Abstract TP138: The Clinical Features and the Long-Term Outcomes of Carotid Symptomatic Low-Grade Stenosis

Abstract

Background: Ischemic events caused by carotid artery stenosis are affected not only by stenosis but also by the instability of plaque. In symptomatic low-grade stenosis cases medical treatment is generally performed, but there are cases with repeated recurrence. The purpose of this study is to clarify the clinical features and long-term outcomes in cases of symptomatic low-grade stenosis. Methods: We included seventy-one symptomatic patients with carotid low-grade stenosis (<NASCET 50%) who were admitted to our hospital from 2005 to 2016. The relative plaque signal intensity (rSI) with reference to muscle and expansive remodeling rate (ERR) were measured using carotid MRI. Antiplatelet therapy and treatment for atherosclerosis risk factors were administered in all cases. Carotid endarterectomy (CEA) was performed when ischemic symptoms appeared or the stenosis rate progressed despite medical treatment. Results: The mean stenosis rate, rSI and ERR on admission were 20.4, 1.75 and 1.96, respectively. Seventy percent of cases involved intraplaque hemorrhage and positive remodeling. During a mean of 52-months follow-up, a recurrence of ischemic events was confirmed in 33 cases (46%), from which the duration until recurrence was within 7 days (33%), 3 months (18%), 1 year (18%), 2 years (21%), and over 2 years (15%). Nine cases had impending stroke, 3 of which were associated with major artery occlusion. CEA was performed in 28 cases (39%) for impending stroke (25%), recurrence of ischemic events (46%), asymptomatic infarction (7%), and stenosis rate progression (11%). During a mean of 47-months follow-up after CEA, 2 cases of death (fetal intracerebral hemorrhage, asphyxia) and one case of brain stem lacunar infarction were observed, but an ipsilateral ischemic event was not observed. Conclusion: Most of the symptomatic patients with low-grade stenosis had both intraplaque hemorrhage and positive remodeling. The risk of recurrence and stenosis progression was high. CEA might have had a preventive effect against ischemic events in low-grade stenosis.