Asthma-chronic obstructive pulmonary disorder (COPD) overlap (ACO) is characterized by the coexistence of features of both asthma and COPD and is associated with rapid progress and a poor prognosis. Thus, the early recognition of ACO is crucial.We sought to explore the plasma levels of biomarkers associated with asthma , COPD (NGAL) and their possible correlation with lung function, the bronchodilator response and radiographic imaging in patients with asthma, COPD and with features of ACO.We enrolled 423 subjects from 6 clinical centers. All participants underwent blood collection, lung function measurements, bronchodilator response tests and high-resolution CT. Correlations of the plasma biomarkers with lung function, the bronchodilator response and percentemphysema were calculated by Spearman’s rank correlation and multivariate stepwise regressionanalysis.1) Patients with features of ACO had lower plasma YKL-40 than COPD patients and a moderate elevated plasma level of NGAL compared with asthma patients. 2) Patients with features of ACO had an intermediate degree of airflow obstruction, the bronchodilator response and emphysema between patients with COPD and asthma. 3) Plasma YKL-40 was negatively correlated with lung function and with the bronchodilator response, and plasma NGAL was positively correlated with the extent of emphysema.Plasma YKL-40 is a promising candidate for distinguishing between patients with features of ACO and COPD patients, while plasma NGAL may be a valuable biomarker for differentiating between patients with features of ACO and asthma patients.ChiCTR-OOC-16009221. Asthma and chronic obstructive pulmonary disease (COPD) are common pulmonary diseases with significant impacts on public health throughout the world –3. ThereThere is increased awareness of the importance of recognizing ACO because it is associated with more frequent and severe exacerbations, a rapid decline in pulmonary function, poor quality of life and higher mortality than asthma or COPD alone , 9. In aTo date, the universally accepted definition of ACO remains elusive. In fact, the definition of ACO is evolving, and different definitions are being applied in various studies –13. ACO Previous studies have demonstrated that asthma, COPD and ACO differ in their biomarker profiles –16, thusIt is generally accepted that ACO has two clinical phenotypes: asthma with long-term smoking developed non-fully reversible airflow obstruction in elderly adults and COPD accompanied by reversible or partially reversible airflow obstruction with a history of asthma or “asthmatic” symptoms , 18.BasePrevious studies have revealed several key features of ACO, including the intermediate degree of emphysema and airflow obstruction between asthma and COPD and mixed, moderate airway neutrophil and eosinophil infiltration , 18. We In our study, ACO had significantly lower plasma levels of YKL-40 than COPD and an intermediate degree of plasma NGAL, airflow obstruction and emphysema between COPD and asthma. Additionally, univariate and multivariate stepwise analyses displayed that both YKL-40 and NGAL were correlated with airflow limitation and an impaired bronchodilator response, and NGAL was independently correlated with the degree of emphysema. Our results strongly suggest that YKL-40 is a promising candidate for identifying ACO from COPD, while plasma NGAL is helpful in distinguishing ACO from asthma.This study was part of a multicenter case-control study hosted by the Department of Respiratory Medicine, the 2nd clinical hospital of Chongqing Medical University, China. Additionally, 6 respiratory medicine departments at other public hospitals participated in this study. We recruited 423 participants: 147 with COPD, 124 with asthma, 102 with AOCS and 50 healthy nonsmokers. All participants were Chinese who presented to the inpatient department of these hospitals from January 2016 to May 2017.At the time of enrollment, all subjects completed standardized questionnaires regarding sex, age, BMI, smoking habits, medication use, and exacerbation history. Simultaneously, all subjects, except for the healthy nonsmokers, completed the St. George’s Respiratory Questionnaire (SGRQ). All subjects underwent spirometry, high-resolution computed tomography (HRCT) and blood collection on the same day. The diagnosis of asthma and COPD was based on the GINA  and GOLDControl subjects were recruited from healthy nonsmokers and no history of biomass exposure with normal spirometry (FEV1 ≥ 80% predicted and FEV1/FVC ≥0.7). The subjects were excluded from the study if they: (1) had a respiratory tract infection in the 2 weeks preceding the study; (2) had coexisting pulmonary diseases, such as bronchiectasis, cystic fibrosis, interstitial lung disease, or lung cancer; and 3) had any cognitive disorder or impairment in renal or liver function .Spirometry was performed on a computerized spirometer  in accordance with the American Thoracic Society and European Respiratory Society (ATS/ERS) recommendations. The examination included pre- and post-bronchodilator spirometry. The parameters collected were FVC, FEV1, percent predicted values of these parameters  and the FEV1/FVC ratio. The bronchodilator response was quantified in two ways: as an absolute number  and as a percent of the pre-bronchodilator value ).Peripheral whole venous blood was separately collected into EDTA tubes to measure various biomarkers. Plasma was prepared by centrifugation for 10–15 min at 4500 rpm and was stored at − 80 °C until analysis. YKL-40, periostin, TSLP and NGAL levels were measured using commercially available enzyme-linked immunosorbent assay (ELISA) kits  according to the manufacturer’s instructions.Neutrophil and eosinophil counts of peripheral blood were detected using a routine blood test and serum level of creatinine was measured using enzymatic methods.http://www.slicer.org). The degree of emphysema was defined as the percentage of lung voxels with attenuation values less than or equal to − 950 Hounsfield units.Chest HRCT was performed at maximal inspiration, with the participants in the supine position using a 64-slice spiral CT scanner . The HRCT images were reconstructed with a window setting appropriate for the lungs , with a 1-mm slice thickness using a high spatial frequency algorithm. All CT images were analyzed using 3D Slicer software  and were analyzed with repeated measures ANOVA and unpaired t-test. Receiver operating characteristic (ROC) curves were obtained to elucidate the predictive capability of plasma biomarkers in distinguishing ACO from COPD and asthma. The correlations of lung function, the bronchodilator response and percent emphysema with the plasma biomarkers were calculated by Spearman’s rank correlation, linear regression was used to adjust plasma biomarkers level for age, BMI and smoke, and multivariate stepwise regression analysis was constructed to examine the independent variables on the plasma biomarker levels.All statistical analyses were performed with the SPSS 22.0 software program  and The demographics and clinical characteristics of the subjects are shown in Table p < 0.0001) and those with features of ACO  and were highest in patients with COPD (15.23 [12.31–20.72) .The results are presented as the medians . Compared with the plasma YKL-40 levels in healthy control subjects (7.08 [6.17–7.99] ng/ml), levels were significantly elevated in patients with asthma  Fig. . There wp < 0.001).We further performed regression analyses to ensure that the relationship between disease group and plasma biomarkers could be assessed after adjustment for potentially confounding variables, we found that after adjustment for all the subjects characterstics parameters  the statistically significant difference above remained markedly . The difference between the control (78.59 [62.55–110.39] ng/ml) and asthma (87.33 [71.92–95.43] ng/ml) groups was not statistically significant(p = 0.90), and both groups showed significantly lower levels than those in the COPD  and ACO  groups.Regarding the plasma level of NGAL, all three patient groups were significantly different from each other , and a significant difference also remained between patients with features of ACO and COPD (p = 0.016).Also, following regression analyses with adjustment for all the subjects characterstics parameters, patients with COPD and features of ACO both still had significantly higher NGAL levels than patients with asthma (p > 0.05) and TSLP (p > 0.22) were observed among the asthma, COPD and ACO patient groups . The measures of lung function showed negative correlations with the levels of YKL-40, NGAL and TSLP, and the measures of the bronchodilator response showed negative correlations with the levels of YKL-40 and NGAL and positive correlations with the levels of TSLP. The percent of emphysema (% LAA-950) was found to be positively correlated with the levels of YKL-40 and NGAL . Blood eosinophil counts were found positively correlated with TSLP, while blood neutrophil counts and serum creatinine positively correlated with NGAL. In our present study, no correlation was established between the plasma periostin level and measures of lung function , the bronchodilator response , however, a weak but statistically significant negative correlation with the percent of emphysema and blood neutrophil counts was found .All the study subjects were pooled as a whole in order to analyze the possible correlations between the level of plasma biomarkers and subject characteristics including lung function and HRCT Table . Age andp < 0.1 were retained in a stepwise analysis procedure.Because the Spearman’s rank analysis above implied that plasma YKL-40, NGAL and TSLP levels are affected by several factors, we further performed multivariate stepwise analysis to ensure that the relationship between disease group and plasma biomarkers could be assessed after adjustment for potentially confounding variables  and the studied disease categories  on the plasma levels of YKL-40, NGAL and TSLP (Table Our present study explored plasma levels of 4 biomarkers associated with asthma, COPD and their possible correlation with lung function, bronchodilator response and radiographic imaging in asthma and COPD patients and patients with features of ACO. Our results demonstrate that patients with features of ACO displayed distinct features, they had lower plasma YKL-40 than COPD patients and a moderate elevated plasma level of NGAL compared with asthma patients; had an intermediate degree of airflow obstruction, bronchodilator response and emphysema between patients with COPD and asthma. Furthermore, negative correlation between plasma YKL-40 and lung function and the bronchodilator response, and positive correlation between plasma NGAL and the extent of emphysema were observed. Therefore, ACO was an intermediate condition between COPD and asthma with distinct pathophysiological features. Plasma YKL-40 and NGAL are promising candidates for distinguishing ACO from asthma and COPD.One of the main findings of our present study is that the plasma YKL-40 levels were significantly lower in asthma patients and patients with features of ACO than in COPD patients. YKL-40 was originally shown to be a key regulator in Th2-mediated inflammation and tissue remodeling , 27. ClePrevious studies have indicated that plasma YKL-40 levels are positively correlated with subepithelial basement membrane thickness and extracellular matrix deposition in the airway walls, suggesting its important role in airway remodeling , 32. AirThe differences in plasma YKL-40 levels between patients with features of ACO and those with asthma were not statistically significant in our present study, although the ACO groups indeed had a higher median value. One possible reason may be that most asthma subjects were severe and therapy-resistant in-patients enrolled from exclusively teaching hospitals or district general hospitals in our study, and it was widely demonstrated that the plasma YKL-40 levels in those patients were notably higher than those in the mild to moderate, well-controlled asthma patients .NGAL, a member of the lipocalin family released from neutrophils  upon actOur experimental findings showed that the plasma NGAL levels were lower in the overlapped patients than in patients with COPD, highlighting that plasma level of NGAL may also exert an important function in differentiating ACO from COPD. Additionally, in terms of the pathophysiological mechanism, in contrast to the dominant neutrophilic airway inflammation in COPD, inflammation in ACO seems to be more complex and may be predominantly driven by both neutrophils and eosinophils .Increasing studies have demonstrated that emphysema is a characteristic imaging manifestation of patients with features of ACO. Compared with COPD patients, patients with features of ACO usually have a lower degree of emphysema , 36. OurIndeed, the increased NGAL level has been proven to be a valid and reliable molecular marker that correlates with the extent of emphysema associated with smoking . TherefoTSLP has been identified as a “master switch” for allergen-induced inflammation through the activation of dendritic cells to induce type 2 inflammation , 38. HowPeriostin is an extracellular matrix protein expressed in mesenchymal cells and bronchial epithelial cells . As a doPlasma YKL-40 is a promising candidate for distinguishing ACO from COPD, while plasma NGAL may be a valuable biomarker for distinguishing ACO from asthma. These were beneficial for the early recognition of ACO and subsequent targeted intervention, which is important given the rapid progress and worse prognosis of this disease. Further studies are required to investigate the possible role of these biomarkers in the pathogenesis of ACO. Regarding the three conventional Th2-type biomarkers chosen in our study, only YKL-40, which is now recognized as a non T-helper cell type 2 biomarker, was found to play a role in screening out ACO; other Th2-type biomarkers need to be explored in the future.


