Renal venous renin activity in various forms of curable renal hypertension

The diagnostic and predictive value of renal venous renin determinations was investigated in 73 patients who had various forms of hypertension associated with unilateral renal disease and who were operated upon. Patients with fibromuscular hyperplasia showed a markedly higher cure rate than cases with arteriosclerotic renal artery stenosis (64% vs. 25%) and were less frequently not improved (4% vs. 12%). Patients with unilateral (non-vascular) small kidney and patients with unilateral hydronephrosis showed comparable high cure rates (53% and 50%, respectively), whereas in no patient with a unilateral renal cyst did postoperative blood pressure return to normal. In the present study no statistically significant correlation was found between postoperative pressure reduction and PRA-ratios in either the whole group of patients or in the various subgroups. A negative PRA-ratio (less than or equal to 1.4) was found in 36% of all cured patients. In particular, cured patients with fibromuscular hyperplasia showed a high percentage (38%) of falsely negative tests. As expected, characteristic differences were observed in simple clinical data between cured and improved patients. Patients with normal postoperative blood pressure were significantly young (34.7 +/- 13.6 years) than improved cases (47.3 +/- 10.8 years; P less than 0.001) and cured patients showed lower preoperative blood pressure values (192 +/- 29/119 +/- 15) than improved ones (214 +/- 31/126 +/-117 mm Hg). Thus our results document a limited prognostic value of renal venous renin determination in patients with hypertension due to unilateral renal disease.