RS07. The Incidence of Carotid In-Stent Stenosis Is Underestimated: Is It 50% or 80% and Its Clinical Implications

Abstract

The incidence of carotid in-stent stenosis has been reported to vary between 1% and 30%. Most published studies have relatively short follow-up periods, which may lead to underestimating the incidence of carotid in-stent stenosis rates. This study analyzed the incidence of 50% and 80% carotid in-stent restenosis using validated duplex velocity criteria and its clinical implications. This retrospective analysis included prospectively collected data from 450 carotid artery stent (CAS) procedures. All patients had postoperative carotid duplex ultrasound examination, which was repeated at 1 month, 6 months, and every 6 to 12 months thereafter. A Kaplan-Meier analysis was used to estimate the freedom rates from 50% in-stent restenosis (internal carotid artery peak systolic velocity of 224 cm/s) and 80% in-stent restenosis (internal carotid artery peak systolic velocity of 325 cm/s) and its clinical implications. The mean age was 68.3 years, with a mean follow-up of 40.3 months. A total of 201 of 450 patients (45%) underwent CAS for symptomatic disease. Primary CAS was done in 291 patients (65%) and the remaining 35% were done for post-CEA stenosis. A total of 101 patients (23%) had 50% late carotid in-stent restenosis, and of these, 33 (7.4%) had 80% in-stent restenosis. 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 restenosis in the whole series were 85%, 79%, 75%, 72%, and 70% at 1, 2, 3, 4, and 5 years, respectively (Fig 1). The rates of freedom from 50% in-stent restenosis for primary CAS and CAS for post-CEA restenosis were not statistically significant (P = .540). The rates of freedom from 80% in-stent restenosis for the whole series were 96%, 95%, 93%, 90%, and 89% at 1, 2, 3, 4, and 5 years, respectively (Fig 2). The rates of freedom from 80% in-stent restenosis for primary CAS and CAS for post-CEA restenosis, were also not significant (P = .516). The rates of freedom from reintervention were 98%, 96%, 93%, 93%, and 91% at 1, 2, 3, 4, and 5 years, respectively, and there were no differences between primary CAS and CAS for post-CEA stenosis (P = .939). The overall late survival rates were 99%, 97%, 96%, 94%, and 91% at 1, 2, 3, 4, and 5 years, respectively. The incidence of 50% in-stent restenosis is relatively high; however, the rates of 80% restenosis and late neurologic events are low.Fig 2Freedom from >80% restenosis.View Large Image Figure ViewerDownload Hi-res image Download (PPT)