CABG and PCI in Unprotected Left Main Disease

Study Questions:

What are the long-term clinical outcomes following coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in patients with unprotected left main disease (ULMD)?


Between 2004 and 2010, 4,046 consecutive patients with ULMD were treated with either CABG (n = 2,604) or PCI (n = 1,442) with drug-eluting stents. The primary outcome was 3-year all-cause mortality and the secondary outcome was the composite of death, nonfatal myocardial infarction, or nonfatal stroke. For comparisons of long-term outcomes between two treatment groups, the investigators used adjusted survival curves and weighted Cox proportional hazards regression with inverse probability-of-treatment weighting to determine hazard ratios (HRs).


The unadjusted 3-year all-cause mortality was higher in the PCI group as compared with the CABG group (3.8% vs. 2.5%; log-rank p = 0.03), although there was no significant difference in the composite outcome (7.5% vs. 9.4%; log-rank p = 0.07). After adjustment for differences in baseline risk factors, PCI was associated with significantly higher risk of all-cause mortality (HR, 1.71; 95% confidence interval [CI], 1.32-2.21; p < 0.001), but similar risk of the composite outcome (HR, 0.94; 95% CI, 0.82-1.09; p = 0.43). These differences were not statistically significant among patients with low or intermediate SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) score (≤32) or diabetes; however, PCI was associated with an increased risk among those with a high SYNTAX score (>32), with HRs of 3.10 (95% CI, 1.84-5.22; p < 0.001) for all-cause mortality and 1.82 (95% CI, 1.36-2.45; p < 0.001) for the composite outcome. CABG was associated with lower risk of repeat revascularization, but higher risk of stroke in each clinically relevant subgroup.


The authors concluded that in this single-center observational study, among patients with ULMD, CABG was associated with improved long-term outcomes, especially in patients with more complex disease.


This single-center study reports that for patients with ULMD and less complex disease (low or intermediate SYNTAX scores), PCI is a reasonable alternative treatment to CABG, whereas greater survival benefit of CABG over PCI was found in patients with high SYNTAX scores. Furthermore, there was no evidence of a differential association of coronary revascularization strategy with diabetes mellitus. The optimum revascularization strategy for an individual patient should balance the risks and benefits associated with each procedure in conjunction with the baseline risk profile and patient preferences and with input from a multidisciplinary team. The ongoing EXCEL trial, using more contemporary revascularization techniques and randomizing patients with SYNTAX scores ≤32 to PCI or CABG, will provide more definitive conclusions about the optimal treatment of ULMD.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Atherosclerotic Disease (CAD/PAD), Aortic Surgery, Interventions and Coronary Artery Disease

Keywords: Cardiac Surgical Procedures, Coronary Artery Bypass, Coronary Artery Disease, Diabetes Mellitus, Drug-Eluting Stents, Myocardial Infarction, Myocardial Ischemia, Myocardial Revascularization, Percutaneous Coronary Intervention, Risk Assessment, Risk Factors, Stroke

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