Endoscopic versus Open Vein-Graft Harvesting

To the Editor: Lopes and colleagues (July 16 issue) 1 report data on vein-graft harvesting techniques from the Project of Ex-vivo Vein Graft Engineering via Transfection IV (PREVENT IV) study and conclude that endoscopic vein-graft harvesting, as compared with open harvesting, is independently associated with increased vein-graft failure and adverse outcomes. In another analysis from the same study, 2 offpump and on-pump coronary-artery bypass grafting (CABG) were compared. An interesting finding was that with endoscopically harvested grafts, the probability of graft failure was significantly higher in the off-pump group than in the on-pump group (odds ratio, 1.78 vs. 1.27). In addition, vein grafts of poor or fair quality (as compared with those of good quality) had a significantly higher rate of failure with off-pump than with on-pump CABG. The failure rate of left internal thoracic artery grafts was about 8%, as compared with a failure rate of about 25% for vein grafts. The failure rate of grafts to the left anterior descending artery was much lower than that of grafts to the right coronary artery and circumflex arteries. The study by Lopes et al. does not adjust for the use of off-pump CABG or of left internal thoracic artery grafts. Furthermore, there is no information on the quality of the veins or of the target vessels. These are major omissions that may have an effect on the results and conclusions of the study.