caucasian/White, 26 were solely American Indian/Native American, 16 were solely Hispanic, and 4 were solely Asian. Race/ethnic category was coded as missing for girls who declined to provide this information (p <0.05) in the distribution of any subject characteristic according to whether BP measurements were or were not performed (data not shown), leading us to conclude that BP data were missing at random. All further analyses were conducted on the 730 participants with complete BP and HR data; their characteristics are presented in Table Due to time and staffing constraints, BP and HR measurements were omitted on 59 participants. There was no significant difference  with correlation coefficients ranging from 0.08 – 0.30. In addition, all measures of body size were strongly related to each other with correlation coefficients ranging from 0.66 – 0.96.The correlates of DBP and SBP were examined separately. Table t = 8.89) and HR (t = 7.77), respectively. For SBP the variable selection involved 3 steps, adding FFM (t = 5.11), HR (t = 3.25), and height (t = 2.66), respectively.The variable selection for DBP involved 2 steps, adding FFM . To visualize this parameter, the log odds ratio was converted to a prevalence estimate as shown in Fig. The stepwise, logistic regression variable selection procedure with H-N/EBP as the dependent variable selected WHtR as the sole independent correlate of H-N/EBP. The correlation with WHtR was confirmed using the generalized estimating equation to take intra-school clustering into account. The log odds ratio parameter estimate from the generalized estimating equation was 5.89 for WHtR p <0.000. To visuIn multivariable analyses the variable that explained the greatest variability in DBP and SBP was FFM. Most studies of the relation between body composition and BP consider only measures of fatness even though FFM is always available whenever fat mass or percentage of body fat is assessed. However, in this and the few other studies , 15 wherFollowing FFM, the variable that explained the greatest inter-individual variability in BP was HR. HR was not correlated to FFM or any other measure of body size, making HR and FFM independent correlates of BP. It is well-known that HR and BP are correlated in rested individuals , 15. IncHeight was independently associated with SBP and has – like FFM and HR – previously been associated with BP in both adults and children. This finding has been attributed to the necessity of a higher BP to secure adequate cerebral perfusion in the presence of the higher hydrostatic pressure generated between the brain and the heart in a taller person. Consistent with reports of others , we did We did not find an independent effect of race on BP. While this lack of evidence may be due to limited statistical power as a result of the small cell sizes for all groups but African Americans it is consistent with a study of 98 African Americans and 103 Caucasians .In contrast to our analysis of blood pressure as a continuous variable, the stepwise selection procedure indicated that WHtR was the sole independent correlate of H-N/EBP. As shown in Fig. z-scores or percentiles.WHtR was first used as a measure of central obesity in the Framingham Heart Study . For useThe correlation between WHtR and H-N/EBP is biologically plausible because the adverse consequences of excess weight are thought to be explained by adipokines  such as In summary, in this population of adolescent girls of whom 5.5 % met criteria for H-N/EBP we found conflicting statistical findings depending on whether our dependent variable was BP (continuous variable) or pathologically elevated blood pressure (dichotomous variable). As a synthesis of our data and the mechanistic studies of others, we posit that in generally healthy youths with a modest enrichment for HTN, the independent correlates of BP studied as a continuous variable mostly reflect inter-individual variation in BP within the normotensive range, which is explained by physiological adaptation to linear growth and expansion of lean tissue rather than visceral fat deposition. On the other hand, the correlation between WHtR and elevated BP (as a dichotomous variable) reflects pathophysiological processes revolving around VAT deposition, superimposed on the mechanisms involving lean tissue.Consistent with our observation that it is visceral fat accumulation, not FFM, that distinguishes H-N/EBP, physical activity interventions do not increase risk of HTN although they increase lean mass. In fact, in controlled studies, assignment to an exercise program has been successful in reducing BP in obese children –24.z-score) and a measure of central obesity .In analogy to other studies of children and adults , our datLike most of the work on which current knowledge is based , 20, 21,th and 7th grade girls that enrolled are representative of the 22 participating schools. Less than 5 % of girls who sought enrollment were excluded for any reason, medical or practical. (2) We did not collect information on antihypertensive use, albeit rare in this age group. (3) BP was measured by oscillometry. Although this method correlates well with intra-arterial BP measurements, auscultation is the preferred method [Several minor limitations exist. (1) We have no way of gauging to which extent the 43 % of the 6d method . (4) SexThese 5 limitations are minor because the main purpose of this investigation was variable selection in the context of associations between variables, not the exact assessment of population estimates.The report adds to current knowledge because as far as we are aware no other pediatric study of this topic examines as independent variables both FFM and WHtR and as dependent variables both the continuous variables of SPB and DBP and the dichotomous variable of elevated BP. This comprehensive analytical approach promotes novel insights and confirms that FFM, although seldom considered by investigators, is reproducibly the strongest anthropometric correlate of BP , 15.th percentile, was best explained by WHtR, tripling in prevalence for those with a WHtR of 0.7 as compared to 0.5. Our findings suggest the relevance of longitudinal investigations to determine the utility of using WHtR – alone or with other biomarkers – to risk stratify adolescents for HTN.We found that (1) inter-individual variation in DBP and SBP was best explained by FFM and HR (and height in the case of SBP), and (2) the presence of elevated blood pressure, defined as SBP or DBP at or above the 90


Investigators from University of Melbourne, Australia, studied Pressure-Reactivity Index (PRx) and optimal Cerebral Perfusion Pressure (CPP) in 36 children aged between 6 months and 16 years treated for traumatic brain injury (TBI) at the Royal Children's Hospital, Melbourne, from 2007 to 2013. Investigators from University of Melbourne, Australia, studied Pressure-Reactivity Index (PRx) and optimal Cerebral Perfusion Pressure (CPP) in 36 children aged between 6 months and 16 years treated for traumatic brain injury (TBI) at the Royal Children's Hospital, Melbourne, from 2007 to 2013. All patients received care according to the local TBI protocol. Patients were monitored for a median of 3.8 days. The authors described PRx in this cohort of children with TBI and examined its association with other patient variables. They also compared patients in the favorable and unfavorable outcome groups. PRx quantifies the correlation between intracranial pressure (ICP) and arterial blood pressure to assess the integrity of cerebral blood flow autoregulation. CPP refers to the difference between mean arterial pressure and ICP. Optimal CPP is the ideal pressure gradient driving cerebral perfusion in light of the evolution of PRx over time for each patient.PRx was significantly higher in children with unfavorable outcome (p<0.01). Therefore, loss of cerebral autoregulation was associated with worse outcome. The ideal PRx threshold to discriminate between favorable and unfavorable outcome is still unknown, but a threshold PRx value of both 0 and 0.25 seem to delineate between a favorable and an unfavorable outcome . Nonetheless, PRx is a useful prognostic marker.In line with previous adult studies, the relationship between the PRx and CPP respected a U-shape curve, allowing detection of an optimal CPP for each patient. The optimal CPP varied significantly with age. In this cohort of patients the optimal CPP ranged from 53 to 78 mm Hg. Furthermore, the patients with unfavorable outcome spent a greater percentage of their monitoring time with a CPP at least 5 mm Hg inferior to their optimal CPP. COMMENTARY. The prognostic role of PRx has been established in adult studies, but the concept is relatively new in the pediatric population . An impaSecondary brain injuries are the result of events following the initial TBI. Avoidance of further secondary insult to the injured brain is the basis of TBI management. The Guidelines for the acute medical management of severe pediatric TBI suggest a CPP threshold of 40 to 50 mm Hg to avoid secondary ischemic injury, with the understanding that age-specific threshold probably exists, with infants at the lower end and adolescents at the higher end of this range . This cuIn summary this article emphasizes the potential value of PRx monitoring as both a prognostic marker and a determinant of individualized optimal CPP. The potential therapeutic role of individualized care for patient and optimal CPP targeting based on PRx evaluation need further clinical evaluation to assess the clinical impact on patient outcome .


