Background: Although the appropriateness use criteria for coronary revascularization were constructed to incorporate the most common clinical scenarios, a significant proportion of patients with stable coronary artery disease (CAD) cannot be assigned an appropriateness score. We sought to characterize patients with unclassified appropriateness score, and to evaluate whether coronary revascularization is associated with improved clinical outcomes.
Methods: A population-based cohort of all patients over the age of 66 years who underwent cardiac catheterization in Ontario, Canada was assembled from 2008 to 2011. Appropriateness for coronary revascularization was adjudicated at the time of coronary angiography. Demographic and clinical characteristics were compared between patients with and without an appropriateness score. Clinical outcomes between coronary revascularization and medical therapy without revascularization among patients with missing appropriateness score were compared using inverse probability of treatment weighted propensity method for confounder adjustment.
Results: Among the 19,228 patients with stable CAD, 11.2% (2,153 patients) had an unclassified appropriateness score, mostly (92.9%) due to a lack of ischemic evaluation or a non-interpretable test. Unclassified patients were older, more likely to experience severe angina and had higher number of comorbidities, but were on less medical treatment as compared to patients with an appropriateness score. At 2 years, the rate of death or myocardial infarction was 15.3% in the coronary revascularization group vs. 20.7% in the medical therapy group in the propensity weighted cohort. A significantly lower adjusted hazard ratio of death or myocardial infarction (HR 0.70; 95% CI 0.61 to 0.79) was associated with coronary revascularization compared with medical therapy.
Conclusions: In a population-based cohort of patients with stable CAD and unclassified appropriateness score, coronary revascularization is associated with improved clinical outcomes compared with medical therapy.
