Saralasin bolus test. Rapid screening procedure for renin-mediated hypertension

The angiotensin-blocking agent, saralasin, was given by rapid intravenous (bolus) injection to 21 hypertensive patients. A marked depressor response (average blood-pressure decrease of 30 mm Hg systolic and 20 mm Hg diastolic at 10 minutes after injection) was noted in 13 patients, of whom 11 had renovascular hypertension and 2 had high-renin essential hypertension. No change from prebolus blood-pressure was apparent at 10 minutes in 8 control patients with essential hypertension and normal or low peripheral plasma-renin activity. In all patients, blood-pressure response to saralasin bolus (10 mg) correlated with blood-pressure response to subsequent infusion of saralasin (10 microgram/kg/min). Blood-pressure response to rapid intravenous injection of saralasin--the "saralasin bolus test"--has many characteristics of an ideal screening procedure for renin-mediated hypertension.