Hypertensive crisis is a medical emergency that can cause acute damage to multiple end-organs. However, relatively little is known on the etiology, treatment, and outcomes of hypertensive crisis in Korean children. The aim of this study was to determine the etiologies and efficacy of drugs for hypertensive crisis in children during the past 5 years at a single center in Korea.We analyzed data from 51 children with hypertensive crisis during the period between January 1, 2010 and April 1, 2014. The patients were divided into two groups: those diagnosed with a hypertensive emergency  and those diagnosed with a hypertensive urgency . Baseline etiologies and risk factors were compared between the two groups. In addition, systolic and diastolic blood pressures were evaluated at 1, 2, 4, and 5 hours after the administration of intravenous antihypertensive drugs.Kidney injury and cancer were the common causes in patients with hypertensive crisis. Cardiovascular complications (cardiac hypertrophy) (p = 0.002), central nervous system complications (p = 0.004), and retinopathy (p = 0.034) were more frequently observed in children with hypertensive emergency than those with hypertensive urgency. However, the proportion of renal complications was similar in both groups. Hydralazine was most commonly used in both groups to control acute increasing blood pressure at first. However, it was often ineffective for controlling abrupt elevated blood pressure. Therefore, intravenous antihypertensive drugs were changed from hydralazine to nicardipine, labetalol, or nitroprusside to control the high blood pressure in 45.1 % of the patients. Particularly, in patients with hypertensive crisis, there was no significant difference in reduction of systolic and diastolic blood pressure and in improvement of clinical outcomes between nicardipine and labetalol administration.Close blood pressure monitoring and careful examinations should be mandatory in children with underlying disease, especially renal diseases and cancer. Furthermore, both nicardipine and labetalol may be effective antihypertensive drug in lowering high blood pressure in children with hypertensive crisis. Hypertension in children is defined as a sustained systolic blood pressure (SBP) or diastolic blood pressure (DBP) elevation status greater than or equal to the 95th percentile for age, gender, and height . SeveralHypertensive crisis is a clinical syndrome of severe hypertension that can cause life-threatening status –6. This Hypertensive crisis, however, is rare in children, and the prevalence of hypertensive crisis in children is currently unknown . In addiThe medical records were retrospectively reviewed to search for patients with hypertensive crisis admitted to Yonsei University Severance Hospital during the study period . The inclusion criteria for patients were as follows: 1) below 20 years of age; 2) diagnosis of hypertensive crisis which has symptoms and significant elevations in blood pressure with or without accompanying end-organ damage; and 3) treated with intravenous hydralazine or continuous nicardipine, labetalol, and nitroprusside infusion. Participants were excluded if they had an immediately-postoperative status. Therefore, we enrolled a total number of 51 patients.The patients with hypertensive crisis were divided into two groups according to the presence of end-organ damage: hypertensive emergency  and hypertensive urgency . The definition of end-organ damage was having signs or symptoms suggesting a hypertensive emergency such as visual symptoms, seizure, anuria, hematuria, or abnormal findings in a 12-lead electrocardiogram or echocardiography. Data collected included age, sex, and etiology of hypertension. Additionally, serum blood urea nitrogen (BUN) and creatinine (Cr) were collected as laboratory data. SBP and DBP were measured hourly after continuous infusion of antihypertensive agent. Baseline etiologies and characteristics were also compared between the two groups.Baseline blood pressure was also assessed and was defined as the patient's highest blood pressure before starting the medication. Blood pressure was then measured every hour until 5 hours after initiation of the antihypertensive medication.t-test, and a chi square test was used for categorical variables using SPSS version 18.0 . A p-value of <0.05 was considered to have statistical significance. This study was approved by the Institutional Review Board (IRB) of Severance Hospital .For statistical analysis, continuous-value data for each group were compared using a student Baseline etiologies were presented in Table Systemic signs and symptoms suggestive of potential end-organ damage were presented in Table Treatment of the patients with hypertensive crisis included hydralazine, nicardipine, and labetalol Table . HydralaIn both hypertensive emergency and hypertensive urgency group, there was no significant difference in reduction of SBP and DBP between nicardipine and labetalol administration Table . HoweverWe further evaluated the clinical outcomes after finishing treatment of intravenous nicardipine or labetalol single infusion in both hypertensive emergency and urgency patients Table . Total 6The main goal of this study was to investigate the causes of pediatric hypertensive crisis and the efficacy of drugs used to control it. We found that cancer and renal disease were the two common causes of hypertensive crisis as described in other studies , 15. OurAlthough hypertension is usually regarded as a disease of adulthood, with a prevalence of 30 % , it can Nicardipine hydrochloride, approved by the Food and Drug Administration in December 1988, belongs to the class of dihydropyridine calcium channel blockers used to treat vascular disorders including high blood pressure, Raynaud’s phenomenon, and chronic stable angina , whereasThe Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure declared that arterial blood pressure must be decreased by no more than 10 %–25 % during the first hour of treatment . Both niThere is concern that iatrogenic effects such as hypotension and bradycardia can occur when using nicardipine and labetalol. Rapid blood pressure declines in nicardipine and labetalol patients were not observed, possibly owing to physician understanding and acknowledgment. In fact, reported adverse events including drowsiness, weakness, hyperkalemia, and drug eruption were uncommon in our study due to the short period of treatment. Both medications are metabolized by the liver; therefore, patients with renal impairment may be treated without profound complications.We were not able to draw firm conclusions with regard to the comparative efficacy and safety of nicardipine vs. labetalol in children and adolescents with hypertensive crisis. As the data were insufficient for measuring long-term outcomes in patients experiencing hypertensive crises, further research is necessary in the near future. There is a possibility that some with hypertensive emergency may not have been ultimately diagnosed with acute end-organ damage due to a low SBP under 180 mmHg or a DBP under 120 mmHg. In the treatment of such patients without hypertensive emergency, oral antihypertensive medication may have been a reasonable option. It can be very challenging to collect data on children and adolescents with true hypertensive emergencies. Thus, the study population may not represent the patients to whom nicardipine and labetalol would most likely be prescribed. Additionally, ethnic differences between Asian, African, and Caucasian populations should be taken into account.In conclusion, there was no difference between nicardipine and labetalol for a rapid and controlled BP decrease of administration in children and adolescents with hypertension and renal disease. However, these results should be considered in the context of the patient population and tempered with further studies to determine whether the controlled blood pressure improvement obtained by nicardipine or labetalol truly has any clinical significance.


In spite of several research studies help to describe the heart in Fabry disease (FD), the cardiomyopathy is not entirely understood. In addition, the impact of blood pressure and alterations in geometry have not been systematically evaluated.In 74 FD patients  the extent of myocardial fibrosis and its progression were quantified using cardiac magnetic-resonance-imaging with late enhancement technique (LE). Results were compared to standard echocardiography complemented by 2D-speckle-tracking, 3D-sphericity-index (SI) and standardized blood pressure measurement. At baseline, no patient received enzyme replacement therapy (ERT). After 51±24 months, a follow-up examination was performed.Systolic blood pressure (SBP) was higher in patients with vs. without LE: 123±17 mmHg vs. 115±13 mmHg; P = 0.04. A positive correlation was found between SI and the amount of LE-positive myocardium  indicating an association of higher SI in more advanced stages of the cardiomyopathy. SI at baseline was positively associated with the increase of LE-positive myocardium during follow-up. The highest SBP (125±19 mmHg) and also the highest SI (0.32±0.05) was found in the subgroup with a rapidly increasing LE . Multivariate logistic regression analysis including SI, SBP, EF, left ventricular volumes, wall thickness and NT-proBNP adjusted for age and sex showed SI as the most powerful parameter to detect rapid progression of LE .LV geometry as assessed by the sphericity index is altered in relation to the stage of the Fabry cardiomyopathy. Although patients with FD are not hypertensive, the SBP has a clear impact on the progression of the cardiomyopathy. Fabry disease (FD) is an X-linked lysosomal storage disorder caused by a deficiency of α-galactosidase A. The clinical presentation is a multi-systemic disease affecting kidneys, nervous system and the heart. , 2 The cAs main drivers for the development of the Fabry cardiomyopathy, the storage of globotriaosylceramides in myocytes  with subAn easy, non-invasive tool for the assessment of LV geometry is the 3D sphericity index.  