Should We Set a Higher Bar for Coronary Angiography?

Compared with Ontario, obstructive disease is less common in patients who undergo catheterization in New York.

A recent study indicated that more cardiac catheterizations are performed per capita in New York State than in Ontario, Canada). Now, the same investigators have compared the prevalence of obstructive coronary artery disease (CAD) — defined as diameter stenosis ≥50% in the left main or ≥70% in a major epicardial vessel — in patients undergoing the procedure in the two regions.

Obstructive CAD was found in significantly more of approximately 55,000 patients undergoing a first elective cardiac catheterization during 2008–2011 in Ontario than in some 18,000 such patients in New York (45% and 30%, respectively). Compared with the Canadian patients, the New Yorkers were younger and more likely to be women or to have no or atypical symptoms; the prevalence of several other risk factors also differed significantly between the two groups. Fewer patients in New York than in Ontario had noninvasive evaluations (63% vs. 75%, P<0.001), and the predicted preprocedure probability of obstructive CAD was significantly lower in New York.

Among patients with obstructive CAD, those in New York were significantly more likely than those in Ontario to undergo revascularization (percutaneous coronary intervention, 55% vs. 35%; coronary artery bypass grafting, 20% vs. 14%). Higher crude 30-day mortality in New York than in Ontario was mainly attributable to higher mortality in patients without obstructive CAD.


These findings suggest that the relatively high cardiac catheterization rate in New York results primarily from selecting patients at lower predicted probabilities of obstructive coronary artery disease. The investigators could not control for regional differences in patient, societal, and physician characteristics, preferences, and expectations; nor could they assess which catheterization rate is more appropriate. Nonetheless, the higher prevalence of interventionalists and cardiac invasive capabilities — as well as market-oriented financing — in New York seems likely to account for much, if not all, of the disparity; if so, these data illuminate an opportunity to reduce unnecessary healthcare expenditures.

Source: NEJM