Aboubacar Sidibé

Aortic-Brachial Pulse Wave Velocity Ratio: A Blood Pressure-Independent Index of Vascular Aging.

Aortic stiffness, a cardiovascular risk factor, depends on the operating mean arterial pressure (MAP). The impact of aortic stiffness on cardiovascular outcomes is proposed to be mediated by the attenuation or the reversal of the arterial stiffness gradient. We hypothesized that arterial stiffness gradient is less influenced by changes in MAP. We aimed to study the relationship between MAP and aortic stiffness, brachial stiffness, and arterial stiffness gradient. In a cross-sectional study of a dialysis cohort (group A, n=304) and a cohort of hypertensive or kidney transplant recipient with an estimated glomerular filtration rate of >45 mL/min/1.73 m2 (group B, n=114), we assessed aortic and brachial stiffness by measuring carotid–femoral and carotid–radial pulse wave velocities (PWV). We used aortic–brachial PWV ratio as a measure of arterial stiffness gradient. Although there was a positive relationship between MAP and carotid–femoral PWV (R2=0.10 and 0.08; P<0.001 and P=0.003) and MAP and carotid–radial PWV (R2=0.22 and 0.12; P<0.001 and P<0.001), there was no statistically or clinically significant relationship between MAP and aortic–brachial PWV ratio (R2=0.0002 and 0.0001; P=0.8 and P=0.9) in group A and B, respectively. Dialysis status and increasing age increased the slope of the relationship between MAP and cf-PWV. However, we found no modifying factor (age, sex, dialysis status, diabetes mellitus, cardiovascular disease, and class of antihypertensive drugs) that could affect the lack of relationship between MAP and aortic–brachial PWV ratio. In conclusion, these results suggest that aortic–brachial PWV ratio could be considered as a blood pressure–independent measure of vascular aging.Aortic stiffness, a cardiovascular risk factor, depends on the operating mean arterial pressure (MAP). The impact of aortic stiffness on cardiovascular outcomes is proposed to be mediated by the attenuation or the reversal of the arterial stiffness gradient. We hypothesized that arterial stiffness gradient is less influenced by changes in MAP. We aimed to study the relationship between MAP and aortic stiffness, brachial stiffness, and arterial stiffness gradient. In a cross-sectional study of a dialysis cohort (group A, n=304) and a cohort of hypertensive or kidney transplant recipient with an estimated glomerular filtration rate of >45 mL/min/1.73 m2 (group B, n=114), we assessed aortic and brachial stiffness by measuring carotid–femoral and carotid–radial pulse wave velocities (PWV). We used aortic–brachial PWV ratio as a measure of arterial stiffness gradient. Although there was a positive relationship between MAP and carotid–femoral PWV ( R 2=0.10 and 0.08; P <0.001 and P =0.003) and MAP and carotid–radial PWV ( R 2=0.22 and 0.12; P <0.001 and P <0.001), there was no statistically or clinically significant relationship between MAP and aortic–brachial PWV ratio ( R 2=0.0002 and 0.0001; P =0.8 and P =0.9) in group A and B, respectively. Dialysis status and increasing age increased the slope of the relationship between MAP and cf-PWV. However, we found no modifying factor (age, sex, dialysis status, diabetes mellitus, cardiovascular disease, and class of antihypertensive drugs) that could affect the lack of relationship between MAP and aortic–brachial PWV ratio. In conclusion, these results suggest that aortic–brachial PWV ratio could be considered as a blood pressure–independent measure of vascular aging. # Novelty and Significance {#article-title-24}

Levels of Angiopoietin-Like-2 Are Positively Associated With Aortic Stiffness and Mortality After Kidney Transplantation

