The STS AVR+CABG composite measure uses the same statistical approach as its predecessors and comprises two outcomes domains, risk-adjusted mortality and risk-adjusted morbidity, the latter of which includes the same complications as the other composites (i.e., reoperation, stroke, kidney failure, infection of the chest wound, or prolonged need to be supported by a breathing machine, or ventilator). Similar to the STS AVR composite, the AVR+CABG composite score does not include process measures. It is important to note that experts believe that at least one of the arteries from the underside of the chest wall—the internal mammary (or internal thoracic) artery—should be used whenever possible to graft a diseased left anterior descending coronary artery during combined AVR + CABG. However, evidence to include this as a performance measure in the composite was not sufficient. In addition, due to the smaller number of AVR+CABG surgery patients compared with CABG, a 95% Bayesian credible interval for star rating determination and a data collection period of 3 years (rolling) are used.
STS Public Reporting Online lists participants’ scores for each separate domain as well as the STS AVR+CABG overall composite score. As in the CABG and AVR composites, numerical scores and star ratings are provided. The star rating calculation again begins by assuming all providers are average and then determines statistically if there is at least a 97.5 percent probability that the performance of any specific provider is lower than average (one star) or higher than average (three star). Otherwise, the participant receives two stars.