Abstract 175: Efficacy and Safety of Extra-Cranial Carotid Stent Placement - a Nation-Wide Case-Series Report

Abstract

Background: Carotid angioplasty and stent (CAS) placement has been applied to the patients with internal carotid artery stenosis in the symptomatic and asymptomatic patients with significant carotid atherosclerosis. However, the efficacy and safety of extra-cranial CAS were not fully evaluated. Methods: We analyzed the data from the patients who received CAS in the Taiwan National Health Insurance claims database from 2005 to 2008. The incidence of ischemic stroke in the periods after CAS (0-30 days, 31-90 days, 91-180 days, and 181-365 days) was compared with that in the year prior to the procedure as a self-controlled case series approach. A conditional Poisson regression model was applied to estimate the incidence ratio and 95% confidence intervals relative to the patient’s baseline risk. Results: A total of 1193 patients who had 70% stenosis in at least unilateral internal carotid artery underwent CAS. Among them, 93 had experienced ischemic stroke in the year prior to the procedure. In the first 365 days following CAS, 237 incident ischemic events occurred and the incidence ratio was 2.45 (95% CI: 1.95-3.13). There was a significantly increased risk for ischemic stroke in the first 30 days after CAS (incidence ratio: 26.27, 95% CI: 20.68-33.37). However, the incidence ratio of ischemic stroke decreased to 0.50 (95% CI: 0.24-1.03) in 31-90 days, 0.31 (95% CI: 0.08-0.51) in 91-180 days, and 0.20 (95% CI: 0.07-0.39) in 181-365 days. Conclusions: The results of this study have demonstrated that the risk of ischemic stroke was extremely high in the first 30 days after CAS. The protective effect against ischemic stroke gradually developed after the first month. Future work should be focused on exploring the factors that might predispose to peri- and post-procedural stroke in the early phase following CAS.