The captopril test in the detection of renovascular disease in hypertensive patients.

A number of reports share the conclusion that the captopril test is an adequate screening procedure for the detection of renovascular disease among hypertensive patients. Therefore, we prospectively studied the value of this test in 149 consecutive hypertensive patients. The test was considered positive if plasma renin activity, after an oral dose of 25 mg of captopril, rose by more then 4.44 ng.L-1.s-1 (16.0 ng/mL per hour). The sensitivity of the test was 39%, the specificity was 96%, the positive predictive value was 81%, and the negative predictive value was 79%. No clinically important cutoff point identifying patients with renal artery stenosis could be detected in the values of baseline and stimulated plasma renin activity nor in baseline blood pressure or changes after captopril testing. The low sensitivity makes the captopril test unfit to be used as a screening procedure in an unselected hypertensive population.