Sirolimus-Eluting Stents versus CABG in Unprotected Left Main Coronary Stenosis

A randomized Korean study found percutaneous coronary intervention (PCI) with sirolimus-eluting stents noninferior to coronary artery bypass grafting (CABG) in patients with unprotected left main coronary stenosis.

Despite PCI’s apparent effectiveness, the study was not sufficiently powered to inform practice decisions, and CABG remains the treatment of choice. One- and 2-year findings from the PRECOMBAT (Premier of Randomized Comparison of Bypass Surgery Versus Angioplasty Using Sirolimus-Eluting Stent in Patients with Left Main Coronary Artery Disease) trial were reported in the New England Journal of Medicine [2011;364(18):1718-1727]. From April 2004 to August 2009, the prospective, open-label study randomized 600 adults (median age, 62 years; 76.5% men) with a new diagnosis of stable or unstable angina, silent ischemia, or non–ST-elevation myocardial infarction (MI) to undergo PCI (n=300) or CABG (n=300).

All patients had newly diagnosed stenosis >50% of the diameter of the left coronary artery and were suitable candidates for either procedure. Patient and angiographic characteristics at baseline were balanced between the groups, but only 6.0% of patients in the PCI arm versus 8% in the CABG arm had a euroSCORE (European System for Cardiac Operative Risk Evaluation) ≥6, which indicates high operative risk. The trial’s primary end point was the 1-year cumulative rate of major cardiac and cerebrovascular adverse events in each group. This end point included mortality, MI, stroke, and ischemia-driven target vessel revascularization. Secondary end points were incidences of each event per arm, as well as a composite end point of death, MI, stroke, and stent thrombosis. CABG was associated with a slightly higher yet nonsignificant rate of complete revascularization compared with PCI (68.3% vs 70.3%, respectively). Patients assigned to PCI spent significantly fewer days in the hospital than individuals treated with CABG (3.1±5.8 vs 8.4±14.5, respectively; P<.001). Yet patients in the PCI arm were more likely than those in the CABG group to receive antiplatelet medications, beta-blockers, and calcium channel blockers after discharge and to undergo follow-up angiography at 8 to 10 months (75.3% vs 24.7%, respectively; P<.001).

The 1-year analysis found more patients assigned to PCI than to CABG experienced major cardiac or cerebrovascular cardiovascular events incorporated in the composite primary end point (26 [8.7%] vs 20 [6.7%], respectively), with an absolute difference in risk of 2.0% (95% confidence interval [CI], –1.6 to 5.6; P=.01 for noninferiority). Little variation was observed between groups in the incidences of each adverse event included in the composite end point. A post hoc analysis 2 years after randomization found 36 patients in the PCI group and 24 in the CABG group had suffered a major cardiac or cerebrovascular event (12.2% vs 8.1%, respectively; hazard ratio [HR] with PCI, 1.50; 95% CI, 0.90-2.52; P=.12). Incidence rates for individual events were similar with the exception of ischemia-driven target vessel revascularization, which occurred significantly more often in the CABG group than the PCI group (12 vs 26, respectively; HR, 2.18; 95% CI, 1.10-4.32; P=.02).

At 2 years, 2 patients randomized to PCI developed definite or probable stent thrombosis and 4 assigned to CABG had symptomatic graft occlusion (2 died). The authors said the 1-year analysis demonstrates that PCI with sirolimus-eluting stents is noninferior to CABG for this patient population, with a noninferiority margin of 7 percentage points. Rates of cardiac and cerebrovascular events in PRECOMBAT were lower than expected, however, and below the rates observed in other studies comparing PCI and CABG for left main coronary artery stenosis. “For this reason, the findings cannot be considered clinically directive,” they said. They identified various factors that might be behind the surprisingly low event rate, such as a lower mean euroSCORE, less complex disease, or differences in procedure execution or protocol. The authors noted their findings might be biased due to the large number of patients crossing over from the PCI arm to the CABG arm.