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Rates of Intervention for Claudication versus Chronic Limb-Threatening Ischemia in Canada and United States
Ben Li1, Philippe Rizkallah1, Naomi Eisenberg1
1Division of Vascular Surgery, Peter Munk Cardiac Centre & University Health Network, University of Toronto, Toronto, Ontario, Canada.
Insights
Peripheral artery disease (PAD) interventions show geographic variations. The US performs more interventions for claudication, leading to better 1-year amputation-free survival compared to Canada.
Area of Science:
- Vascular surgery
- Health services research
- Comparative effectiveness research
Background:
- Geographic variations in peripheral artery disease (PAD) management persist despite guidelines.
- Significant differences exist in PAD intervention patient characteristics, procedural techniques, and outcomes between Canada and the United States.
Purpose of the Study:
- To assess and compare patient demographics, procedural approaches, and outcomes for PAD interventions in Canada versus the United States.
- To identify factors contributing to variations in PAD management and patient outcomes between the two countries.
Main Methods:
- Utilized the Vascular Quality Initiative (VQI) database for PAD endovascular or surgical bypass interventions from 2010-2019.
- Compared demographic, clinical, and procedural characteristics using t-tests and chi-square tests.
- Analyzed primary outcomes (claudication vs. chronic limb-threatening ischemia [CLTI] interventions) and secondary outcomes (in-hospital mortality, amputation, 1-year amputation-free survival) using regression and Cox proportional hazards models.
Main Results:
- US had a higher proportion of endovascular interventions (75.9% vs. 69.2%) and interventions for claudication (42.3% vs. 35.7%) compared to Canada.
- Perioperative outcomes (in-hospital mortality, limb amputation) were similar between countries after adjustment.
- 1-year amputation-free survival was significantly higher in the US (84.1% vs. 71.0%).
Conclusions:
- Significant variations in PAD management exist between the US and Canada, with a greater focus on claudication in the US.
- Performing interventions for CLTI is strongly associated with adverse 1-year outcomes (amputation or death).
- Future studies should investigate reasons for these differences, and quality improvement projects could standardize evidence-based care.
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.
