Arterial conduits for coronary artery bypass grafting: a bridge over troubled water
2002; Elsevier BV; Volume: 73; Issue: 5 Linguagem: Inglês
10.1016/s0003-4975(02)03567-1
ISSN1552-6259
Autores Tópico(s)Mechanical Circulatory Support Devices
ResumoCoronary artery bypass grafting (CABG) is one of the most striking surgical achievements in the 20th century. Over the 35-year history of CABG, surgical outcomes have become excellent by technical refinements, myocardial protection, and searches for better conduits. In a sense, it has been a journey to find an ideal conduit. Since the influential report of Loop and colleagues from the Cleveland Clinic in 1986 [1Loop F.D. Lytle B.W. Cosgrove D.M. et al.Influence of the internal-mammary-artery graft on 10-year survival and other cardiac events.N Engl J Med. 1986; 2: 314-316Google Scholar], which disclosed a superiority of the internal thoracic artery graft to the left anterior descending artery on postoperative survival, searches for other suitable arterial con duits for CABG have remained a high priority. These searches introduced the right gastroepiploic artery (GEA) and inferior epigastric artery to clinical application and revived the radial artery. While CABG with multiarterial conduits has been enthusiastically advocated, it is difficult to show a benefit on late survival and rates of cardiac events because the internal thoracic artery to left anterior descending artery bypass confers most of the advantages of arterial grafting. Careful observation of large numbers of patients for long periods is necessary to show the difference between one or several arterial grafts. Recently, however, Lytle and associates [2Lytle B.W. Blackstone E.H. Loop F.D. et al.Two internal thoracic artery grafts are better than one.J Thorac Cardiovasc Surg. 1999; 117: 855-872Abstract Full Text Full Text PDF PubMed Scopus (765) Google Scholar] and Endo and colleagues [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: 76-80Google Scholar] have shown that two internal thoracic artery grafts are better than one. The superiority of other arterial conduits over saphenous vein has not been shown convincingly, however, or statistically established. Doctor Amano’s group should be congratulated for their successful results in a large number of patients using several arterial conduits, particularly the GEA graft, in combination with the internal thoracic artery graft [4Hirose H. Amano A. Takahashi A. Coronary artery bypass grafting using the gastroepiploic artery 1,000 cases.Ann Thorac Surg. 2002; 73: 1371-1379Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar]. It was 15 years ago that Pym and colleagues [5Pym J. Brown P.M. Charrette E.J. Parker J.O. West R.O. Gastroepiploic-coronary anastomosis. A viable alternative bypass graft.J Thorac Cardiovasc Surg. 1987; 94: 256-259PubMed Google Scholar] reported GEA to right coronary artery grafting and Suma and coworkers [6Suma H. Fukumoto H. Takeuchi A. Coronary artery bypass grafting by utilizing in situ right gastroepiploic artery basic study and clinical application.Ann Thorac Surg. 1987; 44: 394-397Abstract Full Text PDF PubMed Scopus (183) Google Scholar] reported GEA to left anterior descending artery grafting for reoperation. Although surgical results were satisfactory, many cardiac surgeons said “it’s crazy” to open the abdomen during cardiac surgery. Five years later when I presented 200 cases with GEA grafts without serious abdominal complications at the AATS meeting [7Suma H. Wanibuchi Y. Terada Y. Fukuda S. Takayama T. Furuta S. The right gastroepiploic artery graft. Clinical and angiographic midterm results in 200 patients.J Thorac Cardiovasc Surg. 1993; 105: 615-622PubMed Google Scholar], Noel Mills told me that Japanese GEAs are big enough possibly because of Sushi and Sukiyaki rather than beef steak. Fifteen years later GEA is a successful conduit in Japan but is disappearing with increased use of the radial artery in the United States despite a Sushi-boom in the USA. In the report of Hirose and colleagues [4Hirose H. Amano A. Takahashi A. Coronary artery bypass grafting using the gastroepiploic artery 1,000 cases.Ann Thorac Surg. 2002; 73: 1371-1379Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar] in-situ GEA grafts were generally used to bypass the posterior descending coronary artery in association with internal thoracic artery to the anterior descending artery bypass in 1,000 isolated CABGs during a 10-year period. Other conduits such as right internal thoracic artery, radial artery, and saphenous vein were mostly used to bypass the circumflex and diagonal arteries to produce a mean of 3.7 distal anastomoses. Operative mortality was 0.8% with no abdominal complications. Five-year survival and cardiac-related event free rates were 92.6% and 84.2%, respectively. The 5-year graft patency rates of GEA and left internal thoracic artery grafts were 84.4% and 97.0% (p < 0.005), respectively. But remember, the target coronary artery was different between the two grafts. Patency rates of other conduits were 91.7% for right internal thoracic artery and 88.5% for saphenous vein at 5 years and 91.3% for radial artery at 3 years. In our recent investigation with 936 patients having GEA graft [8Suma H. Isomura T. Horii T. Sato T. Late angiographic results of using the right gastroepiploic artery as a graft.J Thorac Cardiovasc Surg. 2000; 120: 496-498Abstract Full Text Full Text PDF PubMed Scopus (125) Google Scholar] cumulative patency rate of the in-situ GEA graft was 91.4%, 80.5%, and 62.5% at 1, 5, and 10 years, respectively. The most common cause of late occlusion of the GEA graft was primary anastomotic stenosis and anastomosis to a coronary artery with a low-grade stenosis (competitive flow). In other words a good anastomosis to the critically stenotic coronary artery improves GEA patency. In angiograms 10 years after operation wall irregularity or a new stenotic lesion was quite uncommon in GEA conduits and this suggests less graft disease than in the saphenous vein (Fig 1). Although the internal thoracic artery to the left anterior descending artery bypass is an established gold standard, the ideal conduit for other coronary arteries is yet to be determined and several tactics are ongoing. There is no one best for all. The more options we have, the more chances to be successful. The report of Hirose and associates [4Hirose H. Amano A. Takahashi A. Coronary artery bypass grafting using the gastroepiploic artery 1,000 cases.Ann Thorac Surg. 2002; 73: 1371-1379Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar] is important because it shows that multiarterial grafting combined with GEA, internal thoracic artery, and other conduits can be performed safely and effectively. Careful angiographic follow-up of these patients after 10 to 15 years will determine over which bridge we should walk.
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