Volume-outcome relation for hospitals performing angioplasty for acute myocardial infarction - Results from the nationwide Japanese registry

Background: The purpose of this study was to use a contemporary database to examine the relationship between annual hospital volume and the outcomes of percutaneous coronary interventions (PCIs) for acute myocardial infarction (AMI), given the wide spread use of coronary stents. An inverse relation exists between the number of PCIs and short-term outcome, but PCI practice has been changing with the availability of new devices such as stents. Methods and Results: Data from the 1997 Japanese nationwide registry were analyzed to determine the relation between the annual hospital volume of PCI procedures for patients with AMI and in-hospital mortality, as well as the need for coronary artery bypass graft (CABG) surgery. A total of 129 hospitals (2,491 patients) were divided into terciles according to the annual volume. Of the procedures, 39% involved coronary stents. Median annual PCI volumes varied across terciles from low=10, middle=33, and high=89. After adjusting for patient characteristics, there was no significant relationship between volume and in-hospital mortality (trend P=0.66) and CABG (trend P=0.35). Among patients who received stents (n=958), there was no significant association between volume and either mortality or CABG. Conclusions: Using the contemporary database, there was no significant relationship between hospital volume and in-hospital outcome among AMI patients undergoing PCIs.