Association of Intradialytic Blood Pressure Variability With Increased All-Cause and Cardiovascular Mortality in Patients Treated With Long-term Hemodialysis

Abstract

Background Blood pressure is known to fluctuate widely during hemodialysis; however, little is known about the association between intradialytic blood pressure variability and outcomes. Study Design Retrospective observational cohort Setting & Participants A random sample of 6,393 adult, thrice-weekly, in-center, maintenance hemodialysis patients dialyzing at 1,026 dialysis units within a single large dialysis organization. Predictor Intradialytic systolic blood pressure (SBP) variability. This was calculated using a mixed linear effects model. Peri-dialytic SBP phenomena were defined as starting SBP (regression intercept), systematic change in SBP over the course of dialysis (2 regression slopes), and random intradialytic SBP variability (absolute regression residual). Outcomes All-cause and cardiovascular mortality. Measurements SBPs (n=631,922) measured during hemodialysis treatments (n=78,961) over the first 30 days in study. Outcome data were obtained from the dialysis unit electronic medical record and were considered beginning on day 31. Results High (ie, greater than the median) versus low SBP variability was associated with a greater risk of all-cause mortality (adjusted HR, 1.26; 95% CI, 1.08–1.47). The association between high SBP variability and cardiovascular mortality was even more potent (adjusted HR, 1.32; 85% CI, 1.01–1.72). A dose response trend was observed across quartiles of SBP variability for both all-cause (p=0.001) and cardiovascular (p=0.04) mortality. Limitations Inclusion of subjects from a single large dialysis organization, over-representation of African Americans and patients with diabetes and heart failure, and lack of standardized SBP measurements. Conclusions Greater intradialytic SBP variability is independently associated with increased all-cause and cardiovascular mortality. Further prospective studies are needed to confirm findings and identify means of reducing SBP variability to facilitate randomized study.

Intradialytic Hypotension and Risk of Cardiovascular Disease

“…Strict BP control, however, is challenging in the ESRD population, and the relationship between IDH and predialysis and postdialysis BP is complex (9,14). One study examined strict control of BP to minimize the risk of hypertension.…”

“…We do know that IDH is related to interdialytic weight gain (IDWG), which has been associated with higher risk of all-cause mortality, CV events, and CV mortality (8,9). Greater IDWG implies the need for more rapid fluid removal because dialysis time is essentially fixed for individual patients.…”

Blood Pressure Variability and Dialysis

“…9 Flythe et al examined BP fluctuations during dialysis (i.e., intradialytic BPV) and reported a link between intradialytic BPV and all-cause and cardiovascular death. 10 In a prior study, the same authors identified older age, shorter dialysis vintage, and greater ultrafiltration (rate and volume) as associated with greater intradialytic BPV. 11 Contrary to findings in the general population, neither Chang et al nor Flythe et al found antihypertensive agents to play a significant role in visit-to-visit or intradialytic BPV-outcome associations among HD patients.…”

“…9 Patients are treated with 1 mg/kg agalsidase-b intravenously every other week or 0.2 mg/kg agalsidase-a every other week; other than the amount of infused protein, there appears to be very little difference between the two products. 10,11 There may be differences in the response to ERT, and it appears that the 5-fold difference in the delivered dose could affect the stabilization of renal function, at least in some patients. 12,13 The issue of effective ERT dosing for Fabry disease was brought into sharp focus by an unfortunate lapse in manufacturing practices that resulted in a worldwide shortage of the Genzyme product (Fabrazyme) between June 2009 and January 2012.…”

e impact of visit-to-visit systolic blood pressure variability on residual renal function and le ventricular hypertrophy in peritoneal dialysis patients

“…Some studies demonstrated that visit-tovisit BP variability was a novel risk factor for stroke (3), cardiovascular events (3), and all-cause mortality in the general population (6). It is reported that visit-to-visit BP variability also predicted cardiovascular events and allcause mortality in patients with chronic kidney disease (7,8) and hemodialysis (5,(9)(10)(11)(12)(13)(14). Note, however, that different dialysis modalities should have different effects on BP due to the intermittent nature of hemodialysis and continuous nature of peritoneal dialysis (PD).…”