Medical therapy and coronary revascularization for patients with stable coronary artery disease and unclassified appropriateness score

Although the appropriate use criteria incorporate common clinical scenarios for coronary revascularization, a significant proportion of patients with stable coronary artery disease (CAD) cannot be assigned an appropriateness score. Our objective was to characterize these patients and to evaluate whether coronary revascularization is associated with improved outcomes. A population-based cohort of patients 66 years old or older, who underwent cardiac catheterization in Ontario, Canada were included. Clinical characteristics were compared between patients with and without an appropriateness score. Clinical outcomes between coronary revascularization and medical therapy among patients with unclassified appropriateness score were compared using the inverse probability of treatment weighted propensity method for confounder adjustment. Among the 19,228 patients with stable CAD, 11.2% (2,153 patients) were not assigned to an appropriateness score, mostly (92.9%) due to a lack of ischemic evaluation or a non-interpretable test. These patients were older, had higher rate of severe angina and had more medical comorbidities as compared to patients with an appropriateness score. The 2-year rate of death or myocardial infarction among patients with unclassified appropriateness score was 15.3% in the revascularization group vs. 20.7% in the medical therapy group. After propensity weighting, revascularization was associated with significantly lower hazard ratio (0.70; 95% CI 0.61 to 0.79) for death or myocardial infarction compared with medical therapy. In conclusion, in patients 66 years or older with stable CAD and unclassified appropriateness score, revascularization is associated with improved outcomes.