Stage 5 chronic kidney disease patients on haemodialysis (HD) often present with dizziness and pre-syncopal events as a result of the combined effect of HD therapy and cardiovascular disease. The dysregulation of blood pressure (BP) during orthostasis may be implicated in the aetiology of falls in these patients. Therefore, we explored the relationship between baroreflex function, the haemodynamic responses to a passive orthostatic challenge, and falls in HD patients.o (HUT-60°) test on an automated tilt table. ECG signals, continuous and oscillometric BP measurements and impedance cardiography were recorded. The following variables were derived from these measurements: heart rate (HR) stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), number of baroreceptor events, and baroreceptor effectiveness index (BEI).Seventy-six HD patients were enrolled in this cross-sectional study. Participants were classified as “fallers” and “non-fallers” and completed a passive head up tilting to 60The forty-four participants who were classified as fallers (57.9%) had a lower number of baroreceptor events  and BEI . In addition, fallers experienced a significantly larger drop in systolic  and diastolic  oscillometric BP from supine to HUT-60° compared with non-fallers. None of the variables taken for the analysis were significantly associated with falls in multivariate logistic regression analysis.This cross-sectional comparison indicates that, at rest, HD patients with a positive history of falls present with a lower count of baroreceptor sequences and BEI.Short-term BP regulation warrants further investigation as BP drops during a passive orthostatic challenge may be implicated in the aetiology of falls in HD. The World Health Organization (WHO) global report on falls prevention in older age  states tA few prospective cohort studies have explored the association of potential clinical risk factors and falls in CKD-5 patients undergoing HD therapy with physical frailty primarily, older age, comorbidity, previous history of falls, and polypharmacy –4, 6 appWe already know that aging, history of falls and physical frailty are the most consistent risk factors that stand out from the rest, as predictors of future falls in the general geriatric and CKD population . MoreoveThe baroreceptor reflex, or baroreflex, is the main physiological mechanism involved in the short-lived haemodynamic responses to change in body position, by regulating BP, heart rate, cardiac output, peripheral resistance, and thus preventing hypotension . This meThe aims of this study were to explore the hypotheses that impaired baroreflex function would be associated with falls behaviour, amongst HD patients and that self-reported fallers would be more likely to have worse haemodynamic responses to an orthostatic challenge.An observational prospective study design was used to explore the relationship between baroreflex function and the falling status  in a group of prevalent HD patients.The study was conducted in two Renal Units located in North Lanarkshire and Fife, United Kingdom, between October 2015 and August 2018. Recruitment started in October 2015 and continued on a rolling basis until December 2017. All baseline assessments were performed between October 2015 and December 2017, while the follow-up period ran from November 2015 to August 2018.This research project abided by the ethical principles for medical research involving human subjects, as set out by the world medical association declaration of Helsinki, and received ethical approval by the West of Scotland NHS and Queen Margaret University Research Ethics Committees .Ambulatory adult (>18 years) haemodialysis patients stable on HD therapy for at least 3 months fluent in spoken and written English were considered eligible to participate in the study.Exclusion criteria were unstable dialysis and medication treatment, lower limb amputation without prosthesis, unstable cardiac condition, suspected or known aneurysm, clinically severe left ventricular outflow obstruction, critical mitral stenosis, critical proximal coronary artery stenosis, critical cerebrovascular stenosis, pregnancy and severe cognitive impairment.Eligible patients were provided with a participant information sheet and were given seven days to consider whether to participate in the research project. All patients who agreed to take part provided written informed consent.The assessment visit lasted about 2 hours, and occurred on a non-dialysis day, in order to minimise the influence of fluid and electrolyte shifts on data collected. Participants were instructed to follow standardised assessment protocol procedures that included no meals, caffeine or alcohol-containing drinks for at least 2 hours before the assessment, no smoking and no unaccustomed physical exercise on the 24 hours preceding testing. No changes to medication prescription and timings were imposed.Participant demographics , and clinical characteristics  were obtained from the patients’ medical records. Height and weight were measured on the day of assessment.A fall was operationally defined as an unexpected event in which the participant comes to rest on the ground, floor, or lower level . The reso).The haemodynamic and baroreflex function was assessed at rest, in the supine position, and in response to a passive orthostatic challenge that involved head up tilting to 60 degrees from the supine position , which represents how often the baroreflex produces a change in HR in response to a perturbation in BP . The TasThe following variables were also derived and included in the analyses: i) blood pressure (BP) ramps defined as either an increase (up-ramp) or decrease (down-ramp) in contBP of at least 1 mmHg for 3 consecutive heart beats: “total-ramps” were defined as the sum of all down-ramps and up-ramps, ii) baroreceptor events, defined as the simultaneous coupling of a BP ramp with either an increase or decrease of the RRI of at least 4 ms. More precisely, a “down-event” was classified as a concomitant decrease of continuous systolic BP (contSBP) and RRI of at least 1 mmHg and 4ms respectively, while an “up-event” was classified as a concomitant increase of contSBP and RRI of at least 1 mmHg and 4ms respectively. “Total-events” were classified as the sum of all down-events and up-events iii) The BEI was then computed as the ratio of occurred baroreceptor events and detected BP ramps expressed as a percentage. This index can be characterised by three components: the “down-BEI” that represents the ratio of occurred down-events and detected down-ramps, the “up-BEI” that represents the ratio of occurred up-events and detected up-ramps, and the “total-BEI” that represents the ratio of occurred total-events and detected total-ramps. In addition, the baroreflex sensitivity (BRS) was automatically computed by the Task Force Monitor software as the average slope of the regression lines between the RRIs and the contSBP values resulting from every baroreceptor event .Statistical analyses were performed with SPSS . The Shapiro-Wilk Test (S-W) was used for the normal distribution checks of all data. Differences between fallers and non-fallers in demographic and clinical characteristics were analysed by means of a Chi-Squared test for categorical variables, and by either Mann-Whitney U or independent t-tests, as appropriate, for continuous variables: results are expressed as mean and standard deviation (SD).p = .05.The effect of grouping, i.e. fallers vs non-fallers, on the baroreflex and haemodynamic variables was analysed by means of either parametric (independent t-tests) or non-parametric (Mann-Whitney U) independent comparisons, based on normal distribution assumptions. Statistical limits for interpretation were set at an alpha level of The association between the baroreflex function/haemodynamic resposes and falls (yes or no) was analysed by means of logistic regression analysis: variables reaching a statistical significance level of p≤ 0.10, in the preliminary independent comparisons, were entered in a univariate logistic regression model, which was adjusted a posteriori in a multivariate analysis. Statistical limits for interpretation of the logistic regression analysis were also set at an alpha level of p = .05.Three hundred and five patients undergoing outpatient HD therapy at the Renal Units were screened for eligibility by members of the renal team. Of these, 215 patients were deemed eligible to participate and therefore approached for recruitment and consenting. The recruitment rate was 35.3%, with 76 patients agreeing to participate in the study, and completing all baroreflex and haemodynamic measurements. Nine patients (11.8%) were lost to follow-up due to renal transplantation  and death , although 5 of these patients were retained in the data analysis due to their positive history of falls. Moreover, 14 patients were excluded from the baroreflex function data analysis due to atrial fibrillation  and to poor circulatory blood flow to the fingers, which rendered the contBP measurement unusable . This resulted in the inclusion of 62 patients in the baroreflex function analysis. After the exclusion of the 7 patients with poor blood circulation, 69 patients were retained for the haemodynamic responses analysis.The demographic and clinical characteristics of patients are summarised in During the 12-month follow-up, 26 of 72 patients (36.1%) experienced at least one fall, of which 14 (53.8%) experienced multiple falls. The maximum amount of falls experienced by one patient was 21. A total of 80 falls were recorded, resulting in an incidence of 1.11 falls/patient-year. In addition, 33 of 76 patients (43.4%) reported falling at least once in the previous 12 months and, overall, 44 of 76 patients (57.9%) reported either a fall in the previous year or during follow-up, and were therefore classified as fallers.The most commonly reported factors perceived as a contributing cause of the falls experienced during follow-up were gait and balance issues (65.4%), environmental hazards (46.2%), and dizziness or syncope-like events (42.3%).The differences between fallers and non-fallers in all baroreflex variables are summarised in The haemodynamic variables of fallers and non-fallers, in the supine position and during HUT-60°, are described in In univariate logistic regression, diabetic nephropathy, number of “down-events” and “total-events” in the supine position, “up-BEI” in the supine position, “up-BEI” in HUT-60°, OscSBP and OscDBP difference from the supine position to HUT-60° were associated with increased odds of falling .The univariate analysis was adjusted for diabetic status, as we retrospectively identified this factor to be potentially a significant confounder of the study results . In thisIn order to evaluate the weight of the confounding effect of diabetes on the study results, we compared diabetic vs non-diabetic patients in terms of baroreflex function and BP response to HUT-60°. The independent comparisons between the two groups indicate that these variables were markedly decreased in diabetic patients Figs  and 2.s ≤ -0.088; 0.151 ≤P-values≤ 0.583) when diabetic patients were removed.In addition, we also performed a point biserial correlation analysis in the sub-group of non-diabetic patients (N = 44) to explore the relationship between the factors entered in logistic regression analysis and falls. No significant correlations were found for any of the baroreflex function/haemodynamic variables and falls (-0.223 ≤RThe heart rate variability (HRV) characteristics of the study participants are also summarised in We hypothesised that HD patients classified as fallers would have worse baroreflex function than patients free from