Comparing clinical outcomes in high-volume and low-volume off-pump coronary bypass operation programs

Background. A growing body of data suggests that physicians or medical centers performing a higher volume of patient services achieve better outcomes. We hypothesized that an important dimension of coronary artery bypass graft (CABG) volume is the cardiovascular surgical team experience with performing off-pump coronary artery bypass (OPCAB) procedures, as well as the team’s ability to provide the optimal approach for the patient’s clinical condition. Teams performing 100 or more OPCAB operations have improved clinical decision-making processes and technical skills regarding treatment of all CABG patients, regardless of whether cardiopulmonary bypass is used. We hypothesized that this experience and choice of approaches for CABG procedures translates into better clinical outcomes. Methods. Using data on 16,988 consecutive patients in 72 hospitals from the HCA—The Healthcare Company casemix database, we identified high- and low-volume OPCAB sites and then analyzed the patient and hospital characteristics that had an impact on clinical outcomes. Results. The mortality rates for the high- and low-volume OPCAB facilities both averaged 2.9% (p = NS). Patients at the high-volume OPCAB facilities had significantly lower rates of major complications (shock/hemorrhage, neurologic, renal, and cardiac) than those at the low-volume OPCAB facilities. Of the seven minor complications, rates for six were lower in the high-volume OPCAB facilities, but none of the differences reached statistical significance. High-volume OPCAB sites were significantly more likely to discharge their patients directly home than were low-volume OPCAB sites (80% versus 66%; p = 0.001). Conclusions. The results suggested that surgical team experience and choice of approaches to performing CABG had an impact on patient outcomes.