On- versus off-pump CABG—adding to the debate

Abstract

Dr. O.P. Yadava, CEO and chief cardiac surgeon of National Heart Institute, New Delhi, India, and editor-in-chief of Indian Journal of Thoracic and Cardiovascular Surgery in conversation with Prof. David Taggart from University of Oxford, England, discuss the current status of off-pump coronary artery bypass surgery including the indications and issues related to training.

Electronic supplementary material

The online version of this article (10.1007/s12055-019-00898-9) contains supplementary material, which is available to authorized users.

On being provocatively asked, why, despite reams of literature on the subject, the debate still rages between on- and off-pump bypass surgery, Dr. Taggart brought in the role of surgical experience, while deciphering various studies. As against the ROOBY Trial [1] which showed inferior outcomes with off-pump, the CABG Off or On Pump Revascularization Study (CORONARY) Trial [2] and the German Off-Pump Coronary Artery Bypass in the Elderly (GOPCABE) Trial from Germany [3] showed equivalent survival at 5 years. He further warranted that his group was in the process of publishing the analysis of the Arterial Revascularisation Therapies (ART) Trial, where 40% of patients were done off-pump. They found no difference in 10 years survival in the two groups. To prove his point of surgeon experience, Dr. Taggart resorted to the ART Trial, where a similar confounder of surgical experience affected the results. He comments, “You cannot separate the operation from the operator, it comes as a package.” He further issues a caveat, “If you use off-pump surgery as an occasional technique for your high risk patients, that is the worst scenario ……. when you have a high risk patient, the last thing you want to do is to change your technique.” So to get the best results, “you have to be facile in doing off-pump surgery in all cases.”

Dr. Taggart feels that there is a definite subset of 5–10% of patients, where on-pump surgery does better, e.g., large dilated hearts, which do not tolerate long periods of hypo-perfusion and thus suffer kidney insult, and patients with multiple, small, diffusely diseased coronary arteries. Sounding a discording note, Dr. Yadava feels that the Asian spectrum of diffusely diseased and small coronaries lend themselves supremely for off-pump techniques [4], as long as one is prepared to spend time in doing a meticulous anastomosis.

Shifting gears to teaching and training, Dr. Taggart believes that for an intermediate level surgeon, one can teach off-pump techniques directly, sans any exposure to on-pump CABG. He likes to teach left internal thoracic artery (LITA) to left anterior descending (LAD) coronary artery grafting as the first graft to the trainees. Though it feels like a paradox that the single most important graft is being used as a first step for trainees, he is able to do that because graft assessment and validation using flow measurements is mandatory in his practice. The second graft he teaches is the posterior descending artery (PDA), and the most difficult, obtuse marginal (OM), and circumflex is the last graft to be taught. On the issue of incompleteness versus completeness of revascularisation with off-pump surgery, Dr. Taggart opines that if the surgeon is sufficiently experienced, incompleteness of revascularisation is not an issue with off-pump CABG. Though Chikwe and David Adam’s group in New York showed higher incidence of incomplete revascularisation with off-pump (CABG) [5], both CORONARY Trial [2] and the GOPCABE Trial [3] showed equivalent degree of revascularisation with the two techniques.