Prognosis of the elderly with asymptomatic atherosclerotic plaques of the carotid arteries

Objective To elucidate the prognosis of the elderly with neurologically asymptomatic atheromatous plaques of the carotid arteries. Methods A total of 228 subjects aged 60 years or older, examined by carotid ultrasonography and platelet aggregation test, were studied. They were divided into 3 groups based on plaque morphology: the no lesion group (n=110), the nodular plaque group (n=47), and the mural plaque group (n=71). Platelet aggregability was assessed as suppressed, normal, or accelerated. Results During the 4.0 years of mean follow-up period, 31 subjects died, and 16 of the deaths were due to vascular events such as cerebral infarction or ischemic heart disease. The annual mortality rate due to vascular events was 0.5% in the no lesion group, 1.4% in the nodular plaque group, and 4.1% in the mural plaque group, and Kaplan-Meier survival curve showed poor prognosis of the mural plaque group (logrank statistics: 12.8, Df=2, p=0.0017). According to the Cox proportional hazard model, a high hazard ratio (HR) was seen in the mural plaque group (5.3) and also the accelerated platelet aggregability group (4.0). Conclusion These findings suggested that subjects with mural plaques and accelerated platelet aggregability, even when asymptomatic, have a poor prognosis due to vascular events. Antiplatelet therapy and exercise stress test for detecting coronary artery disease should be considered in these subjects.