Author + information
- Joon Bum Kim, MD, PhD and
- Suk Jung Choo, MD, PhD∗ ()
- ↵∗Department of Thoracic and Cardiovascular Surgery, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Pungnap-dong Songpa-gu, Seoul 138-736, South Korea
The association of fewer bypass anastomoses and possibly inferior completeness of revascularization has been frequently reported with off-pump coronary artery bypass grafting (OPCAB) when compared with on-pump coronary artery bypass grafting (CABG) (1,2). Consequently, despite the superior early results, reports of the ensuing relatively inferior longer-term outcomes with OPCAB (3–5) have raised concerns about the current inclination toward OPCAB as the strategy of choice for CABG. Our study (6) is consistent with these reports and adds supportive long-term information.
Dr. Kajimoto and colleagues point out that the lower number of bypasses in our OPCAB group is a limitation and suggest the possibility of different outcomes with more competent hands. However, they provide no evidence of equal or greater numbers of bypasses with OPCAB compared with on-pump CABG in the Japanese registry. The early OPCAB outcomes in the Japanese registry are excellent, but so are the OPCAB outcomes of experienced surgeons throughout the world. Our question was whether the early benefits of OPCAB are more sustainable over significantly longer periods than on-pump CABG, and our results cast doubts on this possibility. Again, Dr. Kajimoto and colleagues provide no evidence showing superior long-term benefits in terms of reduced mortality with OPCAB over on-pump CABG in the Japanese registry. If a lower number of bypass grafts is a technical limitation of OPCAB, perhaps surgeons should revise their strategy accordingly to ensure superior bypass quality and completeness of revascularization (3–5), especially in light of recent studies, including ours that support this viewpoint.
With regard to possible bias in coronary lesion severity, the 2 groups in our study were matched by a rigorous process of statistical verification, including propensity score matching and inverse probability weighting. If there was any bias in lesion severity, the inclination would have been toward on-pump CABG rather than OPCAB.
Finally, Dr. Kajimoto and colleagues question the quality of our OPCAB data and, by extension, the reliability of our study by pointing that “South Korean surgeons were still acquiring the required techniques.” We would like to note that our study was not a registry outcome analysis (i.e., a Korean registry), as erroneously alluded to by Kajimoto et al., but rather a single institutional analysis of the outcomes of experienced surgeons. Our single institutional study draws on a population of more than 5,000 patients with isolated CABG, including more than 2,000 patients who underwent OPCAB. Questioning the experience and expertise of surgeons in such a setting places a higher standard than that considered more than acceptable internationally. The OPCAB data derived from surgeons showing an on-pump conversion rate of 2% and early mortality rate of 0.9% can hardly be seen as premature or inadequate by any standards in published research, even from Japan. Unless the credibility of our report itself is in question, which would be another matter, the confusion of Dr. Kajimoto and colleagues regarding the details and design of our report upon which their hasty conclusions were based warrants careful re-perusal of the contents.
- American College of Cardiology Foundation
- Hattler B.,
- Messenger J.C.,
- Shroyer A.L.,
- et al.,
- for the Veterans Affairs Randomized On/Off Bypass (ROOBY) Study Group
- Kim J.B.,
- Yun S.C.,
- Lim J.W.,
- et al.