Right Internal Thoracic Artery for Coronary Bypass Surgery: Did We Get It Wrong?

HomeCirculationVol. 146, No. 17Right Internal Thoracic Artery for Coronary Bypass Surgery: Did We Get It Wrong? Free AccessArticle CommentaryPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissionsDownload Articles + Supplements ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toSupplemental MaterialFree AccessArticle CommentaryPDF/EPUBRight Internal Thoracic Artery for Coronary Bypass Surgery: Did We Get It Wrong? Mario Gaudino and Bruce Lytle Mario GaudinoMario Gaudino Correspondence to: Mario Gaudino, MD, PhD, Department of Cardiothoracic Surgery, Weill Cornell Medicine, 525 E 68th St, New York, NY 10065. Email E-mail Address: [email protected] https://orcid.org/0000-0003-4680-0815 Department of Cardio-thoracic Surgery, Weill Cornell Medicine, New York (M.G.). Search for more papers by this author and Bruce LytleBruce Lytle Department of Cardiac and Thoracic Surgery, Baylor Scott & White, The Heart Hospital-Plano, TX (B.L.). Search for more papers by this author Originally published24 Oct 2022https://doi.org/10.1161/CIRCULATIONAHA.122.061766Circulation. 2022;146:1266–1267In 1986, an observational study by Loop and colleagues1 reported that the left internal thoracic artery (LITA) to left anterior descending coronary artery (LAD) graft was associated with better clinical results of coronary artery bypass (CABG) when compared with a saphenous vein graft (SVG) to the LAD. This finding was consistent with the favorable biology of the LITA and its unique histology and paracrine vasoactive activity compared with all the other CABG conduits. Since that seminal study, a myriad of observational data supporting similar conclusions have accumulated, and by the mid-1990s the LITA-LAD graft was universally recognized as the most important part of the CABG operation. Today the LITA-LAD graft is the only CABG technical strategy that is widely recognized as a quality indicator.It occurred to some surgeons—because one could harvest the right internal thoracic artery (RITA) through the same median sternotomy incision and the RITA had the same favorable biology as the LITA—that multivessel CABG could be performed using both internal thoracic arteries (ITAs). Initially, a relatively small numbers of these operations were performed. At times the RITA was used as a graft because other conduits were not available, and at times on the basis of the thought that if 1 ITA graft was good, 2 might be better. As the LITA-LAD graft became an essential part of the CABG operation, the concept of using both ITAs was investigated, and large observational studies reported by surgeons committed to ITA use supported the notion that, in many patients, 2 ITA grafts may produce better clinical results than 1 does.1 Although it is known that nonrandomized, comparative effectiveness studies in surgery are prone to experience and treatment allocation bias, the results in favor of the RITA were consistent and provided support to the intuitive concept that the RITA was the natural second best conduit for CABG.It was, therefore, with surprise and disappointment that the CABG community learned of the results of the ART (Arterial Revascularization Trial)—the only randomized trial to test the RITA versus SVG hypothesis. ART reported in 2019 no clinical benefit at 10 years with the use of the RITA.1 The high crossover rate, as well as the use of the radial artery (RA) in both trial arms, were offered as explanations for the unexpected lack of differences between groups—although the results were consistent in all the sensitivity analyses.Furthermore, after the publication of ART, several angiographic patency studies reported worryingly high RITA failure rates. In an angiographic analysis of 6 CABG trials, the 5-year occlusion rate of the RITA was 13.5%,2 and in a post hoc analysis of the COMPASS (Cardiovascular Outcomes for People Using Anticoagulation Strategies) CABG study, the RITA failure rate at 1 year was 26.8%.3 Although these analyses included a relatively small number of grafts, they were based on prospective imaging follow-up within the context of a randomized trial, with a lower risk of bias compared with observational series. In addition, the RAPCO trial (Radial Artery Patency and Clinical Outcomes) showed, at 10 years of follow-up, that the occlusion rate of the free RITA was significantly higher than that of the RA (20% versus 11%).4 Those reported RITA failure rates were all higher than that of the LITA, but also higher than historical RITA failure rates had been.In the early years of CABG surgery, the RITA was sometimes used as a graft to the LAD. Surgeons reporting the outcomes of RITA grafts often had a commitment to their use. From those early data, it appeared that when used as a graft to the LAD, the patency rates of the RITA were excellent, almost as good as those of the LITA. Patency of the RITA, however, was not as good when used to graft the circumflex and worst when used as a graft to the right coronary artery. Some of those graft failures may have been related to competitive flow in the native circumflex and right coronary artery systems, and some to technical issues when the RITA was anastomosed to more distal coronary targets. Time has shown that all arterial grafts have their best patency when grafted to a severely stenotic native vessel and that the RITA is certainly more subject to competitive flow than the SVG. Also, the results of the RITA are operator-dependent, and a volume/outcome association has been reported for the RITA but not for the RA.5 As the number of surgeons using RITA grafts has expanded, and the vessels grafted have become more limited to the