Ultrasonographic markers of vascular risk in patients with asymptomatic carotid stenosis

Six-hundred twenty-one subjects with unilateral asymptomatic severe internal carotid artery (ICA) stenosis were prospectively evaluated with a median follow-up of 27 months (min=6, max=68). Vascular risk profile, plaque characteristic, stenosis progression, and common carotid artery intima-media thickness (IMT) were investigated in all patients. Outcome measures were occurrence of ischemic stroke ipsilateral to ICA stenosis and vascular death, while myocardial infarction, contralateral strokes, and transient ischemic attack were considered as competing events. A total of 99 subjects (15.9%) suffered from a vascular event. Among them, 39 were strokes ipsilateral to the stenosis (6.3%). Degree of stenosis, stenosis progression, and common carotid artery IMT resulted as independent predictive factors of ipsilateral stroke. Considering a stenosis of 60% to 70% as reference, a degree between 71% and 90% increased the risk by 2.45, while a degree between 91% and 99% increased the risk by 3.26. The progression of stenosis was a strong risk factor (hazard ratio=4.32). Finally, the role of carotid IMT was confirmed as crucial additional measure, with an increased risk by 25% for each 0.1 mm IMT increase. Our data suggest that IMT, stenosis progression and severity should be considered as risk factors for cerebrovascular events in asymptomatic subjects with severe ICA stenosis.