Relationship between coronary angioplasty laboratory volume and outcomes after hospital discharge

Background Although an inverse association has been established between short-term complications of percutoneous coronary interventions (PCIs) and the volume of angioplasty procedures performed by catheterization laboratories, no data are available on the association between laboratory volume and long-term outcomes. Methods A cohort study of 25,222 patients undergoing PCI in 43 laboratories in Pennsylvania from October 1994 to December 1995 was performed by use of the Pennsylvania Health Care Cost Containment Council database. The association of laboratory volume with inhospital, 1-month, and 6-month events was estimated by use of multivariable analyses adjusting for patient and procedural characteristics. Results Although a higher volume of procedures was associated with reduced inhospital coronary bypass ([CABG] 0.6 odds ratio [OR] for 400 vs <400 PCIs/year; 95% CI 0.4, 0.8), it was not associated with CABG occurring within 1 month after discharge (P = .71; OR 1.0, 95% CI 0.6, 1.7). Laboratory volume was also not significantly associated with postdischarge revascularization (PCI or CABG) at 1 month (P = .58; OR 1.1, 95% CI 0.8, 1.4) or 6 months (P = .47; OR 1.04, 95% CI 0.91, 1.19). In addition, laboratory volume was not associated with rates of myocardial infarction (P =.14), death (P =.28), or the combined outcome of PCI, CABG, myocardial infarction, or death (P = .90) at 1 month after hospital discharge. Conclusions Although our study confirmed the volume/complication relationship for inhospital CABG, it did not reveal an association between volume and postdischarge events. These results suggest that inhospital complications will remain the standard for assessing laboratory volume and that selective use of higher-volume laboratories may not improve long-term outcomes.