Lower blood flow velocity, higher resistance index, and larger diameter of extracranial carotid arteries are associated with ischemic stroke independently of carotid atherosclerosis and cardiovascular risk factors

Abstract

To investigate the association between diameter and flow velocity of the carotid arteries and ischemic stroke. Peak systolic velocity, end diastolic velocity, Pourcelot resistance index, blood flow volume, luminal diameter, and carotid plaque burden were measured and compared in 240 ischemic stroke (IS) patients without history of stroke, 163 chronic stable IS patients, and 236 nonstroke controls (age, >or=40 years). Data were also compared between stroke subtypes (large artery atherosclerosis, lacunar, cardioembolic, or undetermined origin). Acute as well as chronic stable IS patients had significantly lower flow velocities and flow volume, higher resistance index than nonstroke controls in the common carotid artery (CCA), internal carotid artery and external carotid artery, and larger common carotid artery diameter. The differences were found across all IS subtypes and in stroke patients with as well as without carotid plaque. Comparisons between these subgroups showed significant differences in end diastolic velocity, resistance index, flow velocity, and diameter that were more prominent in the CCA. After adjusting for carotid plaque and cardiovascular risk factors, the associations between the above-mentioned parameter and stroke remained significant. Stroke patients in acute as well as chronic stable phase appeared to have larger CCA diameters, lower carotid flow velocities and volume, and higher resistance index than nonstroke patients independently of extracranial carotid atherosclerosis. These findings need to be confirmed by a prospective study.