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Dr Om P. Yadava of the National Heart Institute in New Delhi, India, and Editor-in-Chief of the Indian Journal of Thoracic and Cardiovascular Surgery discusses contemporary issues in coronary artery bypass grafting (CABG) with Professor David Taggart of the University of Oxford in the UK at the 2018 Annual Conference of the Indian Association of Cardiovascular and Thoracic Surgeons.
Dr Yadava begins by suggesting that more ink has been spilt than blood over total arterial revascularization, and he asks for Prof Taggart’s thoughts as to why venous conduits continue to be used so often. Prof Taggart feels strongly that there is enough evidence favoring the radial artery over the saphenous vein and showing an increased survival benefit of bilateral internal mammary arteries (IMAs), and therefore it is unclear why surgeons continue to use venous grafts in almost 80% of cases. He is critical of the suggestion that the 5-year ART Trial [1] results favor the use of single IMA against bilateral IMAs, clarifying that the comparison shows them as equivalent. Prof Taggart mentions that even in the five year results there were signals, nearly approaching statistical significance, of a survival advantage for bilateral mammary arteries in patients under 70 years of age.
Commenting on the ways to improve patency rates of the saphenous vein, Prof Taggart talks of minimal handling, improved storage solutions, use of no-touch harvest techniques as propagated by Dr Domingo Souza, attaching the vein to the IMA as suggested by Ki Bong Kim in the Save RITA Trial [2], and the use of external stents [3]. He traces the history of external stents and addresses reasons for their failure in previous trials. He also discusses the VEST 3 Trial, presented at the 2017 Annual Meeting of the AATS, in which they observed a patency rate of 90% at six months. The difference from the previous stents was that these current stents are very flexible and thin, hence the patency rates have increased from 27% to 90% at six months. Further, there is no external fixation with use of fibrin glues; the stents have memory, and once fixed they stay in place and require no stitch suture to the vein.
The ten-year ART trial results were presented at the European Society of Cardiology (ESC) Congress 2018, after this discussion was recorded. Read the ESC press release here.
References
- Taggart DP, Altman DG, Gray AM, et al; ART Investigators. Randomized trial of bilateral versus single internal-thoracic-artery grafts. N Engl J Med. 2016;375(26):2540-2549.
- Kim KB, Hwang HY, Hahn S, Kim JS, Oh SJ. Randomized comparison of the Saphenous Vein Versus Right Internal Thoracic Artery as a Y-Composite Graft (SAVE RITA) trial: one-year angiographic results and mid-term clinical outcomes. J Thorac Cardiovasc Surg. 2014;148(3):901-908.
- Taggart DP, Ben Gal Y, Lees B, et al. A randomized trial of external stenting for saphenous vein grafts in coronary artery bypass grafting. Ann Thorac Surg. 2015;99(6):2039-45.
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1 Comment
I wish it was not the “real world” among cardiac surgeons, what Prof. Taggart has quoted, namely 80 % of the CABG procedures are being performed with saphenous vein grafts.
In a mere two years time this community is to celebrate the 50th anniversary of the GREEN procedure (LIMA to LAD). Since then, profound basic scientific research revealed the unique nature of the IMA, and that is, its’ endothelium produced NITRIC OXIDE, which has a key role in the excellent patency rate of this bypass graft by its constant vasodilator effect ,and the inhibition of thrombocyta aggregation and adhesion. Also, it has a profound effect by these means on the recipient coronary artery, which seems to become resistent to further atheroclerotic deformation. Therefore one may truly wonder, why is it not COMPULSORY to utilize both of the two IMAs. As a matter of fact, in my institution since the first years of the 90s, last century the situation exactly has been the other way round, i.e: 80 % TAR is the method of choice. This means, that in exceptional situation one should not use the IMA (anatomical variation, poor free cut end flow, etc) which are in fact, rare.