Title

The incidence of carotid in-stent stenosis is underestimated ≥50% or ≥80% and its clinical implications

Document Type

Article

Publication Date

12-11-2018

Abstract

Background:The incidence of carotid in-stent stenosis has been reported to vary between 1% and 30%. Most publishedstudies have short follow-up, which may lead to underestimation of the incidence of in-stent stenosis. This study analyzedthe incidence of$50% and$80% in-stent stenosis using validated duplex ultrasound criteria and its clinical implications.Methods:This is a retrospective analysis of prospectively collected data of 450 carotid artery stenting (CAS) procedures(February 6, 2001-December 19, 2016). All patients had postoperative carotid duplex ultrasound examination, which wasrepeated at 1 month, 6 months, and every 6 to 12 months thereafter. A Kaplan-Meier analysis was used to estimate rates offreedom from$50% in-stent stenosis (internal carotid artery peak systolic velocity of$224 cm/s) and$80% in-stentstenosis (internal carotid artery peak systolic velocity of$325 cm/s), freedom from reintervention, and survival.Results:The mean age was 68.3 years, with a mean follow-up of 40.3 months. A total of 201 patients (45% [201/450]) hadCAS for symptomatic disease. Primary CAS was done in 291 patients (65%); in the remaining 35%, CAS was done forpostcarotid endarterectomy (CEA) stenosis. A total of 101 patients (23%) had$50% late carotid in-stent stenosis, and ofthese, 33 (7.4%) had$80% in-stent stenosis. Nineteen patients (4.3%) developed late transient ischemic attack and three(0.7%) late stroke. Twenty-three (5.2%) patients had late reintervention. Rates of freedom from$50% in-stent stenosis inthe whole series were 85%, 79%, 75%, 72%, and 70% at 1 year, 2 years, 3 years, 4 years, and 5 years, respectively. The rates offreedom from$50% in-stent stenosis for primary CAS and CAS for post-CEA stenosis were not statistically significant(P¼.540). The rates of freedom from$80% in-stent stenosis for the whole series were 96%, 95%, 93%, 90%, and 89% at1 year, 2 years, 3 years, 4 years, and 5 years, respectively. The rates of freedom from$80% in-stent stenosis for primary CASand CAS for post-CEA stenosis were also not statistically significant (P¼.516). Rates of freedom from reintervention were98%, 96%, 93%, 93%, and 91% at 1 year, 2 years, 3 years, 4 years, and 5 years, respectively, and there were no significantdifferences between primary CAS and CAS for post-CEA stenosis (P¼.939). The overall late survival rates were 99%, 97%,96%, 94%, and 91% at 1 year, 2 years, 3 years, 4 years, and 5 years.Conclusions:The incidence of$50% in-stent stenosis is relatively high; however, the rates of$80% stenosis and lateneurologic events are low. Longer follow-up of patients with$50% carotid in-stent stenosis may yield higher incidence of$80% stenosis. (J Vasc Surg 2019;69:1807-14.)

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