This indIn general, a (very) high blood pressure is not considered typical for Fabry patients. , 18, 19 The aim of this study was to explore links between the severity and progression of the Fabry cardiomyopathy and geometrical changes of the LV myocardium, as well as blood pressure. Additionally, predictors for progression of the cardiomyopathy were investigated. We hypothesized that standard echocardiography can detect geometry changes of the LV and that an altered geometry, in association with the blood pressure, is connected with replacement fibrosis and progression of the cardiomyopathy. To understand the interaction of these factors would greatly enhance our concepts regarding the clinical assessment and follow-up of patient with Fabry cardiomyopathy.In total, 162 consecutive FD patients were screened at their first visit at the Fabry center Wuerzburg. No patient used enzyme replacement therapy (ERT). Criteria for inclusion were (1) genetically proven Fabry disease, (2) feasibility of cardiac magnetic resonance imaging (cMRI) with contrast agent, (3) feasibility of echocardiography, (4) absence of coronary artery disease, and (5) informed consent for the examinations and participation in the study. Finally, 74 patients  were included in this study. Reasons for exclusion (n = 88) were: contraindications for cMRI, such as claustrophobia or pacemakers; stage 4 or 5 renal dysfunction; uncontrolled hypertension (SBP >140 mmHg); insufficient quality of echocardiography. At baseline (n = 74) and at the follow-up visit (n = 46) cardiac imaging using cMRI and echocardiography techniques as described below was performed in all patients. In addition, standard clinical data were obtained from clinical examination in the context of our standard clinical investigation program for Fabry patients. Non-invasive measurement of blood pressure was performed manually three times on two different days using a standardized protocol. Prospective follow-up examinations (including cMRI and echocardiography) were performed at the next visit, resulting in a mean observation period of 51 ± 24 months.According to the Declaration of Helsinki, written informed consent of all patients or their guardians was obtained. Ethics committee University of Würzburg approved this study. As it is a rare disease part of the patients were already included in other studies. , 7, 20N-terminal propeptide of brain natriuretic peptide (NT-proBNP) was determined as an easy applicable marker for cardiac dysfunction. In order to register early stages, NT-pro-BNP instead of brain natriuretic peptide (BNP) was used due to its higher sensitivity in patients with slight dysfunction. We abstained from using atrial natriuretic peptide (ANP) because of its restricted clinical relevance, mostly caused by the low biochemical half-life of only 3 minutes. NT-proBNP was measured with electro chemoluminescence immunoassayassay in our routine laboratory (coefficient of variation <7%).CMRI was performed after intravenous injection of gadopentetate dimeglumine 0.2 mmol/kg on a 1.5 Tesla scanner . Pictures were acquired with segmented inversion-recovery turboFLASH sequences . The time of inversion (TI) was set to null normal myocardium (range 230-330ms). All consecutive short axis slices were used for manually tracing the area with pathological mid- or transmyocardial LE. The sum of areas was multiplied with the slice thickness and then set in relation to LV myocardium volume.LV parasternal long axis images with M-Mode echocardiography  were used to measure end-diastolic and end-systolic dimensions  and thickness of the interventricular septum (IVST) and LV posterior wall (LVPWT). Additionally, left atrial (LA) diameter and the diameter of the aortic root were measured. By application of Simpson’s formula, LV ejection fraction (EF) was calculated based on 2- and 4-chamber view. Blood-pool pulsed Doppler of the mitral valve inflow was used to quantify the ratio of early-to-late (E/A) diastolic flow velocity and the deceleration time. The transmitral flow was determined by placing the Doppler window between the tips of the mitral valve leaflets and peak flow velocities in early (E wave) and late (A wave) diastole were measured. In case the E/A ratio was insufficient to quantify diastolic function, the difference between duration of blood flow in pulmonary veins and duration of blood flow in the left ventricle  was calculated, indicating elevated filling pressure with values >30 ms. Additionally, tissue Doppler was performed for measuring the ratio between early transmitral flow and peak early tissue Doppler velocity (E/e’). Measurements of movement of septal and lateral mitral ring were averaged over three cycles. Using those parameters, diastolic function was graded either as normal, relaxation abnormalities (grade 1), pseudonormal (grade 2) or restrictive (grade 3). 3) is calculated with half the longitudinal diameter of the heart as the radius. This volume is then compared to the end-diastolic volume calculated by Simpson’s formula. The closer this index approximates the value “1.0” the better the LV shape resembles a spherical structur. SI values lower than 0.25 are considered normal. For patients after myocardial infarction a sphericity index of larger than 0.25 was suggested as a sign of myocardial alteration. [The global LV geometry can be quantified by the 3D sphericity index (SI). It is based on calculating how much the overall shape  deviates from a sphere. Therefore, the volume of a virtual globe  by two-dimensional speckle tracking using ECHO-Pac Software . After manual selection of the region of interest (ROI), the myocardium was tracked, and tracking accuracy was confirmed by the reader. By semiautomatic postprocessing, longitudinal systolic strain of the 17 LV segments was extracted. Global strain was calculated as the mean value of all valid segments. Intra- and interobserver variability of longitudinal strain, was 9.8% and 11.4%, respectively, for single segments as previously described in our laboratory.  Using thrd quartile of the amount of fibrosis among patients with pathological LE) was chosen to compare patients with mild and severe LE. At baseline, 39 patients showed no LE , 23 mild LE  and 12 patients severe LE .For staging of the severity of the cardiomyopathy, patients were grouped according to the amount of late enhancement (LE) in the LV myocardium. A value at baseline of ≥2% of LE positive myocardium , as appropriate. Correlation were expressed by Pearson´s or Spearman´s correlation coefficient, as appropriate. Differences between paired and unpaired groups were tested using t-test, Mann-Whitney U-test or Wilcoxon rank sum test, as appropriate. For categorical data, Chi-squared test or Fisher’s exact test were used. All differences were tested two-sided. Higher numbers of groups were tested using two-way ANOVA. Receiver operating characteristic analysis (ROC) as well as multivariable logistic regression analysis was performed to evaluate the ability of different values to distinguish between patients with different amounts of LE. P values <0.05 were considered statistically significant. Data was analyzed using SPSS version 21.0 .Values are presented as mean ± SD, median with 25The clinical characteristics of the study sample are presented in In the total sample the mean SBP and DBP was 118 ± 15 mmHg and 80 ± 11 mmHg, respectively. However, SBP was higher in patients with myocardial fibrosis and depended on the stage of cardiomyopathy .The mean SBP was highest in the group with a fast increase of replacement fibrosis, ie, >0.2% LE increase per year , compared to the group without such increase . Similarly, the subgroup with mild progression of LE showed higher SBP  than subjects without progression (p<0.05). There was also a trend for a gradient of higher diastolic blood pressures across these groups .Among all patients, 35 47%) showed mid- or transmyocardial LE  with a mean volume of 1.69 ± 1.79% of LV mass. Male and female patients did not show significant differences in the amount of LE-positive volumes . Pathological LE was mainly restricted to the basal postero-lateral LV segments as described before.  Patients% showed Those patients exhibiting LE already at baseline showed an increase of the total amount of LE-positive myocardium of 1.18 ± 0.30% during the follow-up period . This amounted to a median increase of 0.23 (0.09–0.50). No patient showed a reduction of the amount of LE during follow-up. Two patients were LE-negative at baseline but developed new LE during follow-up. The progression of LE is shown in The results from the standard echocardiography divided in the different cardiomyopathy groups are presented in 2; intermediate stage: 80.7 ± 25.9 g/m2; severe stage: 84.3 ± 21.4 g/m2; p<0.01).LV mass was increased in advanced stages of the disease  compared to men . Patients in advanced stages of Fabry cardiomyopathy showed higher SI values compared to patients without cardiomyopathy . The same significant difference was detected when analyzing both genders separately .We performed analysis of SI in 20 healthy controls . This resulted in mean SI of 0.24±0.01 with no difference between gender (p = 0.56).A positive correlation was found between the amount of LE-positive myocardium and baseline SI  suggesting a (possibly direct) link between worsening sphericity and advancing stages of Fabry cardiomyopathy. Examples of typical echocardiographic images are shown in In general, patients with a faster progression of fibrosis during follow-up presented higher SI values at baseline. The subgroup without increase of LE (n = 15) had baseline values of 0.27 ± 0.06. The subgroup with mild increase of LE  presented with a SI of 0.29 ± 0.05 at baseline (p>0.001). The highest SI was found in the subgroup with fast increase of LE  with 0.32 ± 0.05 (P = 0.04).In addition, patients with elevated SI (SI ≥ 0.25) at baseline showed higher SBP compared to the subgroup with normal SI .At baseline, no patient received ERT. The follow-up was performed after 51±24 months. No significant difference for the change in SI was found between subjects with (n = 20) and without ERT.To quantify the dependency of various independent variables with fast progression of fibrosis, univariate regression analysis was performed for SI (p = 0.011), SBP (p = 0.047), IVST (p = 0.021), LA (p = 0.025), LVEDD (p = 0.89), EDV (p = 0.28), EF (p = 0.31) and FS (p = 0.71).Variables with significant results were included in a multivariate logistic regression analysis adjusted for age and sex showed SI as the parameter to predict rapid progression of LE . ReceiveDuring the follow-up period, two patients developed new myocardial replacement fibrosis. The mean SI at baseline from both patients was 0.32 ± 0.02. In addition, these two patients presented with higher SBP at baseline (121 ± 2 mmHg). In contrast, patients without fibrosis at baseline and during follow-up had lower SI values (0.27 ± 0.07) and lower SBP (113 ± 15 mmHg). While this additionally underscores the relation of SI with progression and development of fibrosis, no statistical test was performed due to the small sample size in this subgroup (n = 2).The use of Angiotensin- (AT) or Angiotensin-Converting-Enzyme (ACE)-blockers was not significantly different in the subgroups.Global peak systolic strain as a parameter for global LV function was not significantly different between patients with normal and elevated SI . In contrast, regional systolic strain in the basal postero-lateral, where replacement fibrosis is usually located, was significantly decreased in patients with elevated SI (-15 ± 4% in patients with an SI lower than 0.25 (n = 32) and -11 ± 7% in patients with elevated SI; n = 42; p = 0.025). The lowest systolic strain in postero-lateral wall segments was found in patients with rapid increase of LE .NT-proBNP levels were positively correlated with the severity of the cardiomyopathy (early stage: 68 (39–79) pg/ml; intermediate stage: 95 (27–290) pg/ml; severe stage: 121 (55–844) pg/ml; ANOVA P = 0.009 with logarithmic transformation). Higher NT-proBNP levels were found in patients with an elevated SI (86 (51–520) pg/ml) compared to patients with normal SI (49 (33–158) pg/ml; P = 0.02). In the subgroup with fast increase of replacement fibrosis, higher NT-proBNP levels were found than in patients with slow and without increase of fibrosis (fast increase: 170 (58–361) pg/ml; slow increase: 86 (31–180) pg/ml; no increase: 62 (39–90) pg/m; P<0.001, respectively; ANOVA P = 0.311).The current study shows for the first time the impact of LV geometry and blood pressure on both the stage at presentation and the adverse progression of the cardiomyopathy over time in a larger, well-characterized Fabry cohort. The main findings were: 1) The presence of myocardial replacement fibrosis assessed by LE imaging seems to determine the future accelerated progression of the cardiomyopathy. 