BACKGROUND Angiopoietin‐like‐2 (ANGPTL2) is a secreted proinflammatory glycoprotein that promotes endothelial dysfunction, atherosclerosis, and cardiovascular disease (CVD). Circulating ANGPTL2 is increased in chronic kidney disease (CKD), where the risk of CVD is amplified. The objectives of the present study were to (i) examine whether kidney transplantation (KTx) reduces ANGPTL2 levels, (ii) identify the determinants of ANGPTL2 after KTx, (iii) study the association of ANGPTL2 with aortic stiffness, and (iv) assess the impact of ANGPTL2 on mortality after KTx. METHODS In 75 patients, serum ANGPTL2 levels were measured at baseline and 3 months after KTx. Aortic stiffness was determined by carotid‐femoral pulse wave velocity, glomerular filtration rate was estimated by CKD‐EPI formula, and serum cytokines and endothlin‐1 levels were determined 3 months after KTx. Survival analysis was performed using Kaplan‐Meier and Cox regression after a median follow‐up of 90 months. RESULTS After 3 months of KTx, ANGPTL2 levels decreased from 71 ng/ml (53‐95) to 11 ng/ml (9‐15) (P < 0.001). In multivariate analysis, age, lower renal function, and endothelin‐1 were independently associated with higher post‐KTx ANGPTL2 levels. ANGPTL2 was positively associated with aortic stiffness after KTx, even when adjusted for mean blood pressure (standardized &bgr; = 0.314; P = 0.008). During follow‐up, 13 deaths occurred. The group of patients with higher post‐KTx ANGPTL2 levels had a hazard ratio for mortality of 3.9 (95% confidence interval: 1.07‐14.4; P = 0.039). CONCLUSION KTx significantly reduced serum ANGPTL2 levels. The positive association between post‐KTx ANGPTL2, aortic stiffness and mortality, suggests that ANGPTL2 may play a biological role in CKD‐related CVD.

Fracture risk in dialysis and kidney transplanted patients: a protocol for systematic review and meta-analysis

BackgroundChronic kidney disease (CKD) is associated with an increased risk of fracture and cardiovascular mortality. The risk of fracture in hemodialysis (HD), peritoneal dialysis (PD), and kidney transplantation (KT) is higher when compared to the general population. However, uncertainties remain about which group has the highest risk of fracture. We aim to identify the risk of fracture and cardiovascular mortality post-fracture in HD compared to PD or KT and in PD compared to KT population.MethodsWe will conduct a systematic review of observational studies and randomized control trials on patients with CKD. Eligible studies will be searched on MEDLINE, Embase, Web of Science, Cochrane Library, and in gray literature. Two independent reviewers will screen all identified references in order to include studies reporting the risk of fracture without a comparator or comparing that risk in HD vs KT, PD vs KT, or HD vs PD. Studies comparing the risk of fracture in a renal replacement therapy group to general population or to non-dialyzed CKD patients will also be included. Data on study settings, population characteristics, intervention, comparator, and outcomes will be extracted. Study data will be summarized and analyzed in RevMan and SAS. Risk of bias in cohort design studies will be assessed with an adapted version of the ROBINS-I tool and by the Cochrane handbook tool for RCTs. The quality of evidence and strengths of recommendations will be evaluated by the Grading of Recommendations Assessment, Development and Evaluations (GRADE) tool. We will pool relative risks with random-effect models and Mantel-Haenszel methods. Subgroup and sensitive analysis are planned according to the intervention and comparator, study design, and type of fracture.DiscussionThis review will provide new pooled data about fracture risk in dialysis and KT patients. Our results should guide the implementation of future preventive strategies targeting patients with the highest fracture risk. A pooled analysis of observational studies could be limited by a probable considerable heterogeneity among these studies.Systematic review registrationPROSPERO CRD42016037526

Reduction of Arterial Stiffness After Kidney Transplantation: A Systematic Review and Meta‐Analysis

Background End‐stage kidney disease is associated with increased arterial stiffness. Although correction of uremia by kidney transplantation (KTx) could improve arterial stiffness, results from clinical studies are unclear partly due to small sample sizes. Method and Results We conducted a systematic review and meta‐analysis of before‐after design studies performed in adult KTx patients with available measures of arterial stiffness parameters (pulse wave velocity [PWV], central pulse pressure [PP], and augmentation index) before and at any time post‐KTx. Mean difference of post‐ and pre‐KTx values of different outcomes were estimated using a random effect model with 95% confidence interval. To deal with repetition of measurement within a study, only 1 period of measurement was considered per study by analysis. Twelve studies were included in meta‐analysis, where a significant decrease of overall PWV by 1.20 m/s (95% CI 0.67‐1.73, I2=72%), central PWV by 1.20 m/s (95% CI 0.16‐2.25, I2=83%), peripheral PWV by 1.17 m/s (95% CI 0.17‐2.17, I2=79%), and brachial‐ankle PWV by 1.21 m/s (95% CI 0.66‐1.75, I2=0%) was observed. Central PP (reported in 4 studies) decreased by 4.75 mm Hg (95% CI 0.78–10.28, I2=50%). Augmentation index (reported in 7 studies) decreased by 10.5% (95% CI 6.9‐14.1, I2=64%). A meta‐regression analysis showed that the timing of assessment post‐KTx was the major source of the residual variance. Conclusions This meta‐analysis suggests a reduction of the overall arterial stiffness in patients with end‐stage kidney disease after KTx.

