[Prospective evaluation of the captopril test in diagnosing renal artery stenosis in hypertensive patients].

In order to verify the utility of the captopril test (CT) in diagnosing renal artery stenosis we performed a prospective study in 94 consecutive patients (40 females, 54 males, mean age 52.4 +/- 12.3 years) suspected of having renovascular hypertension and with a serum level of creatinine < 2 mg/dl. Antihypertensive drugs were withdrawn one week before the CT or, if this was considered unsafe, patients were treated with nifedipine or diltiazem (53 subjects; 56.4%). We used renal angiography and the Muller criteria to interpret the CT. Our results were as follows: sensitivity, 92%; specificity, 96%; positive predictive value, 88%; and negative predictive value, 97%. In our study a simplified criterion for positive CT-postcaptopril plasma renin activity > 10 ng/mL/h-provided a similar diagnostic value. We conclude that the captopril test is a useful screening test for the detection of renal artery stenosis in selected hypertensive patients and that it can also be reliably performed in patients who are taking calcium antagonists.