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In this international trial, SYNTAX, which was sponsored by the manufacturer of a drug-eluting stent (DES), 1800 patients with three-vessel or left main coronary artery disease were randomly assigned to coronary artery bypass grafting or percutaneous coronary intervention with DES. Before randomization, an interventional cardiologist and a cardiac surgeon evaluated all patients’ angiograms and agreed that equivalent anatomic revascularization was feasible with either technique. The primary endpoint, a composite of major adverse cardiac and cerebrovascular events (MACCE), included repeat revascularization.
About 40% of patients had left main disease with or without three-vessel disease, and about 25% had diabetes. More than four lesions were treated per patient. The rate of complete revascularization was slightly higher in the CABG group (63%) than in the PCI group (57%; P=0.005).
After 12 months, the MACCE rate was significantly lower in the CABG group (12%) than in the PCI group (18%). The CABG group had a significantly higher stroke rate than the PCI group (2.2% vs. 0.6%), whereas the PCI group had a significantly higher repeat revascularization rate than the CABG group (13.5% vs. 5.9%). Mortality was similar in the two groups. PCI was associated with a higher MACCE rate in patients with the highest scores of disease severity than in lower-scoring patients; the same association was not seen with CABG. This finding thus increased the between-group difference in MACCE among the most severely ill patients (PCI, 23%; CABG, 11%). In an observational analysis of the left main subgroup, the overall MACCE rate was similar after CABG and after PCI, although somewhat greater benefit with CABG was observed in left main patients who also had two- or three-vessel disease.
Serruys PW et al for the SYNTAX Investigators. PCI versus coronary-artery bypass grafting for severe coronary artery disease. N Engl J Med 2009 Feb 18; [e-pub ahead of print]. (http://dx.doi.org/10.1056/NEJMoa0804626)
Lange RA and Hillis LD. SYNTAX in context. N Engl J Med 2009 Feb 18; [e-pub ahead of print]. (http://dx.doi.org/10.1056/NEJMe0900452)
Comment
These findings from the largest randomized study to date comparing current revascularization strategies in patients with severe CAD failed to demonstrate that PCI is noninferior to CABG at 12 months. Interventionalists are likely to propose that the rate of repeat revascularization with PCI is less important than the higher rate of stroke with CABG (thereby minimizing differences between the treatments) and that a similar 12-month mortality rate renders PCI an equivalent and less-invasive alternative to CABG, even in patients with left main disease. However, given the trend toward worse outcomes with PCI in the highest-risk patients, as well as the lack of long-term follow-up, this hypothesis is unsupported without additional evidence. The newly defined SYNTAX score (measuring lesion complexity based on angiograms) used in both the randomized trial and a registry of excluded patients could help inform clinical decision making.