Fracture Risk in Dialysis and Kidney Transplanted Patients: A Systematic Review: FRACTURE RISK IN DIALYSIS AND KIDNEY TRANSPLANTED PATIENTS

Chronic kidney disease is associated with an increased risk of fracture and cardiovascular mortality. The risk of fracture in hemodialysis (HD), peritoneal dialysis (PD) and kidney transplant (KT) patients is higher when compared with the general population. However, there exists a knowledge gap concerning which group has the highest risk of fracture. We aimed to compare the risk of fracture in HD, PD, and KT populations. We conducted a systematic review of observational studies evaluating the risk of fracture in HD, PD, or KT patients. Eligible studies were searched using MEDLINE, Embase, Web of Science, and Cochrane Library from their inception to January 2016, and in grey literature. Incidences (cumulative and rate) of fracture were described together using the median, according to fracture sites, the data source (administrative database or cohort and clinical registry), and fracture diagnosis method. Prevalence estimates were described separately. We included 47 studies evaluating the risk of fracture in HD, PD, and KT populations. In administrative database studies, incidence of hip fracture in HD (median 11.45 per 1000 person‐years [p‐y]), range: 9.3 to 13.6 was higher than in KT (median 2.6 per 1000 p‐y; range 1.5 to 3.8) or in PD (median 5.2 per 1000 p‐y; range 4.1 to 6.3). In dialysis (HD+PD), three studies reported a higher incidence of hip fracture than in KT. Prevalent vertebral fracture (assessed by X‐rays or questionnaire) reported in HD was in a similar range as that reported in KT. Incidence of overall fracture was similar in HD and KT, from administrative databases studies, but lower in HD compared with KT, from cohorts or clinical registry studies. This systematic review suggests an important difference in fracture risk between HD, PD, and KT population, which vary according to the diagnosis method for fracture identification.

Aortic–Brachial Pulse Wave Velocity RatioNovelty and Significance

Aortic stiffness, a cardiovascular risk factor, depends on the operating mean arterial pressure (MAP). The impact of aortic stiffness on cardiovascular outcomes is proposed to be mediated by the attenuation or the reversal of the arterial stiffness gradient. We hypothesized that arterial stiffness gradient is less influenced by changes in MAP. We aimed to study the relationship between MAP and aortic stiffness, brachial stiffness, and arterial stiffness gradient. In a cross-sectional study of a dialysis cohort (group A, n=304) and a cohort of hypertensive or kidney transplant recipient with an estimated glomerular filtration rate of >45 mL/min/1.73 m2 (group B, n=114), we assessed aortic and brachial stiffness by measuring carotid–femoral and carotid–radial pulse wave velocities (PWV). We used aortic–brachial PWV ratio as a measure of arterial stiffness gradient. Although there was a positive relationship between MAP and carotid–femoral PWV (R2=0.10 and 0.08; P<0.001 and P=0.003) and MAP and carotid–radial PWV (R2=0.22 and 0.12; P<0.001 and P<0.001), there was no statistically or clinically significant relationship between MAP and aortic–brachial PWV ratio (R2=0.0002 and 0.0001; P=0.8 and P=0.9) in group A and B, respectively. Dialysis status and increasing age increased the slope of the relationship between MAP and cf-PWV. However, we found no modifying factor (age, sex, dialysis status, diabetes mellitus, cardiovascular disease, and class of antihypertensive drugs) that could affect the lack of relationship between MAP and aortic–brachial PWV ratio. In conclusion, these results suggest that aortic–brachial PWV ratio could be considered as a blood pressure–independent measure of vascular aging.Aortic stiffness, a cardiovascular risk factor, depends on the operating mean arterial pressure (MAP). The impact of aortic stiffness on cardiovascular outcomes is proposed to be mediated by the attenuation or the reversal of the arterial stiffness gradient. We hypothesized that arterial stiffness gradient is less influenced by changes in MAP. We aimed to study the relationship between MAP and aortic stiffness, brachial stiffness, and arterial stiffness gradient. In a cross-sectional study of a dialysis cohort (group A, n=304) and a cohort of hypertensive or kidney transplant recipient with an estimated glomerular filtration rate of >45 mL/min/1.73 m2 (group B, n=114), we assessed aortic and brachial stiffness by measuring carotid–femoral and carotid–radial pulse wave velocities (PWV). We used aortic–brachial PWV ratio as a measure of arterial stiffness gradient. Although there was a positive relationship between MAP and carotid–femoral PWV ( R 2=0.10 and 0.08; P <0.001 and P =0.003) and MAP and carotid–radial PWV ( R 2=0.22 and 0.12; P <0.001 and P <0.001), there was no statistically or clinically significant relationship between MAP and aortic–brachial PWV ratio ( R 2=0.0002 and 0.0001; P =0.8 and P =0.9) in group A and B, respectively. Dialysis status and increasing age increased the slope of the relationship between MAP and cf-PWV. However, we found no modifying factor (age, sex, dialysis status, diabetes mellitus, cardiovascular disease, and class of antihypertensive drugs) that could affect the lack of relationship between MAP and aortic–brachial PWV ratio. In conclusion, these results suggest that aortic–brachial PWV ratio could be considered as a blood pressure–independent measure of vascular aging. # Novelty and Significance {#article-title-24}

