Objectives: The goals of this analysis were: 1) to evaluate outcomes among non-ST-segment elevation myocardial infarction (NSTEMI) patients presenting to hospitals with on-site cardiac surgery (OHS hospitals) and without on-site cardiac surgery (No-OHS hospitals); and 2) to specifically examine outcomes among the subset of NSTEMI patients undergoing percutaneous coronary intervention (PCI).
Background: Whether backup cardiac surgery improves outcomes among NSTEMI patients or is simply a marker of better adherence to guideline recommendations is unknown.
Methods: The NRMI (National Registry of Myocardial Infarction) enrolled 100,071 NSTEMI patients from 2004 to 2006. Outcomes were evaluated in the population as a whole and in propensity-matched analyses in the entire population and in the subset of patients undergoing PCI.
Results: In-hospital mortality was significantly lower at OHS hospitals (5.0% vs. 8.8%, p < 0.001). Patients presenting to OHS hospitals were significantly more likely to receive aspirin, beta-blockers, and statins (p < 0.05 for all) and to undergo PCI (38.4% vs. 14.1%, p < 0.001). In the propensity-matched model, the difference in mortality remained significant (5.9% vs. 8.5%, p < 0.001). After adjusting for differences in medications administered within 24 h of arrival and hospital characteristics, the difference in mortality was nearly attenuated (hazard ratio: 0.89, 95% confidence interval: 0.79 to 1.00, p = 0.050). When the propensity-matched model was restricted to patients undergoing PCI, there was no significant difference in mortality (1.3% vs. 1.0%, p = 0.51).
Conclusions: NSTEMI patients presenting to No-OHS hospitals have significantly higher mortality. This appears to be due to both modifiable (lower use of guideline-recommended medications) and nonmodifiable factors (hospital size, myocardial infarction volume). In a propensity-matched analysis of patients undergoing PCI for NSTEMI, there was no significant difference in mortality.