Anesthesia Experts | Stenting of the Left Main Artery vs. Bypass Surgery: Another Take

Authors: Mack M and Holmes DR., Lancet 2016 Oct 31;

A large randomized trial surprisingly demonstrates superior 5-year outcomes for coronary-artery bypass surgery in patients with left main coronary artery disease.

For years, coronary-artery bypass grafting (CABG) has been the standard method for revascularization in patients with left main coronary artery disease. In NOBLE, a noninferiority study supported by a stent manufacturer, researchers randomized 1201 such patients to CABG or percutaneous coronary intervention (PCI); patients had stable or unstable angina or non–ST-elevation myocardial infarction.

In 5-year follow-up estimates, the primary composite endpoint — major adverse cardiac or cerebrovascular events (all-cause mortality, nonprocedural myocardial infarction, any repeat coronary revascularization, and stroke) — was more common after PCI than after CABG (hazard ratio [HR], 1.48), mainly driven by a higher rate of revascularization (HR, 1.50). PCI was associated with more nonprocedural myocardial infarctions (HR, 2.88) and showed a nonsignificant trend towards higher risk for stroke (5%; CABG, 2%). All-cause mortality did not differ by treatment group.

Comment

This study showed CABG to be superior to PCI in patients with left main artery disease. How can we balance these surprising results against other recent findings? Those from EXCEL (NEJM JW Cardiol Dec 2016 and N Engl J Med 2016 Oct 31; [e-pub]) showed noninferiority of left main stenting.

NOBLE may have had a high rate of repeat revascularization because 81% of patients had a bifurcation stenosis (distal left main), which is difficult to treat percutaneously and because all types of anatomical complexity were allowed. The larger EXCEL trial used a more contemporary stent and more frequent ultrasound validation of optimal stent deployment (as is recommended for left main PCI), and focused on patients with low and intermediate SYNTAX scores. The higher late stroke rate found in NOBLE perplexed editorialists and is difficult to explain; with no strokes found up to 30 days after PCI, the problem was hardly periprocedural. Nevertheless, both studies found a trend with PCI towards higher need for later revascularization but fewer early adverse events. Overall, these results caution us about the EXCEL findings, especially for more complex/distal left main disease, but are unlikely to change the trend towards increasing use of PCI for left main revascularization.

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