Combined antiretroviral therapy (cART) in HIV-infected patients has been associated with lipodystrophy, metabolic abnormalities, and an increased risk of cardiovascular disease. Ultrasound measures of carotid artery intima-media thickness (cIMT) have been used as a valid measure of subclinical atherosclerosis and as a tool to predict the risk of cardiovascular events. Our aim was to evaluate the progression of cIMT in HIV-infected patients subjected to cART, with and without lipodystrophy, over a one-year period., from the first to the second year of evaluation. Means of cIMT, adjusted for age, glucose, triglycerides levels, systolic blood pressure (SBP), and waist to hip ratio were calculated, using generalised linear models for repeated measures.We performed a one-year prospective cohort study to compare changes in cIMT, metabolic and inflammation markers in HIV-infected patients undergoing cART. Body composition was assessed by dual-energy X-ray absorptiometry (DXA) and abdominal computed tomography (CT). Levels of blood pressure, lipids and inflammatory markers were evaluated, as well as ultrasound measures of cIMT. Lipodystrophy defined by Fat Mass Ratio (L-FMR) is measured as the ratio of the percentage of trunk fat mass to the percentage of lower limb fat mass by DXA. Categorical variables were compared, using the chi-square or Fisher’s exact test. Wilcoxon ranks tests and the McNemar chi-square tests were used to compare results of selected variablesp = 0.037], as well as in patients without lipodystrophy . In the overall sample, the progression of cIMT was statistically significant after the adjustment for age, glucose, triglycerides, and SBP, but the significance of the progression ceased after the adjustment for waist/hip ratio .L-FMR was present in 44.3% of patients, and the mean of cIMT increased significantly in this group [0.82 (0.26) vs 0.92 (0.33); Carotid IMT progressed significantly in both groups of this HIV-infected cohort, however no association between the progression of cIMT and the presence of lipodystrophy defined by FMR was found. Visceral adipose tissue had an impact on the increment of cIMT, both in patients with, and without lipodystrophy defined by FMR. The use of combined antiretroviral therapy (cART) in HIV-infected patients has significantly increased the life expectancy of these subjects . HoweverThe relative contributions of conventional cardiovascular risk factors, metabolic side effects of antiretroviral drugs, and HIV infection itself on cardiovascular risk are difficult to identify, as these factors frequently occur simultaneously . In thisIn a previously published study, we showed that HIV-infected patients under cART with lipodystrophy defined by FMR had a significantly higher cIMT than those without lipodystrophy, which was also associated with classical cardiovascular risk factors, such as visceral adipose tissue and age . The purWe evaluated 115 HIV-infected patients undergoing cART in this longitudinal study. Only non-institutionalised caucasian adults who were subjected to cART were evaluated, and all patients were referred from the Infectious Diseases Outpatient Clinic. We excluded institutionalised patients with the objective of ruling out acute intercurrences that could have an impact on the metabolic and inflammatory parameters. Participants were evaluated at baseline, and after one year for each parameter . All patients were referred to a nutrition appointment, were motivated to comply with a structured diet plan, walk or exercise regularly and were also advised to stop smoking. Overweight patients, or those suffering from obesity were motivated to lose weight. Prediabetes, diabetes, hypertension, and dyslipidemia were treated according to the standard of care for the HIV-population. This study was approved by the Ethics Committee for Health of the Hospital São João in Porto and each patient provided their written, informed consent.For each patient, the following information was collected at both baseline and after the follow-up period (12 months), using a standard protocol that covered: age, gender, known duration of HIV infection, and duration of cART exposure, HIV risk factor, characterisation of the infection, smoking history, family history of cardiovascular diseases, and use of anti-hypertensive, anti-diabetic, or lipid lowering drugs.We used the “Centers for Disease Control and Prevention” (CDC) HIV staging classification , wherebyMeasures of blood pressure were taken with the patient in a supine position, employing a standardised technique, as previously described .We evaluated body composition using whole-body, dual-energy X-ray absorptiometry . DXA measurements were carried out whilst in a supine position, and standard positioning of the arms and feet was established according to the manufacturer’s instructions. Regional fat mass values were grouped and analyzed for the following anatomical regions: arms, legs, trunk, and total body. The fat mass ratio (FMR) was measured as the ratio between the percentage of trunk fat mass and the percentage of lower limb fat mass (FMR = % of the trunk fat mass/% of the lower limb fat mass) . We used2, rounded to the nearest centesimal.The quantification of total, visceral, and subcutaneous fat was performed with a 64-slice, abdominal computed tomography (CT) scanner (Siemens Sensation 64 Cardiac), with the same technique as previously described , 14. AllA venous blood sample was taken after a 12 h overnight fast. All the samples were analyzed at the central laboratory of our hospital. The measurements of total cholesterol (TC), low density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, apolipoprotein A1 (Apo A1), apolipoprotein B (Apo B), lipoprotein (a) [Lp (a)], fibrinogen, high sensitivity C-reactive protein (hsCRP), homocysteine, uric acid, lactates, NT-proBNP, glucose, insulin, and A1c serum levels were determined using commercial kits. Non-HDL-C was defined as TC-HDL. Microalbuminuria was determined in a 24-h urine sample. Patients without a previous diagnosis of diabetes were submitted to an oral glucose tolerance test (OGTT). This test was performed as instructed by the World Health Organisation .6 cell/L) was determined by flow cytometry and plasma HIV-1 RNA loads were measured by a quantitative reverse transcriptase polymerase chain reaction , which had a lower limit of detection of 50 copies/mL.The CD4+ cell count (×10Insulin resistance was defined by the homeostasis model assessment of insulin resistance (HOMA), using the following formula:HOMA – IR index = (insulin 0 x glucose 0)/22.5 .We defined Metabolic Syndrome (MS) according to the modified NCEP-ATP III criteria, requiring the presence of three of the following risk factors: (1) elevated waist circumference (>102 cm); (2) elevated triglycerides (≥150 ml/dL or specific treatment); (3) reduced HDL-C levels (<40 mg/dL); (4) elevated blood pressure (>130/ 85 mmHg or treatment with anti-hypertensive drugs), and; (5) elevated fasting glucose (≥100 mg/dL or use of glucose-lowering drugs). We performed high-resolution B-mode and Doppler ultrasounds measures of the carotid arteries using a Philips iU22 machine , equipped with a 17–5 MHz high-frequency linear-array transducer. Patients were examined in the supine position, with the head in a neutral position, or slightly turned away from the side that was being scanned. The left and right common carotid arteries (CCA) were examined in multiple directions. The carotid bifurcation was included in the image plane to serve as a landmark and provide accurate serial measurements. The IMT was measured along a segment of the artery free of atherosclerotic plaque with clearly defined lumen-intima and media-adventitia interfaces if possible 3 cm below the carotid bulb. The far wall was preferred for the measurement and only when the image quality of the far wall was not satisfactory was the near wall used. The measurements were done by manual tracking and were repeated three times. The mean IMT of these values was calculated. All studies were performed by the same radiologist, who had 12 years of experience in vascular ultrasound, and were carried out using the same machine.The presence of subclinical carotid atherosclerosis was defined as IMT > 0.80 mm, the presence of plaque, or both –20.Data were described as the mean and standard deviation (SD) for quantitative variables and were compared using Student-t or Mann-Whitney tests, as appropriate. Categorical variables were described as counts and proportions, and compared using the chi-square or Fisher’s exact test. To study the association between cIMT and clinical and metabolic characteristics, Spearman correlation coefficients were estimated. In addition, Wilcoxon ranks tests and the McNemar chi-square tests were used to compare results of selected variables from the baseline to the first follow-up evaluation. Means of cIMT were calculated, using generalised linear models for repeated measures, adjusted for age, glucose, triglycerides levels, systolic blood pressure, and waist to hip ratio.p values of <0.05 were regarded as significant.Statistical analysis was performed using SPSS version 24.0 software . All probabilities were two-tailed, and p = 0.036) and were subjected to a greater length of cART (p = 0.001). No differences in weight, height, BMI, waist, neck, and thigh and arm circumferences among patients with or without lipodystrophy were found.In 115  HIV-infected patients undergoing cART, 51 (44.3%) presented lipodystrophy defined by FMR. The characteristics of the study sample according to the presence of lipodystrophy defined by FMR are illustrated in Table p = 0.006 and 0.003, respectively).Patients with lipodystrophy had a lower value of hip circumference and a higher waist/hip circumference ratio, compared to the patients without lipodystrophy. , systolic blood pressure, and CD4+ cell count.p = 0.017 and <0.001, respectively), both in % and Kg , lower subcutaneous adipose tissue (SAT) (p = 0.011), and no significant difference in total fat at abdominal level.Patients with lipodystrophy had a higher visceral adipose tissue (VAT) value and VAT/SAT ratio , uric acid, lactates, HOMA, HbA1c, Apo A1, Apo B, ratio Apo B/Apo A1, Lp(a), homocysteine, CRP, hsCRP, NT-proBNP, fibrinogen, and microalbumin urinary excretion between patients with or without lipodystrophy.Furthermore, no significant differences regarding the prevalence of metabolic syndrome were observed between the two groups Table .p = 0.050]  0.82 (0.26) vs. 0.73 (0.20); 0] Table .The cIMT was positively correlated with lipodystrophy evaluated by FMR, age, neck circumference, waist/hip ratio, systolic blood pressure, glucose at 0 and 120 min on OGTT, HbA1c, non-HDL cholesterol, visceral obesity defined by total body fat mass by quantitative CT, VAT and VAT/SAT ratio, trunk fat mass evaluated by DXA, uric acid, CRP, hsCRP, and homocysteine, as is shown in Table The progression of the study sample’s characteristics throughout the period of follow-up (12 months) is illustrated in Table p < 0.001 and 0.049, respectively). The systolic and diastolic blood pressure also decreased significantly in the follow-up period (p = 0.005 and <0.001), as well as total cholesterol, non-HDL cholesterol, and triglycerides levels . The values of HDL, LDL and Apo A1 increased since the baseline , and the values of Apo B and the ratio apo B/ apo A1 decreased (p < 0.001 for both variables).With regards to the progression of body composition and metabolic parameters during one year in the total of the sample, the values of thigh and arm circumference are lower than those obtained at baseline (p = 0.005 and 0.002), when compared with the baseline, and the values of hsCRP and uric acid were lower (p = 0.030 and 0.022).Lastly, values of homocysteine and lactates were higher (p = 0.023), but higher values of leg fat mass, both in Kg and % . The analysis according to quantitative CT showed a decreased value of VAT and VAT/SAT ratio (p = 0.049 and 0.019). Diastolic blood pressure, total cholesterol, non-HDL cholesterol and triglycerides levels were lower compared with baseline values . Furthermore, HDL and Apo A1 levels increased (p = 0.018 and 0.001), and the Apo B/Apo A1 ratio decreased (p = 0.001). The values of homocysteine were higher, while uric acid levels were lower than the ones obtained at the baseline .Patients with lipodystrophy presented lower thigh circumference when compared with the baseline (p < 0.001 and 0.047). The value of VAT increased in this group during the follow-up period (p = 0.024). In addition to the decline of systolic and diastolic blood pressure , CRP and hsCRP levels also decreased (p = 0.038 and 0.066). The values of LDL, Apo A1 and lactates increased , while triglycerides levels and Apo B/Apo A1 ratio decreased .Patients without lipodystrophy presented lower thigh circumference and leg fat mass (Kg) compared with the baseline , and this remained higher in patients presenting lipodystrophy when compared to those without lipodystrophy, although without significant differences between them (p = 0.178).During one year of follow-up there was an increase in carotid IMT in the total of HIV-infected patients and in those with and without lipodystrophy, when compared with the baseline  and 1 year after 117.2 (18.1) mmHg; p = 0.005], diastolic blood pressure , total cholesterol , non-HDL cholesterol , triglycerides , apo B , hsCRP  and uric acid . The only variable positively correlated with cIMT that significantly increased in the total population was homocysteine.Table p < 0.001], for age, glucose and triglycerides  and for age, glucose, triglycerides, and systolic blood pressure . However, after further adjustment for age, glucose, triglycerides, systolic pressure, and waist/hip ratio, this difference did not remain statistically significant.Using generalised linear models for repeated measures, means of cIMT between the baseline and the 1 year follow-up were calculated and adjusted for age, glucose, triglycerides levels, systolic blood pressure and waist to hip ratio Table . In the p = 0.030], adjusted for age , age and glucose , and age, glucose and triglycerides . The same results were observed for patients without lipodystrophy  vs 0.919 0.825–1.01) 1 year after; –1.01 1 yAtherosclerosis is a progressive disease, and its contribution to cardiovascular risk increase is well-known . This coFurthermore, the presence of lipodystrophy defined by FMR was not associated with the progression of cIMT. Our data suggest that the increase of cIMT is associated with body fat abnormalities, particularly visceral body fat. It has been established that cART can cause a wide spectrum of metabolic disturbances and abnormalities in body fat distribution, and its contribution to premature and accelerated atherosclerosis in HIV infected patients is well-known , 24, 25.As pointed out above, the mean values of cIMT increased significantly in both groups of the population, despite the fact that, at the baseline, lipodystrophic patients had a higher waist/hip circumference ratio, VAT and VAT/SAT ratio. At follow-up, on the other hand, this group had lower WHR values, but showed equivalent results for cardiometabolic markers, when compared with patients without lipodystrophy. During the one year of follow-up, the values for VAT, VAT/SAT ratio, and WHR did not change significantly in the total of the population, and neither in those with and without lipodystrophy. Analyses from large observational cohorts have demonstrated that cIMT increase ranging from 0.03 to 0.2 mm are associated with 33% to 300% higher risk of coronary heart disease and stroke –28. In oThe degree to which cART therapy contributes to the increased cardiovascular risk in HIV patients is not completely clear yet. Even though there is a large body of evidence in the literature pointing to a moderate association between HIV infection and increased cIMT, in both cross-sectional and prospective studies, the results are still controversial –31. A prAdditional research, with a large sample-size, is needed to better characterize the underlying proatherogenic mechanisms of HIV infection and cART, as well as to evaluate the impact of body composition, namely lipodystrophy, on long-term cardiovascular risk in HIV-infected patients.The limitations of this study are mainly related to the small size of the sample. Therefore, this study might have been underpowered for the detection of small differences in cIMT progression between the two groups. Due to the fact that the design of this study did not include an HIV-uninfected control group, it remains unclear whether the observed increased cardiovascular risk can be fully explained by the effects of antiretroviral drugs and their metabolic side effects, body composition, or whether chronic HIV infection itself may play a role. Another limitation of our study is the absence of data regarding the exposure time to each drug, since we only have information on the current class of antiretroviral, thus the impact of the duration of cART regimen could not be assessed in this study.This study emphasizes the role of body composition, namely VAT, in addition to other traditional risk factors in the progression of cIMT. Moreover, it was performed in a unit that is highly experienced in the assessment of metabolic and body fat abnormalities in HIV-infected patients. All clinical evaluations were carried out by the same practitioner, and an objective definition of lipodystrophy was used (fat mass ratio by DXA).Carotid IMT progressed significantly in HIV-infected patients under cART, both in those with and without lipodystrophy. Although patients with lipodystrophy defined by FMR had a higher cIMT when compared with those without lipodystrophy, there was no association between the progression of cIMT and the presence of lipodystrophy defined by FMR. Visceral adipose tissue had an impact on the increment of cIMT during the follow-up period (both in patients with and without lipodystrophy defined by FMR), which suggests an independent association between VAT and the increasing of subclinical carotid atherosclerosis.


Renal autotransplantation is a kidney-saving surgical procedure used in selected patients. The purpose of this report is to review nine typical and atypical indications for kidney autotransplantation and evaluate its effectiveness in maintaining kidney function and avoiding cancer recurrence.  From 1999 till 2014, nine renal autotransplantations were performed in our center. A retrospective case review was done. Four of nine patients had a solitary functioning kidney. Typical indications for autotransplantation included extended ureteric disease in 5 patients, intrasinusal tumor on a solitary kidney in 1 patient, and renal artery aneurysm in 1 patient. Atypical indications consisted in bilateral urothelial tumors in 1 patient and interrupted live kidney transplantation in 1 patient. Mean cold ischemia time was 209 minutes. Demographic factors, indications, renal function before and after surgery, and in the long term, cancer recurrence and disease-free survival were evaluated. p value 0.3). In the other 4 patients with a solitary kidney, mean discharge creatinine clearance was 99.24 ml/min surprisingly higher than the preoperative value 96.92 ml/min. At the last follow-up, kidney function was preserved for the two groups  with relatively stable creatinine clearance values: 108.45 ml/min and 85.9 ml/min, respectively. No patients required secondary dialysis.  Renal function was maintained in 8 patients during the early follow-up. No serious complications occurred in the postoperative period. Median duration of follow-up was 50 months. In 4 patients with a normal contralateral kidney, mean preoperative and at discharge creatinine clearance were 105.45 ml/min and 121.02 ml/min, respectively. Although values showed an improvement in the kidney function, the difference was not significant ( Renal autotransplantation is a rare, safe, and effective surgical procedure for the treatment of complex urologic conditions. In some instances, it may be of great utility for kidney salvage in some carefully selected patients. Renal autotransplantation (RA) is a rare, safe, and effective surgical procedure for the treatment of complex urologic conditions. It was first reported by J. D. Hardy in 1963 when he repaired a high ureteric injury following aortic surgery by reimplanting the repaired organ into the ipsilateral iliac fossa.Hardy's accomplishment was made possible, thanks to allotransplantation techniques developed by Dr Murray and colleagues in Boston a decade earlier. Managing renal disease via a “benchwork” approach soon became a novel idea pursued worldwide by surgeons .After this landmark surgery, RA has been steadily improved to a safe and effective procedure and has been used in the treatment of different complex urologic diseases like extensive ureteric injuries, complex nephrolithiasis, loin-pain syndrome, renovascular diseases , tumors of the kidney and ureter, and retroperitoneal fibrosis , even moAs minimal invasive surgery has started to take the lead, decrease in surgical morbidity is now seen with laparoscopic and even completely intracorporeal robotic surgery .The purpose of this report is to present nine typical and atypical indications for kidney autotransplantation in order to evaluate its effectiveness in maintaining kidney function and avoiding cancer recurrence and to review the current literature.From 1999 till 2014, nine renal autotransplantations were performed in our center . A retrospective case review was done. The series included five females and four males with a mean age of 49.8 years. 4/9 patients had a solitary functioning kidney. Typical indications for autotransplantation included extended ureteric disease in 5 patients, intrasinusal tumor on a solitary kidney in 1 patient, and renal artery aneurysm in 1 patient. Atypical indications consisted in bilateral urothelial tumors in 1 patient and interrupted live kidney transplantation in 1 patient.The kidneys were removed through a flank incision over the 11th rib or laparoscopically and transplanted to the iliac fossa. In all patients, the ureter was reimplanted in the bladder using the Lich–Gregoir technique. Mean cold ischemia time was 209 minutes.Demographic factors, indications, renal function before and after surgery, and in the long term, cancer recurrence and disease-free survival were evaluated Tables –3.Renal function was evaluated by creatinine clearance estimate using the Cockcroft–Gault equation. This was maintained in 8 patients during the early follow-up .p value 0.3).No serious complications occurred in the postoperative period. Median duration of follow-up was 50 months. In 4 patients with a normal contralateral kidney, mean preoperative and at discharge creatinine clearance were 105.45 ml/min and 121.02 ml/min, respectively. Although values showed an improvement in the kidney function, the difference was not deemed significant . At the last follow-up, kidney function was preserved for the two groups  with relatively stable creatinine clearance values: 108.45 ml/min and 85.9 ml/min, respectively. No patients required secondary dialysis. The patient with bilateral pelvic and ureteric tumors is still cancer free, 7 years after surgery, with no recurrence on the annual CT scan. Finally, the patient with solitary kidney and intrasinusal tumor is also cancer free after 10 years of follow-up.In the other 4 patients with a solitary kidney, mean discharge creatinine clearance was 99.24 ml/min surprisingly higher than the preoperative value 96.92 