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Plasma renin activity in hemodialyzed patients during long-term follow-up
G Kimura1, N Takahashi, Y Kawano
1Division of Nephrology, National Cardiovascular Center, Osaka, Japan.
Insights
Long-term hemodialysis patients showed increased plasma renin activity (PRA) and decreased mean arterial pressure (MAP). Higher baseline PRA correlated with greater MAP reduction, suggesting continued renin secretion despite kidney dysfunction.
Area of Science:
- Nephrology
- Endocrinology
- Cardiovascular Physiology
Background:
- Chronic kidney disease (CKD) often involves dysregulation of the renin-angiotensin-aldosterone system (RAAS).
- Maintenance hemodialysis (MHD) is a life-sustaining treatment for end-stage renal disease (ESRD).
- The long-term effects of MHD on PRA and MAP require further investigation.
Purpose of the Study:
- To investigate the long-term changes in plasma renin activity (PRA) and mean arterial pressure (MAP) in patients undergoing maintenance hemodialysis.
- To explore the relationship between baseline PRA and the subsequent changes in PRA and MAP during long-term MHD.
Main Methods:
- Prospective study involving 11 patients on MHD for 8-10 years.
- Measurement of PRA and MAP at baseline and during follow-up.
- Statistical analysis including correlation studies.
Main Results:
- Significant increase in PRA from 2.3 +/- 0.5 to 6.5 +/- 1.3 ng/mL/h during MHD.
- Significant reduction in MAP during follow-up, with a strong correlation (r = 0.88, P < 0.001) between PRA increase and MAP reduction.
- Negative correlation between pre-hemodialysis PRA and PRA increase (r = 0.62, P < 0.05).
- Positive correlation between pre-hemodialysis PRA and MAP reduction (r = 0.65, P < 0.05).
- Patients with initially low PRA exhibited elevated PRA and reduced MAP, while those with higher PRA showed reduced PRA and stable MAP.
Conclusions:
- Renin secretion persists even in kidneys with severe excretory dysfunction and disuse atrophy.
- Long-term hemodialysis can lead to significant alterations in the RAAS, characterized by increased PRA and decreased MAP.
- The interplay between baseline PRA and hemodynamic changes highlights the complex regulation of blood pressure in MHD patients.
Abstract:
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.