Out-of-hemodialysis-unit blood pressure is a superior determinant of left ventricular hypertrophy

Abstract

Blood pressures (BPs) obtained in the dialysis unit correlate poorly with ambulatory BP and left-ventricular hypertrophy (LVH). We compared the performance of BP obtained within and outside the dialysis unit as a correlate of LVH. BP was obtained in the dialysis unit using routine and standardized methods and outside the dialysis unit using home and ambulatory BP monitoring in 140 patients (mean age, 56 years; 89 men; 129 blacks; and 59 with diabetes mellitus) on chronic hemodialysis for > or =3 months. Dialysis unit BP recordings were averaged over 2 weeks, and home BP averaged over 1 week. Ambulatory BP monitoring was performed during an interdialytic interval. Echocardiography was performed immediately after dialysis for the assessment of left-ventricular mass. Left ventricular mass/height(2.7) of >51 g/m2 was taken as evidence of LVH. Test performance of various BPs was compared using receiver operating characteristic curves. Average ambulatory BP was 129.7+/-21.2/73.6+/-13.1 mm Hg, home BP was 139.4+/-21.2/79.0+/-12.5 mm Hg, standardized predialysis BP was 142.1+/-21.7/74.9+/-13.3 mm Hg, postdialysis was 120.9+/-20.8/69.6+/-12.5 mm Hg, routine predialysis was 145.6+/-20.7/79.4+/-13.1 mm Hg, and postdialysis was 132.0+/-19.3/72.6+/-11.1 mm Hg. Left ventricular mass/height(2.7) was 59.1+/-16.5, and 68% had LV hypertrophy. Diastolic BP measured by any technique was not associated with LVH. Routine and standardized measurements of BP were similarly weak correlates of LVH. Systolic BP outside the dialysis unit was a stronger correlate of LVH compared with dialysis unit BP.