Long-term clinical spectrum and circulating RAS evaluation of anephric patients undergoing hemodialysis: A report of four cases and literature review.

INTRODUCTION: Bilateral nephrectomy leads to a short-term reduction in blood pressure. This is mainly due to a sharp change in the circulating renin-angiotensin system (RAS), but data on the long-term outcomes of their clinical status and further changes in circulating RAS are rare.

MATERIALS AND METHODS: We enrolled four Chinese patients who had both of their kidneys removed two (1), six (1) and eight (2) years prior to this study, respectively. Their clinical data were collected retrospectively and circulating RAS was evaluated by radioimmunoassay.

RESULTS: Hypotension after surgery occurred in two patients who suffered thrombosis of the arteriovenous fistula, but no life-threatening complications occurred. The average hemoglobin level was 103.3±12.3 g/l. Two patients without hemorrhage received intravenous erythropoietin (EPO) of 4500-8000 iu/week. Extremely low plasma renin activity (PRA) of 0.08±0.03 ng/ml (normal range 0.93-6.56 ng/ml) showed in the patients. Surprisingly, plasma angiotensin II concentration (71.37±8.28 pg/ml) and aldosterone level (0.17±0.02 ng/mlng/ml) were within the normal range.

CONCLUSIONS: The four anephric individuals did not suffer life-threatening complications while their hypotension gradually subsided and their EPO dosage was relatively low. Although their PRA level was extremely low, they produced normal levels of angiotensin II and aldosterone in plasma, which indicates the kidney-independent mechanism of angiotensin II production likely compensated in the long term.