ml/min. Note that the difference between these means was not significant  and survival (87%) in patients with low-grade (1 or 2), low-stage (I or II), bilateral orsolitary renal cell carcinoma treated with conservative surgical treatment  compared to radical surgery after 5 years of follow-up [Two recent studies on ex vivo nephron-sparing surgery for renal carcinoma were published in 2014.The first series included 9 patients. The absolute indications were organ saving and technical impossibility of renal tumor resection in situ. The mean duration of operation was 297.8 minutes, and the mean period of hypothermic ischemia consisted of 112.6 minutes. A postoperative follow-up (maximum 4 years) revealed that there is not noted dissemination of the tumor, and functional condition of the transplanted kidney was satisfactory [The second series included 3 patients. Two patients had complex renal cell carcinoma, and 1 patient had bilateral large angiomyolipoma. All 3 patients did not have renal replacement therapy and currently live a good quality of life. According to the authors, the advantage of this procedure over renal replacement therapy is better quality of life and cost-effectiveness .In this new era of minimal invasive surgery, laparoscopic renal harvest for autotransplantation provided an opportunity to decrease morbidity. Fabrizio et al. performed the first laparoscopic nephrectomy with open autotransplantation  .Gill et al. described retroperitoneoscopic laparoscopic nephrectomy followed by open autotransplantation using a Gibson incision for both extraction and subsequent transplantation .One of the largest series of laparoscopic nephrectomies for autotransplantation was reported by Tran et al. in 2015 including 52 patients with more than 90% success rate over a 6-year follow-up period .Also, although a very challenging procedure, completely intracorporeal robot-assisted nephrectomy with RA is now a feasible approach to renal preservation after major ureteral injury .Finally, a randomized study comparing RA to another approach like “bowel interposition” is necessary to determine the differences in benefits and risks associated with these procedures.Analysis of values and changes in renal clearance revealed that the majority of patients had an improvement in renal function, with the exception of two patients with a postoperative clearance of <60 ml/min , knowing that these 2 patients had some degree of kidney failure before surgery . This reflects the improvement in renal function and the rarity of delayed complications.In our study, the patient with pelvic and bilateral ureteral tumors showed remission, without any recurrence on the annual scan even 7 years after the surgery, as well as for the patient with a solitary and an intrasinusal tumor who is disease free after 10 years of follow-up.In this study, the relatively long follow-up (average of 55 months) empowers the study and explains RAs validity and effectiveness. However, a retrospective study like ours could be criticized. The limited number of patients enrolled, the one center-one surgeon experience are some of the limitations of this study.Renal autotransplantation is a rare, safe, and effective surgical procedure for the treatment of complex urologic conditions. In some instances, it may be of great utility for kidney salvage in some carefully selected patients. Our center's experience in renal autotransplantation showed low complications rate, preserved kidney function, and no cancer recurrence on the early and late follow-up.


Attempts to investigate the mechanisms by which continuous positive airway pressure (CPAP) therapy improves heart function in patients with obstructive sleep apnea (OSA) have been limited by the lack of non-invasive methods to assess cardiac performance. We used transthoracic electrical bioimpedance (TEB) to assess acute hemodynamic changes including heart rate (HR), stroke volume (SV), cardiac output (CO) and cardiac index (CI) during PAP titration in (1) post-operative cardiac surgery patients, (2) patients with severe OSA, and (3) normal healthy volunteers.Post-operative cardiac surgery patients were studied via TEB and pulmonary artery catheter (PAC) during acute titration of positive end-expiratory pressure (PEEP) while mechanically ventilated. Patients with severe OSA were studied non-invasively by TEB during acute CPAP titration in supine stage 2 sleep, and normal subjects while awake and recumbent.2O significantly reduced SV and CI relative to baseline. There was no difference between TEB and PAC in terms of ability to assess variations in hemodynamic parameters. In patients with severe OSA (n = 3), CPAP titration to optimal pressure to alleviate obstructive apneas reduced HR, SV, CO and CI significantly compared to without CPAP. In three healthy subjects, maximal tolerated CPAP reduced SV and CO significantly compared to baseline.In post-operative cardiac surgery patients (n = 3), increasing PEEP to 18 cmHAcute administration of CPAP causes a decrease in CO and CI, apparently a consequence of a reduction in SV. TEB appears to be an accurate and reproducible non-invasive method of detecting changes in hemodynamics. Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder associated with an increased risk of cardiovascular disease . OSA is Attempts to further investigate the mechanisms by which CPAP therapy improves heart function have been limited by the availability of methods to assess cardiac performance. Pulmonary artery catheterization (PAC) has traditionally been used to measure hemodynamic variables, and is also considered to be the clinical gold standard for cardiac output monitoring . HoweverRecently, the use of transthoracic electrical bioimpedance (TEB) devices has gained popularity in the assessment of hemodynamics in various clinical and research settings. The accuracy and reproducibility of the results have repeatedly been confirmed in studies demonstrating that CO measured by TEB correlate closely, and with clinically acceptable agreement and precision, compared with CO measurements obtained by pulmonary artery thermodilution among both stable and unstable post-cardiac surgery patients , 13. AdvFew studies, however, have investigated the use of TEB in patients with OSA. Stoohs et al  used nonWe used a bioimpedance device that has previously been validated as a method of monitoring CO as compared to the direct Fick method and to thermodilution , 21, to This study was approved by the Research Ethics Board at Queen’s University. All participating subjects provided informed consent. Normal subjects were recruited using word-of-mouth, whereas patients suspected of having severe OSA and those undergoing elective cardiac surgery were recruited from Sleep Clinics and from Cardiac Surgery Clinics, respectively.Non-invasive measurements of hemodynamic parameters  were obtained using TEB . This device utilizes bioimpedance to derive indices of CO and SV by placing six adhesive electrodes on the patients’ thorax and neck . The device was set so that acquisition of data was averaged over 5 heart cycles. Additional output included HR and cardiac index (CI). The CI was calculated by dividing the measured CO by the patients’ body surface area (BSA), where BSA was calculated using the Dubois-Dubois formula: BSA (m2) = 0.007184 × weight (kg)0.425 × height (cm)0.725.2O. PEEP was then sequentially increased to 10, 15, and 18 cmH2O and was finally returned to a baseline of 5 cmH2O. After each change in PEEP, hemodynamic variables were measured both invasively and non-invasively. Thermodilution assessment of cardiac parameters was performed as per accepted techniques; a mean of three measurements at each level of PEEP was reported. Data acquired by the bioimpedance device was exported to a Microsoft Excel Spreadsheet for determination of hemodynamic variables by averaging values obtained in the last 120 seconds prior to changing PEEP; each individual measurement generated by TEB represents an average of 5 heart cycles. For hemodynamic variables, the percentage change was calculated using the following formula: measure obtained at a given PEEP, minus baseline value (PEEP = 5 cm H2O), divided by baseline value.Patients undergoing elective cardiac surgery with the anticipated placement of a PAC were eligible to participate. Post-operatively, patients were managed according to current routine practice. Once hemodynamic stability was obtained, baseline hemodynamic parameters  were determined both invasively (using the thermodilution technique via the PAC) and non-invasively (using TEB) while the patient was mechanically ventilated  with a positive end-expiratory pressure (PEEP) of 5 cmH2), and the event lasted for at least 10 seconds. Arousals were scored based on American Sleep Disorders Association criteria [Patients suspected of having severe OSA and scheduled for a split-night (diagnostic to CPAP therapy titration) sleep study were screened for entry. Patients found to meet the criteria for severe OSA (defined as an apnea-hypopnea index of > 30/h)  during tcriteria . ArousalData acquired by the bioimpedance device was exported to a Microsoft Excel Spreadsheet. Obstructive events  were identified using the scored sleep studies. Only those events occurring during Stage 2 (NREM) sleep and in the supine body position were included in the analysis in order to limit confounding variables. Matched time-periods corresponding to each obstructive event was located in the bioimpedance data. The values for HR, SV, and CO, as obtained every 5 heart cycles from the bioimpedance device, during each obstructive period were averaged. Each obstructive event was matched with a corresponding period of equivalent duration, also occurring in Stage 2 (NREM) sleep and in the supine body position, when there were no obstructive events or flow limitations, both prior to CPAP administration and at an optimal pressure where obstructive events were absent. Matched periods were chosen on the basis that there was at least 10 seconds separating the last obstructive period from the selected time-matched obstruction-free period. Average HR, SV and CO during these time-matched periods were calculated.2O) as the baseline value. After 3 - 5 minutes of lying still, and after steady state of hemodynamic parameters was attained, CPAP was initiated at a pressure of 4 cmH2O. In 2 - 3 minute intervals, the CPAP pressure was increased in 2 cmH2O increments to the maximal tolerated pressure of each subject . The pressure was then decreased back to 4 cmH2O, and in the subsequent 2 - 3 minute interval, CPAP was terminated.Healthy individuals with no history of cardiac or respiratory disease, no OSA, and no significant chronic medical conditions were recruited. Subjects were studied while awake, during the daytime, to evaluate the acute effects of CPAP therapy. They were fitted with a full-face CPAP mask and were studied during recumbency with the head of the bed raised to 25 degrees. The bioimpedance electrodes were attached and the recording was started initially with no CPAP pressure  undergoing cardiac surgery (coronary artery bypass grafting) had a mean age of 64 (range 57 - 74) with either preserved (grade I) or mildly impaired (grade II) left-ventricular function as assessed intraoperatively with transesophageal echocardiography. 