Effect of institutional volume and academic status on outcomes of coronaryinterventions: The IMPACT-II experience

Background Rates of morbidity and mortality after interventional procedures are reported to be inversely associated with institutional volume. Methods This study assessed both procedural volume and academic status at t he 82 US centers that participated in the IMPACT-II trial. Interventional v olumes at the sites ranged from 90 to 3300 cases per year. Patients were ra ndomly assigned to a platelet glycoprotein IIb/IIIa inhibitor (eptifibatide ) or placebo during procedures done by experienced operators. The primary e nd point was the composite of death, myocardial infarction, nonelective rep eat coronary intervention, or nonelective coronary artery bypass surgery at 80 days, or placement of an intracoronary stent for abrupt closure during the initial procedure. Results Baseline patient characteristics and median length of stay were sim ilar between the academic and nonacademic centers. In univariable analysis, volume as a continuous variable had a nonlinear relation with the incidenc e of the composite end point, with better outcomes noted at the highest vol ume institutions. Academic status did not predict outcome. When added to a predictive model that contained the variables unstable angina,weight, prior coronary artery bypass grafting, heart rate, and platelet count, procedura l volume continued to be associated with the composite outcome (P = .04). Conclusions We conclude that among hospitals participating in this trial, t here is a nonlinear relation between annual interventional volume and outco mes. This relation is complex, involving variations in periprocedural infar ction rates and additional, undefined institutional differences (other than academic status) that result in differences in procedural outcome.