On-Pump versus Off-Pump CABG

To the Editor: In the Veterans Affairs Randomized On/Off Bypass (ROOBY) trial, Shroyer et al. (Nov. 5 issue)1 assigned 2203 patients to receive coronary-artery bypass grafting (CABG) either with the use of cardiopulmonary bypass (on-pump CABG) or without such bypass (off-pump CABG). The trial enrolled low-risk male patients in whom avoidance of cardiopulmonary bypass was unlikely to greatly improve the expected excellent outcomes.2 In a majority of patients, CABG was performed by surgical trainees under the supervision of attending surgeons who were remarkably inexperienced in the off-pump procedure and much more experienced in the on-pump procedure. The reported 12.4% rate of intraoperative conversion from planned off-pump CABG to on-pump CABG was five times the rate reported in the national database of the Society of Thoracic Surgeons3 and is an explicit indictment of the off-pump inexperience of surgeons, trainees, and anesthesia– nursing teams participating in the ROOBY trial.4 It is illogical to conduct a randomized trial comparing patient outcomes with alternative surgical techniques among surgical operators who have grossly asymmetric experience and expertise with the two procedures that are being compared. This is the “fatal flaw” of the ROOBY trial. Off-pump CABG is a technically challenging surgical procedure that offers substantial benefit to patients at high risk for death and complications with on-pump CABG.3,5 It remains a very important tool for surgical coronary revascularization. John D. Puskas, M.D.