falls. In addition, we hypothesised that patients with falls would have worse haemodynamic responses to an orthostatic challenge.o which warrants further investigation.We found that at rest, fallers had lower counts of baroreceptor “down-events” and “total-events”, as well as a lower down-BEI and total-BEI compared to non-fallers. Although we also expected to see a significantly impaired ability to effectively regulate the haemodynamic variables via the arterial baroreflex mechanism in the fallers group, in response to a passive orthostatic challenge, this was not confirmed. However, we noted a significantly larger drop in OscBP during the transition from supine to HUT-60Our findings on baroreflex function suggest that a lower number of baroreceptor sequences might discriminate patients with falls from those who are falls-free. Although no differences in the baroreflex slope, as assessed by BRS, were detected between fallers and non-fallers, measures reflecting how often the baroreflex is activated, such as the number of “down-events” and the “total-events”, among other BEI indices, were significantly lower in the group of fallers. Interestingly, in resting conditions, the baroreceptor down-regulation seemed to better discriminate fallers from non-fallers. A baroreceptor down-event occurs when a systolic BP drop is coupled with a concomitant decrease of the RRI, namely an increase in HR. This is a physiologic response to a spontaneous perturbation of BP, which allows the maintenance of haemodynamic homeostasis . TherefoIt should also be noted that, even though we did not assess a control group of healthy participants, the BEI indices measured in our patients  are considerably lower than the average 58±20% BEI measured in healthy individuals , while tAlthough a direct biologic mechanism may exist between baroreflex function and falls, given the relationship between impaired baroreflex function and orthostatic BP decrements , the stuThe role of diabetes, in the context of our study, plays a crucial role as 34.9% of the patients classified as fallers had diabetic nephropathy as PRD, compared to only 12.9% in the group of non-fallers. Diabetic nephropathy represents an advanced stage of diabetes, which is commonly associated with cardiovascular autonomic neuropathy and chronic sympathetic over-activity, both of which can affect the baroreflex and potentially the haemodynamic responses to orthostasis . TherefoThe point biserial correlation analysis performed in the subgroup of non-diabetic patients did not reveal any significant correlations between any of the baroreflex/haemodynamic variables and falls, which highlights the mediating effect of diabetes on the study results.This is an interesting finding considering that diabetes has been found to be an independent risk factor for falls in HD patients , and ourSurprisingly, we did not find any differences in the SV, CO, TPR, HR, contSBP, and contDBP responses to the HUT-60° between fallers and non-fallers. This lack of effect may be explained in light of the relatively short duration of the orthostatic challenge. Although 5 minutes of orthostasis are considered to be sufficient for the diagnosis of orthostatic hypotension, according to the current guidelines , it is pDuring HUT-60°, for instance, the contSBP and contDBP reflect the overall BP performance over the 5 minutes of data acquisition and it is possible that a longer recording interval may also have revealed a larger decrement of BP in fallers. Moreover, the discrepancy between contBP and OscBP measurements during HUT-60° could also be explained in light of a possible hydrostatic effect: because postural changes can modify the distribution of hydrostatic pressures in fluid-filled body compartments , it is pIt should also be acknowledged that the resting BP of the study participants was surprisingly low considering that HD patients are usually hypertensive. This relatively low BP may be explained in light of the strict testing standardisation procedures which were designed to ensure the best possible haemodynamic state balance , and also by a possible underestimation of BP from the Task Force Monitor . AlthougOnly a few studies examined the BP changes in response to orthostasis in HD patients, and found no association between the BP response to a pre-dialysis  or post-In addition, it should be acknowledged that the tilting angle might also be partly responsible for the lack of response. Typically, angles of 60°-90° are widely implemented in clinical practice  and thusThe incidence of falls recorded was 1.11 falls/patient-year and is approximately 2.3 times greater than seen in the non-uraemic, community-dwelling elderly . This coAlthough the current study was conducted in a small cohort of patients, our findings relating to the incidence of falls are broadly in agreement with those of larger observational studies. In particular, Desmet et al., , reporteFirst of all, the classification of patients in fallers and non-fallers was based on self-reported information. As previous research has highlighted how recalling information about falls might be subjected to misreporting , this coIn addition, the relatively small sample size did not allow the application of a more exhaustive, a priori, multivariate logistic regression analysis to more robustly test the interrelationships between baroreflex function, haemodynamic responses, and falls.This study indicates that, at rest, HD patients classed as “fallers” present with worse baroreflex indexes reflecting how often the baroreflex is activated, as highlighted by the lower number of baroreceptor-mediated sequences of coupled HR and BP. Additionally, a significantly larger decrement of OscBP was observed in “fallers”, even though other haemodynamic responses to HUT-60° were not seen to differ between fallers and non-fallers. Patients with falls were also more likely to have diabetes as PRD, and the diabetic status seems to at least partly mediate the relationship between baroreflex function/BP responses to orthostasis and falls. The short-term BP regulation warrants further investigation as BP drops during the transition from supine to an upright position may be implicated in the aetiology of falls in HD.S1 File(XLSX)Click here for additional data file.S1 Protocol(DOC)Click here for additional data file.S1 Table(DOCX)Click here for additional data file.


The aim of this study was to identify predictive factors and develop a model to assess individualized risk of postnatal surgical intervention in patients with antenatal hydronephrosis. This is a retrospective cohort study of 694 infants with prenatally detected congenital anomalies of kidney and urinary tract with a median follow-up time of 37 months. The main event of interest was postnatal surgical intervention. A predictive model was developed using Cox model with internal validation by bootstrap technique. Of 694 patients, 164 (24%) infants underwent surgical intervention in a median age of 7.8 months. Predictors of the surgical intervention in the model were: baseline glomerular filtration rate, associated hydronephrosis, presence of renal damage and the severity of renal pelvic dilatation. The optimism corrected c statistic for the model was 0.84 . The predictive model may contribute to identify infants at high risk for surgical intervention. Further studies are necessary to validate the model in patients from other settings. Antenatal hydronephrosis (ANH) is one of the most common birth defects and is a surrogate marker of potential congenital renal anomalies , 2. CongThe prenatal detection of CAKUT has permitted a refinement of the management of these conditions –11. NeveWe have previously described the clinical course of children with prenatally detected CAKUT and we identified variables that are possible predictors of progression to CKD , 19. Then = 819) admitted at the Pediatric Nephrology Unit , Brazil) from 1987 to 2013 were followed-up. Patients with aneuploidy, multiple malformations, neurogenic bladder or loss of follow-up soon after the birth were excluded (n = 125). In total, 694 infants were included in the analysis.All infants with diagnosis of CAKUT (Tc−99mDMSA and Tc−99mDTPA) was performed after the first month of life for patients with APRPD ≥10 mm  ≥5 mm were placed on prophylactic antibiotics at birth and submitted to an extensive imaging protocol, including renal ultrasonography (RUS), voiding cystourethrogram (VCUG), and renal scintigraphy. After 2000, we developed a more tailored clinical protocol, based mainly on the severity of the renal pelvic dilatation . Renal sD ≥10 mm . AntibioD ≥10 mm .After initial clinical and imaging evaluation, RUS scans, clinical visits, and laboratory reviews (including urine culture and serum creatinine) were scheduled at 6-month intervals. In short, the clinical approach consisted of full physical examination, including evaluation of anthropometric measurements and blood pressure performed at 6-month intervals. Urine cultures were obtained at each 6-month follow-up visit, and it was recommended that urine samples be collected during any unexplained febrile episode or in the presence of urinary symptoms.The main event of interest was defined as the time from birth until the first surgical intervention.Tc−99mDMSA scan and APRPD. Combined data obtained by VCUG, renal scan and sequential RUS were considered for the diagnosis of urinary tract anomalies. The absence of any recognized uropathy was classified as idiopathic hydronephrosis. Isolated hydronephrosis was defined as the presence of APRPD ≥5 mm without any other alterations of the urinary tract. Associated hydronephrosis was defined as the presence of APRPD >5 mm combined with other alterations, including megaureter and megacystis. When bilateral renal pelvic dilation was present, the largest APRPD was considered for analysis. Presence of RD on Tc−99mDMSA scan was classified as none, unilateral and bilateral, when there was renal scarring and/or parenchymal atrophy in none, one or both kidneys, respectively. The diagnosis of oligohydramnios was based on amniotic fluid index  based on conventional or modified Schwartz formulas , 25, oliid index . Since cid index  for datap < 0.1, the strongest prognostic factors were included in the final model  or frequencies when appropriate. Survival analyses were performed by the Kaplan–Meier method (KM) and by the Cox proportional hazards model to evaluate time until the occurrence of the event. Differences between dichotomous variables were assessed by the two-sided log-rank test. The Cox proportional hazards model was applied to identify variables that were independently associated with the occurrence of the event. Variables selected for multivariable analyses were used to build a final model after discarded any violation of proportionality assumptions. Cox proportional hazards regression analysis was used to assess the association between the candidate predictors and the occurrence of surgery. Hazard ratios for continuous variables were given for the 75 percentile vs. 25 percentile of the variable. Using a backward elimination strategy with al model .Missing values for candidate predictors were filled in with multiple imputation (MI) procedure. Each missing value was imputed five times. Imputed values were drawn from the predictive distribution in an imputation model that included all candidate predictors and the outcome (time to surgery). MI resulted in five complete datasets, which were analyzed with standard complete data methods. The results were combined to produce overall estimates and standard errors that reflect missing data uncertainty .When prediction models are developed in relatively small samples, they may be overfitted