2O to 18 cmH2O) as measured by both PAC and TEB. Compared to baseline (PEEP 5 cmH2O), there was a significant reduction in SV and CI with increasing PEEP returning to baseline levels when the PEEP was subsequently decreased back to the baseline (5 cmH2O). HR remained unaltered by changing PEEP.2 were studied. The participants had a mean respiratory disturbance index of 57.9 ± 39.4/hr. Data from 88 obstructive hypopneas of an average of 23.3 ± 7.6 seconds in duration  were compiled from three patients in the supine position with a CPAP pressure of 0 cmH2O. Data from 30 individual time periods of an average of 28.4 ± 7.4 seconds in duration  were compiled from two of these same patients in the supine position at the same CPAP pressure when no apneas occurred. One patient was excluded because there were no periods of sufficient duration during which no apneas occurred when CPAP pressure was 0 cmH2O . Fifty-eight individual time periods of an average of 23.3 ± 6.7 seconds in duration  were compiled from all three patients once CPAP had been titrated to an optimal pressure at which apneas were eliminated in the supine position .Three patients with severe OSA  aged mean 53.3 ± 20.8 years with BMI of 36.3 ± 7.6 kg/m2O, range 5 - 9 cmH2O) reduced HR significantly from 71.8 ± 7.1 min-1 to 60.9 ± 5.2 min-1 (P < 0.0001); SV from 93.5 ± 4.8 mL to 83.1 ± 6.9 mL (P < 0.0001), CO from 6.7 ± 0.4 L/min to 5.1 ± 0.6 L/min (P < 0.0001) and CI from 2.9 ± 0.1 L/min/m2 to 2.3 ± 0.3 L/min/m2 (P < 0.0001) compared to without CPAP but in the absence of apneas.The results are presented in 2) are presented in 2O), at the maximal tolerated CPAP pressure  and at the minimal CPAP pressure achieved prior to termination of bioimpedance recordings  are shown.Data for normal, healthy subjects  and a trend towards a reduction in CO  at maximal CPAP pressures. On decreasing CPAP from the maximal tolerated pressure to the minimal pressure achieved prior to termination of bioimpedance recordings, both SV and CO returned to baseline values.This study used a non-invasive bioimpedance device to assess the acute hemodynamic changes during positive airway pressure titration in post-operative cardiac surgery patients with PACs, patients with severe OSA, and normal healthy subjects. To our knowledge, this study represents the first reported use of electrical bioimpedance in assessing hemodynamic variables in patients undergoing positive airway pressure titration.We found that the administration of acute positive airway pressure consistently leads to a decrease in CO and SV across the three groups investigated. The effect was also found to be directly proportional to the amount of CPAP delivered. These findings are similar to those reported using echocardiography. For example, a recent study by Johnson et al  using ecIt has been suggested that acute CPAP therapy increases intrathoracic pressure and may therefore decrease systemic venous return. At higher levels of positive airway pressure, it has also been postulated that pulmonary vascular resistance may increase, which in turn would increase right ventricular afterload; at extremes this may translate into reduced right ventricular performance with subsequent reduction in left ventricular preload and SV -31. In l-1) as part of routine post-operative care, so this may have obscured the ability to detect changes in HR with PEEP titration. Importantly, however, since the heart rate did not change (since the patients were paced) during application of positive end-expiratory pressure, any observed reduction in cardiac output with PEEP must have resulted from a reduction in stroke volume.Interestingly, in our study, the observed reduction in CO seemed to be largely a consequence of a reduction in SV, which was observed across all patient populations. In patients with severe OSA, administration of CPAP titrated to optimal pressure to eliminate obstructive apneas was associated with a reduction in HR as compared to stage- and position-matched control epochs without CPAP. Similar to our results, acute administration of CPAP therapy during sleep to patients with concurrent moderate-to-severe OSA and congestive heart failure resulted in a reduction in HR with CPAP . FurtherBy investigating the hemodynamic changes that occur with positive pressure titration in post-operative CABG patients using both TEB and PAC, it was possible to examine agreement and reproducibility of these two devices. Pulmonary artery catheterization is generally considered to be the clinical gold standard for CO monitoring, but this invasive method is not without complications and, thus, its use has declined over the past several years . This stThese findings offer a better understanding of the acute effects of CPAP therapy on the cardiovascular system, yet the mechanisms by which CPAP therapy improves cardiovascular outcomes are still unclear. Further studies are warranted to better define the impact of CPAP therapy on hemodynamic parameters, both acutely and chronically. Meanwhile, our study suggests that TEB may be equally efficacious in assessing acute changes in hemodynamic parameters as PACs, and the non-invasive nature of this device renders it a very attractive alternative to conduct further studies in this field.


The aim of this study was to evaluate the association between arterial stiffness and albuminuria and glomerular filtration rate (GFR) in patients with type 2 diabetes mellitus. 2 versus ≥60 mL/min/1.73 m2).  This multicenter cohort study analyzed 2613 patients with type 2 diabetes. Brachial-ankle pulse wave velocity (baPWV) was used as a noninvasive marker of arterial stiffness. Additionally, the patients were categorized into four groups according to their albumin-to-creatinine ratio  and estimated GFR  and eGFR . A multivariate analysis adjusted for significant clinical variables and eGFR showed that baPWV remained significantly correlated with the ACR . Also, baPWV was correlated positively with the ACR in patients with an eGFR ≥ 60 mL/min/1.73 m2 . However, baPWV was not correlated with eGFR after adjustment for significant clinical variables.  A univariate analysis revealed that maximal baPWV was significantly associated with both the ACR ( The present findings indicate that arterial stiffness is more associated with albuminuria than a decrease in GFR in patients with type 2 diabetes mellitus. Diabetic nephropathy is one of the most serious microvascular complications that influence the mortality of diabetic patients . It is eμg/min)  + 14.4014) divided by the pulse wave time interval between the brachial region and ankle (ΔT) while the participants were kept supine for 5 minutes [–1.154 × (age in years)–0.203 [All data were collected from the medical records and physical examinations of the patients. Laboratory data obtained within the 3 months prior to enrollment were collected from available sources, and blood samples intended for biochemical analyses were collected after the participants fasted for at least 8 hours. Using an automatic waveform analyzer , baPWV was measured automatically by the brachial-ankle distance ( minutes . The rigs)–0.203 ; an adju2 versus ≥60 mL/min/1.73 m2).Of the 3058 patients enrolled in the REBOUND study, 445 were excluded from the analysis due to a violation of the inclusion and/or exclusion criteria or because there were no available data for baPWV, eGFR, or ACR. In the present subanalysis, the data of 2613 patients were analyzed. The patients were categorized into four groups according to the ACR  and eGFR (<60 mL/min/1.73 mχ2) test was applied to analyze categorical variables. Pearson's correlation coefficient test was used to assess the relationship between two variables. Multivariate regression analyses using either ACR or eGFR as the dependent variable and baPWV as the independent variable were conducted, and several models were used to adjust for confounding variables. A two-tailed P value < 0.05 was considered to indicate statistical significance for all statistical tests.The statistical package SPSS version 15.0  was used for all data analyses. The data are presented as means ± standard deviations (SD) for normally distributed variables and as medians (interquartile ranges) for nonparametric variables. The distribution of the continuous variables was examined for skewness and kurtosis, and the logarithm-transformed values were used for the analysis. Differences among groups were analyzed by analysis of variance (ANOVA) followed by a Bonferroni's test for parametric values and the Kruskal-Wallis test for nonparametric values. Pearson's chi-squared , and informed consent was obtained from all patients for which identifying information is included in this article.2, the average waist circumference was 88.8 ± 8.7 cm, the average glycated hemoglobin (HbA1c) level was 7.6 ± 1.6% (59.8 ± 18.0 mmol/mol), and the prevalence rates of albuminuria and CKD of stage 3 or greater were 31.2% and 18.3%, respectively. The patients were categorized into four groups according to albuminuria status and eGFR: those with an eGFR ≥ 60 mL/min/1.73 m2 and normoalbuminuria (n = 1575), those with an eGFR < 60 mL/min/1.73 m2 and normoalbuminuria (n = 223), those with an eGFR ≥ 60 mL/min/1.73 m2 and albuminuria , and those with an eGFR < 60 mL/min/1.73 m2 and albuminuria (n = 256).The demographic characteristics of the patients are shown in 2 than in patients with an eGFR ≥ 60 mL/min/1.73 m2. Among the albuminuric patients, there were no differences in BMI, waist circumference, DBP, heart rate, HbA1c, LDL cholesterol, triglyceride, and ABI levels according to eGFR between the two groups. However, the M-baPWV was higher in patients with an eGFR < 60 mL/min/1.73 m2 than in patients with an eGFR ≥ 60 mL/min/1.73 m2. Among both normoalbuminuric and albuminuric patients, CVD was more prevalent in patients with an eGFR < 60 mL/min/1.73 m2 than in patients with an eGFR ≥ 60 mL/min/1.73 m2 , heart rate, low-density lipoprotein (LDL) cholesterol level, and the ABI significantly differed between the two groups according to the eGFR . The M-b/1.73 m2 . Additiohttps://doi.org/10.1155/2017/7047909. After adjusting for age, sex, and significant clinical variables such as BMI, duration of diabetes, SBP, pulse pressure, heart rate, smoking, alcohol consumption, HbA1c, HDL cholesterol, hsCRP, insulin treatment, and RAS inhibitors, baPWV was significantly correlated with the ACR . When the patients were stratified by eGFR, baPWV was positively correlated with the ACR in the final model after adjusting for several clinical variables and eGFR in patients with an eGFR ≥ 60 mL/min/1.73 m2  and <60 mL/min/1.73 m2 .A univariate regression analysis of the entire population revealed that baPWV was significantly associated with the ACR model 1;  and eGFRHowever, the significant association of baPWV with eGFR among all patients was lost after adjusting for clinical variables  and that this relationship is enhanced in subjects with hypertension, diabetes, or macroalbuminuria . SimilarThe mechanisms underlying the relationship between a greater degree of arterial stiffness and heightened albuminuria or a decreased GFR in diabetic patients have not been established. As arterial stiffness increases, the myocardium and kidneys are exposed to higher systolic pressures and greater pressure fluctuations resulting in myocardial hypertrophy and fibrosis, renal microvascular damage, and an increased risk of renal dysfunction . The comOne strength of the present study was the use of a large population-based cohort that included 2613 patients from eight general hospitals. Furthermore, arterial stiffness was evaluated by baPWV, which may be more applicable in general practice because its measurement is automated and easier to perform compared to that of cfPWV . HoweverIn conclusion, the present findings demonstrated that, compared with a decrease in the GFR, arterial stiffness was more associated with albuminuria in patients with type 2 diabetes mellitus. The effect of arterial stiffening on albuminuria or a decreased GFR needs to be analyzed in future large longitudinal studies.Supplementary Table 1. Comparison of clinical characteristics according to M-baPWV quartiles. Supplementary Table 2. Multivariate regression analyses with eGFR as a dependent variable and baPWV as an independent variable.


