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

INTRODUCTION Radiation-induced carotid artery stenosis (RICS) is a well-described phenomenon seen after head and neck cancer radiation. Previously published literature suggests that compared to 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 56472 patients had undergone carotid revascularization (CEA, n=48307; TCAR, n=4593; CAS, n=3572), 1244 patients with prior radiation and 54925 patients without prior radiation. Prior radiation group was more likely to be male (71.9% vs. 60.3%, P<0.01), to receive a stent (47.5% vs. 13.5%, P<0.01), and to be on P2Y12 inhibitor (55.2% vs. 38.3%, P<0.01). 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 (Table I). The prior radiation group had higher rates of cranial nerve injury (3.7% vs. 1.8%, p = 0.04) and 90-day readmission (23.5% vs. 18.3%, p = 0.01) after CEA. For long-term outcomes, prior radiation significantly increased mortality risk for CEA and CAS (HR 1.77, CI [1.38 – 2.27] and 1.56, CI [1.02 – 2.36], respectively). The 3-year risk of stroke for CEA in radiated patients was also significantly higher (HR 1.47, CI [1.03 – 2.09]) compared to 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. CONCLUSION 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.