and may show optimistic performance. To adjust for overfitting and optimistic performance of the model, we used bootstrap resampling for internal validation. One hundred bootstrap samples were drawn with replacement; a prognostic model was developed in each sample; and the performance was evaluated in the bootstrap sample and in the original sample . The modThe main baseline clinical characteristics of 694 patients included in the analysis are summarized in c statistic was 0.81 (95% CI 0.77–0.83), after correction for optimism.After adjustment by the Cox model, four predictors had strong effects and remained in the final model: eGFR, associated hydronephrosis, renal damage, and severity of renal pelvic dilatation . FiguresThe predictive model is presented as nomogram to provide the risk that a patient undergoes surgical intervention within 2 years . To use The formula with shrunk coefficients used to calculate the individual absolute risks of postnatal surgical intervention was calculated as follow:lp = − 0.012 × eGFR + 0.62 × associated hydronephrosis +0.83 × RD uni + 1.37 × RD bi + 0.037 × APRPD; S0(12) = 0.962; S0(36) = 0.920; S0(60) = 0.910.2 (10 points), associated hydronephrosis (5 points), bilateral RD (9 points), APRPD of 40 mm (10 points). The total of 34 points corresponds to a more than 90% of risk of surgical intervention before 2 years age.For example, a child with eGRF of 40 ml/min/1.73 mP < 0.001, Finally, the sample was divided into three risk scores: low-risk (<20 points), medium-risk (20–28 points) and high-risk (≥29 points). The risk of surgical intervention at 2 years of age was estimated as 10% for patients assigned to the medium-risk group and 53% for patients of the high-risk group . After adjustment by Cox multivariate model, four variables remained as predictive factors for surgical intervention: eGFR, associated hydronephrosis, presence of RD on baseline DMSA scan and the APRPD. Finally, we combined the factors in a clinical predictive model for surgical intervention with a good predictive performance.CAKUT is a heterogeneous and complex group of diseases associated with UTI, CKD and hypertension in children –34. AnteAs expected, in our series, patients admitted at the first period of the study (1983–1999) had a greater probability to undergo surgical intervention . The prenatal detection of CAKUT has permitted a refinement of the management of these conditions. For instance, it has been clearly demonstrated by longitudinal studies that many children with partial ureteropelvic or ureterovesical junction obstruction will spontaneously resolve their hydronephrosis , 41. ConPrevious studies have also identified predictive factors of surgical intervention in patients with CAKUT , 39 For Post-natally, the most common measurements of urinary tract dilation (UTD) are APRPD and the SFU grading system . An accuSome clinical and methodological considerations should be taken into account in evaluating our findings. From the methodological point of view, we did not validate this risk prediction instrument in an independent cohort. External validation is important, because accurate predictions in our cohort do not necessarily guarantee good accuracy in other patients . MissingIn summary, we have developed a clinical predictive model of surgical intervention in children with CAKUT. The magnitude of renal pelvic dilatation, renal function at baseline, presence of associated hydronephrosis and of renal damage are independent predictors of surgical intervention during follow-up. This clinical predictive model, if confirmed in future studies and after external validation, may help the medical team to identify infants with antenatal hydronephrosis at high-risk for surgical intervention during the first years of life.The datasets generated for this study are available on request to the corresponding author.The study was approved by the Ethics Committee of our institution. Parents or legal guardians responsible for the children gave written informed consent to participate.This study was carried out in accordance with the recommendations of Ethics Committee of the UFMG with written informed consent from all subjects. All subjects gave written informed consent in accordance with the Declaration of Helsinki. The protocol was approved by the Ethics Committee of the UFMG.EO and RM: research idea and study design. MV, AS, CF, AC, and CD: data acquisition. MV, EO, AS, RM, ES, and YV: data analysis/interpretation. MV, ES, and YV: statistical analysis. EO and AS: supervision or mentorship. Each author contributed important intellectual content during manuscript drafting or revision and accepts accountability for the overall work by ensuring that questions pertaining to the accuracy or integrity of any portion of the work are appropriately investigated and resolved. EO takes responsibility that this study has been reported honestly, accurately, and transparently; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned  have been explained.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


The cardiovascular phenotype is poorly characterized in treated pediatric hypertension. Cardiovascular magnetic resonance imaging (MRI) can be used to better characterize both cardiac and vascular phenotype in children with hypertension.To use MRI to determine the cardiac and vascular phenotypes of different forms of treated hypertension and compare the results with those of healthy children.Sixty children  underwent MRI with noninvasive blood pressure measurements. Cardiovascular parameters measured include systemic vascular resistance, total arterial compliance, left ventricular mass and volumetric data, ejection fraction and myocardial velocity. Between-group comparisons were used to investigate differences in the hypertension types.P≤0.007) and normal arterial compliance. Conversely, children with essential hypertension had normal resistance but increased compliance (P=0.001). Renovascular hypertension was associated with both increased resistance and compliance (P≤0.03). There was no difference in ventricular volumes, mass or cardiac output between groups. Children with renal hypertension also had lower systolic and diastolic myocardial velocities.Renal hypertension was associated with elevated vascular resistance (Cardiovascular MRI may identify distinct vascular and cardiac phenotypes in different forms of treated childhood hypertension. Future studies are needed to investigate how this may inform further optimisation of blood pressure treatment in different types of hypertension.The online version of this article (10.1007/s00247-019-04393-6) contains supplementary material, which is available to authorized users. Pediatric hypertension is a rare but serious condition, with a prevalence of approximately 3–6% , 2. ChroAnother benefit of MRI is that it enables simultaneous cardiac phenotyping. This includes reference standard assessment of left ventricular mass and volumes , as wellThe aim of this study is to use to MRI to determine the cardiac and vascular phenotypes of children with renal disease and hypertension, renovascular disease and essential hypertension and to compare the results with those of healthy children.The study population consisted of 60 children: 15 children with renal parenchymal disease and hypertension , 15 children with renal artery stenosis associated hypertension (renovascular), 15 children with idiopathic essential hypertension and 15 healthy controls. Only patients with stable, treated hypertension were recruited. Exclusion criteria were: 1) age <7 or >18 years, 2) congenital structural heart disease or primary myocardial disease, 3) significant renal impairment in renovascular or essential hypertension, 4) active vasculitis, 5) cardiac arrhythmia precluding the use of cardiac gated MRI sequences, 6) medical devices precluding MRI, 7) other causes of secondary hypertension, and 8) current or previous renal replacement therapy. The exclusion criteria were selected to ensure that the study groups did not have any other condition that may account for cardiovascular abnormalities.This study was approved by the United Kingdom national research ethics service . Informed parental consent and patient assent were obtained from all participants. Patients were consecutively recruited from hypertension and renal clinics in Great Ormond Street Hospital over 24 months.The renal group was a subset of a previously examined group of pediatric chronic kidney disease patients who had been phenotyped using MRI . Only reIn the renovascular group, renal artery stenosis was confirmed with a combination of noninvasive and invasive investigations . All renThe essential hypertension group was clinically evaluated to exclude other secondary causes of hypertension and treated according to published recommendations .Imaging was performed on a 1.5-T MRI system . All MRI data were processed using in-house plug-ins developed for open-source DICOM  software OsiriX   during acquisition of MRI data. This enabled an optimum combination of blood pressure and flow data for calculating vascular indices. All blood pressure measurements were acquired with an appropriately sized arm cuff after the subject had been prone in the scanner for at least 10 min. Pulse pressure was the difference between systolic and diastolic blood pressure.Total systemic vascular resistance was calculated by dividing mean blood pressure by cardiac output . Total aP-value<0.05 was considered statistically significant. Data were examined for normality using the Shapiro-Wilk normality test and non-normally distributed data were transformed using a zero-skewness log transform to ensure normal distribution before analysis. Descriptive statistics were expressed as mean (±standard deviation) or geometric mean (±geometric standard deviation) if data were log transformed. The chi-square test was used to determine if there were differences in the use of hypertensive medications among the three hypertension groups and in gender distribution across all groups. Group differences were assessed using analysis of variance (ANOVA). Levene’s test was used to assess for homogeneity of variances across the groups and Welch’s correction was applied for nonhomogeneous variance. Post hoc pairwise comparison was performed for significant results on ANOVA, using Duncan’s method to adjust for potential Type 1 errors. Age- and gender-adjusted ANOVA tests were also performed for indices with significant group differences. To determine if group differences in myocardial velocities were due to associated cardiac and vascular factors, Pearson’s correlations were first performed between myocardial velocities (with significant group differences) and possible variables. ANOVA tests for these myocardial velocities were then repeated after adjustment for any significantly correlated variables (as well as age and gender).Statistical analyses were performed using Stata 13 . A 2. The causes of renal impairment were congenital abnormalities of the kidney and urinary tract (n=8), renal dysplasia (n=3), hemolytic uremic syndrome (n=2), glomerulonephritis (n=1) and tubulointerstitial disease (n=1). All patients were diagnosed with hypertension and received hypertensive treatment  with stable renal function. Mean estimated glomerular filtration rate was 53±25 ml/min/1.73 mn=6) had bilateral renal artery stenosis. The majority (n=10) were treated initially with angioplasty, while the remaining patients received ethanol embolization of a renal artery (n=1), unilateral nephrectomy (n=1), surgical revascularization (n=1) or medical management (n=2). None was awaiting further invasive treatment. All patients had been deemed by their clinicians to have controlled