Coronary artery bypass grafting (CABG) should remain the standard of care for patients with complex coronary artery disease (CAD), according to results from the SYNTAX study, which are published in the March 5 issue of the New England Journal of Medicine.
The SYNTAX study, jointly led by Patrick Serruys, MD, PhD, from Erasmus University Medical Center in Rotterdam, the Netherlands, and Fred Mohr, MD, from the University of Leipzig in Germany, set out to compare CABG and PCI using drug eluting stents to investigate whether the standard of care has changed. The findings of the SYNTAX study were first presented at the 2008 European Society of Cardiology (ESC) meeting in Munich.
"The SYNTAX study shows the importance of including both interventional cardiologists and cardiac surgeons in the decision making process. The fact SYNTAX concludes CABG should be considered the standard of care means all centers should be standing back and considering it," according to William Wijns, MD, spokesperson for the ESC and president of the European Association for Percutaneous Cardiovascular Interventions (EAPCI).
For SYNTAX, between March 2005 and April 2007, 1800 patients with three-vessel or left main CAD from 62 sites in Europe and 23 sites in North America were randomly assigned to undergo CABG or PCI in a 1:1 ratio. Researchers said that patients were only entered into the randomization if an interventional cardiologist and cardiac surgeon both judged that they could achieve equivalent results with either procedure. Patients for whom only one treatment option was considered suitable were entered into either a PCI registry (198 patients) or a CABG registry (1,077 patients), with data reported separately.
Results at 12 months show that the rates of major adverse cardiac or cerebrovascular events-defined as the primary end point for the study-were significantly higher in the PCI group than the CABG group (17.8 vs. 12.4 percent), according to the authors. The differences could be largely accounted for by patients in the PCI group requiring increased repeat revascularization. Altogether, 13.5 percent of patients in the PCI group underwent repeat revascularization compared with 5.9 percent of the patients in the CABG group.
At 12 months the rates of overall death—defined as the secondary end point were similar for the two groups—3.5 percent in the CABG group vs. 4.4 percent in the PCI group, the researchers reported. Stroke, however, was significantly more likely to occur in the CABG population—2.2 percent of CABG patients experienced stroke compared with 0.6 percent of PCI patients.
For the first time investigators used a measure known as the SYNTAX score, which has been designed to evaluate the complexity of the CAD. By splitting the population in tertiles, a low score was defined as less than 22, an intermediate score as between 23 and 32 and a high score as greater than 33. For patients receiving CABG, the major adverse cardiac or cerebrovascular events were similar in all three SYNTAX score groups. In contrast, for patients receiving PCI, the rate of major adverse cardiac or cerebrovascular events was 23.4 percent for those with high SYNTAX scores, 16.7 percent for those with intermediate scores and 13.6 percent for those with low scores.
Commenting on the SYNTAX score data for PCI, Wijns said that wider use of the scoring system would provide clarity on which patients were most appropriate for different procedure.
"Until now the borders between PCI and CABG have been quite blurred, but these results show that PCI can give excellent results in a predefined lower to intermediate risk sub group, but that it's not appropriate for high risk groups," he said, adding that he looked forward to the score becoming widely available so that clinicians could use it in their decision making process.
In an accompanying editorial, Richard Lange, MD, and David Hillis, MD, from the University of Texas Health Science Center in San Antonio, considered the increased risk of stroke in CABG patients. "The investigators do not discuss whether the strokes were related to the procedure or whether the risk of having a stroke was influenced by differences between the two groups in the occurrence of atrial fibrillation, use of aspirin or other antiplatelet agents, or presence of risk factors for atherosclerosis," they wrote.