Delayed hypotensive response to dialysis in hypertensive patients with end-stage renal disease.

This study was designed to determine the ambulatory arterial blood pressure profile in hypertensive patients with end-stage renal disease during and following hemodialysis. Blood pressure was noninvasively monitored at 15-min intervals for 24 h using a fully automatic portable recorder, while the 10 patients studied followed their customary activities and were not receiving any antihypertensive medications. Prior to dialysis, the blood pressure was 179 +/- 7.0/101 +/- 3.7 mm Hg. After 4 h of dialysis, the systolic blood pressure did not change, while the diastolic blood pressure fell only slightly (178 +/- 4.2/94 +/- 2.4 mm Hg). After dialysis was completed, a progressive fall in both systolic and diastolic blood pressures was observed reaching the lowest value in the 5th h after dialysis (146 +/- 5.5/75 +/- 3.2 mm Hg). Thereafter, the fall in blood pressure was sustained during sleep (147 +/- 1.7/77 +/- 0.9 mm Hg) and during routine daily activities (147 +/- 2.0/78 +/- 1.0 mm Hg). The delayed fall in blood pressure was observed in patients in whom the plasma renin activity was elevated (8.4 +/- 2.4 ng/ml/h) and in patients in whom the plasma renin activity was low or normal (0.9 +/- 0.2 ng/ml/h). Our data suggest that during dialysis vasopressor mechanisms are activated to sustain blood pressure and that following dialysis such mechanisms are attenuated allowing the blood pressure to fall towards normal levels. The delayed fall in blood pressure documented by this study indicates that in many hypertensive patients with end-stage renal disease antihypertensive drug therapy is not required the day after dialysis.