hypertension with clinically stable blood pressure. The majority of renovascular children (n=9) continue to receive hypertension medication (Table n=6) were no longer on hypertension medication.All renovascular patients had objective evidence of renal artery stenosis. Of those, 50%  among groups, even after adjusting for age and gender. On pairwise comparison, the essential hypertension patients were significantly heavier compared to the renovascular and renal groups (P≤0.017).Although there was no difference in age or gender distribution Table , weight P<0.001), but there were no differences among the three hypertension groups (P>0.11). The systolic blood pressure percentiles were also higher in all the hypertension groups compared to controls (P<0.001). Nineteen patients  had uncontrolled systolic hypertension (systolic blood pressure >90 percentile).Blood pressure data are shown in Table P≤0.008). In addition, children with renal disease had higher diastolic blood pressure than both the renovascular (P=0.004) and essential hypertensive (P=0.035) groups. A similar pattern was seen in diastolic blood pressure percentiles, with six patients  having uncontrolled diastolic hypertension (diastolic blood pressure >90 percentile) at the time of the MRI scan.Diastolic blood pressure was higher in the hypertension groups compared to the controls (P<0.001). Furthermore, the renal group had a significantly higher mean blood pressure than the renovascular group (P=0.027). Conversely, pulse pressure was only elevated in the essential hypertension children compared to the controls (P=0.019). The pulse pressure was also significantly higher in the essential hypertension patients compared to the renal patients (P=0.012). These differences remained broadly present after controlling for age and gender.The mean blood pressure was higher in all hypertension groups compared to controls (P≤0.028) and there were no significant differences between the hypertension groups (P>0.15). However, after correcting for age and gender, the systemic vascular resistance in the essential hypertension group was no longer significantly different from the controls (P=0.13).Vascular measures are shown in Table P≤0.026) and in the essential hypertension group compared to the renal children (P=0.01). Local ascending aortic compliance was also lower in the essential hypertension and renovascular children compared to the controls (P≤0.018). Furthermore, the renovascular children had significantly lower ascending aortic compliance compared to the renal patients (P=0.005). Differences in total and local compliance remained after correcting for age and gender. The cardiac output was similar in all groups . However, renal and renovascular children did have lower radial peak systolic velocities compared to the essential hypertension children . After adjustments for age and gender, only renal children had lower radial peak systolic velocities than both the controls and the essential hypertension children . Radial peak systolic velocity was negatively correlated with systemic vascular resistance  and positively correlated with left ventricular mass . Radial peak systolic velocity did not correlate with other hemodynamic metrics (P>0.15). Group differences in radial peak systolic velocities were abolished after adjusting for systemic vascular resistance (P=0.41), but they remained after adjustment for left ventricular mass (P=0.043). There were no group differences in longitudinal peak systolic velocity.Myocardial velocities are shown in Table P=0.009) and the renovascular children (P=0.009). These differences remained after correcting for the influence of age and gender. Radial early diastolic velocity only correlated with diastolic blood pressure , mean blood pressure , systemic vascular resistance  and radial peak systolic . Group differences remained after adjusting for systemic vascular resistance (P=0.045) or radial peak systolic (P=0.022), but were abolished after adjusting for diastolic (P=0.25) or mean blood pressure (P=0.11).The radial early diastolic velocity was significantly reduced in the renal group compared to both the controls (P=0.009), the renovascular (P=0.006) and the renal children (P=0.009). These differences remained after correcting for the influence of age and gender. The longitudinal early diastolic velocity was only correlated with the left ventricular mass . After adjusting for the left ventricular mass, there was only a trend for group differences (P=0.055).The longitudinal early diastolic velocity was significantly increased in the essential hypertension group compared to the controls  was higher in essential hypertension and renovascular, but was normal in renal disease.Children with renal disease had reduced radial systolic and diastolic function  compared to the controls and the other hypertension groups.This study investigated the cardiovascular phenotype in different forms of treated hypertension in children with MRI. Our findings were:It is increasingly recognised that differences in the pattern of hypertension is associated with differential mortality risk . SystoliIn this study, the blood pressure phenotype in the three hypertension groups was slightly different, despite having similar systolic blood pressure. Specifically, the renal patients had higher diastolic blood pressure and mean blood pressure, while the essential hypertension group had greater pulse pressure. These findings are in keeping with previous large studies of blood pressure in these populations , 19 and We demonstrated that hypertensive renal disease was associated with increased systemic vascular resistance, whilst essential hypertension was characterized by decreased total arterial compliance and ascending aortic compliance. Children with renovascular hypertension fell somewhere in between these two groups. These findings are in keeping with the blood pressure phenotypes of elevated pulse pressure in the essential hypertension patients and elevated mean blood pressure in the renal disease patients. However, it should be noted that this is a treated population and untreated children may have different or more marked vascular abnormalities. Consequently, extrapolating these findings may be premature, and further studies are required. Nevertheless, our findings suggest that treated children cannot be considered to have normal vascular phenotype.Raised systemic vascular resistance is known to occur in renal parenchymal disease  and possRenal artery stenosis results in renal ischaemia, which in turn leads to wide-ranging maladaptive neurohumoral and vascular responses. Vasoconstriction is primarily mediated through renin-angiotensin-aldosterone axis activation and increased sympathetic activity in renovascular hypertension , 28. ThuOur results indicate that this does not completely normalize after therapy. Furthermore, the increased arterial stiffness in renovascular cases suggests that any abnormal vascular remodelling that may be the result of high pre-treatment blood pressure appears to persist despite successful therapy.The fact that these treated patients continue to have raised blood pressure is important as even mildly elevated blood pressure confers additional cardiovascular risk, particularly in those burdened from a young age . Thus, fOne of the major benefits of using MRI to assess these children is the ability to comprehensively evaluate the myocardial response to elevated blood pressure. In this study, conventional metrics of left ventricular systolic and diastolic function were normal. Furthermore, the left ventricular mass was not increased in the hypertension groups. The lack of significant changes in the left ventricular structure and global function is probably related to the fact that this was a treated population. However, we did find abnormal myocardial velocities with both radial peak systolic and early diastolic velocities being different amongst the groups. We also showed that radial peak systolic and early diastolic velocities correlated with measures of afterload, particularly systemic vascular resistance (peak systolic and early diastolic velocities) and diastolic blood pressure (early diastolic velocities). This is in keeping with the well-recognized association between afterload and both systolic and diastolic function . InteresThere is also evidence from our study that radial early diastolic velocity correlates with radial peak systolic velocity. This is in keeping with the known association between systolic and diastolic function , but didThe main limitation of this study is the small number of patients in each group. The main reason for the small numbers was the difficulty in recruiting renal artery stenosis patients. Renal artery stenosis is a relatively rare condition and may be associated with other comorbidities. As other conditions such as significant midaortic syndrome may have potential confounding effects, it was important that only a “pure” population of renal artery stenosis was included in the study. Hence, it was not possible to recruit a larger number of renal artery stenosis children from a single-centre study. However, in spite of that, we were able to demonstrate significant differences in cardiovascular structure and function among the groups using MRI. Nevertheless, larger multicentre studies are required to properly confirm our results. The relatively small study numbers also precluded the inclusion of additional potential confounding factors into the ANOVA models such as differences in hypertensive treatment and the length of treatment among the groups. Variation in current medication therapy may contribute to differences in vascular phenotype among the groups. Future studies will need to consider multicentre recruitment to increase the power of the study population to adjust for the potential effects of different hypertensive treatment.Another important limitation was that the majority of patients were being actively treated with anti-hypertensive medication. This was because of difficulties in recruiting patients before they began therapy. In particular, most patients were referred to our center having already been diagnosed with hypertension and started on therapy. This also made it difficult to ascertain the length of diagnosis and therapy. Thus, we cannot make firm conclusions about the differences in cardiac and vascular phenotype in treatment-naïve patients or the response to treatment in the different groups. In particular, we are not powered to investigate the effect of length of treatment on vascular or cardiac phenotype. Nonetheless, we were able to demonstrate persistent vascular changes associated with renal disease and hypertension despite optimal clinical treatment in this population. Future studies should consider a prospective evaluation of the effects of anti-hypertensive therapy in treatment-naïve children, including investigation of the time course of any improvements.A final limitation is that the supine resting position may also be associated with elevated systemic vascular resistance . HoweverWe have shown that there are differences in vascular and cardiac phenotype among the different types of treated hypertension in childhood. Future studies in treatment naïve children are needed to better understand if these different phenotypes have any prognostic implications or could be used to optimise blood pressure control.ESM 1(DOCX 58 kb)


