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.