The results of a randomized controlled trial led by Dr. Gregg W. Stone presented at TCT 2019 and published in the New England Journal of Medicine showed that in patients with left main coronary artery disease of low or intermediate complexity, there was no significant difference in the composite endpoint of death, stroke, or myocardial infarction at 5 years in patients who received either percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG).
While PCI is currently an acceptable treatment for some patients with left main coronary artery disease, there is a lack of long-term data from randomized controlled trials to support this. The investigators aimed to compare long term outcome data of patients with left main disease who undergo either CABG or PCI.
The EXCEL trial was a randomized controlled trial that randomized patients with left main coronary artery disease to either coronary artery bypass grafting (CABG) or PCI with thin-strut cobalt-chromium fluoropolymer-based everolimus-eluting stents (XIENCE, Abott Vascular). Left main coronary artery disease was defined as stenosis of 70% or more that was directly visualized or stenosis of 50% to 70% as determined by non-invasive testing or invasive means but determined to be of hemodynamic significance. Additionally, patients who had low or intermediate anatomic complexity as determined by the center and had a Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score of 32 or less. Dual antiplatelet therapy was administered for at least 1 year from the index intervention. The primary outcome was defined as a composite of death, stroke, or myocardial infarction at 5 years. Secondary outcomes included the primary composite outcome (death, stroke or myocardial infarction) by 30 days, and the composite of death, stroke, myocardial infarction or ischemia-driven revascularization at 5 years.
“PCI may thus be considered an acceptable revascularization modality for selected patients with LMCAD, a decision which should be made after heart team discussion, taking into account each patient’s individual risk factors and preferences.” – Gregg W. Stone, M.D.
A total of 1,905 patients were randomized to either PCI (948 patients, 49.7%) or CABG (957 patients, 50.3%). Baseline characteristics were well balanced between the two groups. The mean age was 66.0, with a standard deviation of 9.6 years. 76.9% were male and 29.1% had diabetes. The mean SYNTAX score calculated by the site was 20.6 +/- 6.2 and 26.5 +/- 9.3 as determined by the angiographic core lab. A total of 93.2% and 90.1% in the PCI and CABG groups had a five-year follow-up. The primary outcome of death, stroke or myocardial infarction occurred in 22.0% of the PCI group and 19.2% of the CABG group (Difference of 2.8%, 95% CI -0.9 to 6.5%, p = 0.13). The investigators also compared outcomes between PCI and CABG at three time periods. The three time periods were 0 to 30 days (HR 0.61, 95% CI 0.42 to 0.88), 30 days to 1 year (HR 1.07, 95% CI 0.68 to 1.70), and 1 year to 5 years (HR 1.61, 95% CI 1.23 to 2.12). The secondary outcome occurred in 31.3% of patients in the PCI group and 24.9% of patients in the CABG group (6.5% difference, 95% CI 2.4% to 10.6%).
The findings of this study suggest that at the end of the 5 year follow-up period, there is no statistically significant difference in ischemic events between the PCI and CABG group. In this study, although patients with PCI had a lower risk of peri-procedural complications (during the first thirty days), this risk was attenuated by the increased risk of adverse events later on in the clinical course (1 year to 5 years). The overall cumulative mean time free from adverse events was similar in both treatment groups by 5 years. When discussing the implication of this study, Dr. Stone noted, “PCI may thus be considered an acceptable revascularization modality for selected patients with LMCAD, a decision which should be made after heart team discussion, taking into account each patient’s individual risk factors and preferences.”
However, this study does have its limitations. Blinding was not possible and therefore, some degree of event ascertainment is expected. Additionally, a ten-year follow-up period is required in order to ascertain the very late safety profile for PCI and CABG as both stents and bypass grafts can fail over time. Regardless, the findings of this study highlight the possibility of PCI being an acceptable alternative to CABG in certain patients with left main coronary artery disease.
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