Continuous renal replacement therapy (CRRT) is the treatment of choice for critically ill children with acute kidney injury. Hypotension after starting CRRT is frequent but very few studies have analyzed its incidence and clinical relevance.A prospective, observational study was performed including critically ill children treated with CRRT between 2010 and 2014. Hemodynamic data and connection characteristics were collected before, during, and 60 min after CRRT circuit connection. Hypotension with the connection was defined as a decrease in > 20% of the mean arterial pressure from baseline or when intravenous fluid resuscitation or an increase in vasopressors was required.p = 0.004).One hundred sixty-one connections in 36 children (median age 18.8 months) were analyzed. Twenty-eight patients (77.8%) were in the postoperative period of cardiac surgery, 94% had mechanical ventilation, and 86.1% had vasopressors. The heparinized circuit priming solution was discarded in 8.7% and infused to the patient in 18% of the connections. The circuit was re-primed in the remaining 73.3% using albumin (79.3%), red blood cells (4.5%), or another crystalloid solution without heparin (16.2%). Hypotension occurred in 49.7% of the connections a median of 5 min after the beginning of the therapy. Fluid resuscitation was required in 38.5% and the dose of vasopressors was increased in 12.4% of the connections. There was no relationship between hypotension and age or weight. Re-priming the circuit with albumin reduced the incidence of hypotension from 71.4 to 44.6% (Hypotension after the connection to CRRT is very frequent in critically ill children. Re-priming the circuit with albumin could improve hemodynamics during connection. Acute kidney injury (AKI) is observed in up to 30% of the children admitted to a pediatric intensive care unit (PICU) . ApproxiChildren are at a higher risk than adults for developing complications associated with CRRT due to the large extracorporeal volume of the system (filters and lines) in proportion to their whole blood volume, which predisposes to hypotension at the time of connection. They require a more accurate control of volume status in order to avoid fluid and electrolyte disturbances. However, this complication has not been analyzed in depth in children. In a previous study of our group, hypotension during CRRT was found in 30.4% of the critically ill children .There are a number of strategies that attempt to reduce the risk of hypotension at the time of connection, such as priming the circuit with whole blood or colloids but, as of yet, there are no comparative studies proving its efficacy over conventional priming solutions .The objective of the present study was to analyze the process of CRRT connection, to determine the incidence of hypotension, and to analyze the predisposing risk factors.2); an HF20 filter (Gambro Int.) for patients weighing less than 10 kg ; M60 filter  for patients between 10 and 35 kg ; and M100 filter  for patients weighing over 35 kg . The caliber of the hemofiltration catheters depended on the age and weight of the patients, ranging between 4F and 11F. We used a blood warmer  in the return bloodline to compensate for heat loss to the atmosphere during the therapy.We conducted a single-center, longitudinal observational study of a cohort follow-up including critically ill children treated with CRRT between 2010 and 2014. Data were collected using a single-page case report form. Hemodynamic data  and connection characteristics were collected before, during, and 60 min after the connection to CRRT. The circuit consisted of the Prismaflex® CRRT pump  and either an AN69 polyacrylonitrile  or a polyarylethersulfone (HF20) hemofilter set according to the age and weight of the patient: An M10 filter  was used in three patients weighing less than 10 kg at the beginning of the study period , the amount of heparin administered with the connection was subtracted from the total 50 UI/kg.The following data were gathered prospectively in all patients upon starting CRRT: age, weight, sex, diagnosis, indication for CRRT, severity scores, number of affected organ systems (with dysfunction or failure), blood pressure, need for vasoactive drugs, dose of dopamine and adrenaline, lactic acid levels, type of hemofilter set and hemofiltration prescription variables and settings.A specific CRRT connection protocol was not available in our PICU at the time of the study, so the way patients were connected to CRRT was determined by the physician in charge of the patient: some patients were connected after discarding the priming solution, some were connected directly using the original priming solution , while other patients were connected after re-priming the circuit with 5% albumin. The investigator was present during the initiation of CRRT, recording the characteristics of the connection and the changes in hemodynamic parameters  during the first hour of therapy. Hypotension prior to connection was defined as a mean arterial blood pressure under the 10th percentile according to age and height, and hypotension during connection was defined as a decrease in mean arterial pressure > 20% from baseline, the need for intravenous fluid expansion or the need to increase the dose of vasopressors during the first 60 min after the connection to CRRT.p value less than 0.05. Wilcoxon rank test was used for the analysis of repeated measures.STATA® statistical software version 13  was used for statistical analysis. Quantitative variables are expressed as means and standard deviations (SD) or as medians and interquartile range (IQR) (p25–p75), according to the normality or not of their distribution. Qualitative variables are expressed as percentages. The chi-square test, Fisher exact test, and Mann-Whitney test were used to compare qualitative and quantitative variables. Significance was taken as a During the study period, the characteristics of the connection to CRRT were studied in 36 children (27 boys (75%) and 9 girls (25%)) with a median age of 18.8 months (interquartile range (IQR) 5.2–84.0) and median weight of 9.95 kg (IQR 5.7–23.5). Table 2 surface filter (47%), followed by the 0.6-m2 surface filter (45%), and the 0.9-m2 filter (8%). Median blood flow at the time of connection was 5 ml/kg/min (IQR 3–6 ml/kg/min). The priming solution was discarded in 8.7% of the connections, the heparinized priming solution was infused in 18% of the connections, and the circuit was re-primed with albumin 5% or crystalloid solutions (0.9%) without heparin in 73.3% of the cases. Figure p < 0.01) without any significant changes in heart rate. Hypotension was recorded in 49.7% of the connections. Lowest mean arterial pressure was registered at a median of 5 min after initiating CRRT. Fluid resuscitation was required in 38.5% of the connections (median fluid volume 5.2 ml/kg) and the dose of inotropes had to be increased in 12.4% (median increment of the vasoactive-inotropic score from 41 to 52 points). All parameters except heart rate returned to baseline at 30 and 60 min of therapy. Heart rate slowly and progressively decreased throughout the first hour of therapy.A total of 161 circuit connections were analyzed. The most commonly used filter was the 0.2-mTable p = 0.008.There was no relationship between hypotension and age or weight Table  but the There were no differences between hemodynamic parameters at baseline Table .We did not find a relationship between hypotension during connection and severity illness scores or lactic acid levels either. Nevertheless, patients with a higher vasopressor-inotropic score and lower mean arterial pressure MAP prior to CRRT initiation had a greater  incidence of hypotension Table .p = 0.004). The incidence of hypotension was higher in circuits that were re-primed with crystalloids than with albumin . We also observed that after the first 2 years of the study, the incidence of hypotension during connection significantly decreased from 70 to 43.3% (p = 0.001).Re-priming of the circuit before the connection reduced the incidence of hypotension from 71.4 to 44.6% . Hypotension prior to the beginning of CRRT was observed in 20.5% of the cases. It is to be expected that patients with greater hemodynamic alterations at baseline would be at a higher risk for developing hypotension when connecting to CRRT. In our study, hypotensive patients became even more hypotensive during connection in 65.6% of the cases, whereas the incidence of hypotension upon connection in previously non-hypotensive patients was 47.9%. This difference, however, did not reach statistical significance. Global incidence of hypotension in our study was 49.7% of the connections, a median of 5 min after the beginning of the therapy. This incidence is even higher than that reported in our previous study, which was 30.4% [We did not find any relationship between hypotension and age or weight. Interestingly, the quotient filter-surface/BSA was significantly higher in patients who developed hypotension. This fact highlights the relevance that the priming volume of the set has on hemodynamics during connection, as it can represent up to 5 to 10% of the patients’ total blood volume [No individual risk factors for hypotension were found in this study. Nevertheless, it is possible that different individual factors combined together  could add up to the risk of developing hypotension after connection to CRRT.In 2012, Eastwood et al.  analyzedNevertheless, that same group  publishep = 0.004).We did not have a specific “CRRT connection protocol” at the time of the study. A slow CRRT connection protocol was introduced afterwards, in the light of the results of the present study. During the first years of the study, the priming volume was discarded in most cases (14 connections) to avoid administering a high dose of heparin to the patient. Only the most unstable patients were connected after re-priming the circuit with crystalloids or colloids without heparin. The incidence of hypotension in this study period was very high (71.4%). After the first 2 years of the study, we decided not to discard the priming solution and encouraged physicians to re-prime the circuit with albumin 5%. The incidence of hypotension decreased significantly in this period from 71.4 to 44.6% (p = 0.07)). Further studies are necessary to determine the efficacy of re-priming the circuit with albumin in reducing the incidence of hypotension at the time of connection.The difference in the incidence of hypotension between colloids and crystalloids were almost statistically significant (58.7% vs 41.6% (The way hypotension was managed differed with each patient’s situation. The first step was usually volume resuscitation with 10 to 20 ml/kg of a colloid solution. The median volume that was necessary to restore blood pressure was 5 ml/kg. Next, if hypotension was severe or if it did not respond to volume resuscitation, the dose of vasoactive drugs was increased. The median increase in vasoactive-inotropic score to restore hemodynamic stability in our study was 11 points. Some patients could benefit from a preventive increase in vasopressors prior to connection to avoid or minimize hypotension.Excessive ultrafiltration is also a risk factor for hypotension . To prevOur study has several limitations. In the first place, the way the patient was connected to CRRT depended on the physician in charge of the patient. The results are a good reflection of the clinical practice at that moment, but could be biased due to the personal preferences of each physician. Another limitation is that we only analyzed initial blood flow during connection, but not the speed at which the blood flow was increased.Hypotension after the connection to CRRT is frequent in critically ill children. For this reason, close hemodynamic monitoring during connection is necessary. Re-priming the circuit with albumin 5% could improve hemodynamics during connection. Further studies are needed to determine the ideal priming solution and the relevance of a slow blood flow protocol.


