Unprotected left main revascularization in patients with acute coronary syndromes

Abstract

Aims: In acute coronary syndromes (ACS), the optimal revascularization strategy for unprotected left main coronary disease (ULMCD) has been little studied. The objectives of the present study were to describe the practice of ULMCD revascularization in ACS patients and its evolution over an 8-year period, analyse the prognosis of this population and determine the effect of revascularization on outcome.

Methods and results: Of 43 018 patients enrolled in the Global Registry of Acute Coronary Events (GRACE) between 2000 and 2007, 1799 had significant ULMCD and underwent percutaneous coronary intervention (PCI) alone (n = 514), coronary artery bypass graft (CABG) alone (n = 612), or no revascularization (n = 673). Mortality was 7.7% in hospital and 14% at 6 months. Over the 8-year study, the GRACE risk score remained constant, but there was a steady shift to more PCI than CABG over time. Patients undergoing PCI presented more frequently with ST-segment elevation myocardial infarction (STEMI), 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 vs. no revascularization, significant for PCI (hazard ratio (HR) 2.60, 95% confidence interval (CI) 1.62-4.18) but not for CABG (1.26, 0.72-2.22). From discharge to 6 months, both PCI (HR 0.45, 95% CI 0.23-0.85) and CABG (0.11, 0.04-0.28) were significantly associated with improved survival in comparison with an initial strategy of no revascularization. Coronary artery bypass graft revascularization was associated with a five-fold increase in stroke compared with the other two groups.

Conclusion: Unprotected left main coronary disease in ACS is associated with high mortality, especially in patients with STEMI and/or haemodynamic or arrhythmic instability. Percutaneous coronary intervention is now the most common revascularization strategy and preferred in higher risk patients. Coronary artery bypass graft is often delayed and performed in lower risk patients, leading to good 6-month survival. The two approaches therefore appear complementary.

Figure 1

Study flow diagram.

Figure 2

Temporal trends in acute coronary syndrome (A) score severity and (B) type of revascularization in left main disease.

Figure 3

(A) Cumulative death rate by revascularization group as a time-varying covariate. The number of patients analysed in each group were as follows: n = 513 for percutaneous coronary intervention, n = 607 for coronary artery bypass graft, and n = 670 for neither. (B) Cumulative rate of stroke by revascularization group as a time-varying covariate. The number of patients analysed in each group were as follows: n = 492 for PCI, n = 581 for CABG, and n = 633 for neither.