Published 5-year results had been neutral for bilateral vs. single internal-thoracic artery grafts, but, at the time, surgeons argued that the time period analyzed was not enough and that a difference would be observed after 10 years of follow-up, once the trial finished. Such follow-up was presented at the European Society of Cardiology (ESC) Congress 2018 and the disappointment was big: bilateral internal-thoracic artery grafts offer no advantage.
After a decade of follow-up, there was no difference between patients who underwent myocardial revascularization surgery involving two bilateral internal-thoracic artery grafts and those with a single arterial graft, plus vein or radial artery grafts, as regards a composite endpoint of death, infarction, and stroke.
No differences were observed either as regards major bleeding or repeat revascularization, although patients who received bilateral internal-thoracic artery grafts experienced more infections.
The study faced difficulties from the beginning. In fact, 36% of patients received a different strategy than that to which they had originally been randomized. A full 14% of patients randomized to bilateral internal-thoracic artery graft finally received a single internal-thoracic artery graft, while 22% of patients randomized to a single internal-thoracic artery graft received a second arterial graft, generally a radial artery graft.
The use of medical treatment was one of the highlights, ranging from 73% to 89%, following clinical practice guidelines (which include aspirin, statins, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and beta-blockers).
The primary endpoint, a composite of death, infarction, and stroke, showed no differences between groups (hazard ratio [HR]: 0.90; 95% confidence interval [CI]: 0.78-1.03). Survival curves were nearly juxtaposed throughout the study.
There are several explanations for this disappointment: one might obviously be a lack of difference between these strategies, although there might be other factors involved. High adherence to medical treatment (a novelty, quite higher than rates observed in all other works comparing surgery and angioplasty, for example) may have diluted the expected differences in reintervention. The use of radial artery grafts in the single internal-thoracic artery graft group also may have influenced reinterventions (radial artery grafts proved to be superior to vein grafts), as well as the observed crossover rate, which may have played a part in the results.
Original title: Randomized Comparison of Single Versus Bilateral Internal Thoracic Artery Grafts in 3102 CABG Patients: Major Cardiovascular Outcomes at Ten Years of Follow Up.
Presenter: Taggart DP.
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