Since the first publication of the Surviving Sepsis Campaign (SSC) guidelines , a corpuIt is now recommended to infuse at least 30 mL/kg of IV crystalloids within the first 3 h of resuscitation of sepsis-induced hypoperfusion. We are concerned by both the predefined volume and timeframe. First, all septic patients do not exhibit the same degree of hypovolemia. For instance, abdominal sepsis inducing massive internal or external fluid losses is generally not equivalent to community-acquired pneumonia in terms of volume deficit. Deliberate administration of 30 mL/kg of fluids in patients with pneumonia with cardiovascular comorbidities might eventually result in pulmonary edema and hasten the need for mechanical ventilation. Initial fluid resuscitation should be individualized according to several elements, including clinical signs of hypovolemia, body temperature, pulse pressure, age, comorbidities, and sepsis origin. If hypovolemia is assumed to be a major component of hypoperfusion, fluids should be infused as a rapid fluid bolus to increase mean systemic filling pressure, venous return, and stroke volume . The samFrom the last version of the SSC publication , it is u2) as a target for early resuscitation of septic shock [2 as part of standard monitoring. This could lead to a loss of confidence in the value of multimodal perfusion monitoring to assess the adequacy of systemic blood flow in relation to oxygen demand. This is profoundly regrettable since a low ScvO2 generally reveals an inadequate cardiac output and suggests the presence of a hypoperfusion context in case of a persistent hyperlactatemia (“flow-sensitive” hyperlactatemia) [After several recent negative trials testing the use of central venous oxygen saturation  .2, central venous-arterial PCO2 gradient (P(cv-a)CO2), and peripheral (skin) perfusion markers exhibit a very fast normalization rate in relation to systemic flow optimization, whereas blood lactate shows a biphasic response with an initial rapid improvement in parallel with the above-mentioned variables, followed by a much slower trend thereafter [2, or high P(cv-a)CO2, or abnormal peripheral perfusion defines a “hypoperfusion context” in which increasing systemic blood flow may contribute to blood lactate decrease. Applying these criteria to septic hyperlactatemic patients in a recent proof-of-concept study clearly differentiated two subpopulations of patients exhibiting markedly different risk of morbidity and mortality [Normalization of lactate is recommended by the SSC as a resuscitation goal since it is assumed that tissue hypoxia is the main source of lactate production. However, there are several unresolved concerns about the role of lactate as an appropriate resuscitation target. First, besides hypoperfusion, adrenergic-driven aerobic lactate production and impaired hepatic lactate clearance have been suggested as important contributors to persistent hyperlactatemia . Since nereafter . Thus, aortality .Important knowledge on the pathophysiology of septic shock has been built up over decades of experimental and clinical research. Translation of these scientific foundations into clinical practice has, however, been slow and erratic. For such a condition with a mortality risk of at least 30–40%, we should expect the rationale of consensus recommendations to be firmly grounded on pathophysiology. Our opinion is that some of the recent SSC’s hemodynamic recommendations move far away from this objective and might not constitute a valuable contribution to improve septic shock morbidity or mortality.


Objective. The possible effect of blood pressure measurements per se on heart rate variability (HRV) was studied in the setting of concomitant ambulatory blood pressure monitoring (ABPM) and Holter ECG monitoring (HM). Methods. In 25 hypertensive patients , 24-hour combined ABPM and HM were performed. For every blood pressure measurement, 2-minute ECG segments  were analyzed to obtain time domain parameters of HRV: SDNN and rMSSD. Mean of normal RR intervals (MNN), SDNN/MNN, and rMSSD/MNN were calculated, too. Parameter variations related to blood pressure measurements were analyzed using one-way ANOVA with multiple comparisons. Results. 2281 measurements (1518 during the day and 763 during the night) were included in the analysis. Both SDNN and SDNN/MNN had a constant  and significant change related to blood pressure measurements: an increase during measurements and a decrease after them (p < 0.01 for any variation). Conclusion. In the setting of combined ABPM and HM, the blood pressure measurement itself produces an increase in short-term heart rate variability. Clarifying the physiological basis and the possible clinical value of this phenomenon needs further studies. Ambulatory blood pressure monitoring (ABPM) coupled with Holter ECG monitoring (HM) is more and more used in clinical practice, mainly in hypertensive patients, for diagnosing arrhythmias and ischemic events and for establishing their relationship with blood pressure variations . On the HRV has a clinically important significance: decreased HRV is an established negative prognostic marker in many cardiac and noncardiac conditions –10. AlsoIn the context presented above, we proposed to examine the interaction of HRV with blood pressure measurement itself, a phenomenon which was not studied before in the Holter literature. We considered that finding a significant interaction could be of interest both methodologically and clinically.As a part of routine exploration, 25 ambulatory hypertensive patients  underwent 24-hour combined ABPM and HM for diagnosing possible arrhythmic events related to blood pressure variations. All subjects gave written informed consent, and the study was approved by the local Ethical Committee, according to the International Ethical Guidelines and Declaration of Helsinki.Blood pressure measurements were set at 15 minutes during the whole 24-hour monitoring. For every blood pressure measurement, 2-minute ECG segments  were analyzed to obtain time domain parameters of HRV: SDNN  and rMSSD . MNN , SDNN/MNN, and rMSSD/MNN  were extracted, too. HRV parameters were calculated using standard formulas . SDNN reThe measurements were performed using the card(X)plore combined 24-hour blood pressure monitor  with 600 Hz, 12-bit sampling characteristics. First, the moments of blood pressure measurements were identified (start points) on the Holter recording. Then, after manual editing and corrections, the RR series data of the 2-minute segments were exported to Matlab R2015a software for HRV calculations and statistical analysis. The 2-minute interval was chosen because of the duration of blood pressure measurement (cuff inflation and deflation).All 2-minute ECG segments with ectopic beats and/or artifacts affecting 10% of the recording were excluded from analysis.(1)before), during (SDNNduring), and after (SDNNafter) the measurement.For each blood pressure measurement, we computed the SDNN parameter value within the 2-minute intervals occurring before (SDNN(2)We defined the temporary stationarity index (TSI) as(3)Blood pressure measurements having TSI > 1.5 were excluded from the analysis due to the temporary nonstationary behavior of the ECG signal.Blood pressure measurements occurring during nonstationary ECG signal segments were detected according to the following protocol:p < 0.05).The variations of HRV parameters related to blood pressure measurements  were analyzed using one-way ANOVA with multiple comparisons  were included in the analysis. p values resulting by applying ANOVA are presented graphically in The behaviors of parameters related to blood pressure measurements  and the corresponding Combined devices of ABPM with HM are popular nowadays, mainly for assessing blood pressure related changes of heart rate , not only in hypertensive patients. HRV, a measure of cardiac autonomic balance, is analyzed routinely by these devices . AccuratStudying the possible impact of blood pressure measurements per se on short-term HRV, we found a significant increase of total variability, reflected by SDNN, during the blood pressure measurements. This effect was not related to the change in heart rate and was not associated with the increase of the more vagally mediated, beat-to-beat based rMSSD. However, an important vagal influence in the determination of SDNN in the case of short-term recordings is well known –4. The pOur finding could have a clinical relevance from many points of view: (1) existence of a significant influence on the values of SDNN calculated from short-term segments of Holter recordings, especially in the case of noncontinuous blood pressure measurement triggered ECG recordings and (2) the possible application of the phenomenon in improving risk stratification. To clarify the latter aspect, a study is needed on the characteristics of patients who show/do not show this behavior of HRV. The lack of the increase in HRV during blood pressure measurement could serve as a new criterion for risk stratification, reflecting an impaired baroreflex control. It could also be of clinical interest to examine the relationship of the observed phenomenon with the measured individual blood pressure values and with diverse characteristics of the 24-hour blood pressure profile.During combined (ABPM + HM) monitoring, blood pressure measurements per se induce a perturbation of HRV, provoking increase of global variability during measurements. This phenomenon could have methodological and clinical implications when evaluating patients undergoing this kind of monitoring. However, clarification of the physiological background and the possible clinical value of this phenomenon needs further studies.


