Launched in 1999, the Global Registry of Acute Coronary Events (GRACE) is the world's largest international database tracking outcomes of patients presenting with acute coronary syndromes (ACS), including myocardial infarction or unstable angina. GRACE data are derived from 247 hospitals in North America, South America, Europe, Asia, Australia and New Zealand, and from more than 100,000 patients with ACS. Data from 43,018 ACS patients in the Registry were analyzed to determine the optimal revascularization strategy for unprotected left main coronary disease, which has so far been little studied.

Results of the analysis showed that unprotected left main coronary disease (ULMCD) in ACS is associated with high in-hospital mortality, especially in patients presenting with ST-segment elevation myocardial infarction (STEMI) and/or hemodynamic or arrhythmic instability. Percutaneaous coronary intervention (PCI) is now the most common revascularization strategy in this population, and is preferred in higher-risk patients. Coronary artery bypass grafting (CABG) is often delayed and is associated with the best 6-month survival. The two approaches therefore appear complementary in this high-risk group.

Of the 43,018 patients in the analysis, 1799 had significant ULMCD and underwent PCI alone (n=514), CABG alone (n=612), or no revascularization (n=673). Mortality was 7.7% in hospital and 14% at six months.

Over the eight-year study period, the GRACE risk score remained constant, 20 points higher in PCI than in CABG, but there was a steady shift to more PCI than CABG revascularization over time. Patients undergoing PCI presented more frequently with acute myocardial infarction, after cardiac arrest, or in cardiogenic shock; 48% of PCI patients underwent revascularization on the day of admission vs. 5.1% in the CABG group. After adjustment, revascularization was associated with an early hazard of hospital death compared with no revascularization, significant for PCI (HR 2.60, 95% CI 1.62-4.18) but not for CABG (HR 1.26, 95% CI 0.72-2.22).

From discharge to six months, both PCI (HR 0.45, 95% CI 0.23-0.85) and CABG (HR 0.11, 95% CI 0.04-0.28) were significantly associated with improved survival in comparison with an initial strategy of no revascularization. CABG revascularization was associated with a five-fold increase in stroke compared with the other two groups.

Says investigator Professor Gilles Montalescot from the Hopital Pitie-Salpetriere in Paris: "The results show that CABG surgery and PCI are not used in similar types of patients and provide complementary treatment options in ACS."