P4.03 SUB-ACUTE EFFECTS OF BLOOD PRESSURE LOWERING WITH AMLODIPINE OR LISINOPRIL ON LOCAL CAROTID ARTERY HAEMODYNAMICS

Abstract

Introduction: Anti-hypertensive agents differ in their ability to slow progression of the increase in carotid artery intima-media thickness (IMT) with disease and have different effects on the lumen diameter (LD) of the carotid artery. We hypothesised that changes in flow and shear stress in the common carotid artery may contribute to these differences in remodelling. Methods: 10 treatment naïve hypertensive subjects were recruited into a double blind, placebo controlled, randomised 3-way cross-over study comparing the effects of 7 days treatment with amlodipine or lisinopril. Brachial and carotid blood pressure (BP), common carotid artery (CCA) flow rate, IMT and LD were measured at the end of each treatment period. Magnetic resonance imaging-based computational fluid dynamics was used to calculate time averaged wall shear stress (WSS) in the carotid artery bifurcation. There were significant reductions in brachial and carotid BP with both active treatments compared to placebo, but brachial and carotid BP did not differ significantly between the antihypertensive agents. CCA flow rate was significantly lower and distal vascular resistance was higher following lisinopril treatment compared with amlodipine. WSS on the inner wall of the CCA was significantly lower after lisinopril treatment compared with amlodipine. Conclusion: Amlodipine causes increased carotid blood flow and increased WSS compared with lisinopril, probably as a result of greater cerebrovascular vasodilatation. These effects could account for differences in arterial remodelling caused by these agents.