ACUTE BLOCKADE OF THE RENIN SYSTEM AND DIFFERENTIAL RENAL-VEIN RENIN DETERMINATIONS IN THE DIAGNOSIS OF RENOVASCULAR HYPERTENSION

For validation of differential renal vein renin determinations in the diagnosis of renovascular hypertension (RVH), we investigated 102 pati ents suspected of suffering from RVH before and 1 h after administrati on of 25 mg captopril. Sensitivity, specificity and posterior probabil ity for renin ratio (RR) and renin secretion (RS) were calculated base d on 44 patients with proven RVH and 58 patients with primary hyperten sion (PH) using discriminant analysis. There is good (>95%) and identi cal specificity of both variables under all conditions, whereas sensit ivity remains poor even after Captopril administration (RR 23% vs. 32% ; RS 20% vs. 34%). The posterior probabilities obtained by discriminan t analysis revealed a cutoff point of 2.5 for the renin ratio and of 1 .9 for the renin secretion. No change is observed after ACE inhibition . We conclude that the acute blockade of the renin system by captopril in differential renin sampling yields no advantages in diagnosing RVH and that there is no difference between RR and RS in the diagnosis of RVH.