Lower Hospital Volume Is Associated With Higher In-Hospital Mortality in Patients Undergoing Primary Percutaneous Coronary Intervention for ST-Segment–Elevation Myocardial Infarction

Abstract

Current guidelines recommend >36 primary percutaneous coronary interventions (PCIs) per hospital per year. Whether these standards remain valid when routine coronary stenting and newer pharmacological agents are used is unclear. We analyzed patients who underwent primary PCI from July 2006 through June 2009 included in the CathPCI Registry. Hospitals were separated into 3 groups: low (≤36 primary PCIs/y, current guideline recommendation), intermediate (>36-60 primary PCIs/y), and high volume (>60 primary PCIs/y). In-hospital mortality and door-to-balloon time were examined for each group. A total of 87 324 patient visits for 86 044 patients from 738 hospitals were included. There were 278 low- (38%), 236 (32%) intermediate-, and 224 (30%) high-volume hospitals. The majority of patients with primary PCI (54%) were treated at high-volume hospitals, with 15% at low-volume hospitals. Unadjusted mortality was significantly higher in low-volume hospitals compared with high-volume hospitals (5.6% versus 4.8%; P<0.001), which was maintained after multivariate adjustment (1.20; 95% confidence interval, 1.08-1.33; P=0.001). In contrast, mortality was not significantly different between intermediate-volume and high-volume hospitals (4.8% versus 4.8%; adjusted odds ratio, 1.02; 95% confidence interval, 0.94-1.11; P=0.61). Door-to-balloon times were significantly shorter in high-volume hospitals compared with low-volume hospitals (median, 72 minutes; interquartile range, [53-91] versus 77 [57-100] minutes; P<0.0001). Higher annual hospital volume of primary PCI continues to be associated with lower mortality, with higher mortality in hospitals performing ≤36 primary PCIs/y.