The study aimed to evaluate the clinical utility of ultrasonographic intra-renal blood flow parameters, together with the wide range of different risk factors, for the prediction of contrast-induced acute kidney injury (CI-AKI) in patients with preserved renal function, referred for coronary angiography or percutaneous coronary interventions (CA/PCI). This prospective study covered 95 consecutive patients  subject to elective or urgent CA/PCI. Data regarding 128 peri-procedural variables were collected. Ultrasonographic intra-renal blood flow parameters, including renal resistive index (RRI) and pulsatility index (RPI), were acquired directly before the procedure. CI-AKI was defined as ≥50% relative or ≥0.3 mg/dL absolute increase of serum creatinine 48 h after procedure. CI-AKI was confirmed in nine patients (9.5%). Patients with CI-AKI had higher SYNTAX score (p = 0.0002), higher rate of left main disease (p < 0.00001), peripheral artery disease , coronary artery anomaly (p = 0.017), more frequently underwent surgical revascularization (p = 0.0003), ‘had greater...’ intima-(p = 0.004) and extra-medial thickness (p = 0.001), and received higher contrast media dose (p = 0.049), more often overused non-steroidal anti-inflammatory drugs (p = 0.001), and had substantially higher pre-procedural RRI  and RPI values . Logistic regression confirmed age, SYNTAX score, presence of PAD, diabetes mellitus, and pre-procedural RRI independently predicted CI-AKI onset . Pre-procedural RRI > 0.69 had 78% sensitivity and 81% specificity in CI-AKI prediction. High pre-procedural RRI seems to be a useful novel risk factor for CI-AKI in patients with preserved renal function. Coronary, peripheral and renal vascular pathology contribute to the development of CI-AKI following CA/PCI. Ubiquitous application of contrast media (CM) confers a major risk of contrast induced-acute kidney injury (CI-AKI). The rate of this frequently overlooked complication varies from 2.5 to 13.1% of coronary angiographies and percutaneous coronary interventions (CA/PCI) . Given tWe thus hypothesized that RRI, after adjustment for its covariates, could serve as an indicator of baseline renal vascular resistance and contribute to CI-AKI risk stratification in patients devoid of preexisting kidney pathology. Accordingly, the purpose of the study was to evaluate the clinical significance of preoperative ultrasonographic parameters of intra-renal blood flow, along with numerous pre- and intra-operative risk factors, for the prediction of CI-AKI in patients with coronary artery disease (CAD) and preserved renal function, referred for elective and urgent coronary angiography.This research represents a prospective observational study, which involved 95 consecutive patients with either stable angina (SA) or non-ST-elevation acute coronary syndrome (NSTE-ACS). All patients were hospitalized in the department of cardiology between 2013 and 2015 and referred for planned or urgent CA/PCI. Patients were enrolled for the study during the initial check-up at hospital, prior to the procedure. The study was conducted in adherence to Declaration of Helsinki Guidelines and was approved by the local Ethics Committee. On admission all patients gave their written informed consent to participation in the research.Inclusion criteria comprised: (a) stable angina with high pre-test probability of CAD or SA with positive treadmill electrocardiographic stress test or echocardiographic dobutamine test; or (b) non-ST-elevation acute coronary syndrome that met diagnostic criteria as established in ESC NSTE-ACS 2011 guidelines.2 or proteinuria >500 mg/L; (e) active urinary tract infection; (f) evidence of renal artery stenosis or hydronephrosis (g) moderate to severe aortic valve stenosis; (h) severe valvular heart disease of any kind; (i) high pulse pressure >80 mmHg; (j) tachycardia >100 bpm or bradycardia <50 bpm; (k) severe obesity ; (l) active neoplastic disease; (m) liver dysfunction (any hepatic aminotransferase >3× upper reference limit); (n) intolerance of statin or history of rhabdomyolysis or myositis or (o) age <18 or >80 years old.Exclusion criteria were as follows: (a) significant hemodynamic instability  <90 mmHg or acute decrease by 40 mmHg or catecholamine use dependence); (b) acute or chronic respiratory failure (blood oxygen saturation <90%); (c) severe heart failure with left ventricular ejection fraction (LVEF) <35%; (d) chronic kidney disease with eGFR < 50 mL/min/1.73 mThe primary endpoint was the onset of CI-AKI defined according to Acute Kidney Injury Network criteria, namely ≥50% relative or ≥0.3 mg/dL absolute increase of serum creatinine concentration (SCr) at 48 h after procedure . Data reBlood samples were collected from antecubital or radial vein at admission, 24 and 48 h following CA. Baseline standard laboratory panel, including serum creatinine concentration (SCr) was evaluated at admission, while 24-h and 48-h blood samples were assayed only for SCr.Ultrasonographic indices of intra-renal blood flow in arcuate/interlobular arteries were assessed directly before and 1 h after the procedure. The renal Doppler ultrasound was performed by one experienced physician using Vivid 7  with a 5C probe (4.4–6.7 MHz) designed for high-frequency vascular applications within abdominal cavity. The study was performed on patients in supine position, after 10 min of rest and prior blood pressure measurement. Initially, length and width of renal artery was determined and main renal artery stenosis was excluded by means of peak systolic and end-diastolic flow velocity calculation.Subsequently, ultrasonographic parameters of renal blood flow in arcuate/interlobular arteries, located on the border of renal cortex and core were evaluated using a 2–4 mm pulse-wave Doppler gate. Intra-renal blood flow velocity was assessed using the smallest scale allowing for precise measurements without the aliasing phenomenon (pulse repetition frequency), but with the highest possible gain and the lowest possible value of wall motion filter. The Doppler intra-renal blood flow parameters comprised peak systolic (PSV) and end-diastolic velocity (EDV), augmentation index (AI), acceleration time (AT), and further derivatives, including renal resistive index (RRI) and pulsatility index (RPI). RRI was defined as RRI = (PSV − EDV)/PSV, while RPI was defined as: RPI = (PSV − EDV)/MV, where MV stands for mean flow velocity. Renal to abdominal aorta flow velocity ratio (RAR) was calculated as the ratio of arithmetic mean of PSV in main renal arteries and PSV in abdominal aorta. The measurements were performed three times for each kidney during pre-procedural evaluation on different intra-renal arteries . The final result represented an arithmetic mean of three blood flow scans of right and left kidney . The intra-observer variability was 96% for RRI and 91% for RPI. The duration of the bilateral renal Doppler ultrasound was approximately 5–10 min.Echocardiographic check-up was conducted using Vivid 7  with a 2.5-MHz probe by a single investigator. Subsequently, carotid scans were performed using a Logic 7, GE ultrasound machine with a 7–12-MHz linear array transducer and then analyzed using quantitative analysis package (Siemens) characterized by an axial resolution of 0.001 mm.All the study participants received standard prophylaxis of CI-AKI. Only low-osmolar and iso-osmolar CM at the lowest possible dose was used in all study participants. CA and PCI were performed by five different experienced interventional cardiologists. All the patients with moderately impaired kidney function (eGFR 50–60 mL/min) received an IV infusion of 0.9% saline at a rate of 1 mL/kg/h starting from 12 h before to 24 after CA. Patients with eGFR > 60 mL/min only obtained a single infusion of 500 mL 0.9% saline prior to procedure.HTN was diagnosed if blood pressure exceeded 140/90 mmHg on two separate measurements during index hospitalization or in the event of former HTN diagnosis or antihypertensive medication use. Diabetes mellitus /impaired fasting glucose/impaired glucose tolerance were analyzed jointly. DM was diagnosed if fasting blood glucose was >125 mg/dL on two separate days or if patients received insulin or oral hypoglycemic agents. Non-steroidal anti-inflammatory drugs (NSAID) use was defined >1 dose/per week use of NSAIDs. The pre-procedural risk of CI-AKI development was additionally estimated based on Mehran et al. risk score [The coronary anatomy and morphology of coronary lesions were assessed by an experienced interventional cardiologist. The SYNTAX score was calculated using widely accessible online calculator.t test for unpaired samples was used, while Mann–Whitney U test was implemented in non-normally distributed parameters. Qualitative variables were compared using the Pearson’s Chi square test. Initially all CI-AKI predictor variables were evaluated in univariate analysis and odds ratios (OR) with 95% confidence interval (CI) were calculated. All the variables with p < 0.1 in univariate model were incorporated into the logistic regression analysis model. The area under (AUC) receiver operating characteristic (ROC) curve for the model was calculated. Optimum cut-off point of pre-procedural renal blood flow parameters were established using Youden’s J statistic estimation. In order to determine the relationship between variables, the Pearson’s and Spearman coefficient of correlation were calculated. A ‘p’ value of less than 0.05 was regarded as statistically significant.Statistical analysis was performed using MedCalc v.14.8.1 software . Quantitative variables were presented as the mean value ± standard deviation (SD) or median (boundaries of 25 and 75 percentile) and qualitative parameters were expressed as number and percentage. The type of distribution was verified using Shapiro–Wilk test. In case of normally-distributed variables, Student’s The study involved 95 consecutive patients referred for elective or urgent coronary angiography. Demographic and clinical characteristics are highlighted in Table Following coronary angiography, 44.2% (n = 42) of patients were referred for direct PCI, while 14.7% (n = 14) required elective or urgent coronary artery bypass grafting (CABG). Operators predominantly used femoral access, while radial approach was chosen only in 18.8% of cases (n = 18). The median duration of the procedure was 36 min. . Drug-eluting stents were used exclusively in all study participants qualified for PCI. No patients required intra-aortic balloon pump use during the peri- and post-procedural period. Transient period of intra-procedural hypotension occurred in five patients (5.3%). Fractional flow reserve and intravascular ultrasound were utilized in only one patient respectively (1.1%).During the procedure merely low-osmolar  or iso-osmolar CM  were utilized. The median volume of administered CM was 100 mL . The volume of CM to weight ratio was equal to 1.27 mL/kg , and the volume adjusted to creatinine clearance was 1.47 .The CI-AKI defined by AKI Network criteria occurred in nine patients (9.5%). The median SCr at 24 h after CA/PCI was 0.96  mg/dL, while at 48 h SCr amounted to 1.01  mg/dL. Seven patients suffered from mild stage 1 AKI, defined by relative 1.5-2-fold SCr increase, whereas two subjects exhibited more severe AKI at stage 2 with 2-3-fold relative SCr increase. None of the study participants required dialysis therapy. Local vascular complications were reported in 11 patients (11.6%). No deaths occurred during the index hospitalization.Data regarding inter-group differences of qualitative and quantitative parameters are denoted in Tables The results of the univariate analysis are presented in Table The ROC curve analysis revealed that pre-procedural RRI had high predictive power for CI-AKI prediction . The threshold value of RRI > 0.69, associated with the calculated Youden’s J statistic, had sensitivity of 78%, specificity of 81%, positive likelihood ratio of 4.18 95% CI 2.4–7.3), negative likelihood ratio of 0.27 (95% CI 0.08–0.9) for CI-AKI prediction . Only 17 patients were characterized by eGFR between 50 and 60 mL/min/1.73 m2. Interestingly, these participants had baseline RRI values comparable with the rest of population (p = 0.67), suggesting that RRI is rather an indicator of susceptibility to AKI and contrast-mediated renal injury than a marker of impaired kidney function [The final predictive model was characterized by a very good diagnostic power for CI-AKI prediction Fig. . The maifunction .The results of logistic regression analysis allowed for the identification of patients, who could benefit the most from the pre-procedural screening with renal Doppler ultrasound. Analysis of RRI yields best results in terms of CI-AKI assessment in elderly patients with advanced peripheral and coronary atherosclerosis and presence of DM type 2. Based on the results of the study RRI assessment cannot be routinely recommended, yet it is worth consideration in subjects fraught with cardiovascular risk factors, in order to select individuals requiring more intensive peri-procedural hydration regimen with forced diuresis (furosemide preceded by volume expansion) , the cesThe main limitation of the study is the imperfection of the renal Doppler ultrasonography itself, as patients with morbid obesity, extreme parameters of pulse pressure and heart rate and renal pathology had to be excluded from the study. Since this method is characterized by rather low repeatability, the RRI and RPI could have varied depending on the current view angle or patient’s position. Nevertheless, we have made an effort to overcome this shortcoming by way of using an arithmetic mean of serial measurements in two kidneys. During both pre- and post-procedural examination patients remained in supine position, as the majority of the patients were confined to this position following CA via femoral access. The ideal method should employ the measurement of resistive index by an invasive Doppler flow wire , which rIn the broader perspective, the results of the study underscore the importance of coronary, peripheral and renal vascular pathology in the development of CI-AKI in patients without preexisting renal pathology who are referred for coronary angiography. Pre-procedural evaluation of RRI is a relatively plain diagnostic tool, which independently contributes to risk stratification of CI-AKI.


