Commentary: Conduit selection in the COMPASS trial: Pointing in the wrong direction?

Central MessageAlarmist messages that are based on very small numbers of patients and ignore a much larger and contradictory body of literature should be discouraged. Surgical results depend on surgeon experience.See Article page 1080. Alarmist messages that are based on very small numbers of patients and ignore a much larger and contradictory body of literature should be discouraged. Surgical results depend on surgeon experience. See Article page 1080. The Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) investigators report 1-year computed tomography angiography patency rates of 4 different coronary artery bypass graft conduits.1Albom A. Browne A. Sheth T. Zheng Z. Dagenais F. Noiseux N. et al.Conduit selection and early graft failure in coronary artery bypass surgery: a post hoc analysis of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) coronary artery bypass grafting study.J Thorac Cardiovasc Surg. 2023; 165: 1080-1089.e1Abstract Full Text Full Text PDF Scopus (7) Google Scholar In the overall study, 1068 patients received 3480 grafts, or an average of 3.3 grafts per patient.1Albom A. Browne A. Sheth T. Zheng Z. Dagenais F. Noiseux N. et al.Conduit selection and early graft failure in coronary artery bypass surgery: a post hoc analysis of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) coronary artery bypass grafting study.J Thorac Cardiovasc Surg. 2023; 165: 1080-1089.e1Abstract Full Text Full Text PDF Scopus (7) Google Scholar The operations were performed by more than 100 surgeons in 83 centers in 22 countries.1Albom A. Browne A. Sheth T. Zheng Z. Dagenais F. Noiseux N. et al.Conduit selection and early graft failure in coronary artery bypass surgery: a post hoc analysis of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) coronary artery bypass grafting study.J Thorac Cardiovasc Surg. 2023; 165: 1080-1089.e1Abstract Full Text Full Text PDF Scopus (7) Google Scholar Overall, there were 2239 saphenous vein grafts (SVGs) (64%), 1068 left internal thoracic artery (LITA) grafts (31%), 90 radial artery (RA) grafts (2.6%), and 82 right internal thoracic artery (RITA) grafts (2.4%). Respectively, the mean number of grafts per patient was 2.1, 1, 0.08, and 0.08. Overall failure rates at 1 year for SVG, LITA, RA, and RITA grafts were, respectively, 10.4%, 6.4%, 9.9%, and 26.8%. Accordingly, in both the Conclusions and the Perspective Statement (ie, the take-home messages), the authors state “high rates of RITA failure are worrisome and highlight the need for a thorough evaluation of the patency and safety of RITA in coronary artery bypass graft surgery.”1Albom A. Browne A. Sheth T. Zheng Z. Dagenais F. Noiseux N. et al.Conduit selection and early graft failure in coronary artery bypass surgery: a post hoc analysis of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) coronary artery bypass grafting study.J Thorac Cardiovasc Surg. 2023; 165: 1080-1089.e1Abstract Full Text Full Text PDF Scopus (7) Google Scholar Are these very alarmist statements actually justifiable based on the evidence presented? To place the COMPASS findings into perspective, 3 questions require addressing to explain a near 5-fold difference in LITA and RITA graft patency:•Is there a plausible intrinsic biological or mechanistic explanation?•Are the COMPASS findings consistent with much larger angiographic studies also reporting substantial inferior patency of RITA versus LITA grafts?•If the answer to the first 2 questions is no, then what most probably explains this difference? The answer to the first question is a definite no (indeed the RITA is usually larger than the LITA). Regarding the second question, the answer is not only a resounding no, but it is also highly pertinent—and disappointing—that the authors ignore far larger studies (around 1000 patients) from more than a decade ago that report identical angiographic patency rates for both ITA grafts.2Calafiore A.M. Contini M. Vitolla G. Di Mauro M. Mazzei V. Teodori G. et al.Bilateral internal thoracic artery grafting: long-term clinical and angiographic results of in situ versus Y grafts.J Thorac Cardiovasc Surg. 2000; 120: 990-996Abstract Full Text Full Text PDF PubMed Scopus (160) Google Scholar, 3Endo M. Nishida H. Tomizawa Y. Kasanuki H. Benefit of bilateral over single internal mammary artery grafts for multiple coronary artery bypass grafting.Circulation. 2001; 104: 2164-2170Crossref PubMed Scopus (151) Google Scholar, 4Tatoulis J. Buxton B.F. Fuller J.A. The right internal thoracic artery: is it underutilized?.Curr Opin Cardiol. 2011; 26: 528-535Crossref PubMed Scopus (41) Google Scholar Regarding the third question, the authors fail to discuss the crucial relevance of surgeon experience. Per patient, the average use of SVG and LITA graft was as expected, whereas the use of RA and RITA grafts (0.08) was very low. Consequently, the most credible interpretation of the COMPASS data is that whereas surgeons were appropriately experienced with both SVG and LITA grafts, they were very inexperienced with the use of both RA and RITA grafts. However, RA harvesting and deployment is technically far easier than for an RITA graft. The Arterial Revascularization Trial emphasized the importance of surgeon experience in terms of crossovers from bilateral to single ITA grafts: 14% overall, but varying from 0% to 100% per individual surgeon.5Benedetto U. Altman D.G. Flather M. Gerry S. Gray A. Lees B. et al.Incidence and clinical implications of intraoperative bilateral internal thoracic artery graft conversion: insights from the Arterial Revascularization Trial.J Thorac Cardiovasc Surg. 2018; 155: 2346-2355Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar Nevertheless, the authors effectively condemn the use of RITA grafts based on very small numbers of patients and ignoring far larger angiographic studies that completely refute their findings and the most probable explanation of surgeon inexperience. Rather than the alarmist message of these investigators, who imply an intrinsic biological/mechanistic problem with the RITA graft, perhaps their real message is that a good vein graft is much better than a poorly harvested/deployed RITA graft. Conduit selection and early graft failure in coronary artery bypass surgery: A post hoc analysis of the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) coronary artery bypass grafting studyThe Journal of Thoracic and Cardiovascular SurgeryVol. 165Issue 3PreviewRelative rates of early graft failure and conduit selection in coronary artery bypass grafting (CABG) surgery remain controversial. Therefore, we sought to determine the incidence and determinants of graft failure of the left internal mammary artery (LIMA), radial artery, saphenous vein, and right internal mammary artery (RIMA) 1 year after CABG surgery. Full-Text PDF Author Reply to Commentary: Conduit selection in the COMPASS trial: Pointing in the right directionThe Journal of Thoracic and Cardiovascular SurgeryVol. 165Issue 3PreviewIn this issue, our colleague Dr David Taggart1 is presenting a commentary on our recent publication,2 concluding “Rather than the alarmist message of the investigators, implying an intrinsic biological/mechanistic problem with the RIMA graft, perhaps their real message is that 'a good vein graft is much better than a poorly harvested/deployed RIMA graft.'” I believe that he is pointing in the wrong direction. The best evidence today is that right internal mammary artery (RIMA) is a poor conduit3 and using it could bring harmful consequences for the patient. Full-Text PDF