2) The LV geometry is altered in Fabry cardiomyopathy, attaining an increasingly spherical shape. The extent of sphericity is positively related to the stage of the cardiomyopathy, thus predicting the progression of the disease. 3) Although (baseline) blood pressure was not markedly increased in patients with FD, a slightly elevated SBP was associated with an unexpectedly adverse impact on the cardiomyopathy. SBP is therefore closely related to alterations of the geometry and morphology of the myocardium and may–directly or indirectly–contribute to disease progression. 4) Levels of NT-proBNP are increased in relation to the stage of the cardiac involvement and can thus be used as a biomarker for the severity of the cardiomyopathy.The early affection of myocardial function, even in absence of myocardial replacement fibrosis has recently been shown , 23. OurWhile the blood pressure was always assumed an irrelevant factor in FD , the curAll factors discussed above progressively stress the Fabry heart, increase enddiastolic pressures and thus NT-proBNP levels, and will ultimately cause heart failure.Another important factor, regarding the heart in FD, is the influence of impaired kidney function on blood pressure, LE and altered volume relations, which could have several affections on the heart. To illustrate all these effects a much larger number of patients is necessary, which very difficult in Fabry disease.The two patients who were free of replacement fibrosis at baseline but developed LE during follow-up are particularly interesting. As they were not hypertrophic and free of replacement fibrosis they were classified as “early cardiomyopathy” at baseline. However, both patients had an increased SBP and SI, which might have triggered the relatively fast progression towards a more advanced cardiomyopathy stage with replacement fibrosis. These findings are important for three reasons: First, it confirms our hypothesis that the geometry and the blood pressure are important factors for the progression of the cardiomyopathy. Second, they suggest that an altered LV geometry is not necessarily secondary to myocardial replacement fibrosis but actually might be an early indicator for subsequent development of fibrosis. Third, when a Fabry patient is followed clinically, even a slight increase of blood pressure may indicate the susceptibility for an accelerated progression. It needs to be shown, however, whether a targeted treatment of SBP in these subjects might slow or halt progression.Therefore, all these factors are influencing each other and affect the progression of the CM, as shown in Echocardiography and cardiac MRI are part of the current standard clinical protocol for the assessment of Fabry cardiomyopathy. Not only the current stage of the disease, but also an estimate of the future progression of the cardiomyopathy are clinically important. From the presented data the recommendation might be derived not only measure the established parameters like LE (by cMRI) and end-diastolic wall thickness , but also to observe morphological features like the SI. The SI is simple to measure with most echo machines and values can be reliably compared across repetitive follow-up examinations.Prediction of fast progression of fibrosis will not be possible with one single measurement or one single parameter. Thus, physicians working with Fabry patients should be aware of changes in those parameters during disease progression, indicating a higher fibrosis progression rate.In all Fabry patients, independent of the stage of the disease, the blood pressure should be adequately controlled. Thus, a 24-hour blood pressure measurement should be done routinely and oral medication with, i.e., renin-angiotensin-aldosterone-system (RAAS) blockers should be considered. These substance classes have the advantage, to positively influence SBP (enhance unloading), cardiac remodeling (prevent/slow cardiac fibrosis) and the kidney function (decrease proteinuria). , 31, 32 The current data is in line with the view that the development of the Fabry cardiomyopathy is an ongoing process as soon as changes in geometry and myocardial fibrosis are present. This suggests that very early treatment ERT before these markers can be detected might be preventive. The collection of data in a randomized controlled trial supporting this notion constitutes probably one of the most urging issues of the Fabry research agenda.Because of ethical reasons, myocardial biopsies could not be obtained for definite proof of fibrosis. However, this technique allows to sample only selected amounts of tissue, thus not allowing to quantify the amount of fibrosis.The reported blood pressure data result from isolated measurements in hospital setting. The results would be more meaningful with ambulatory Holter blood pressure measurements, which could not be performed in this study.SI was significantly different according to gender. A possible explanation is the higher age of male patients in our cohort and the fact that male patients are usually more affected in this x-chromosomal disease.Another limitation is the fact that the impact of treatment with i.e ACE inhibitors and also ERT cannot be evaluated in detail. The influence of other factors of impaired kidney function on fibrosis and blood pressure could not be eliminatedThe current study is focusing on new parameters, relating to and influencing on the Fabry CM. The investigation of these parameters  is helpful for the understanding of the development of the cardiomyopathy. Myocardial cells with enzyme deficiency tend to be more vulnerable for extrinsic influences like slightly increased blood pressure. Left-ventricular geometry is altered in relation to the stage of the cardiomyopathy. These alterations can be easily detected by repetitive echocardiographic measurement of the sphericity index, which is predicting progression of the disease.


The decision of when to stop septic shock resuscitation is a critical but yet a relatively unexplored aspect of care. This is especially relevant since the risks of over-resuscitation with fluid overload or inotropes have been highlighted in recent years. A recent guideline has proposed normalization of central venous oxygen saturation and/or lactate as therapeutic end-points, assuming that these variables are equivalent or interchangeable. However, since the physiological determinants of both are totally different, it is legitimate to challenge the rationale of this proposal. We designed this study to gain more insights into the most appropriate resuscitation goal from a dynamic point of view. Our objective was to compare the normalization rates of these and other potential perfusion-related targets in a cohort of septic shock survivors.We designed a prospective, observational clinical study. One hundred and four septic shock patients with hyperlactatemia were included and followed until hospital discharge. The 84 hospital-survivors were kept for final analysis. A multimodal perfusion assessment was performed at baseline, 2, 6, and 24 h of ICU treatment.2 gradient, and capillary refill time were already normal in more than 70% of survivors at 6 h. Lactate presented a much slower normalization rate decreasing significantly at 6 h compared to that of baseline  but with only 52% of patients achieving normality at 24 h. Sublingual microcirculatory variables exhibited the slowest recovery rate with persistent derangements still present in almost 80% of patients at 24 h.Some variables such as central venous oxygen saturation, central venous-arterial pCOPerfusion-related variables exhibit very different normalization rates in septic shock survivors, most of them exhibiting a biphasic response with an initial rapid improvement, followed by a much slower trend thereafter. This fact should be taken into account to determine the most appropriate criteria to stop resuscitation opportunely and avoid the risk of over-resuscitation. The. The3]. mization ,5]. In . In 2) a targets –8]..2) as re2 could eventually result in severe adverse effects such as fluid overload, pulmonary edema, intra-abdominal hypertension, cardiac arrhythmias, and myocardial ischemia, thus possibly increasing morbidity and mortality ..2 could 2 optimization  wer wer16] wThe following measurements as part of a multimodal perfusion assessment were obtained at baseline and at 2, 6, and 24 h after starting ICU resuscitation:1. Macro-hemodynamic variables: mean arterial pressure (MAP), heart rate, norepinephrine (NE) or vasoactive drug doses, central venous pressure (CVP), pulse pressure variation (%), and pulmonary artery catheter-derived values (when in place). Fluid administration was also registered at each predefined time-point.2, arterial lactate and P(cv-a)CO2.2. Metabolic-related perfusion variables: ScvO3. Peripheral perfusion was assessed with the capillary refill time (CRT)  .In a subgroup of patients who arrived within the first 2 h of onset of septic shock and were already in mechanical ventilation, we performed also the following microcirculatory and micro-oxygenation assessments:2) was measured by a tissue spectrometer   mmHg, respectively. Dobutamine was used in ten patients. Basal and 24-h intra-abdominal pressures were 13 [9 to 17] and 13 [8 to 15] mmHg, respectively.Patients received 1,750  mL of crystalloids in the pre-ICU setting after meeting septic shock criteria. The rate of fluid administration tended to decrease over time during ICU resuscitation. A total of 1,150  mL of crystalloids were administered during the first 2 h, 980  mL from 3 to 6 h, and 1,020  mL from 7 to 24 h of ICU-based resuscitation. A pulmonary artery catheter was placed in 38 patients. Basal cardiac index and pulmonary arterial occlusion pressure were 3.1 [2.5 to 3.9] L/min/m2, StO2, P(cv-a)CO2, and CRT values, respectively. Medians values for individual macrohemodynamic and perfusion variables at different time-points in patients with abnormal values at baseline are shown in Table p < 0.01).By definition, all patients started ICU-based resuscitation with an abnormal lactate as compared to only 8, 31, 32, and 39 patients with abnormal ScvO2, and CRT values, a biphasic