Carotid Stent Failure as a Predictor for Periprocedural Stroke or Death After Carotid Artery Stenting: A Substudy of the International Carotid Stenting Study (ICSS)

Abstract

Introduction - Compared to carotid endarterectomy (CEA), carotid artery stenting (CAS) has been associated with a higher 30-day stroke rate and increased rate of new postprocedural ischemic brain lesions on magnetic resonance-diffusion weighted imaging (MR-DWI). We assessed whether this periprocedural risk after CAS was related to stent failure within the randomised International Carotid Stenting Study (ICSS). Methods - Patients with recently symptomatic carotid artery stenosis enrolled in ICSS were randomly assigned in a 1:1 ratio to receive CAS or CEA. CAS patients were eligible for the present analysis if a postprocedural computed tomography angiography (CTA) of the treated carotid was available. Two observers independently scored stent failure, defined as presence of any of the following parameters: in-stent lesions (hypo- or hyperattenuating), residual stenosis (>30%, according to NASCET criteria) and stent fracture (by visual assessment). In addition, residual stenosis was scored on completion angiography. The primary outcome measure was the occurrence of any stroke or death within 30 days of treatment. The secondary outcome was the presence of any new ischemic brain lesion on postprocedural MR-DWI. This is a substudy of a registered trial, ISRCTN 25337470. Results - [PRELIMINARY] A total of 92 CAS patients were included. Postprocedural CTA was performed after median 33 (interquartile range 29-35) days. The primary outcome measure occurred in eight patients. No stent fractures occurred. Stent failure was scored as in-stent lesion in 19 [21%] patients, with an occlusion in two. Stent failure was noted in 3 [38%] patients with a stroke, and in 16 [19%] of patients without a stroke (odds ratio [OR] 2.55, 95% confidence interval [CI] 0.55-11.79). One of the stent occlusions resulted in a stroke, the other remained asymptomatic. In-stent lesions were found in two of 11 [18%] patients with a new postprocedural MR-DWI lesion and in six of 37 [16%] patients without a new lesion (OR 1.15, 95% CI 0.20-6.70). Data on residual stenosis on completion angiography will be ready at the time of the ESVS conference. Conclusion - These preliminary data show that stent failure occurred in about one of every five CAS patients. In-stent lesions occurred twice as often in patients who had experienced a 30-day stroke compared to stroke-free patients, although no significance was shown. To allow for definite conclusions, these findings need to be validated in a larger cohort.