Kidney transplantation is the treatment of choice for patients with advanced chronic kidney disease (CKD) and end stage renal disease (ESRD). However, acute rejection (AR) is a common complication in kidney transplantation and is associated with reduced graft survival. Current diagnosis of AR relies mainly on clinical monitoring including serum creatinine, proteinuria, and confirmation by histopathologic assessment in the biopsy specimen of graft kidney. Although an early protocol biopsy is indispensable for depicting the severity of pathologic lesions in subclinical acute rejection (subAR), it is not acceptable in some cases and cannot be performed because of its invasive nature. Therefore, we examined the detection of noninvasive biomarkers that are closely related to the pathology of subAR in protocol biopsies three months after kidney transplantation. In this study, the urinary level of microtubule-associated protein 1 light chain 3 (LC3), monocyte chemotactic protein-1 (MCP-1), liver-type fatty acid-binding protein (L-FABP), neutrophil gelatinase-associated lipocalin (NGAL), and human epididymis secretory protein 4 (HE4) were measured three months after kidney transplantation. Urine samples of 80 patients undergoing kidney transplantation between August 2014 to September 2016, were prospectively collected after three months. SubAR was observed in 11 patients (13.8%) in protocol biopsy. The urinary levels of LC3, MCP-1, NGAL, and HE4 were significantly higher in patients with subAR than in those without, while those of L-FABP did not differ between the two groups. Multivariate regression models, receiver-operating characteristics (ROC), and areas under ROC curves (AUC) were used to identify predicted values of subAR. Urinary HE4 levels were able to better identify subAR (AUC = 0.808) than the other four urinary biomarkers. In conclusion, urinary HE4 is increased in kidney transplant recipients of subAR three months after kidney transplantation, suggesting that HE4 has the potential to be used as a novel clinical biomarker for predicting subAR. Steady advances in immunosuppression of kidney transplant recipients have resulted in a remarkable decrease in the risk of acute rejection, but long-term outcomes still remain suboptimal ,2,3. SubVarious biomarkers for kidney damage have been recently identified such as microtubule-associated protein 1 light chain 3 (LC3), monocyte chemotactic protein-1 (MCP-1), liver-type fatty acid-binding protein (L-FABP), neutrophil gelatinase-associated lipocalin (NGAL), and human epididymis secretory protein 4 (HE4). LC3, which is known as a biomarker for autophagy and has been reported to enhance autophagy and show increased expression during renal injury . MCP-1 iThe characteristics of 80 patients who received kidney transplantation are shown in Five urinary biomarkers were measured in the urine samples, which were collected immediately before the protocol biopsy three months after kidney transplantation. Urinary biomarker levels in no-subAR and subAR patients were summarized . UrinaryThe area under the curve (AUC), sensitivity, and specificity obtained from ROC analysis for each urinary biomarker are summarized in Since severe tubulitis (ST) in protocol renal biopsy is associated with graft outcome, we examined whether these urinary biomarkers could detect ST three months after kidney transplantation. We compared the urinary level of these biomarkers in five patients with ST (grades t3) and 75 patients with milder grades of tubulitis , according to the Banff 2009 classification. The ST group comprised of patients who had developed ST, while the no-ST group comprised of patients who had not developed ST after a three-month postoperative period. Urinary biomarker levels in no-ST and ST patients have been summarized . UrinaryIn this study, we investigated various candidate urinary biomarkers for the early detection and/or prediction of subAR in patients three months after kidney transplantation. The urinary level of HE4 in our ROC results suggests that it could be a useful biomarker for subAR (AUC = 0.808). However, the urinary level of HE4 was found to be less specific than urinary LC3 and L-FABP in detecting subAR. In this regard, urinary HE4 will be a biomarker that can detect subAR more specifically when used in combination with urinary LC3 or L-FABP. Since tubulitis is regarded as an important histological feature of AR, the urinary biomarkers were also investigated for their ability to detect ST three months after kidney transplantation. Interestingly, HE4 also showed the highest AUC for ST in ROC analysis (AUC = 0.875). Serum HE4 has been used as a clinical diagnostic biomarker for epithelial ovarian cancer and is known to have antiprotease and anti-inflammatory effects . RecentlPrevious studies have reported that NGAL is a predictive biomarker of AR ,27. FurtAmong the public database of gene expression omnibus (GEO) and the renal gene expression database (RGED), the information for “kidney transplantation” were found in 19 and 28 trials in GEO and RGED, respectively. However, any results corresponding to “subAR” were found in these trials. The HE4 urinary levels of patients diagnosed with subAR by renal biopsy were significantly higher than those of no-subAR patients. Taken together, it is the first report in which urinary HE4 levels at three months after kidney transplantation was suggested to be a predictive biomarker for subAR. Furthermore, of the five urinary biomarkers examined, HE4, NGAL, and LC3 are synthesized in the proximal tubule as well as the distal tubule. On the other hand, MCP-1 and L-FABP are specifically synthesized in the proximal tubule. In this study, it is considered that the acute rejection may be caused by injury in the renal interstitium including distal tubules rather than the proximal tubules. Additionally, acute rejection is considered to be one of the most important factors related to chronic renal graft fibrosis. In a histological examination, Luo et al.  reportedA total of 87 adult patients underwent kidney transplantation at Kyushu University Hospital between August 2014 and September 2016. The study excluded 7 patients who developed acute rejection within 3 months of kidney transplantation, those who did not receive protocol renal biopsy, and those with focal segmental glomerulosclerosis (FSGS). Ultimately, our study comprised of 80 kidney transplant recipients. All patients in this study received induction therapy with basiliximab (20 mg/body on days 0 and 4) and a triple-drug regimen comprising of tacrolimus, mycophenolate mofetil, and methylprednisolone. This study was conducted in accordance with the Declaration of Helsinki and its amendments, and was approved by the Institutional Review Board of Kyushu University Graduate School and Faculty of Medicine . All patients enrolled in this study gave written informed consent for participation in the study and for the use of their sample.Spot urine samples were collected before the protocol renal biopsy 3 months after kidney transplantation. All urine samples were stored at −80 °C with protease inhibitor cocktail tablets . Urinary creatinine was determined according to the Jaffe reaction by using the Lab Assay Creatinine kit . The biomarker candidates were measured using commercially available ELISA kits, according to the manufacturer′s instructions. LC3, NGAL, MCP-1, and HE4 were measured using ELISA kits purchased from R & D Systems . L-FABP level was determined using ELISA kits from CMIC Co., Ltd. . The level of each urinary biomarker was normalized to urinary creatinine levels to adjust for changes in urine concentration.A protocol biopsy was performed 3 months after kidney transplantation. All biopsy specimens were scored according to the Banff 2009 classification. There were 69 normal biopsies and 11 with subclinical acute rejection. The diagnostic criteria for subAR were stringent, with the requirement of <10% rise in serum creatinine in the 2 weeks before the protocol biopsy, which was similar to that used by other investigators . Patientp < 0.05 was considered statistically significant.All statistical analyses were performed using Prism version 8 . Mann–Whitney U-test and Kruskal–Wallis tests were used to compare the differences between urinary biomarker levels in patients with/without subAR. We determined receiver operating characteristic (ROC) curves and calculated the area under the curve, 95% confidence intervals (CI), sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio. A value of


The spontaneous breathing trial (SBT) assesses the risk of weaning failure by evaluating some physiological responses to the massive venous return increase imposed by discontinuing positive pressure ventilation. This trial can be very demanding for some critically ill patients, inducing excessive physical and cardiovascular stress, including muscle fatigue, heart ischemia and eventually cardiac dysfunction. Extubation failure with emergency reintubation is a serious adverse consequence of a failed weaning process. Some data suggest that as many as 50% of patients that fail weaning do so because of cardiac dysfunction. Unfortunately, monitoring cardiovascular function at the time of the SBT is complex. The aim of our study was to explore if central venous pressure (CVP) changes were related to weaning failure after starting an SBT. We hypothesized that an early rise on CVP could signal a cardiac failure when handling a massive increase on venous return following a discontinuation of positive pressure ventilation. This CVP rise could identify a subset of patients at high risk for extubation failure.Two-hundred and four mechanically ventilated patients in whom an SBT was decided were subjected to a monitoring protocol that included blinded assessment of CVP at baseline, and at 2 minutes after starting the trial (CVP-test). Weaning failure was defined as reintubation within 48-hours following extubation. Comparisons between two parametric or non-parametric variables were performed with student T