curve could be drawn COn Figure  where a 2, CRT, and microcirculatory variables at different time-points for the subgroup of patients arriving within the first 2 h of septic shock are shown in Table p = 0.2) or NE requirements  was observed between patients that had normalized lactate or not at 24 h.Medians values for microcirculatory variables and the percentage of normalization for lactate, P(cv-a)COPerfusion-related variables exhibit markedly different normalization rates in septic shock survivors, most of them exhibiting a biphasic response with an initial rapid improvement, followed by a much slower trend thereafter. This fact should be taken into account to determine the most appropriate criteria to stop resuscitation opportunely and avoid the risk of over-resuscitation.2, and CRT values were already normal in the majority of patients at ICU admission after some previous volume loading, and it appears that these variables are particularly responsive to DO2 increasing maneuvers. In a previous study, ScvO2, increased from 49% to 77% in septic shock patients subjected to early aggressive DO2 optimization . CR. CR2, anmalities ,28]..2, and CThe case of hyperlactatemia is paradigmatic. Although tissue hypoperfusion has been traditionally considered the most common cause of hyperlactatemia, there is increasing evidence for concomitant non-hypoxic and thus, non-flow dependent mechanisms ,29] tha tha29] t2 could lead to detrimental effects of excessive fluids or inotropes. In our study, lactate exhibited a significant decrease of almost 50% of basal median values during the first 6 h of resuscitation associated with a rapid normalization of other metabolic and peripheral perfusion parameters COPPV: proportion of perfused vesselsPVD: perfused vascular densitySOFA: Sequential Organ Failure Assessment2: central venous oxygen saturationScvO2: tissue oxygen saturationStO2: mixed venous oxygen saturationSvOVOT: vascular occlusion testThe authors declare that they have no competing interests.GH, CL, and AB conceived the study, participated in its design and coordination, and helped to draft the manuscript. JB, CI, GF, and GO conceived the study and helped to draft the manuscript. RC helped to draft the manuscript and performed statistical analyses. EK maintained the database, performed statistical analyses, and designed tables and figures. AF registered and analyzed microcirculatory images. CR recruited and followed up patients. TR recruited and followed up patients. All authors read and approved the final manuscript.Hemodynamic and perfusion-related parameters in 20 non-survivors. Click here for file


Bleeding complications in cardiac surgery may lead to increased morbidity and mortality. Traditional blood coagulation tests are not always suitable to detect rapid changes in the patient's coagulation status. Point-of-care instruments such as the TEG (thromboelastograph) and RoTEM (thromboelastometer) have been shown to be useful as a guide for the clinician in the choice of blood products and they may lead to a reduction in the need for blood transfusion, contributing to better patient blood management.The purpose of this study was to evaluate the ability of the TEG, RoTEM and Sonoclot instruments to detect changes in hemostasis in elective cardiac surgery with cardiopulmonary bypass and to investigate possible correlations between variables from these three instruments and routine hematological coagulation tests. Blood samples from thirty-five adult patients were drawn before and after surgery and analyzed in TEG, RoTEM, Sonoclot and routine coagulation tests. Data were compared using repeated measures analysis of variance and Pearson's test for linear correlation.We found significant changes for all TEG variables after surgery, for three of the RoTEM variables, and for one variable from the Sonoclot. There were significant correlations postoperatively between plasma fibrinogen levels and variables from the three instruments.TEG and RoTEM may be used to detect changes in hemostasis following cardiac surgery with CPB. Sonoclot seems to be less suitable to detect such changes. Variables from the three instruments correlated with plasma fibrinogen and could be used to monitor treatment with fibrinogen concentrate. Excessive bleeding in cardiac surgery occurs in as much as 20% of patients. It is associated with increased morbidity and mortality, mainly caused by need for reexploration and transfusion of blood products -6. In 15To date, there is no “gold standard” test for the assessment of microvascular bleeding in cardiac surgery. Perioperative monitoring of the hemostatic process by a combination of conventional coagulation tests may be helpful in diagnosing possible causes of bleeding ,16. HoweIn the last decade, viscoelastic point-of-care (POC) coagulation instruments such as the thromboelastograph (TEG), the thromboelastometer (RoTEM) and the Sonoclot have been increasingly used in clinical practice for perioperative monitoring of excessive bleeding in cardiac surgery -20. ThesAlthough with some differences, these instruments are based on similar principles and provide output in the form of a similar graphical tracing. However, it is still not clear whether TEG, RoTEM and Sonoclot provide identical information. The performance of different POC instruments in cardiac surgery has been evaluated in previous studies -24 but, The primary objective of this study was to evaluate the comparability of the results obtained from the TEG, RoTEM and Sonoclot instruments by assessing their ability to detect changes in hemostasis caused by CPB. In addition, we also investigated whether variables from the TEG, RoTEM and Sonoclot analyses were correlated to results from a selection of conventional coagulation tests.This study was a prospective observational study. Thirty-five patients (22 men and 13 women) scheduled for elective cardiac surgery with the use of CPB were included after giving written informed consent. All patients were treated with aspirin until the day before surgery. Patients who had been treated with clopidogrel within five days prior to surgery were not considered eligible to the study.Patients with unstable angina received low molecular weight heparin preoperatively. Tranexamic acid 30 mg/kg was given to all patients prior to CPB according to departmental routines. Before CPB, the patients received heparin 300 U/kg  through a central venous line to achieve a kaolin activated clotting time (ACT)  of > 480 seconds. Additional heparin was given when needed to keep the ACT above the target. During CPB, the ACT was monitored every 20 minutes. The perfusion circuit was primed with 1800 mL of Ringer’s acetate solution with 7500 U of heparin. A membrane oxygenator without heparin coating was used.Cold antegrade and/or retrograde blood or crystalloid cardioplegia and moderate hypothermia to 34°C were used during CPB. Cardiotomy suction was used while the patients were fully anticoagulated, and the blood was returned to the patients without centrifugation. The patients were warmed to a rectal temperature of at least 36°C before termination of CPB. After CPB, protamine sulphate was given to achieve an ACT within 10% of the baseline value. Blood remaining in the CPB circuit was collected and transfused to the patient. Postoperatively, transfusions of packed red cells were given when the hemoglobin concentration was < 8.5 – 9.0 g/dL. Persistent postoperative bleeding of more than 200 mL/h was treated with infusions of desmopressin, fresh frozen plasma and/or platelet concentrates, or reexploration at the discretion of the attending clinician.2. Blood samples for Sonoclot analysis were drawn into syringes without additives and transferred to the Sonoclot cuvette for immediate analysis. All the tests for the TEG, RoTEM and Sonoclot were performed by the same investigator (AE), and all Sonoclot tracings were interpreted by a single investigator (HP). The operating principles of the TEG , RoTEM  and the Sonoclot analyzer  are described in detail by Ganter and Hofer [To identify possible hemostatic changes caused by CPB in the TEG, RoTEM, Sonoclot and conventional coagulation tests, blood samples were collected at three different time points: preoperatively (immediately before anesthesia induction), and at 1 and 24 hours postoperatively. Blood samples for TEG and RoTEM analyses were drawn into a tube containing citrate and analyzed within 1 hour, after recalcification with 20 μL CaClnd Hofer . NomenclCitrate-anticoagulated samples were analyzed consecutively for hemoglobin concentration, platelet counts, international normalized ratio (INR), activated thromboplastin time (aPTT), fibrinogen, d-dimer and antithrombin by standard methods at the Department of Medical Biochemistry at St. Olav University Hospital.p-values < 0.05 were considered statistically significant in the ANOVA analysis. Linear correlations were evaluated by Pearson’s R. To correct for correlations calculated at multiple time points, correlations with p-values < 0.01 were considered significant. Statistical analysis was performed using the program SPSS for Windows, version 16.0 .Data are given as frequencies or means with standard deviation (SD). For the statistical analysis of the RoTEM variables, only the endpoint and not early values were used to ensure comparability because the TEG and Sonoclot instruments do not give early values. Repeated measures analysis of variance (ANOVA) was used for analysis of changes in continuous variables by time. If necessary to obtain a good model fit, logarithmic or rank transformation was performed. This was a prospective observational study, approved by the Regional Committee for Medical Research Ethics, Central Norway. All patients who were asked to participate in the study consented.Patient demographics, medical data and data on surgical procedures are presented in Table All the analyzed conventional coagulation tests differed significantly with time Table . There wCorrelations between the conventional coagulation tests and POC variables are given in Table Platelet counts correlated with TEG MA (clot strength) 24 hrs postoperatively, and two different RoTEM MCF variables (clot strength) correlated with platelet counts either 1 hr or 24 hrs postoperatively. The only correlations with aPTT were with the Sonoclot variables Son ACT (time until fibrin formation) and Clot Rate (rate of fibrin formation) at 1 and 24 hrs postoperatively. None of the POC variables correlated with INR.Four patients needed a surgical reexploration, due to persistent postoperative bleeding . These patients were transfused with red cell concentrates (6–10 units), platelet concentrates (0–3 units) and FFP (3–6 units). Two of these patients received an additional dose of tranexamic acid postoperatively. The decision of giving tranexamic acid postoperatively was empirical, as the results of the POC instruments were not available for the attending physician. None of the bleeding patients had abnormal baseline values for the TEG, RoTEM or for the coagulation tests. Preoperative