Exploring the Relationship Between Volume and Outcomes in Hospital Cardiovascular Care

Background: Management theories of learning and experience curve effects state that greater levels of scale produce learnings and improved performance. In cardiovascular care, guidelines suggest that high-volume facilities produce better patient outcomes; yet, there are contradictory findings from the few studies conducted. Our goals were to assess the volume-outcome relationship for interventional cardiovascular care. Methods: We examined 9360 patients with ST-segment elevation myocardial infarction who underwent percutaneous intervention (PCI). We analyzed 6 years of data (2010-2015) using systematic extracts provided by 33 PCI-capable hospitals in the Dallas Texas region from the National Cardiovascular Data Registry. We stratified hospitals into 3 procedural volume categories (low, intermediate, and high) to identify changes in 2 key outcome metrics (ie, door-to-balloon times and mortality). Multivariate analyses and tests of differences were utilized. Results: Door-to-balloon performance outcome was significantly different between volume categories, with the highest-volume hospitals performing significantly better than intermediate- and low-volume hospitals (47, 60, and 75 minutes, respectively; P < .001). Mortality followed a similar pattern, with a 3.3% unadjusted absolute lower mortality rate for the high-volume hospitals. Multivariate regressions confirm that volume is statistically significant in both mortality and treatment times. Conclusions: Higher-volume PCI hospitals have 37% shorter treatment times and 53% lower mortality rates than smaller facilities. This study provides evidence of a positive volume-outcome relationship in interventional cardiovascular care.