Future reports will focus on other outcomes, including stroke rates, Dr. Weintraub said. Concurrent with his report at the meeting an article on the findings appeared online (N. Engl. J. Med. 2012 March 27 [doi:10.1056/NEJMoa1110717]).
Perhaps the most striking element in the findings was that the long-term survival benefit with CABG over PCI was consistent across a variety of subgroup analysis, including both women and men, and patients with or without diabetes.
"The advantage of CABG in all subgroups was a major surprise," Dr. Edwards said in an interview. "We thought that we’d see some subgroups that would benefit from PCI. Much to our surprise, all the subsets showed better survival with surgery, generally in the range of 20%-30%" on a relative basis.
Dr. Weintraub highlighted some extra analytic steps he and his associates took in the study. In addition to the primary adjusted analysis, the researchers performed a second, propensity-matched analysis on a subgroup of about 43,000 CABG patients and an equal number of PCI patients who closely matched for a list of over 20 demographic and clinical variables. The propensity-matched calculations found a similar long-term survival advantage for CABG.
They also examined whether the observed differences could be explained by an unmeasured confounder, such as frailty. To explain the observed between-group difference, "the unmeasured confounder would have to have an effect so large that it would have a hazard ratio of two, and would need to occur in about 30% of the patients in one group and in only 10% of those in the other group. How could we have missed that?" Dr. Edwards said.
Dr. Weintraub, Dr. Edwards, and Dr. White said they had no relevant disclosures. Dr. Jacobs said she had received research grants from Abiomed, Accumetrics, and Abbott Vascular. Dr. Gersh said he has been a consultant to Boston Scientific and Abbott Laboratories.