test or Mann Whitney U test, respectively. A logistic multivariate regression was performed to determine the predictive value on extubation failure of usual clinical variables and CVP at 2-min after starting the SBT.One-hundred and sixty-five patients were extubated after the SBT, 11 of whom were reintubated within 48h. Absolute CVP values at 2-minutes, and the change from baseline (dCVP) were significantly higher in patients with extubation failure as compared to those successfully weaned. dCVP was an early predictor for reintubation .An early rise in CVP after starting an SBT was associated with an increased risk of extubation failure. This might represent a warning signal not captured by usual SBT monitoring and could have relevant clinical implications. Mechanical ventilation (MV) is a life-saving intervention in intensive care units (ICUs). Its application, however, may be associated with serious complications including higher mortality and costs, often directly linked to its duration ,2. ConseThe SBT assesses the risk of weaning failure by evaluating physiological responses to the workload imposed by discontinuing positive pressure ventilation during a period of 60 to 120 minutes –12. HoweExtubation failure with emergency reintubation is a serious adverse consequence of a failed weaning process. Reintubation may be required by 5 to 30% of critically ill who initially had a successful SBT and is eventually associated with higher mortality ,19. MoreIn view of the above, we aimed at studying if central venous pressure (CVP) changes were related to weaning failure after starting an SBT. We hypothesized that an early rise on CVP could signal a cardiac failure when handling a massive increase on venous return following the discontinuation of positive pressure ventilation. This CVP rise could identify a subset of patients at high risk for extubation failure.We performed a prospective multicenter observational study between July 2015 and September 2016 in four medical-surgical ICU in Chile and Ecuador. The study was approved by the Institutional Review Board of each center approved the study and waived informed consent due to the observational nature of the study . As the study was intended to rely on the usual clinical practice, the only specific study-related monitoring was a blinded standardized CVP assessment (see below). STROBE guidelines were used for reporting this study .2/FiO2 >150 with FiO2 ≤0.4, positive end-expiratory pressure (PEEP) ≤8 cmH2O and good cough reflex, and arterial pH ≥7.35) and a central venous catheter in place. Patients were excluded if age <18 years-old, had inadequate mentation or permanent neurological damage, non-controlled infection, hemodynamic instability and/or hypoperfusion, tracheostomy in situ, and do-not-resuscitate (DNR) status. Only the first SBT per patient was considered.This study was performed in critically ill patients on MV for ≥24h in whom the attending clinician had decided to initiate an SBT based on clinical criteria. Additional inclusion criteria were resolution or stabilization of the original disease, clinical stability on controlled MV (PaO2O of PEEP and pressure support (PS) before starting SBT to standardize measurements. Subsequently, the SBT was performed on a “T-piece” connected to an O2 source. The duration of SBT was 1 or 2 hours, as decided by attending physicians.Patients eligible for SBT were ventilated with 5 cmHA successful SBT was determined by previously published criteria , whereasEdwards Lifesciences, Irvine, CA) that was zeroed at approximately 5 cm below the sternal angle, which roughly corresponds to the 4th intercostal space in the mid-axillary line. The transducer and the position of the patient remained unchanged during the SBT. CVP measurement was performed at the base of the c wave at the end of expiration in patients on MV and during SBT, except in patients with evident expiratory efforts, where CVP was measured at the start of expiration.Besides usual clinical and laboratory variables, CVP was measured at baseline, at 2-minutes (CVP-test), and at the end of the SBT. CVP data collected for the study were blinded to the attending physicians. A unique researcher per center measured the CVP after previous training. Intra-observer variability was not assessed. CVP was assessed through a jugular or subclavian central venous catheter with the patient in the supine position at 45° . PressurAccording with previous studies and our clinical experience, we estimated that 70–80% of patients would be extubated at the end of SBT, with a reintubation rate ranging from 5–30% ,18. Due Normality of the variables was tested by the Kolmogorov-Smirnov test. Parametric and non-parametric variables were expressed as mean ± standard deviation (SD) with median and interquartile range (IQR), respectively. Categorical variables were expressed as percentages. Comparisons between parametric and non-parametric variables were performed with t- test or Mann Whitney U-test, respectively. Categorical variables were compared using chi-square or Fisher’s exact test, as appropriate.p <0.2 on univariate analysis and relevant clinical variables were considered in the model. Odds ratio (OR) and 95% CI were calculated for age, APACHE II, MV days, ICU length of stay, central venous O2 saturation (ScvO2), heart rate, respiratory rate, and change in CVP (dCVP) at 2-minutes.A logistic multivariate regression was performed to determine the predictive value of clinical variables at 2-min after starting the SBT, on extubation failure. Variables considered for the multivariate model were selected in a stepwise fashion. Variables that met StataCorp. College Station, TX). The level of significance was set at p-value <0.05 and 95% confidence intervals.Statistical analyses were performed with SPSS, version 20  and Stata 15  were significantly higher in patients with extubation failure as compared to those successfully weaned . The other covariates did not reach statistical significance: age , MV days , ScvO2 , heart rate , and respiratory rate .In the multivariate model, the only early (2-minutes) predictor for reintubation was Our main finding was that an early rise in CVP predicts extubation failure during an SBT. In fact, a rise in CVP two minutes after starting the trial increased the risk of reintubation by 70%. At that time-point, no other clinical variable behaved in a similar way of predicting extubation failure.CVP is a complex parameter subject to many measurement errors and biases, and interpretation difficulties . CVP is Strong respiratory efforts resulting in negative pleural pressure swings have an important effect on CVP values. These interferences could have been captured by an esophageal balloon ,30, but Cardiac dysfunction is a frequent cause of extubation failure ,23. PartThis latter consideration is also relevant since almost three-quarters of the included patients had sepsis, trauma or other inflammatory conditions, thus being probably exposed to the risk of fluid overload. In patients with fluid overload venous return may increase after discontinuing positive pressure ventilation leading eventually to weaning-induced cardiac dysfunction or pulmonary edema ,24. Liu Assessment of cardiac dysfunction in an SBT setting is complicated by the fact that pulmonary artery catheters or other cardiac output monitoring devices are usually no longer in place. In addition, echocardiography is difficult to perform in a sitting, sometimes rapidly breathing patient, and the technique might not be easily available in resource-limited settings. In this context, the CVP-test appears to be a potential useful monitor that is currently not included in classic SBT-related assessments. Then, a rise in CVP should be considered only as a warning signal as it does not provide diagnostic clues without additional evaluations.Although our study is only observational and hypothesis-generating, our results suggest a potential clinical relevance in performing a CVP-test. An abnormal early rise in CVP after starting an SBT should promote a prompt cardiovascular assessment in some patients, allowing the establishment of unloading interventions such as diuretics, vasodilators, inodilators, etc., in selected patients. This could halt and even revert the weaning failure track the patient is undergoing into, as suggested by Rousti et al  in the sOur study has many limitations. The measurements of CVP could have been subject to intra-observer variability although we tried to minimize this risk by using a rigorous standardized procedure. Second, in spite of CVP measurement standardization, changes in intrathoracic pressure due to increased respiratory rate or strong respiratory swings could have influenced CVP measurements. Third, the lack of bedside assessment of cardiac function and performance limits the inference of causality in this study. Fourth, we did not register data on fluid balances. Fifth, we did not perform follow-up assessments so we cannot provide data on subsequent weaning attempts after the first extubation failure. Sixth, very few patients with chronic obstructive pulmonary disease were included in this cohort, and thus, our results might not be applicable for that specific subset of patients.In the end, as central venous catheters are still in place in most ventilated patients when and SBT is started, CVP can be easily assessed at the bedside. If confirmed by further studies, a CVP-test might represent a new strategy to identify patients at high risk of failure only minutes after starting a SBT. In addition, this may allow clinicians to order additional evaluations or interventions to improve the probabilities of weaning success.An early rise in CVP after starting a spontaneous breathing trial was associated with an increased risk of extubation failure. This might represent a warning signal not captured by classic SBT monitoring and could have relevant clinical implications. Given the limitations of this current study, these findings need to be explored and confirmed by further studies.


