Association of Ambulatory Blood Pressure with All-Cause and Cardiovascular Mortality in Hemodialysis Patients: Effects of Heart Failure and Atrial Fibrillation

Abstract

Background Evidence on the utility of ambulatory BP monitoring for risk prediction has been scarce and inconclusive in patients on hemodialysis. In addition, in cardiac diseases such as heart failure and atrial fibrillation (common among patients on hemodialysis), studies have found that parameters such as systolic BP (SBP) and pulse pressure (PP) have inverse or nonlinear (U-shaped) associations with mortality. Methods In total, 344 patients on hemodialysis (105 with atrial fibrillation, heart failure, or both) underwent ambulatory BP monitoring for 24 hours, starting before a dialysis session. The primary end point was allcause mortality; the prespecified secondary end point was cardiovascular mortality. We performed linear and nonlinear Cox regression analyses for risk prediction to determine the associations between BP and study end points. Results During the mean 37.6-month follow-up, 115 patients died (47 from a cardiovascular cause). SBP and PP showed a U-shaped association with all-cause and cardiovascular mortality in the cohort. In linear subgroup analysis, SBP and PP were independent risk predictors and showed a significant inverse relationship to all-cause and cardiovascular mortality in patients with atrial fibrillation or heart failure. In patients without these conditions, these associations were in the opposite direction. SBP and PP were significant independent risk predictors for cardiovascular mortality; PP was a significant independent risk predictor for all-cause mortality. Conclusions This study provides evidence for the U-shaped association between peripheral ambulatory SBP or PP and mortality in patients on hemodialysis. Furthermore, it suggests that underlying cardiac disease can explain the opposite direction of associations.

Comparison of 24-hour and Office Pulse Wave Velocity for Prediction of Mortality in Hemodialysis Patients

“…The continuous net reclassification improvement (NRI) for 3-year, all-cause mortality was calculated to show the added prognostic value of 24 h-PWV over established risk factors (model 4) [36]. To provide comparability to existing literature, additional models were performed for patients without heart insufficiency or atrial fibrillation (including pacemakers) as these comorbidities are known to influence PWV measurement significantly and have often been excluded in studies [11,18,20,26,37]. Cardiovascular mortality was analyzed, despite being restricted evaluable due to small event size.…”

“…Patients with atrial fibrillation and heart failure require special emphasis when analyzing hemodynamic measurements. Most recently, Mayer et al [37] could prove a U-shaped association between peripheral ambulatory systolic BP or pulse pressure and mortality in hemodialysis patients, which can be explained by the underlying patients' cardiac diseases as atrial fibrillation or heart failure. The association of PWV with mortality remained linear and positive for all patients, which can be seen in the KM plots comparing tertiles of PWV ( Fig.…”

Briefly Noted

“…Ambulatory BP monitoring was done before HD in 105 patients with heart failure or atrial fibrillation and 239 without. A significant inverse linear relationship of BP with subsequent mortality was found in the heart disease group (low BP, high mortality) in contrast to the positive linear relationship to mortality in those without the evident heart problems (low BP, low mortality) …”

Blood pressure target for the dialysis patient

“…In a study of 344 hemodialysis patients, 105 patients had either atrial fibrillation or HF, or both. A linear relationship between SBP and mortality was only noted in those without cardiovascular comorbidities …”