We developed a technique for measuring patient limb occlusion pressure (LOP) through a tourniquet cuff that overcomes many limitations of existing LOP measurement techniques. The purpose of the study is to determine whether the LOP measured by the proposed technique is statistically or clinically different from that measured by the gold standard Doppler ultrasound technique. The study used randomized crossover multicenter trials. 143 pre- and post-surgical patients with a mean age of 54 years (range 17–86 years) were enrolled in the study. Pneumatic cuffs were applied to the non-operative upper and lower limbs and LOP was measured using the proposed technique and the Doppler ultrasound technique. From a total of 252 usable measurements for each technique (134 for upper limbs and 118 for lower limbs), the mean difference in LOP between the two techniques was 1 ± 8 mmHg for the upper limbs, 0 ± 15 mmHg for the lower limbs, and 1 ± 12 mmHg overall. The differences between the proposed technique and the Doppler technique were neither statistically nor clinically significant. The simplicity, effectiveness, and accuracy of the proposed technique should lead to broader clinical usage and acceptance of LOP measurement, thus leading to safer, personalized pressures in surgical tourniquet applications. Advances in pneumatic tourniquet technology over the last 35 years have significantly improved the safety, efficacy, and reliability of tourniquet instruments and cuffs. However, tourniquet-related nerve injury is a potentially harmful complication of tourniquet use. Nerve injuries from tourniquet use range from a mild transient loss of function to permanent, irreversible damage . Ochoa eSpecific advances in tourniquet technology have reduced the risk of nerve-related injury in recent years. These advances include the design of tourniquet cuffs with lower pressure gradients, and the use of Limb Occlusion Pressure (LOP) to set optimal personalized tourniquet pressure, rather than setting standard tourniquet inflation pressures, which are typically higher and more hazardous. LOP is defined as the minimum pressure required, at a specific time in a specific type of tourniquet cuff applied to a specific patient’s limb at a specific location, to stop the flow of arterial blood into the limb distal to the cuff . HoweverAn automatic technique for measuring LOP was developed in the present study in an effort to overcome these limitations. It uses a tourniquet cuff with a continuous pneumatic passageway surrounding the limb as a dual-purpose patient sensor and pneumatic effector. This circumvents the need for a distal sensor, a limiting factor in prior adoption of LOP measurement. If this technique is shown to have accuracy comparable to that of the current gold standard technique of LOP measurement , its accThe purpose of this study is to determine whether the LOP measured by the proposed technique is statistically or clinically different from that measured by the gold standard Doppler technique  using a The experiment was conducted in three surgical centers in Vancouver, British Columbia, namely the Cambie Surgery Centre, the Complex Joint Clinic at Vancouver General Hospital, and the Foot and Ankle Clinic, St. Paul’s Hospital. Recruitment and data collection commenced in September 2014 and finished in December 2014. Participants were recruited either by a mailed letter sent to them prior to their clinic visit, or during their clinic visit, where they were asked to participate by an assigned research assistant or clinic staff. All participants gave their informed consent prior to their inclusion in the study.The study enrolled 143 pre- and post-surgical patients aged 17–86 years  in three surgical clinics located in Vancouver, British Columbia, Canada: Cambie Surgery Centre (80 patients); Complex Joint Clinic, Vancouver General Hospital 52 patients); Foot and Ankle Clinic, St. Paul’s Hospital (11 patients). Table  patientsThe proposed technique for measuring LOP involves the use of unique dual-purpose disposable tourniquet cuffs along with a tourniquet instrument containing LOP calculation sensors and software. The tourniquet cuffs surround and conform closely to a range of underlying limb shapes, and have a stiffened two-layer design that incorporates a continuous pneumatic passageway that completely surrounds the underlying limb after application. These cuffs can be used for LOP measurement or as a tourniquet to safely stop arterial blood flow during a surgical procedure. The cuffs are described in US Patent 8425,551.The instrument connected to the tourniquet cuff increases the cuff pressure in 10-mmHg stepwise increments, analyzes the pneumatic pressure pulsations induced in the cuff bladder by the arterial pressure pulsations at each cuff pressure increment, and uses these characteristics to determine LOP. Figure Each patient was asked to lie on a clinic bed and an appropriately sized dual-purpose tourniquet cuff with an underlying matching limb protection sleeve was applied to the non-surgical upper arm and non-surgical thigh, in sequence, by an experimenter. The upper and lower limb tourniquet cuffs were not inflated at the same time. A standard blood pressure cuff was applied to the other arm.The patient was instructed to inform the experimenter if the cuff pressure became uncomfortable and measurements were discontinued if a patient requested the cuff to be deflated prior to completion of the measurement.The patient’s blood pressure was taken at the start and end of the measurement sequence. LOP measurements were taken on the non-operative upper and lower limbs. On each limb, one LOP measurement was taken using the proposed technique  and one measurement was taken using the Doppler technique (gold standard/control). The limit for maximum applied tourniquet pressure was 340 mmHg and measurements were taken in randomized order , with randomization determined using a computerized random number generator.For upper-limb measurements using the Doppler technique, one experimenter positioned the Doppler probe at the radial artery in the wrist to monitor arterial flow distal to the tourniquet. For lower-limb measurements, this experimenter positioned the Doppler probe at either the dorsalis pedis artery or the posterior tibial artery on the foot to monitor arterial flow distal to the tourniquet. Once the first experimenter had positioned the Doppler probe and heard a clear distal pulse, a second experimenter continuously inflated the tourniquet cuff using the manual pressure regulator up to the pressure at which the first experimenter verbally indicated that he could no longer hear the distal pulse. This pressure was recorded by the second experimenter as the estimated LOP. The first experimenter was blinded to the cuff pressure during both types of measurement. Both experimenters took turns operating the Doppler probe to reduce experimenter-based measurement bias.For the proposed technique, the instrument increased the cuff pressure in 10-mmHg stepwise increments, analyzed the pneumatic pressure pulsations induced in the cuff bladder by the arterial pressure pulsations at each cuff pressure increment, and used characteristics of the pulsations as the cuff pressure was incremented to determine LOP. The LOP measured by the proposed technique was recorded by the second experimenter to ensure that the first experimenter (operating the Doppler probe) was blinded to this measurement.In both techniques, the cuff was immediately deflated after LOP was determined. Measurements discontinued due to patient-specific factors or due to a data collection error were excluded from the analysis. The reasons for exclusion were documented and are listed in Table t test. Statistical significance was defined as a p-value of less than 0.05.The variable studied was the LOP measured, in mmHg, using the Doppler technique and proposed automatic technique. To determine the accuracy of the proposed technique of LOP measurement  compared to that of the Doppler technique (gold standard/control), data were analyzed for differences between each pair of LOP measurements. The mean of the LOP differences for each limb were calculated, as well as the ranges, SDs, standard errors, and 95 % confidence intervals of the means. Differences in measurements were compared using a paired The distribution of the differences was plotted using a histogram and a Bland–Altman plot . The BlaAn initial sample size of 100 patients was defined after examining the sample sizes of two similar studies (both used 20 patients) . We decip values, ranges, means, SDs, standard errors, and 95 % confidence intervals of the means of the LOP differences between the proposed technique and the Doppler technique are presented in Table From the 143 patients enrolled in the study, usable data were collected from 252 limbs (134 upper limbs and 118 lower limbs). Data collection continued beyond the sample size limit because data collection and patient consent were both scheduled ahead of time in two surgical clinics (Complex Join Clinic and Foot and Ankle Clinic). Data collection stopped after the scheduled clinic days were completed. Table In one LOP measurement using the proposed technique, significant fluctuations in pressure pulsation data indicative of pneumatic noise were observed, indicating a future need for better signal filtering and automatic noise detection and reduction. This patient’s data were included in the statistical analysis.p values were greater than 0.05 for all of the paired t-tests, showing that there is no statistically significant difference between the two measurement methods. The SD of the lower-limb LOP difference was higher than that of the upper-limb LOP difference (15 mmHg). This SD is not clinically significant. An absolute LOP difference of greater than two SDs for the lower-limb mean LOP difference was defined as an outlier measurement (>30 mmHg). Three lower-limb LOP measurements using the proposed technique had LOP differences of greater than 30 mmHg and were classified as outliers. There were no outliers in the upper-limb measurements.The means and SDs listed in Table In further analysis of the three outliers, a predictable difference was identified in the sets of pulsation characteristics at corresponding cuff pressure increments when compared to those for non-outlier data. This difference could form the basis for adding rules to the algorithm of the proposed LOP measurement technique, allowing automatic identification of outlier subject data prior to the completion of LOP measurements, and thus allowing the surgeon to over-ride the proposed tourniquet protocol and revert to a Doppler LOP measurement if desired.Table Of the 34 measurement pairs excluded from the analysis for reasons listed in Table Tourniquet-related nerve injury is a potentially harmful complication of tourniquet use with injuries ranging from a mild transient loss of function to permanent, irreversible damage. Evidence shows that higher tourniquet pressures are associated with higher probabilities of injury . AdvanceOur study has some limitations. As in all studies of this nature, the size of the study population is necessarily small compared to the overall patient population. Another limitation was the inability to repeat measurements to verify the repeatability of measurements. The clinical settings in which the study was conducted prevented repeated LOP measurements on patients due to time constraints and potential patient discomfort and anxiety. The narrow 95 % confidence interval of the difference and small standard error of the mean show that these limitations do not jeopardize our conclusions.The LOP measured using the proposed technique is not clinically nor statistically different from that measured using the gold standard (Doppler ultrasound).Several studies have investigated the measurement of LOP for determining personalized tourniquet pressure levels and reducing applied tourniquet pressures and pressure gradients. Graham et al.  describeThe study by McEwen et al.  comparinThese initial results demonstrate that the proposed technique of LOP measurement has surgically acceptable accuracy that is comparable to that of Doppler ultrasound, and that the proposed technique is feasible for incorporation into improved personalized tourniquet systems. The accuracy is comparable to that of the distal-sensor-based automatic method of LOP measurement, as determined by McEwen et al. . FurtherThe results of this study can be used to develop personalized tourniquet systems consisting of unique dual-purpose cuffs connected to instruments suitable for measuring tourniquet LOP with the proposed measurement technique. The simplicity, effectiveness, and accuracy of this technique should lead to broader clinical usage and acceptance of LOP measurement, thus leading to safer, personalized pressures in surgical tourniquet applications.