CURRENT OPINION Appropriate myocardial revascularization: a joint viewpoint from an interventional cardiologist and a cardiac surgeon

SYNTAX stands for SYNergy between percutaneous coronary intervention (PCI) with TAXus and cardiac surgery. The trial compared the outcome of surgical and catheter-based revascularization in 3075 patients with multivessel and/or left main CAD. At each of the 85 participating sites (62 in Europe, 23 in USA), a team involving cardiac surgeon(s) and interventional cardiologist(s) evaluated both the coronary lesions and the clinical data for treatment suitability either by PCI using drug-eluting stents (DES) or by coronary artery bypass grafting (CABG). When both approaches were deemed feasible, a 1:1 randomization to either therapy was proposed (PCI 1⁄4 903, CABG 1⁄4 897). If not, two prospective registries of preferred PCI (n 1⁄4 198) or preferred CABG (n 1⁄4 1077) were constructed. Severity and extent of CAD were quantified prospectively by the newly designed SYNTAX score. At 1 year follow-up, the trial failed to confirm the non-inferiority hypothesis with respect to the composite endpoint of death, nonfatal myocardial infarction, cerebro-vascular accident, repeat revascularization by PCI or CABG. While the pre-specified margin of non-inferiority was 6.6%, the observed difference in major adverse cardiac and cerebro-vascular events (MACCE) rate was 5.7%, with a 95% confidence interval at 8.3% (P 1⁄4 0.0015 in favour of surgery). With respect to individual components of the primary endpoint, death and myocardial infarction were neutral (P 1⁄4 0.37 for all cause mortality, P 1⁄4 0.11 for myocardial infarction), cerebro-vascular accident favoured PCI (0.06% after PCI, 2.2% after CABG, P 1⁄4 0.003) while repeat revascularization was significantly less after CABG (5.9% vs. 13.7% after PCI, P , 0.001), driving the rate of MACCE well outside the non-inferiority margin. Extensive post hoc subset analyses have been presented, which is problematic since the trial is essentially negative and confirms the value of CABG as the standard of care for the majority of patients with extensive CAD. With PCI, outcome was inversely related to the extent and severity of the disease, as captured by the SYNTAX score. The MACCE rates per tertiles of SYNTAX score ( 22, 23–32, 33) showed a stepwise increase: 13.5, 16.6, 23.3% (P 1⁄4 0.007). The lower tertile subset of SYNTAX scores included patients with left main disease in the absence of diffuse distal involvement. The fewer DES were implanted, the shorter the vessel length covered by stents, the better the outcome. In retrospect, denying PCI attempts in cases with the most complex anatomy, based on a pre-intervention SYNTAX score 33, would most likely have resulted in a positive trial. With CABG, results were more predictable across tertiles of SYNTAX scores, as well as in patients with diabetes. By multivariable analysis in the randomized cohort, poor outcome with surgery was associated primarily with the presence of clinical markers of increased risk such as unstable angina, chronic obstructive lung disease, poor left ventricular function, or prior myocardial infarction. These observations were confirmed by the registry data. Percutaneous coronary intervention was deemed not feasible more often than CABG (5:1), essentially because of excessive lesion complexity. Coronary artery bypass grafting was deemed not feasible because of co-morbidities in 70.7% and lack of suitable conduits for bypass in 9.1% of cases. Not unexpectedly, criticism has been voiced from both sides. Some surgical colleagues have argued that the early risk of CABG was unnecessarily high (on-pump surgery in 85% of cases and frequent use of aortic anastomoses) and that the potential late benefit of CABG will not be fully exercised (complete arterial