Plasma renin activity in hemodialyzed patients during long-term follow-up.

Plasma renin activity (PRA) and mean arterial pressure (MAP) were determined in 11 patients after the initiation of maintenance hemodialysis for 8 to 10 years. PRA increased significantly from 2.3 +/- 0.5 to 6.5 +/- 1.3 ng/mL/h, whereas MAP was lowered during follow-up, and there was a strong correlation between these two (r = 0.88, P < 0.001). Immediately before initiating hemodialysis, PRA was negatively correlated with the increase in PRA (r = 0.62, P < 0.05) and positively correlated with the reduction in MAP (r = 0.65, P < 0.05). PRA was elevated and MAP was markedly reduced in patients whose PRA was relatively low immediately before initiating hemodialysis, whereas PRA tended to be reduced and MAP was unchanged in patients with higher levels of PRA. These data suggest that renin secretion continues even after disuse atrophy of the kidneys with almost complete deterioration of its excretory function.