The captopril test for identification of renovascular hypertension: value and immediate adverse effects.

To develop a screening test for identification of renovascular hypertension, the blood pressure and plasma renin concentration responses to an oral test dose of captopril (6.25 mg) were studied in 47 hypertensive patients of mean age 61 years (range 34-85 years). Blood pressure was measured at 15-min intervals for 90 min after administration of captopril. Blood samples for plasma renin determination were drawn immediately before and 90 min after drug administration. Eleven patients had renal artery stenosis. The fall in diastolic blood pressure in these patients was greater, on average, than in patients with other forms of hypertension (30 mmHg vs. 14 mmHg, P less than 0.01), as was the increase in plasma renin concentration (188 mU l-1 vs. 2 mU l-1, P less than 0.01). This study demonstrates that the short-term captopril test is useful for distinguishing patients with renovascular disease from those with other forms of hypertension. During the test, 7 patients (15%) exhibited reversible cerebral symptoms. In two of these subjects digital subtraction angiography was performed, which revealed stenosis of the carotid artery. Consequently, it is suggested that captopril should not be used in patients with arteriosclerotic stenoses of the carotids.