ART Trial: From the Horse’s Mouth

Filmed during the the 27th ASCTVS and 65th IACTVS Conference, Dr Om P. Yadava, CEO and Chief Cardiac Surgeon of the National Heart Institute in New Delhi, India, and Editor-in-Chief of the Indian Journal of Thoracic and Cardiovascular Surgery, discusses the Arterial Revascularization Therapy (ART) Trial with Professor David Taggart from the University of Oxford in the United Kingdom.

Dr Taggart feels that the ART Trial has something for everyone (1). Those who want to do bilateral internal mammary artery (IMA) surgery have ”As Treated” analysis to support their philosophy, while those wanting to use only a single IMA can resort to ”Intention to Treat” (ITT) analysis data from the ART Trial. He acknowledges that the biggest problem with the ART Trial is that 40% of the patients had a treatment different from what was planned – 14% of the anticipated bilateral IMAs crossed over to the single IMA group, 4% of the anticipated single IMAs crossed over to the bilateral IMA group, and 22% of patients had an additional radial artery (RA) placed as the second arterial conduit in the single IMA group. Dr Taggart candidly admits that this is a major confounder for the ART Trial, and at the time that they were designing the trial, they did not know that the RA could have such a major impact on outcomes as compared to the saphenous vein. However, he feels confident that bilateral IMAs, if analyzed in earnest, would prove to be superior to the single IMA, as was shown when the data of the highest performing surgeon, who contributed 416 surgeries using bilateral IMAs with barely 1.2% crossover, was analyzed independently. In this cohort, even the ITT analysis shows a survival benefit of bilateral IMAs. Unfortunately, surgeon inexperience became a major factor in the ART Trial and, in certain cases, 100% of patients crossed over from bilateral IMA to single IMA.

To a provocative question asking what might occur if the ART Trial was redesigned, Professor Taggart notes that all the lessons learned have been incorporated into the ROMA Trial being carried out by Mario Gaudino et al. Surgeons’ claims of being able to perform the bilateral IMA procedure is not sufficient, but actual performance and the proof thereof is mandatory. Professor Taggart further warrants that the ART Trial will be followed beyond ten years to see whether the survival curves diverge for ITT analysis. Contraindications to bilateral IMAs, according to the ART Trial, would be insulin-dependent diabetes mellitus, specifically in obese individuals, and chronic obstructive airways disease with some early shoots of higher complications in women and the elderly, which were thus relative contraindications.

Reference

Taggart DP, Benedetto U, Gerry S, Altman DG, Gray AM, Lees B, et al for the Arterial Revascularization Trial Investigators. Bilateral versus single internal thoracic artery grafts at 10 years. N Engl J Med. 2019;380:437-446.