circumflex and right coronary systems (because of the establishment of the LITA-LAD graft as a routine), the patency weaknesses of the RITA graft may have been highlighted more often.The RA bypass graft received sporadic and unsuccessful use early in the CABG era but enjoyed a resurgence during the 1990s. Once the use of the RA became more widespread, randomized trials started to demonstrate favorable patency (even superior to the RITA). Many of the advantages of the RA are related to characteristics that make it easier and safer to work with. It is usually larger and more robust than the RITA, is safer to use for sequential and distal grafts, and can be harvested at the same time as the LITA, making the operation more efficient.The use of the RA also avoids sternal devascularization and the risk of sternal wound infection, a severe and potentially lethal early complication of CABG that is also associated with long-term mortality. Surgeons experienced with RITA use have usually developed strategies for decreasing the risk of sternal necrosis including skeletonization of ITAs, use of only part of the length of the RITA, and patient selection. However, as the number of bypass operations has decreased, the number of surgeons facile with ITA use has also decreased, which is a trend that continues to have an effect and likely contributes to the reported differences in RITA outcomes between different eras.Last, it has been shown that long-term death from coronary disease often relates to events in vessels that are not severely stenotic at surgery. Those vessels should be grafted, but not with arterial grafts and particularly not with the RITA.We believe that in an ideal situation (a properly harvested RITA, a tight lesion in a coronary vessel with a favorable size match [almost always a left-sided vessel], in the hands of a surgeon experienced with RITA use), the RITA is still the best second conduit that we can offer to a patient having CABG. We also recognize that modern patency data, reflecting expanded use of the RITA by a higher number of surgeons to graft non-LAD target vessels of different size and quality and with different degrees of stenosis, do not demonstrate superior patency for the RITA over the RA or even the SVG. We believe that differences in the deliverability of the operation using the RITA, rather than conduit biology, explain the reported patency differences.The data as they stand today do not designate the RITA as the best second conduit. We believe that the RITA may be superior in ideal situations, but in many others the RA and the SVG may be as good or even better.Article InformationSources of FundingNone.Disclosures None.FootnotesCirculation is available at www.ahajournals.org/journal/circThe opinions expressed in this article are not necessarily those of the editors or of the American Heart Association.The podcast and transcript are available as Supplemental Material at https://www.ahajournals.org/doi/suppl/10.1161/CIRCULATIONAHA.122.061766.For Sources of Funding and Disclosures, see page 1267.Correspondence to: Mario Gaudino, MD, PhD, Department of Cardiothoracic Surgery, Weill Cornell Medicine, 525 E 68th St, New York, NY 10065. Email mfg9004@med.cornell.eduReferences1. Gaudino M, Fremes SE, Taggart DP. Continuing conundrum of multiple arterial conduits for coronary artery bypass grafting.Circulation. 2018; 137:1658–1660. doi: 10.1161/CIRCULATIONAHA.117.031670LinkGoogle Scholar2. Gaudino M, Benedetto U, Fremes SE, Hare DL, Hayward P, Moat N, Moscarelli M, Di Franco A, Nasso G, Peric M, et al. Angiographic outcome of coronary artery bypass grafts: the Radial Artery Database International Alliance.Ann Thorac Surg. 2020; 109:688–694. doi: 10.1016/j.athoracsur.2019.07.010CrossrefMedlineGoogle Scholar3. Alboom M, Browne A, Sheth T, Zheng Z, Dagenais F, Noiseux N, Brtko M, Stevens L-M, Lee SF, Copland I, 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. 2022;S0022–5223(22)00629–8. doi: 10.1016/j.jtcvs.2022.05.028CrossrefMedlineGoogle Scholar4. Buxton BF, Hayward PA, Raman J, Moten SC, Rosalion A, Gordon I, Seevanayagam S, Matalanis G, Benedetto U, Gaudino M, et al. Long-term results of the RAPCO trials.Circulation. 2020; 142:1330–1338. doi: 10.1161/CIRCULATIONAHA.119.045427LinkGoogle Scholar5. Schwann TA, Habib RH, Wallace A, Shahian DM, O’Brien S, Jacobs JP, Puskas JD, Kurlansky PA, Engoren MC, Tranbaugh RF, et al. Operative outcomes of multiple-arterial versus single-arterial coronary bypass grafting.Ann Thorac Surg. 2018; 105:1109–1119. doi: 10.1016/j.athoracsur.2017.10.058CrossrefMedlineGoogle Scholar eLetters(0)eLetters should relate to an article recently published in the journal and are not a forum for providing unpublished data. Comments are reviewed for appropriate use of tone and language. Comments are not peer-reviewed. Acceptable comments are posted to the journal website only. Comments are not published in an issue and are not indexed in PubMed. Comments should be no longer than 500 words and will only be posted online. References are limited to 10. Authors of the article cited in the comment will be invited to reply, as appropriate.Comments and feedback on AHA/ASA Scientific Statements and Guidelines should be directed to the AHA/ASA Manuscript Oversight Committee via its Correspondence page.Sign In to Submit a Response to This Article Previous Back to top Next FiguresReferencesRelatedDetails October 25, 2022Vol 146, Issue 17 Advertisement Article InformationMetrics © 2022 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.122.061766PMID: 36279413 Originally publishedOctober 24, 2022 Keywordsmammary arteriesradial arterycoronary artery bypassPDF download Advertisement SubjectsCardiovascular Surgery