Carotid wall thickness and stroke risk in patients with asymptomatic internal carotid stenosis

Aim of this study was to investigate if the risk of stroke and other vascular diseases can be predicted in subjects with severe asymptomatic carotid artery stenosis on the basis of carotid wall thickness evaluation.

We included 162 consecutive subjects with asymptomatic internal carotid artery stenosis of 60% or greater reduction in diameter. Demographic characteristics, vascular risk factors, therapy, degree of carotid stenosis and carotid intima-media thickness (IMT) were detailed for all subjects. Subjects were prospectively evaluated for a median period of 35 months (min=10, max=47). Outcome measures were: the occurrence of ischemic stroke ipsilateral to carotid stenosis and any other vascular event.

Thirty subjects (18.5%) suffered a vascular event: 16 (53%) myocardial infarctions and 14 (47%) strokes. Older age and higher IMT values were the only factors significantly associated with the risk of vascular events. The hazard ratio (adjusted for age, sex and other risk factors) for each 0.1 mm of IMT increase resulted 1.30 (95% CI: 1.14, 1.18) for combined vascular events, 1.47 for cerebrovascular events (95% CI: 1.16, 1.87) and 1.24 (95% CI: 1.09, 1.42) for cardiovascular events. Values of IMT above 1.15 mm increased the risk of having a stroke 19 times and the risk of having a myocardial infarction two times.

An increased carotid wall thickness can be considered as a marker of an increased risk of vascular events in asymptomatic subjects with internal carotid artery stenosis>60%. Highest IMT values are able to identify subjects with specific stroke risk. This information could be of interest to recognize subjects who might benefit most from surgical or revascularization procedures.