Sonoclot Son Act (time until fibrin formation) results were abnormal in three of these patients. However, pathological Son Act results were found in the majority of the patients preoperatively. Only one patient showed pronouncedly reduced RoTEM FIBTEM MCF , plasma fibrinogen and TEG alpha (clot strengthening) values in the early postoperative period.As expected, all the conventional coagulation tests showed significant changes following cardiac surgery. This was mirrored in changes in all the TEG variables, some of the RoTEM variables, and only one of the Sonoclot variables. The changes pointed towards a more hypocoagulable state, consistent with dilutional coagulopathy and consumption of platelets and coagulation factors occurring during CPB ,8. In moSeveral previous studies ,25-28 doFrom our study, TEG seemed to be the more sensitive of the POC instruments and the Sonoclot was the least sensitive. None of our patients had markedly abnormal hemostasis and we cannot exclude that the instruments would have given more comparable results in patients with severe hemostatic disturbances.Previous comparative studies to assess the interchangeability between TEG and RoTEM have been reported ,31. EvenFrom our study, it seems that all three POC instruments may be equally useful to quantify changes in fibrinogen. The correlations found between various POC variables and fibrinogen concentrations are consistent with previous studies ,32-34. TNo correlations were found between INR and the TEG variable R (reaction time), the RoTEM CT (clotting time) or the Sonoclot Son ACT (time until fibrin formation), even if these three parameters all measure the time to the first fibrin formation. The reason for the discrepancy for TEG R might be the different activators used; kaolin for TEG and tissue factor for INR. For the other fibrin time measures, the reasons for the discrepancies are unknown. We found that the Sonoclot variables Son ACT and Clot rate (rate of fibrin formation) correlated significantly with aPTT. This is as expected, as aPTT is usually prolonged in hypocoagulable states, where a low Clot Rate can be found.Preoperative platelet counts were within normal ranges in all the patients. None of the POC tests showed correlations with platelet counts at both time points in the postoperative period. The explanation may be that the POC instruments rather assess platelet function than platelet counts even if they may also indicate when platelet counts are too low to provide adequate hemostasis. From this point of view, the POC instruments may be more clinically useful than standard platelet counts.Even if the TEG seemed to be more sensitive to detect hemostatic changes than the two other POC instruments, its use still carries potential problems. The references for the manufacturer’s proposed normal values for the TEG values are very limited and not well validated ,35. The Laboratories should establish standardized procedures to minimize variability. To solve the mentioned problems the International TEG-RoTEM Working Group has been created to try to standardize TEG and RoTEM and to establish protocols to ensure accurate results . Until bThe main limitation of this study is the small number of patients. In addition, there was some missing data for the RoTEM analysis, caused by short-time supplier problems (n = 1-4). However, our results are consistent with previous findings from studies with separate evaluation of the TEG, RoTEM and Sonoclot instruments in cardiac surgery. Our study was not designed to study clinical outcomes in relation to the POC tests, which would require a much larger patient population.In conclusion, TEG and RoTEM can be used to detect postoperative hemostatic changes following cardiac surgery, whereas the Sonoclot seems to be less suitable, at least in patients without grave hemostatic changes. Variables from TEG, RoTEM and Sonoclot may be useful to monitor fibrinogen levels. Further studies are necessary to establish adequate reference values for different patient groups and to standardize these assays to achieve reliable results.The authors declare that they have no competing interests.AE: Literature search, study design, patient enrolment, data collection and TEG, RoTEM and Sonoclot analysis, drafting of manuscript. RS: Study design, critical revision of manuscript. VV: Statistical analysis, critical revision of manuscript. HP: Study design, Sonoclot signature readings, critical revision of manuscript. All the authors read and approved the manuscript for publication.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2253/14/80/prepub


P < 0.0001), while outer diameter and inner diameter did not show significant correlation with age in the normal group . In the normal and hypertensive groups, WLR showed a strong correlation with systolic and diastolic blood pressure . In conclusion, AOSLO provided noninvasive and reproducible arterial measurements. WLR is an early marker of morphological changes in the retinal arteries due to age and blood pressure.The wall-to-lumen ratio (WLR) of the vasculature is a promising early marker of retinal microvascular changes. Recently, adaptive optics scanning laser ophthalmoscopy (AOSLO) enabled direct and noninvasive visualization of the arterial wall. Using AOSLO, we analyzed the correlation between age and WLR in 51 normal subjects. In addition, correlations between blood pressure and WLR were analyzed in 73 subjects . WLR showed a strong correlation with age (r = 0.68,  Retinal vessels serve as informative models of microvasculature changes in systemic diseases. For example, the Keith-Wagener34et al. reported that retinal arteriole WLR measured by SLDF was closely correlated with the media-to-lumen ratio of subcutaneous small arteries evaluated by invasive surgical interventionet al. reported that the WLR in patients with a past cerebrovascular event was significantly increased compared to that in treated hypertensive patients and normotensive subjectsRecently, noninvasive approaches for evaluating the retinal microvasculature have been reported, including scanning laser Doppler flowmetry (SLDF)6789et al. first succeeded in visualizing the retinal wall with AOSLOet al. reported vascular morphometric changes measured with an AO retinal cameraAdaptive optics (AO) technology, first applied to astronomy, is another promising approach for direct and noninvasive retinal arterial wall visualization121315181920In this study, we directly and noninvasively analyzed the vascular wall in hypertensive patients using AOSLO.AOSLO provided clear wall visualization of retinal arterial vessels but not venous vessels  and 2. MInter-evaluator intraclass correlation coefficients (ICCs) showed good agreement; the ICCs for OD, ID, WT, and WLR were 0.980, 0.970, 0.889, and 0.882, respectively. Inter-visit ICCs also showed good agreement; the ICCs for OD, ID, WT, and WLR were 0.961, 0.952, 0.977, and 0.960, respectively.P = 0.36, and r = −0.12, P = 0.41, respectively) . In the hypertensive group, the mean OD, ID, WT, and WLR were 122.3 ± 18.7 μm, 93.1 ± 15.6 μm, 29.2 ± 5.6 μm, and 0.320 ± 0.068, respectively. To adjust for age between groups, and because of the limited prevalence of hypertension in younger patients, we compared subjects aged >50 years between groups (P = 0.04) but not in OD, ID, and WT .In the normal group, the average OD, ID, WT, and WLR were 126.2 ± 12.3 μm, 101.6 ± 11.2 μm, 24.5 ± 4.3 μm, and 0.244 ± 0.047, respectively. OD and ID were not significantly correlated with age  , but WT n groups . There wAmong all 73 subjects, OD showed no significant correlation with systolic blood pressure (SBP), diastolic blood pressure (DBP), age, body mass index (BMI), pulse pressure (PP), and heart rate (HR). ID was significantly correlated with SBP and DBP, but not with age, BMI, PP, and HR. WT and WLR were significantly correlated with SBP, DBP, age, BMI, and PP, but not with HR . We thenP = 0.36; hypertensive group, r = 0.17, P = 0.45). Among the 69 subjects included in this analysis, IVAN-measured diameter was not significantly correlated with SBP, DBP, BMI, PP, or HR. We evaluated vascular caliber (OD and ID) measured by IVAN and AOSLO in both the normal and hypertensive groups using the same artery and found a strong correlation .The mean arterial diameter calculated by the IVAN system was 96.8 ± 9.9 μm in the normal group and 93.1 ± 14.4 μm in the hypertensive group. Four subjects were excluded because of difficulties with IVAN measurements. Calibers did not significantly correlate with age in either group  and 22 hypertensive patients . Either eye, dilated before AOSLO with one drop of tropicamide (0.5%) and phenylephrine hydrochloride (0.5%), was selected for this analysis. The exclusion criteria were as follows: best-corrected visual acuity worse than 20/25; high myopia ; intraocular pressure >21 mmHg; pregnancy; diabetes mellitus; renal failure; any form of secondary arterial hypertension; history of cerebral infarction; history of myocardial infarction; ocular diseases except hypertensive retinopathy; and systemic diseases except for hypertension. Subjects were examined for approximately 15 min in total per eye while in a seated position.et al. reported previouslyThe AOSLO system  is composed of the AO system, a high-resolution confocal SLO imaging system, and a wide-field imaging subsystem . The resHypertension was defined as mean SBP ≥140 mmHg, mean DBP ≥90 mmHg, taking antihypertensive medication at the time of examination, and/or a physician’s diagnosisVascular caliber measurement was performed in zone B337Forty-five-degree digital fundus photographs  and a semi-automated vessel measurement system  were used to measure retinal vessel widths from imported fundus photographs3ICCs were used to evaluate measurement reproducibility of the arteries selected for analyses. To evaluate inter-evaluator reproducibility of vascular calibers , the arteries of 20 normal subjects, at the same locations on the AOSLO images, were examined independently by two retina specialists in a masked manner. To evaluate inter-visit reproducibility, the same arteries were examined independently using two AOSLO images from 20 normal subjects collected on different days.t-tests were used to analyze vascular measurements, age, blood pressure parameters, and BMI. Unpaired t-tests were used to examine differences between measurements in normal and hypertensive participants aged >50 years. Multivariate regression analysis (backward stepwise method) was performed to identify predictors of WLR. All analyses were performed using StatView , except for the ICC and multivariate regression, which were calculated using SPSS . Significance was set at P < 0.05.All values are presented as mean ± standard deviation. Bivariate correlations were analyzed using the Pearson correlation coefficient. Paired How to cite this article: Arichika, S. et al. Effects of age and blood pressure on the retinal arterial wall, analyzed using adaptive optics scanning laser ophthalmoscopy. Sci. Rep.5, 12283; doi: 10.1038/srep12283 (2015).


