Off-pump coronary bypass: Is it for everyone?

O ff-pump coronary artery bypass (OFFCAB) has been adopted enthusiastically by many surgeons throughout the world, but despite more than 5 years’ experience and progressive refinement of techniques and equipment, many surgeons use it only sporadically and some use it hardly at all. This reluctance persists despite the insistence by many of OFFCAB’s advocates that it can be performed regularly by any competent surgeon without compromising the safety and sustained improvement that are hallmarks of the standard operation. It has never been clear whether the reluctance of many surgeons to adopt OFFCAB is due to their unwillingness to struggle with a tedious technique even though it has “obvious” benefits, or whether, as others have insisted, there is still insufficient evidence to show that its modest benefits are worth all the trouble.1,2 The comprehensive and thoughtful article in this issue of the Journal by Mack and associates3 expands our understanding of these issues, but it also highlights our ignorance. Mack and associates3 conducted a retrospective review of a 5-year experience with 12,540 patients who underwent isolated coronary artery bypass grafting (CABG), of whom 1915 underwent OFFCAB. In the introduction to their report, they ask four questions that frame the core of our uncertainties about OFFCAB: 1. Can off-pump surgery be safely incorporated into a surgical practice and be performed by most surgeons? 2. Is there a significant learning curve to the adoption of beating-heart surgery? 3. Does incorporation of off-pump surgery into a surgical practice lead to better overall outcomes? 4. Are the improved outcomes reported with beating-heart surgery related to the technique or to individual surgeon experience and expertise? I would make two additions to this list. As a corollary to question 4, I would also ask: What is the evidence for better outcomes with beating-heart surgery? I would also add a question 5: Are the risk models in the Society of Thoracic Surgeons (STS) National Database, which are derived from experience with on-pump CABG, valid for assessing risk for patients undergoing OFFCAB? To answer question 1, Mack and associates3 commendably analyzed the work of 36 surgeons individually, which unfortunately is rarely done in surgical reports. The number 36 is artifactually inflated by staffing turnover, as there are currently 22 surgeons in the practice. It turns out that the same 6 surgeons who were early, enthusiastic adopters of OFFCAB (“high adopters”) carried out 73% of all OFFCAB procedures, whereas the remaining surgeons did OFFCAB sporadically, and 8 surgeons still do fewer than 10 OFFCAB cases per year (“low adopters”). In the 5-year period before the introduction of OFFCAB, the composite mortality rate for CABG of the 3 lowest adopters was 38% greater than the composite mortality rate of the 3 highest adopters (4.0% vs 2.9%, P .001). Clearly, OFFCAB was being performed predominantly by the most accomplished surgeons. If, as common sense suggests, this group’s experience is typical, the answer to question 1 is that although OFFCAB can be safely incorporated into a large practice, it appears unlikely, at least for now, that OFFCAB will be done regularly by most surgeons. This is true From Lancaster General Hospital, Lancaster, Pa.