Symptom Status of Patients Undergoing Carotid Endarterectomy in Canada and United States

Abstract

Previous studies have demonstrated significant geographic variations in the management of carotid artery stenosis despite standard guidelines. To further characterize these practice variations, we assessed differences in patient selection, operative technique, and outcomes for carotid endarterectomy (CEA) in Canada vs. United States. The Vascular Quality Initiative (VQI) was used to identify all patients who underwent CEA between 2010 and 2019 in Canada and United States. Demographic, clinical, and procedural characteristics were recorded and differences between countries were assessed using independent t-test and chi-square test. The primary outcome was the percentage of CEA performed for asymptomatic versus symptomatic disease. The secondary outcomes were 30-day and long-term stroke or death. Associations between country and outcomes were assessed using univariate/multivariate logistic regression and Cox proportional hazards analysis. During the study period, 131,411 US patients and 701 Canadian patients underwent CEA in VQI sites. Patients from the US were older with more comorbidities including hypertension, diabetes, congestive heart failure, and chronic kidney disease. The use of a shunt, patch, drain, or protamine was less common in the US. Most patients had 70 - 99% stenosis, with no difference between regions. The percentage of CEA performed for asymptomatic disease was significantly higher in the US even after adjusting for demographic, clinical, and procedural characteristics (72.4% vs. 30.7%, adjusted OR 3.91 [95% CI 3.21 - 4.78], p < 0.001). Thirty-day stroke/death was low (1.8% vs. 1.9%) and 1-year stroke/death was similar between groups (HR 0.98 [95% CI 0.69 - 1.39], P=0.89). The similarities in 1-year stroke/death persisted in asymptomatic patients (HR 0.70 [95% CI 0.37 - 1.30], P=0.26) and symptomatic patients (HR 1.14 [95% CI 0.74 - 1.73], P=0.56). There are significant variations in CEA practice between Canada and US. In particular, most US patients are treated for asymptomatic disease, whereas most Canadian patients are treated for symptomatic disease. Furthermore, adjunctive procedures including shunting, patch use, and protamine administration are performed less commonly in the US. Despite these differences, perioperative and 1-year stroke/death rates are similar between countries. Future studies should investigate reasons for these variations and quality improvement projects are needed to standardize care.