The purpose of this study was to examine the relationships among subclinical PTSD symptoms, blood pressure, and several variables linked to both frank PTSD and the basic psychobiological adaptation to stress. The authors recruited a sample of 91 healthy, young men and women between 18 and 35 years. We examined links among subclinical posttraumatic stress disorder symptoms, blood pressure, sleep quality, and hostility. Posttraumatic stress disorder symptoms were associated with poorer sleep quality and higher hostility scores in both women and men. In men, PTSD symptoms were also associated with elevated resting diastolic blood pressure, and sex was an important moderator of that relationship. Moreover, sleep quality and hostility are substantive mediators of the relationship between diastolic blood pressure and PTSD. Behavioral interventions designed to increase sleep quality and restructure hostile attitudes could potentially serve as preventive interventions for PTSD and the underlying cardiovascular comorbidities in young adults. The clinical symptomology of posttraumatic stress disorder (PTSD) and the psychobiology of stress and arousal are intimately related. For example, both PTSD and psychological stress are associated with alterations in autonomic, circulatory, and behavioral mechanisms. Patients diagnosed with PTSD often exhibit hyperarousal, blood pressure dysregulation, sleep disruption, and elevated levels of hostility –6. TheseThe Psychobiology of Stress. Adaptation to acute and chronic psychological stress is accompanied by alterations in the sympathoadrenomedullary and the hypothalamic pituitary adrenocortical systems, with the consequent neuroendocrine cascade affecting blood pressure and a variety of other critical bodily functions. Several factors can influence the magnitude of these changes, including genetic, behavioral, and situational factors. For example, a meta-analysis by Wu et al. [u et al.  found pou et al. . Situatiu et al. . Moreoveu et al.  and, impu et al. .The Psychobiology of PTSD. PTSD is one potential outcome of extreme stress exposure characterized by autonomic dysregulation, increased cardiovascular reactivity, hyperarousal, sleep disturbances, and hostility. According to DSM-5 criteria, PTSD consists of four clusters of symptoms: (1) intrusion ; (2) avoidance; (3) negative alterations in cognitions and mood; and (4) alterations in arousal and reactivity [ymptoms:  intrusioactivity . Moreoveactivity , 18. Comactivity .PTSD is associated with catecholamine, serotonin, and hypothalamic pituitary axis (HPA) dysregulation, which contributes to increased sympathetic and circulatory reactivity in response to stressful demands , 20, 21.Although hyperarousal and stress reactivity likely represents a mechanistic link between PTSD and blood pressure dysregulation, precise etiologic mechanisms underlying this relationship have not been pointedly examined. Several constructs have been investigated independently as risk factors for hypertension and/or blood pressure dysregulation, including stress reactivity, hostility, and sleep disturbance. Hostility, for example, has been linked to blood pressure control mechanisms , risk foThus, blood pressure dysregulation, hostility, and sleep disturbances are associated with frank PTSD, as well as responses to stress in persons without a PTSD history. Even though PTSD symptom clusters are generally employed to classify individuals who have been exposed to traumatic events, current research has not fully examined the relationships among those factors in persons without a history of PTSD. Better understanding of the normal relationships among subclinical PTSD symptoms, blood pressure, sleep quality, and hostility in young healthy populations may provide insight into the psycho- and physiopathology underlying adaptations to traumatic stress.n = 42) and women (n = 49) recruited from the local geographical area. The final sample was 73.1% white, 9.7% black, 9.7% Asian. Exclusion criteria were history of significant cardiovascular, endocrine, or psychiatric disorder including PTSD or current use of cardiovascular or psychoactive medications.Participants between 18 and 35 years of age (average ± SE = 21.4 ± 0.45) provided resting blood pressure levels in a laboratory setting and then completed a series of self-report questionnaires. Participants included a sample of 91 young men  and diastolic blood pressure (DBP) both sphygmomanometrically and with a calibrated GE Dinamap Pro100V2 automated oscillometric device . Dinamap performance was verified on a regular basis for zero offset, integral offset, and gain using a mercury manometer. All resting blood pressure measurements used American Heart Association guidelines for blood pressure determination . RestingPTSD Checklist. The civilian version of the PTSD Checklist is a 17-item rating scale incorporating self-report of distress over the past 30 days based on accepted PTSD diagnostic criteria [criteria . It has criteria , 33.Pittsburgh Sleep Quality Index. The PSQI is one of the most widely used instruments to measure sleep quality, insomnia, and daytime sleepiness. The PSQI has been systematically evaluated for sensitivity and specificity for sleep disorder screening, is highly related to sleep diary data, and has been assessed in both population-based and clinical studies [ studies . PSQI sc studies .Cook-Medley Hostility Scale. The Cook-Medley Hostility Scale is a widely used self-report assessment including suspiciousness, resentment, and cynical mistrust, rather than overt aggressive behaviors [ehaviors , 35. Perehaviors , 35. Theehaviors .Results were analyzed using SPSS for descriptive statistics and linear regression analyses. These data were analyzed for the total group and for men and women separately. Regression analyses utilized PTSD symptoms as the dependent variable, with age, sex, blood pressure, hostility, and sleep quality as independent variables. Mediation and moderation were assessed by the moderated causal steps approach .p < .001). There were no significant sex differences for DBP, PSQI scores, or PTSD symptoms. However, the average hostility score was significantly higher (p = .006) for men (21.5 ± 1.17) than for women (17.3 ± 0.96).r(88) = .517, p < .001) and higher hostility scores (r(86) = .492, p < .001) in the total sample. These relationships are illustrated in Figures r(87) = .221, p = .038). In young women (see r(46) = .362, p = .011) and poor sleep quality (r(47) = .303, p = .034). In young men, PTSD symptoms were associated with poor sleep quality (r(39) = .691, p < .001) and higher hostility scores (r(38) = .597, p < .001) and were also associated with higher resting diastolic blood pressure (r(39) = .402, p = .009).Zero-order correlations see  among thomen see , PTSD syp < .001), and in men (p < .01). Hostility remained a unique correlate of PTSD symptoms in women (p = .025), while the effect of sleep quality revealed a strong trend (p = .052). In men, both sleep quality and hostility remained significant , whereas diastolic blood pressure was no longer significant when both variables were included in the model (p = .564).Multiple regression analyses were conducted to examine unique contributions of study variables to PTSD symptoms. The models included age, resting diastolic blood pressure, hostility, and sleep quality as independent variables see . Three sR2 = .48) and a milder relation for women (R2 = .09).Systematic analysis of mediation and moderation  indicateThe present study was designed to examine the relationships among subclinical PTSD symptoms and several variables linked to both frank PTSD and the basic psychobiological adaptation to stress in young adults. Subclinical PTSD symptoms have been studied in survivors of intimate partner violence , VietnamThere are several remarkable results from the current study. Diastolic blood pressure is a substantive predictor of PTSD symptoms in men, but not in women. The relationship between diastolic blood pressure and PTSD in men is strongly mediated by sleep quality and to a lesser extent by hostility. In women, sleep quality and hostility predict PTSD (with hostility being a slightly stronger predictor), but BP is not related to either of these, nor to PTSD symptom expression. These findings are particularly interesting since there is a significant literature linking sleep quality and hostility with (1) psychophysiological responses to acute and chronic stress and (2) risk for cardiovascular diseases often found comorbid with PTSD.Our finding that poor sleep quality was associated with higher blood pressure and PTSD symptoms is consistent with prior research examining autonomic dysregulation underlying both sleep dysfunction and physiological responses to stress. Several investigations from our laboratory and others have found that sleep quality is associated with autonomic dysregulation and elevated blood pressure. For example, epidemiologic studies have documented an association between blood pressure elevations and both shorter sleep duration and lower sleep maintenance –42. LaboOur finding that hostility was associated with sleep quality, blood pressure, and PTSD symptoms adds to the literature on potential psychosocial mechanisms accounting for the relation between stress responses, autonomic dysregulation, and symptom expression. Meta-analysis has documented a large effect size for the association between hostility and PTSD, which increased over time since the traumatic event . IndividThe increased arousal resulting from hostility and poor sleep quality may operate in synergy with the physiological response to traumatic stress in production of PTSD symptoms. PTSD symptoms are associated with both hostility and sleep disturbance, which, based on our current findings, could account for the autonomic dysregulation and increased risk for hypertension observed in individuals with PTSD. PTSD involves chronic overactivation of the sympathetic nervous system , in addiEvidence for the potential efficacy of stress management comes from research showing that cognitive behavioral stress management (CBSM) training, especially in small groups, reduces hostility and related psychosocial and physiological characteristics. For example, Bishop and coworkers found that psychosocial skills training reduced anger as well as depression, social isolation, and BP at rest and during anger recall stress in patients following coronary artery bypass graft . MoreoveThis study does not directly address causal connections among study variables. It is likely that the relationships among the study variables are bidirectional in nature, and thus causal influences may be difficult to fully characterize. Longitudinal studies are needed to investigate the nature of these relationships over time. Another limitation is that the study sample was not sufficient to examine the potential effects of race and/or ethnicity. While the current subclinical sample is valuable for examination of precursors to PTSD symptom expression, the results may not generalize to other age groups and/or all racial, ethnic, and socioeconomic populations. Furthermore, it is possible that individuals meeting clinical criteria for PTSD are subject to additional autonomic irregularities and other psychosocial risk factors compared with the subclinical population included in this study. On the other hand, effect sizes in this study may represent underestimates of the effects that may be observed in clinical populations. Finally, caution should be taken in etiologic interpretation of our findings, as it can be difficult to disentangle these constructs in causally meaningful ways without further and more extensive study.In summary, these findings suggest that poor sleep quality and hostility are associated with subclinical PTSD symptoms in healthy young men and women without a known history of PTSD. In young men, elevated blood pressure was associated with more PTSD symptoms, but this effect appeared to be accounted for, at least in part, by both sleep quality and hostility. Thus sleep quality and hostility may underlie some of the hyperarousal and autonomic nervous system disturbance in the expression of clinical PTSD symptoms, at least in men.The fact that both hostility and sleep disturbance were associated with PTSD symptoms independent of blood pressure suggests that they may represent underlying psychobiological mechanisms by which trauma relates to hyperarousal. Sleep quality and hostility accounted for the relation between diastolic blood pressure and PTSD symptoms in men but not women, so it is possible that different psychobiological processes underlie stress responses and autonomic dysregulation in men versus women. For example, researchers have described an oxytocin-associated “tend and befriend” approach to stress among women, in addition to the traditional fight-or-flight response that is more prevalent in men . Future


