Impact of head and neck radiation on long-term outcomes after carotid revascularization

Objective: Radiation-induced carotid artery stenosis (RICS) is a well-described phenomenon seen after head and neck cancer radiation. Previously published literature suggests that, compared with atherosclerotic disease, RICS may result in worse long-term outcomes and early restenosis. This study aims to evaluate the effect of radiation on long-term outcomes after various carotid revascularization techniques using a multi-center registry database. Methods: Patients in the Society for Vascular Surgery (SVS) Vascular Quality Initiative (VQI) registry for carotid artery intervention (carotid endarterectomy [CEA]; transfemoral carotid artery stenting [CAS]; transcarotid artery revascularization [TCAR]), who are 65 years or older were included in the study. VQI Vascular Implant Surveillance and Interventional Outcomes Network (VISION) Medicare-linked database was used to obtain long-term procedure-specific outcomes. Primary endpoints were 3-year death, stroke, and reintervention. We performed propensity matching between patients with prior radiation and those without. Kaplan-Meier analysis and a multivariate logistic regression model were used to analyze the outcome variables. Results: A total of 56,472 patients had undergone carotid revascularization (CEA, n = 48,307; TCAR, n = 4593; CAS, n = 3572), 1244 patients with prior radiation and 54,925 patients without prior radiation. The prior radiation group was more likely to be male (71.9% vs 60.3%; P < .01), to receive a stent (47.5% vs 13.5%; P < .01), and to be on P2Y12 inhibitor (55.2% vs 38.3%; P < .01). Propensity matching was performed on 1223 patients (CEA, n = 655; TCAR, n = 292; CAS, n = 287). There were no significant differences in 30-day outcomes for death, stroke, or major adverse cardiovascular events for all three procedures. The prior radiation group had higher rates of cranial nerve injury (3.7% vs 1.8%; P = .04) and 90-day readmission (23.5% vs 18.3%; P = .01) after CEA. For long-term outcomes, prior radiation significantly increased mortality risk for CEA and CAS (hazard ratio [HR], 1.77; 95% confidence interval [CI], 1.38-2.27 and HR, 1.56; 95% CI, 1.02-2.36, respectively). The 3-year risk of stroke for CEA in radiated patients was also significantly higher (HR, 1.47; 95% CI, 1.03-2.09) compared with non-radiated patients. Prior radiation did not significantly affect death and stroke in patients undergoing TCAR. Prior radiation also did not impact the rates of short and long-term reintervention after CEA, CAS, or TCAR. Conclusions: Prior head and neck radiation significantly increases the risk for mortality and stroke for CEA and the risk for mortality after CAS. Long-term outcomes for TCAR are not significantly affected by prior radiation. TCAR may be the preferred treatment modality for patients with radiation-induced carotid stenosis.