Rates of Intervention for Claudication versus Chronic Limb-Threatening Ischemia in Canada and United States

Background: Previous studies have demonstrated important geographic variations in peripheral artery disease (PAD) management despite existing guidelines. We assessed differences in patient characteristics, procedural technique, and outcomes for PAD interventions in Canada versus United States. Methods: The Vascular Quality Initiative (VQI) was used to identify all patients who underwent endovascular intervention or surgical bypass for PAD between 2010 and 2019 in Canada and United States. Independent t-test and chi-square test were performed to assess differences between countries in terms of demographic, clinical, and procedural characteristics. The primary outcome was the percentage of interventions performed for claudication versus chronic limb-threatening ischemia (CLTI). Perioperative outcomes were in-hospital mortality and index limb amputation. The long-term outcome was 1-year amputation-free survival. Univariate/multivariate logistic regression and Cox proportional hazards analysis were performed to investigate associations between region and outcomes. Results: A total of 246,770 US patients and 3,467 Canadian patients underwent revascularization for PAD during the study period. There was a higher proportion of endovascular interventions in the US (75.9% vs. 69.2%, OR 1.41 [95% CI 1.31–1.51], P< 0.001). American patients were younger with more comorbidities, including hypertension, diabetes, and coronary artery disease. The percentage of interventions performed for claudication was significantly higher in the US (42.3% vs. 35.7%, OR 1.31 [95% CI 1.22–1.44], P< 0.001). This persisted after controlling for demographic, clinical, and procedural characteristics (adjusted OR 1.05 [95% CI 1.01–1.10], P = 0.02). Perioperative outcomes were similar between countries after adjustment for baseline differences: in-hospital mortality (adjusted OR 1.07 [95% CI 0.69–1.62], P= 0.75) and index limb amputation (adjusted OR 0.67 [95% CI 0.43–1.07], P= 0.09). However, 1-year amputation-free survival was higher in the US (84.1% vs. 71.0%, HR 1.61 [95% CI 1.47–1.76], P< 0.001). Multivariable Cox proportional hazards analysis demonstrated that the factor most strongly associated with index limb amputation or death at 1-year was intervention for CLTI (HR 1.56 [95% CI 1.54–1.58], P< 0.001). Conclusions: There are significant variations in PAD management between US and Canada. In particular, a higher proportion of interventions are performed for claudication rather than CLTI in the US compared to Canada. This is an important contributor to the higher 1-year amputation-free survival rate in US patients. Reasons for these differences should be assessed by future studies and evidence-based care may be standardized by targeted quality improvement projects.