No difference in all cause death in PCI and CABG in left main CAD After 5-Years: LANCET

Left main coronary artery disease is associated with high morbidity and mortality owing to a large amount of myocardium at risk. Two studies, EXCEL and NOBEL on the treatment of unprotected left main coronary artery disease have enough data, with conflicting results, to make both cardiac surgeons and interventional cardiologists confused. The debate over the optimal revascularization approach for left main coronary artery disease (CAD) has been simmering for years and remains uncertain. Therefore Prof Marc S Sabatine, MD and his team conducted a study to evaluate long-term outcomes for patients treated with percutaneous coronary intervention (PCI) with drug-eluting stents versus coronary artery bypass grafting (CABG).

They conducted an individual patient data meta-analysis by including 4 studies SYNTAX, PRECOMBAT, NOBLE, and EXCEL which compared PCI with drug-eluting stents and CABG in patients with left main CAD that had at least 5 years of patient follow-up for all-cause mortality. They involved 4394 patients, with a median SYNTAX score of 25·0 (IQR 18·0–31·0) and randomly assigned them to PCI (n=2197) or CABG (n=2197). The major outcome assessed was 5-year all-cause mortality. They also evaluated cardiovascular death, spontaneous myocardial infarction, procedural myocardial infarction, stroke, and repeat revascularisation.

They used a one-stage approach and calculated the event rates using the Kaplan-Meier method. The treatment group were compared using the Cox frailty model, with trial as a random effect. In Bayesian analyses, they further calculated the probabilities of absolute risk differences in the primary endpoint between PCI and CABG being more than 0·0%, and at least 1·0%, 2·5%, or 5·0%.

Key findings of the study were:

• The researchers found that the 5-year Kaplan-Meier estimate of all-cause mortality was 11.2% among those treated with CABG surgery and 10.2% for those treated with PCI, a difference that was statistically insignificant.
• Upon bayesian analyses, they noted that there was a greater likelihood of more deaths from any cause at 5 years with PCI, although that excess risk was "more likely than not" less than 1% over 5 years, or less than 0.2% year.
• They also noted for cardiovascular mortality, the excess risk with PCI was likely less than 0.1% per year compared with surgery.
• They observed that spontaneous myocardial infarction (6·2%; hazard ratio [HR] 2·35) and repeat revascularisation (18·3%; HR 1·78) were more common with PCI than with CABG.
• They mentioned that differences in procedural myocardial infarction between strategies depended on the definition used.
• Overall, they found no difference in the risk of stroke between PCI (2·7%) and CABG (3·1%; HR 0·84). However, they noted that the risk was lower with PCI in the first year after randomisation (HR 0·37).

The authors concluded, "Among patients with left main coronary artery disease and, largely, low or intermediate coronary anatomical complexity, there was no statistically significant difference in 5-year all-cause death between PCI and CABG, although a Bayesian approach suggested a difference probably exists (more likely than not <0·2% per year) favouring CABG. "

They further added, "There were trade-offs in terms of the risk of myocardial infarction, stroke, and revascularization. A heart team approach to communicate expected outcome differences might be useful to assist patients in reaching a treatment decision."

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DOI: https://doi.org/10.1016/S0140-6736(21)02334-5