Is an average of routine postdialysis blood pressure a good indicator of blood pressure control and cardiovascular risk?

Abstract

Introduction: Hypertension is associated with left ventricular hypertrophy (LVH), a predictor of cardiovascular mortality in haemodialysis (HD) patients. The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) blood pressure (BP) targets are pre-HD <140/90 mm Hg, post-HD <130/80 mm Hg. This study aims to assess 3-month mean in-unit BP, pre- and post-HD, for correlations with left ventricular mass index (LVMI), a measure of long-term BP control.

Methods: Of 648 HD patients, including those on HD >6 months, 262 had echocardiograms. Those with significant coronary artery disease, reduced ejection fraction or valvular disease were excluded, as were those without appropriate echocardiogram, leaving 100 patients. Data on BP and confounding factors for LVH were collected covering 3 months prior to echocardiogram.

Results: Mean BP pre-HD was 147/77 ± 19/13 mm Hg, and post-HD, 133/71 ± 20/11 mm Hg; <50% of patients achieved NKF targets. Mean LVMI was 203.7 ± 74 g/m(2); 88% of patients had LVH. On univariate analysis, mean pre- and post-HD systolic BP, mean arterial blood pressure (MAP) and post-HD diastolic and pulse pressure correlated with LVMI. On stepwise multiple regression analysis only post-HD MAP correlated with LVMI (p=0.000047, r=0.395).

Conclusions: We conclude that long-term averages of in-unit post-HD BP measurements are useful in assessing BP control and cardiovascular risk, especially in the absence of routine ambulatory or home BP monitoring.