THE RELATIONSHIP BETWEEN CORONARY ANGIOPLASTY PROCEDURE VOLUME AND MAJOR COMPLICATIONS

Objective.-To assess the relationship between the volume of percutaneo us transluminal coronary angioplasty (PTCA) procedures performed in a cardiac catheterization laboratory and major complications after adjus ting for case mix and to evaluate the applicability of current guideli nes for minimum laboratory volume. Design.-Cohort study using the 1992 and 1993 registries of the Society for Cardiac Angiography and Interv entions. Setting.-Forty-eight cardiac catheterization laboratories fro m throughout the United States and Canada. Patients.-All 19 594 consec utive patients without an acute myocardial infarction (MI) undergoing a first coronary balloon angioplasty. Main Outcome Measures.-Emergency bypass surgery, MI, or in-hospital death. Results.-There was a signif icant decrease in the rates of in-hospital mortality (P=.04), emergenc y bypass surgery (P<.001), MI (P=.001), and major complications (defin ed as one or more of these outcomes; P<.001) with increasing cardiac c atheterization laboratory volume. After adjustment for case mix using multivariable analysis, these associations persisted, although the ass ociation with mortality was no longer statistically significant. There was no significant difference in outcomes in laboratories performing at least 200 vs fewer than 200 procedures per year, the currently reco mmended minimum laboratory volume (odds ratio [OR] for major complicat ions, 0.81; 95% confidence interval [CI], 0.53 to 1.25). However, a st atistically significant decrease in major complications was observed i n laboratories performing more than 400 procedures per year (adjusted OR, 0.66; 95% CI, 0.46 to 0.96; P=.03; and OR, 0.54; 95% CI, 0.38 to 0 .78; P=.001) when laboratories performing 400 through 599 procedures a nd at least 600 procedures per year, respectively, are compared with t hose performing fewer than 200 per year. Conclusions.-An inverse assoc iation between cardiac catheterization laboratory procedure volume and major complications during PTCA exists independent of differences in patients' risk profiles. Our data suggest that the currently recommend ed minimum laboratory volume may be too low to distinguish higher-risk from lower-risk laboratories.