Faculty Bibliography

OBJECTIVE: Neck radiation therapy (XRT) can induce carotid artery stenosis and may increase the technical difficulty of endarterectomy. It is considered a relative indication for carotid angioplasty and carotid artery stenting (CAS). This study sought to evaluate differences in CAS embolic potential and restenosis performed on XRT and non-XRT patients. METHODS: At three institutions, 366 CAS procedures were performed on 321 patients (XRT, n = 43; non-XRT, n = 323). Mean follow-up was 410 days (median, 282 days; range, 7-1920 days). Patients were observed with duplex ultrasound to assess for restenosis. Additional end points included target lesion revascularization (TLR), myocardial and cerebrovascular events, and perioperative complications. Captured particulate from embolic protection filters was analyzed with photomicroscopy and image analysis software for 27 XRT and 214 non-XRT filters. RESULTS: XRT patients were more likely to be male and had lower rates of hypertension, coronary artery disease, and diabetes mellitus, although the mean age at procedure did not differ. There was no increase in severe internal carotid tortuosity among XRT patients (XRT: 50% vs non-XRT: 34.7%; P = .06). Indication for CAS did not differ between the two groups, including the number of CAS procedures performed for symptomatic carotid stenosis (XRT: 39.7% vs non-XRT: 39.0%; P = NS). Perioperative outcomes, including the composite 30-day stroke, myocardial infarction, and mortality, were not significantly different (XRT: 2.6% vs non-XRT: 3.9%; P = NS.) There were no significant differences in restenosis rate at the 50% (XRT: 9.4% vs non-XRT: 8.6%; P = NS) or 70% (XRT: 3.5% vs non-XRT: 8.6%; P = NS) threshold. Filter particle analysis revealed that filters from XRT patients had more numerous large particles per filter (1.4 vs 0.7; P < .05) and larger mean particle size (464.1 mum vs 320.0 mum; P < .05). TLR did not differ significantly between the groups. CONCLUSIONS: In contrast to earlier studies, this analysis reveals that there are significant differences in XRT and non-XRT patients undergoing CAS in terms of medical comorbidities and embolic material captured in embolic protection filters. The decreased incidence of atherosclerotic risk factors was observed in XRT patients probably because XRT was the primary factor responsible for carotid stenosis. Despite increased embolic particle size, CAS can be performed safely with no increased morbidity, TLR, or restenosis in XRT patients.