Glucagon-like peptide-1 (7–36) amide (GLP-1) protects against stunning and cumulative left ventricular dysfunction in humans. The mechanism remains uncertain but GLP-1 may act by opening mitochondrial K-ATP channels in a similar fashion to ischemic conditioning. We investigated whether blockade of K-ATP channels with glibenclamide abrogated the protective effect of GLP-1 in humans.Thirty-two non-diabetic patients awaiting stenting of the left anterior descending artery (LAD) were allocated into 4 groups . Glibenclamide was given orally prior to the procedure. A left ventricular conductance catheter recorded pressure–volume loops during a 1-min low-pressure balloon occlusion (BO1) of the LAD. GLP-1 or saline was then infused for 30-min followed by a further 1-min balloon occlusion (BO2). In a non-invasive study, 10 non-diabetic patients were randomized to receive two dobutamine stress echocardiograms (DSE) during GLP-1 infusion with or without oral glibenclamide pretreatment.max 30-min post-BO1 normalized to baseline after GLP-1: 0.3 ± 6.8 % (p = 0.02) and GLP-1 + glibenclamide: −0.8 ± 9.0 % (p = 0.04) compared to control: −11.5 ± 10.0 %. GLP-1 also reduced cumulative stunning after BO2: −12.8 ± 10.5 % (p = 0.02) as did GLP-1 + glibenclamide: −14.9 ± 9.2 % (p = 0.02) compared to control: −25.7 ± 9.6 %. Glibenclamide alone was no different to control. Glibenclamide pretreatment did not affect global or regional systolic function after GLP-1 at peak DSE stress  or recovery .GLP-1 prevented stunning even with glibenclamide pretreatment; the Δ % dP/dtGlibenclamide pretreatment does not abrogate the protective effect of GLP-1 in human models of non-lethal myocardial ischemia.Trial registration Clinicaltrials.gov Unique Identifier: NCT02128022The online version of this article (doi:10.1186/s12933-016-0416-3) contains supplementary material, which is available to authorized users. Percutaneous coronary intervention (PCI) is the cornerstone of treatment for acute myocardial infarction (AMI) but ischemia–reperfusion (IR) injury may account for up to 50 % of the final infarct size . AdjunctIC has proved challenging to translate into patient benefit so other strategies have focused on pharmacological agents to limit IR injury . One proPatients were aged over 18 years old and able to give informed consent. They had proximal left anterior descending artery (LAD) disease requiring PCI (supply protocol) or any coronary artery disease requiring revascularization (demand protocol). Patients were not enrolled in both studies. Exclusion criteria were presence of diabetes mellitus, use of nicorandil or ranolazine, a serum creatinine >200 μmol/l, presence of a cardiac pacemaker, valvular heart disease, impaired left ventricular systolic function, recent myocardial infarction or life expectancy less than 6-months.Both protocols were approved by the local ethics committee (14/EE/0056 and 08/H0304/68) and informed, written consent was obtained from all participants before enrolment. Studies were carried out in accordance with institutional guidelines. The studies were registered on clinicaltrials.gov (NCT02128022) and ISRCTN (ISRCTN69686930) and were performed in accordance with the Declaration of Helsinki.A timeline for this protocol is shown in Fig. Sheaths were placed in the right femoral artery, right radial artery and right femoral vein. Between 70 and 100 U/kg of unfractionated heparin was administered to maintain an activated coagulation time of >250 s throughout the procedure. An 8-electrode 7F conductance catheter  was connected to an MPVS Ultra  signal-conditioning unit in series with an ADInstruments PowerLab 16/30 Series  16-channel amplifier. It was positioned along the longitudinal ventricular axis with the tip at the apex of the LV  during a breath-hold in mid-expiration. Similarly, pressure–volume loops were recorded at the end of a 1-min low-pressure (<4 atmospheres) coronary balloon inflation (BO1) within the lesion. Contrast was injected during balloon inflation to confirm coronary occlusion.Patients randomized to receive GLP-1 then received an intravenous infusion of GLP-1 at 1.2 pmol/kg/min started immediately after balloon deflation. This dose was selected as it had been effective in inducing cardioprotection in previous studies, with minimal side-effects . Those pmax (maximum rate of isovolumic pressure increase), stroke volume and ejection fraction and diastolic parameters: dP/dtmin (maximum rate of isovolumic pressure decline) and Tau (time constant of isovolumic pressure decline). Tau is calculated from the conductance catheter-derived Pt (time constant of pressure relaxation) which is measured from the time of peak rate of pressure decline (dP/dtmin) to 5 mmHg above end-diastolic pressure.Conductance catheter data analysis was performed offline using LabChart , by investigators blinded to treatment allocation. Five cardiac cycles recorded at each time-point  were sampled  in randomly allocated order, performed at least 1 week apart. Patients attended in the morning following an overnight fast and received a GLP-1 infusion with or without oral glibenclamide 5 mg administered 60-min prior to the GLP-1 infusion. GLP-1 was started at 1.2 pmol/kg/min followed by dobutamine administration 15 min later. An intravenous infusion of 20 % dextrose started at 1.5 mg/kg/min was given during both DSE to minimize the risk of glibenclamide-induced hypoglycaemia. Each patient acted as their own control. Intravenous dobutamine infusion was incrementally increased from 10 μg/kg/min to 20, 30 and 40 μg/kg/min at 3-min intervals. Up to 2 mg of intravenous atropine could be given if necessary to reach the target heart rate. Both GLP-1 and dextrose infusions continued throughout the protocol until recovery was complete  was performed in the left recumbent position at rest, peak stress and 30-min recovery. Images were recorded in 2, 3 and 4 chamber apical views allowing a 12-segment model  of regional wall motion to be assessed. Segments were classified as ischemic or non-ischemic according to whether or not they were subtended by a coronary stenosis >70 % by Quantitative Coronary Angiographic (QCA) analysis, as validated by Baptista et al. . RelevanDuring the supply ischemia protocol venous blood was sampled at baseline and immediately prior to BO1 and BO2. In the demand ischemia protocol venous blood was sampled prior to starting dextrose, GLP-1 and dobutamine infusions, at peak stress and at 30-minute recovery  amide, free fatty acid, insulin and glucose levels were assayed. Samples for GLP-1 were drawn into tubes containing dipeptidyl peptidase 4 (DPP4) inhibitor  to prevent degradation and measured using a commercially available assay . Glucose samples were measured by YSI 2300 STAT Plus analyzer .max at BL2 of −13.4 ± 9.3 % and −1.4 ± 8.5 % respectively. We estimated that to detect a difference of 8 % at BL2  a sample size of 8 per group was required.In the supply protocol a power calculation was carried out based on previous work by our group . AnalysiIn the demand ischemia protocol, previous data has shown that a GLP-1 infusion caused an additional increase in ejection fraction at peak stress from 70.8 ± 4.96 to 77.0 ± 4.39 % in a paired study . We estiAll analyses were pre-specified. Continuous data are presented as mean ± SD unless otherwise stated. Paired and unpaired Student’s t test or Mann–Whitney U test were used to compare continuous variables as appropriate, and Chi Square test was used for categorical variables. In the supply ischemia study, 4-way comparisons between groups were carried out with a one-way independent ANOVA. A p value of <0.05 was deemed statistically significant.Thirty-three patients were recruited into the 4 groups detailed above . Detailed demographic data are summarized in the Additional file Overall there were no significant differences in hemodynamic parameters between the DSE. Importantly, GLP-1 infusion did not increase heart rate during the 15 min prior to the DSE in the GLP-1 only DSE . There was no significant difference in the RPP at peak stress between the DSE. These data are summarized in Additional file There was a rise in GLP-1 levels at peak stress during both DSE of over 50-fold compared with pre-DSE levels. Insulin levels rose in both DSE but were twice as high for the GLP-1 + glibenclamide group (p = 0.04). There was increased suppression of free fatty acids with GLP + glibenclamide. Biochemistry data for the demand ischemia protocol are summarized in Additional file There was no difference in global indices of systolic function between the paired DSE at either peak stress or recovery, indicating that glibenclamide did not attenuate the effect of GLP-1 Table . RegionaIn both the supply and demand ischemia protocols, addition of glibenclamide did not affect GLP-1 cardioprotection; GLP-1 protection against both ischemic left ventricular dysfunction and stunning remained. The implication of this study is that GLP-1 cardioprotection is not mediated through mK-ATP dependent pathways. Similar metabolic profiles (between glibenclamide-treated groups) ruled-out a metabolic explanation for the cardioprotection observed. Only the presence or absence of GLP-1 appeared to be associated with a protective effect and this was independent of both mK-ATP blockade and changes in myocardial substrate and insulin levels.IC acts via mK-ATP-dependent subcellular signaling pathway that is activated by up-stream RISK/SAFE pathways of cardioprotection , 18. IC In the supply protocol both glibenclamide alone and GLP-1 alone produced a rise in insulin levels and a fall in free fatty acids compared to saline control. However, only GLP-1 had a cardioprotective effect. Glibenclamide only produced changes in metabolic parameters without an observed difference in the function of the ventricle compared to control—this suggests that the metabolic effect of glibenclamide does not lead to alteration in cardiac function in this model. The combination of GLP-1 and glibenclamide produced even greater hyperinsulinemia but offered no additional protection beyond that of GLP-1 alone. Insulin levels with glibenclamide were similar to those observed during hyperinsulinemic clamp studies published by our group, which also showed a neutral effect of insulin on myocardial performance during ischemia . It has Studies have suggested that, in the human heart, the GLP-1 receptor is only present in the sinoatrial node . GLP-1 rThe mechanism underlying GLP-1 cardioprotection in non-lethal IR injury remains speculative. Animal evidence of mK-ATP dependent protection may still be applicable to lethal IR injury in humans. Alternatively, mK-ATP independent aspects of subcellular pro-survival kinase pathways may be involved in GLP-1 cardioprotection. Studies have suggested that adenosine may mediate some of the observed GLP-1 effects . AdenosiThe study does not present direct evidence of blockade of the cardiomyocyte mK-ATP channel. This was assumed on the basis of previous studies . It may The supply ischemia protocol did not measure load-independent indices of ventricular function such as the end-systolic pressure volume relationship (Ees) due to the difficulty of simultaneously recording a family of pressure–volume loops during preload reduction  whilst also balloon occluding the coronary artery. However, blood pressure and heart rate remained constant during the procedure allowing valid comparison of the load-dependent parameters studied. Whilst it would also have been statistically preferable to enroll a larger number of patients, ethical and practical considerations limited numbers to those specified in the power calculation.In the demand ischemia protocol it would have been preferable to perform prospectively recruited saline and glibenclamide only DSEs to control comprehensively. This was not possible for both ethical and practical reasons. We instead relied upon our historic control data using the same protocol, which has demonstrated that GLP-1 augments myocardial performance during demand ischemia .The cardioprotective effect of GLP-1 (7–36) amide in non-lethal IR ventricular injury does not appear to be mediated through an mK-ATP dependent pathway. Changes in myocyte substrate utilization and workload after GLP-1 also fail to explain the protection observed. Future mechanistic studies need to consider alternative mechanisms to explain the beneficial effect of GLP-1.