Dataset Information

Aortic Aging in ESRD: Structural, Hemodynamic, and Mortality Implications.

ABSTRACT: Aging incurs aortic stiffening and dilation, but these changes are less pronounced in peripheral arteries, resulting in stiffness and geometry gradients influencing progression of the forward and reflected pressure waves. Because premature arterial aging is observed in ESRD, we determined the respective roles of stiffness and aortic geometry gradients in 73 controls and 156 patients on hemodialysis. We measured aortic pulse wave velocity (PWV) and brachial PWV to evaluate the stiffness gradient [(brachial PWV/aortic PWV)(0.5)] and ascending aortic and aortic bifurcation diameters to assess aortic taper (ascending aortic diameter/aortic bifurcation diameter). The global reflection coefficient was estimated from characteristic impedance and vascular resistance. Cox proportional hazard models were used to determine mortality risk. The age-associated increase in aortic PWV was higher in patients (P<0.001). In controls, aortic ascending and bifurcation diameters increased with age, with an unchanged aortic taper. In patients on hemodialysis, age did not associate with increased ascending aortic diameter but did associate with increased aortic bifurcation diameter and decreased aortic taper, both of which also associated with abdominal aortic calcifications and smaller global reflection coefficient (P<0.001). In patients, multivariate models revealed all-cause and cardiovascular mortality associated with age, aortic PWV, and aortic bifurcation diameter with high specificity and sensitivity. Using stiffness gradient, aortic taper, or global reflection coefficient in the model produced similar results. Thus, whereas aortic stiffness is a known independent predictor of mortality, these results indicate the importance of also evaluating the aortic geometry in patients on hemodialysis.

SUBMITTER: London GM

PROVIDER: S-EPMC4884119 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature

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Aortic Aging in ESRD: Structural, Hemodynamic, and Mortality Implications.

London Gérard M GM Safar Michel E ME Pannier Bruno B

Journal of the American Society of Nephrology : JASN 20151016 6

Aging incurs aortic stiffening and dilation, but these changes are less pronounced in peripheral arteries, resulting in stiffness and geometry gradients influencing progression of the forward and reflected pressure waves. Because premature arterial aging is observed in ESRD, we determined the respective roles of stiffness and aortic geometry gradients in 73 controls and 156 patients on hemodialysis. We measured aortic pulse wave velocity (PWV) and brachial PWV to evaluate the stiffness gradient ...[more]

PMID: 26475595

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Project description:BackgroundSerum bicarbonate or total carbon dioxide (CO2) concentrations decline as chronic kidney disease (CKD) progresses and rise after dialysis initiation. While metabolic acidosis accelerates the progression of CKD and is associated with higher mortality among patients with end stage renal disease (ESRD), there are scarce data on the association of CO2 concentrations before ESRD transition with post-ESRD mortality.MethodsA historical cohort from the Transition of Care in CKD (TC-CKD) study includes 85,505 veterans who transitioned to ESRD from October 1, 2007, through March 31, 2014. After 1,958 patients without follow-up data, 3 patients with missing date of birth, and 50,889 patients without CO2 6 months prior to ESRD transition were excluded, the study population includes 32,655 patients. Associations between CO2 concentrations averaged over the last 6 months and its rate of decline during the 12 months prior to ESRD transition and post-ESRD all-cause, cardiovascular (CV), and non-CV mortality were examined by using hierarchical adjustment with Cox regression models.ResultsThe cohort was on average 68 ± 11 years old and included 29% Black veterans. Baseline concentrations of CO2 were 23 ± 4 mEq/L, and median (interquartile range) change in CO2 were -1.8 [-3.4, -0.2] mEq/L/year. High (≥28 mEq/L) and low (<18 mEq/L) CO2 concentrations showed higher adjusted mortality risk while there was no clear trend in the middle range. Consistent associations were observed irrespective of sodium bicarbonate use. There was also a U-shaped association between the change in CO2 and all-cause, CV, and non-CV mortality with the lowest risk approximately at -2.0 and 0.0 mEq/L/year among sodium bicarbonate nonusers and users, respectively, and the highest mortality was among patients with decline in CO2 >4 mEq/L/year.ConclusionBoth high and low pre-ESRD CO2 levels (≥28 and <18 mEq/L) during 6 months prior to dialysis transition and rate of CO2 decline >4 mEq/L/year during 1 year before dialysis initiation were associated with greater post-ESRD all-cause, CV, and non-CV mortality. Further studies are needed to determine the optimal management of CO2 in patients with advanced CKD stages transitioning to ESRD.

