Pravastatin decreases wall shear stress and blood velocity in the internal carotid artery without affecting flow volume: results from the PROSPER MRI study.

BACKGROUND AND PURPOSE Despite speculations, it is unknown whether statins affect wall shear stress (WSS). Therefore, the effect of pravastatin on WSS was investigated. METHODS In 355 elderly individuals participating in the PROSPER study (follow up after 3 years), the effect of 40 mg pravastatin on WSS was assessed in the internal carotid artery using magnetic resonance imaging. RESULTS WSS and blood velocity decreased both in the pravastatin group and in the placebo group but decreased faster in the pravastatin group (P<0.04, P<0.02). Blood volume flow did not differ between the groups. CONCLUSIONS In elderly subjects, the WSS and blood velocity of the internal carotid artery declines significantly over time and this decline is more pronounced in subjects treated with 40 mg pravastatin compared with the placebo group.