Aortic–Brachial Pulse Wave Velocity RatioNovelty and Significance: A Blood Pressure–Independent Index of Vascular Aging

Aortic stiffness, a cardiovascular risk factor, depends on the operating mean arterial pressure (MAP). The impact of aortic stiffness on cardiovascular outcomes is proposed to be mediated by the attenuation or the reversal of the arterial stiffness gradient. We hypothesized that arterial stiffness gradient is less influenced by changes in MAP. We aimed to study the relationship between MAP and aortic stiffness, brachial stiffness, and arterial stiffness gradient. In a cross-sectional study of a dialysis cohort (group A, n=304) and a cohort of hypertensive or kidney transplant recipient with an estimated glomerular filtration rate of >45 mL/min/1.73 m2 (group B, n=114), we assessed aortic and brachial stiffness by measuring carotid–femoral and carotid–radial pulse wave velocities (PWV). We used aortic–brachial PWV ratio as a measure of arterial stiffness gradient. Although there was a positive relationship between MAP and carotid–femoral PWV (R2=0.10 and 0.08; P<0.001 and P=0.003) and MAP and carotid–radial PWV (R2=0.22 and 0.12; P<0.001 and P<0.001), there was no statistically or clinically significant relationship between MAP and aortic–brachial PWV ratio (R2=0.0002 and 0.0001; P=0.8 and P=0.9) in group A and B, respectively. Dialysis status and increasing age increased the slope of the relationship between MAP and cf-PWV. However, we found no modifying factor (age, sex, dialysis status, diabetes mellitus, cardiovascular disease, and class of antihypertensive drugs) that could affect the lack of relationship between MAP and aortic–brachial PWV ratio. In conclusion, these results suggest that aortic–brachial PWV ratio could be considered as a blood pressure–independent measure of vascular aging.Aortic stiffness, a cardiovascular risk factor, depends on the operating mean arterial pressure (MAP). The impact of aortic stiffness on cardiovascular outcomes is proposed to be mediated by the attenuation or the reversal of the arterial stiffness gradient. We hypothesized that arterial stiffness gradient is less influenced by changes in MAP. We aimed to study the relationship between MAP and aortic stiffness, brachial stiffness, and arterial stiffness gradient. In a cross-sectional study of a dialysis cohort (group A, n=304) and a cohort of hypertensive or kidney transplant recipient with an estimated glomerular filtration rate of >45 mL/min/1.73 m2 (group B, n=114), we assessed aortic and brachial stiffness by measuring carotid–femoral and carotid–radial pulse wave velocities (PWV). We used aortic–brachial PWV ratio as a measure of arterial stiffness gradient. Although there was a positive relationship between MAP and carotid–femoral PWV ( R 2=0.10 and 0.08; P <0.001 and P =0.003) and MAP and carotid–radial PWV ( R 2=0.22 and 0.12; P <0.001 and P <0.001), there was no statistically or clinically significant relationship between MAP and aortic–brachial PWV ratio ( R 2=0.0002 and 0.0001; P =0.8 and P =0.9) in group A and B, respectively. Dialysis status and increasing age increased the slope of the relationship between MAP and cf-PWV. However, we found no modifying factor (age, sex, dialysis status, diabetes mellitus, cardiovascular disease, and class of antihypertensive drugs) that could affect the lack of relationship between MAP and aortic–brachial PWV ratio. In conclusion, these results suggest that aortic–brachial PWV ratio could be considered as a blood pressure–independent measure of vascular aging. # Novelty and Significance {#article-title-24}