Chronic heart failure (CHF) is a complex syndrome that results from structural and functional disturbances that affect the ability of the heart to supply oxygen to tissues. It largely affects and reduces the patient’s quality of life, socio-economic status, and imposes great costs on health care systems worldwide. Endothelial dysfunction (ED) is a newly discovered phenomenon that contributes greatly to the pathophysiology of numerous cardiovascular conditions and commonly co-exists with chronic heart failure. However, the literature lacks clarity as to which heart failure patients might be affected, its significance in CHF patients, and its reversibility with pharmacological and non-pharmacological means. This review will emphasize all these points and summarize them for future researchers interested in vascular pathophysiology in this particular patient population. It will help to direct future studies for better characterization of these two phenomena for the potential discovery of therapeutic targets that might reduce future morbidity and mortality in this “at risk” population. The endothelium is a single layer of squamous epithelial cells called endothelial cells, which line the inside of all blood vessels. In a healthy state, the endothelium is a dynamic tissue whose constituent cells synthesize and secrete substances affecting its own function and that of adjacent structures. It is essentially involved in the regulation of blood flow, blood coagulation, vascular permeability, and structure. Endothelial dysfunction is a pathological condition characterized by loss of balance in all major endothelial mechanisms. It has been implicated in the pathophysiology of different cardiovascular diseases, including chronic heart failure . Its exiThe principle of endothelial function assessment involves measuring the vasodilatory response to endothelium-dependent agonists, such as acetylcholine (Ach), carbachol, methacholine, serotonin , and others, as all induce endothelial cells (ECs) to generate nitric oxide (NO), and then comparing this response to that of agonists that are endothelium-independent, such as sodium nitroprusside (SNP) or glyceryl trinitrate (GTN). These vasoactive substances can be infused locally into forearm blood vessels via a technique called venous occlusion plethysmography (VOP).in vivo in different populations. It is commonly applied to the forearm vascular bed although it can also be applied to lower limbs. The aforementioned vasoactive substances can be infused intra-arterially into the brachial artery under local anesthesia to measure forearm blood flow (FBF) in mL/min/100 mL [VOP is a technique that was first described over 100 years ago and is still considered as a “gold-standard” investigation for the assessment of vascular physiology n/100 mL . ChangesDue to the invasive nature of VOP, flow-mediated dilatation (FMD) was introduced as a non-invasive technique to measure flow-mediated changes in arterial diameters in relatively superficial arteries, such as brachial, radial, or femoral arteries . In prinThe first description of endothelial dysfunction was in 18 patients with essential hypertension who were compared with 18 control subjects in 1990 . Such a p = 0.0003. FBF in response to nitroprusside infusion (endothelium-independent vasodilatation) was not significantly different between the two groups [The description of endothelial dysfunction in the heart failure population started to appear in the literature and was mainly performed on a small scale. A study that included 24 patients with CHF with left ventricle (LV) systolic dysfunction (New York Heart Association NYHA class II–III) demonstrated that endothelium-dependent vasodilatation was impaired in patients when compared with 22 control subjects. Such a finding was demonstrated invasively via the VOP technique with methacholine infusion into the brachial artery with FBF of 5.32 ± 0.31 in CHF patients vs. 9.52 ± 0.60 mL/min/100 mL in control subjects; o groups .Endothelial dysfunction was assessed in nine patients with CHF with LV systolic dysfunction (NYHA class III) and in nine control subjects invasively via the VOP technique with acetylcholine and NG-monomethyl-L-arginine (L-NMMA) as NO synthase inhibitor infusion in the brachial artery. FBF in response to acetylcholine was blunted in CHF patients (endothelium-dependent vasodilatation). In addition, there was an exaggerated decrease in blood flow induced by L-NMMA infusion (nitric oxide derived from L-arginine is preserved/enhanced) in CHF patients when compared with control subjects .Conduit artery distensibility is determined, at least, in part, by endothelial function. Such a method was used to assess endothelial function in nine patients with CHF with LV systolic dysfunction (NYHA class I–III) and in nine control subjects. There was a reduction in the pulse wave velocity in the right common iliac artery in response to acetylcholine local infusion in control subjects but not in CHF patients. The same study assessed the brachial artery diameter and distensibility change in response to reactive hyperemia in the hand. Such a technique has shown increased parameters in control subjects  but not CHF patients (0.3% and −4.5%) for similar blood flow and similar GTN induced effects .p < 0.01). Such a phenomenon was interestingly associated with increased endothelium-bound xanthine oxidase activity and reduced endothelium-bound extracellular superoxide dismutase activity [A fourth study demonstrated the existence of endothelial dysfunction in 14 patients with CHF with LV systolic dysfunction (NYHA class III) who were compared with 10 control subjects. Flow-dependent endothelium-mediated vasodilatation (FDD) assessed the radial artery diameter change in response to wrist occlusion. FDD was impaired in patients with CHF in comparison with control subjects (activity .Later studies started to include patients having heart failure with preserved ejection fraction (HFpEF) as the target population. The suggested pathophysiological mechanism of ED in CHF is related to a state of increased oxidative stress in this patient population via multiple mechanisms, reduced NO synthesis  with posEndothelial dysfunction assessed by brachial artery FMD was a predictor of 5 years incident cardiovascular events in a case-cohort sample of 3026 subjects with traditional cardiovascular risk factors that participated in the Multi-Ethnic Study of Atherosclerosis. FMD findings improved the classification of those subjects as low, intermediate, and high CVD risk compared with the Framingham Risk Score (FRS) . SimilarTwo other studies were less supportive of the predictive value of endothelial dysfunction when compared with another measure of vascular structure, such as the intima-media thickness. The first included 444 patients described as being at risk of cardiovascular events because of underlying coronary artery disease (CAD), renal dysfunction, or the presence of multiple cardiovascular risk factors, who were followed for 24 months. This study has shown that patients with the most severe endothelial dysfunction assessed by brachial artery FMD had greater subsequent cardiac morbidity and mortality compared with those with normal or mild endothelial dysfunction. However, mortality in such a population was independently predicted by carotid intima-media thickness (IMT) and left ventricular mass rather than FMD . The latTwo other studies assessed the significance of endothelial function in CHF after they had undergone major interventions. The first included 185 CHF patients (of ischemic and non-ischemic etiology), 25 months after they received heart transplantation . Epicardial endothelial function, assessed in response to intracoronary acetylcholine administered during coronary angiography, was found to be an independent predictor of 5-year cardiovascular-related events and death after heart transplantation . The secp < 0.001) [In the general population, physical activity is an essential health strategy that needs to be encouraged. Based on the results of a large cohort study that included more than 20,000 middle- aged men and women, regular physical activity (bicycling to work) was related to a lower risk of incident obesity, hypertension, hypertriglyceridemia, and impaired glucose tolerance in comparison with passive travel during 10 years of follow-up . For pat< 0.001) . A later< 0.001) . Suggest< 0.001) , upregul< 0.001) , increas< 0.001) , and lat< 0.001) ,51.Adrenergic System, Physical Exercise, and ED in HFrEF PatientsThe sympathetic nervous system’s (SNS) over activity in heart failure is a well-established mechanism that has a transitional contribution to the pathophysiology, is supportive of cardiac function initially, and is a burden on it ultimately . Researc1AR (77%): β2AR (23%) in a non-failing heart to 60%: 38% with improper signaling mechanisms in a failing heart [suppressor/cytotoxic cells, B cells, natural killer cells, and monocytes [In the myocardium, the most abundant AR are βAR subtypes. Their density changes from a predominant βng heart ,54. βAR ng heart ,56, a prng heart . Peripheonocytes . These nonocytes . In hear2AR sub-type predominance) and directly or via NOS stimulation induce NO-dependent vasodilatation [2AR are also expressed and involved in the activation of NOS and NO-dependent vasodilatation [The benefits of physical exercise in heart failure were studied on myocardial cells and peripheral lymphocytes. In animal models, physical exercise increased myocardial βAR density and reduced G-protein-coupled receptor kinase-2 over-expression, with the resultant improvement of cardiac inotropic activity in response to adrenergic stimulation . In patilatation ,63. α2ARlatation .2AR sub-type predominance) and directly or via NOS stimulation induce NO-dependent vasodilatation [2AR are also expressed and involved in the activation of NOS and NO-dependent vasodilatation [The benefits of physical exercise in heart failure were studied on myocardial cells and peripheral lymphocytes. In animal models, physical exercise increased myocardial βAR density and reduced G-protein-coupled receptor kinase-2 over-expression, with the resultant improvement of cardiac inotropic activity in response to adrenergic stimulation . In patilatation ,63. α2ARlatation .Considering the current findings, we could anticipate that physical exercise in heart failure might modify the molecular changes to the adrenergic system at the EC level and improve endothelial function, as it does enhance autonomic receptor-mediated endothelium-dependent vasodilatation in animal models . Such a There is a paucity of data in the literature on HFpEF patients. A study included 30 patients with HFpEF (NYHA class II–III) who were randomized to functional electrical stimulation (FES)  vs. a placebo “much lower intensity of stimulation”  for 6 weeks. The FES group had a significant improvement in BA-FMD, 6-min walking distance, and quality of life with the HF questionnaire compared with the placebo group . HoweverPharmacological agents explored in the literature include those considered standards of care in the HF population and other newly investigated agents. Standard heart failure therapies include angiotensin-converting enzyme (ACI) inhibitors, angiotensin receptor blockers (ARBs), spironolactone, and the commonly co-administered statins. ACE inhibitors’ beneficial effect on endothelial function was described in the literature, mostly in the hypertensive population, with a meta-analysis that demonstrated that they significantly improved BA-FMD when compared with placebo, no treatment, and other antihypertensive agents, like calcium channel blockers and beta-blockers . Furtherp < 0.001) [In the current literature, new pharmacological agents have started to appear to improve endothelial function in different patient populations. Among them, allopurinol as a XO inhibitor showed some benefit to endothelial function that is most noticeable in CHF patients. This is because circulating XO can bind to the endothelial surface where reactive oxygen species (ROS) are produced to contribute to endothelial dysfunction , and bec< 0.001) .+ channels. In addition, it induces eNOS-dependent NO production in coronary endothelial cells in animal models [Levosimendan is a calcium-sensitizing agent used for the management of HFrEF. It has been shown to possess vasodilatory properties via inhibition of phosphodiesterase III, desensitization of contractile proteins to calcium, and by the opening of ATP-sensitive Kl models . It has l models .After the beneficial effects of ivabradine on clinical outcomes in CHF patients with LV systolic dysfunction  (SHIFT tSince the optimal therapy of patients with HFpEF is still under investigation, the current literature lacks adequate studies on pharmacological therapies for ED in this patient population. A small study included 48 patients with HFpEF and assessed the effect of sildenafil, a phosphodiesterase 5 inhibitor, administered over 24 weeks, with no significant benefits on the reactive hyperemic change in digital blood flow . With thChronic heart failure is a complex syndrome with significant morbidity and mortality worldwide. New staging systems have emerged to address the involvement of not only the heart but also lungs, kidneys, liver, and central nervous system . Endothe