U.S. trends in CABG hospital volume: the effect of adding cardiac surgery programs.

Hospital coronary artery bypass graft (CABG) volume is inversely related to mortality--with low-volume hospitals having the highest mortality. Medicare data (1992-2003) show that the number of CABG procedures increased from 158,000 in 1992 to a peak of 190,000 in 1996 and then fell to 152,000 in 2003, while the number of hospitals performing CABG increased steadily. Predictably, the proportion of CABG procedures performed at low-volume hospitals increased, and the proportion in high-volume hospitals declined. An unintended consequence of starting new cardiac surgery programs is declining CABG hospital volume--a side effect that might increase mortality.