Pressor response to saralasin (1-sar-8-ala-angiotensin II) bolus injection in hypertensive patients.

Abstract

SUMMARY A 10 mg bolus of the angiotensin blocker saralasin was injected 113 times in 68 subjects with essential or renovascular hypertension. Ninety percent of injections caused a transient increase in blood pressure, which correlated with plasma renin activity (PRA) (r = -0.54). Mean increase at 2 minutes was 21/13.4 mm Hg (P < 0.001) and was independent of pre-injection control blood pressure, with a rapid decrease to or below control values thereafter.Thirty-seven subjects were studied on successive days before and after furosemide-induced sodium depletion (152 ± 26 mEq [SE] A VASODEPRESSOR RESPONSE to intravenous administration of saralasin (1-sar-8-ala-angiotensin II), a competitive inhibitor of angiotensin II, signifies the presence of renin-mediated hypertension.1-7 We and others have suggested the use of saralasin testing in widespread screening of hypertensive patients.'I Because the usual method of saralasin administration, i.e., continuous, pump-controlled intravenous infusion, is not applicable for outpatient screening of large populations, we studied the effects of a single, rapid bolus injection of the drug." 8 We noted a close correlation of blood pressure responses to a bolus injection as compared to infusion of saralasin in patients with essential and renovascular hypertension, and concluded that the saralasin bolus test has many characteristics of an ideal screening procedure for renin-mediated hypertension.Severe pressor responses following saralasin infusions have been recently reported.9-12 However, there are few data concerning pressor responses to saralasin bolus administration.' Since the bolus technique involves rapid delivery of a relatively large quantity of saralasin to the receptor sites as compared to the various infusion techniques described,9 12 it has been predicted that saralasin bolus testing ". . . will sooner or later, result in a vascular catastrophe".' Accordingly, the present report presents a detailed systematic analysis of the pressor responses to 113 bolus injections in 68 hypertensive patients. Methods SubjectsThe study group consisted of 68 hypertensive patients (44 males and 24 females) who ranged in age from 10 to 62 years (mean age 40.1 years). Sixty-four were Caucasian and four were black. Before entry into the study, all patients were From sodium loss). In the low renin group, sodium depletion did not change PRA or the magnitude of the pressor response to saralasin, but significantly decreased control MAP by 13 mm Hg (P < 0.01). In normal and high renin patients, MAP was unchanged after diuresis, but PRA increased significantly and the pressor response was attenuated. The net effect of sodium depletion was to reduce the pressor response to saralasin in all renin subgroups by 9 to 12 mm Hg.Saralasin bolus injection, unlike infusion, saturates available vascular receptors only briefly, eliminating prolonged pressor responses.taken off antihypertensive medication for two weeks and then subjected to an extensive inpatient work-up designed to diagnose secondary f...