Project description:BACKGROUND:Recent studies suggest that potassium levels may differ by race. The basis for these differences and whether associations between potassium levels and adverse outcomes differ by race are unknown. STUDY DESIGN:Observational study. SETTING & PARTICIPANTS:Associations between race and potassium level and the interaction of race and potassium level with outcomes were investigated in the Racial and Cardiovascular Risk Anomalies in Chronic Kidney Disease (RCAV) Study, a cohort of US veterans (N=2,662,462). Associations between African ancestry and potassium level were investigated in African Americans in the Atherosclerosis Risk in Communities (ARIC) Study (N=3,450). PREDICTORS:Race (African American vs non-African American and percent African ancestry) for cross-sectional analysis; serum potassium level for longitudinal analysis. OUTCOMES:Potassium level for cross-sectional analysis; mortality and end-stage renal disease for longitudinal analysis. RESULTS:The RCAV cohort was 18% African American (N=470,985). Potassium levels on average were 0.162mmol/L lower in African Americans compared with non-African Americans, with differences persisting after adjustment for demographics, comorbid conditions, and potassium-altering medication use. In the ARIC Study, higher African ancestry was related to lower potassium levels (-0.027mmol/L per each 10% African ancestry). In both race groups, higher and lower potassium levels were associated with mortality. Compared to potassium level of 4.2mmol/L, mortality risk associated with lower potassium levels was lower in African Americans versus non-African Americans, whereas mortality risk associated with higher levels was slightly greater. Risk relationships between potassium and end-stage renal disease were weaker, with no difference by race. LIMITATIONS:No data for potassium intake. CONCLUSIONS:African Americans had slightly lower serum potassium levels than non-African Americans. Consistent associations between potassium levels and percent African ancestry may suggest a genetic component to these differences. Higher and lower serum potassium levels were associated with mortality in both racial groups.

Project description:BackgroundVascular calcification is common among patients undergoing dialysis and is associated with mortality. Factors such as osteoprotegerin (OPG), osteopontin (OPN), bone morphogenic protein-7 (BMP-7), and fetuin-A are involved in vascular calcification.Design, setting, participants, & measurementsOPG, OPN, BMP-7, and fetuin-A were measured in blood samples from 602 incident dialysis patients recruited from United States dialysis centers between 1995 and 1998 as part of the Choices for Healthy Outcomes In Caring for ESRD Study. Their association with all-cause and cardiovascular mortality were assessed using Cox proportional hazards models adjusted for demographic characteristics, comorbidity, serum phosphate, and calcium. An interaction with diabetes was tested because of its known association with vascular calcification. Predictive accuracy of selected biomarkers was explored by C-statistics in nested models with training and validation subcohorts.ResultsHigher OPG and lower fetuin-A levels were associated with higher mortality over up to 13 years of follow-up (median, 3.4 years). The adjusted hazard ratios (HR) for highest versus lowest tertile were 1.49 (95% confidence interval [95% CI], 1.08 to 2.06) for OPG and 0.69 (95% CI, 0.52 to 0.92) for fetuin-A. In stratified models, the highest tertile of OPG was associated with higher mortality among patients without diabetes (HR, 2.42; 95% CI, 1.35 to 4.34), but not patients with diabetes (HR, 1.26; 95% CI, 0.82 to 1.93; P for interaction=0.001). In terms of cardiovascular mortality, higher fetuin-A was associated with lower risk (HR, 0.85 per 0.1 g/L: 95% CI, 0.75 to 0.96). In patients without diabetes, higher OPG was associated with greater risk (HR for highest versus lowest tertile, 2.91; 95% CI, 1.06 to 7.99), but not in patients with diabetes or overall. OPN and BMP-7 were not independently associated with outcomes overall. The addition of OPG and fetuin-A did not significantly improve predictive accuracy of mortality.ConclusionsOPG and fetuin-A may be risk factors for all-cause and cardiovascular mortality in patients undergoing dialysis, but do not improve risk prediction.

Dataset Information

Aortic Aging in ESRD: Structural, Hemodynamic, and Mortality Implications.

Publications

Aortic Aging in ESRD: Structural, Hemodynamic, and Mortality Implications.

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