Long-term outcomes of carotid artery stenting for radiation-associated stenosis

Background: In Taiwan, the prevalence of head and neck cancer is relatively high. Because radiation-associated carotid stenosis is a significant risk factor for stroke, carotid artery stenting (CAS), instead of carotid endarterectomy, is indicated in patients with radiation-associated carotid stenosis. We sought to evaluate the effect of neck radiotherapy (XRT) on the long-term outcome of patients undergoing CAS. Methods: From March 2001 to November 2011, 147 CAS procedures were performed on 129 patients (n = 43 for XRT, n = 86 for non-XRT). Mean follow-up was 42.7 ± 20.5 months (median: 52 months; range: 1-60 months). Duplex velocity criterion for > 50% restenosis after CAS was defined as peak systolic velocity > 175 cm/s. Endpoints included 5-year freedom from mortality, ipsilateral recurrent stroke, and major adverse cardiovascular events (MACE). Results: The mean age of XRT patients was significantly lesser than that of non-XRT patients (61 ± 8 vs. 71 ± 8, p < 0.001). There was significantly less coronary artery disease and other cardiovascular co-morbidities in XRT patients. No significant differences were noted in the composite 30-day ipsilateral stroke/myocardial infarction/mortality (XRT: 8.6% vs. non-XRT: 6%, p > 0.05) and 5-year freedom from mortality, ipsilateral recurrent stroke, and MACE (p > 0.05) between the two groups. Intra-stent carotid restenosis > 50% was significantly higher in the XRT group on follow-up. Conclusion: Long-term outcomes of CAS for radiation-associated stenosis were not altered by a history of neck XRT, except for asymptomatic carotid restenosis.