Hospital variability in the rate of finding obstructive coronary artery disease at elective, diagnostic coronary angiography

Abstract

Objectives: The purpose of this study was to describe hospital variability in the rate of finding obstructive coronary artery disease (CAD) at elective coronary angiography.

Background: A recent national study found that obstructive CAD was found in less than one-half of patients undergoing elective coronary angiography.

Methods: We performed a retrospective analysis of 565,504 patients without prior myocardial infarction or revascularization undergoing elective coronary angiography using CathPCI Registry data from 2005 to 2008 to evaluate the rate of finding obstructive CAD (any major epicardial vessel stenosis ≥ 50%) at coronary angiography at 691 U.S. hospitals.

Results: The rate of obstructive coronary disease found at elective coronary angiography varied from 23% to 100% among hospitals (median 45%; interquartile range: 39% to 52%), and were consistent from year to year and when alternative definitions of coronary stenosis were applied. Sites with lower rates of finding obstructive CAD were more likely to perform procedures on younger patients, those with low Framingham risk (33% in lowest yield quartile vs. 21% in highest yield quartile, p < 0.0001); with no or atypical symptoms (73% vs. 58%, p < 0.0001); and with a negative, equivocal, or unperformed functional status assessment. Hospitals with lower rates of finding obstructive CAD also less frequently prescribed aspirin, beta-blockers, platelet inhibitors, and statins (all p < 0.0001). The CAD rate was lower at facilities with small-volume catheterization laboratories and was not associated with hospital ownership or teaching program status.

Conclusions: The rate of finding obstructive CAD at elective coronary angiography varied considerably among reporting centers and was associated with patient selection and pre-procedure assessment strategies. This institutional variation suggests that an important opportunity may exist for quality improvement.