Coronary artery bypass graft surgery (CABG) has been the standard of care for revascularisation of patients with complex coronary artery disease since its introduction in 1968. 

When percutaneous coronary intervention (PCI) was introduced in 1977, it was thought to be appropriate only for patients with single-vessel disease but, as operator ability and device technologies have advanced, the use of PCI has expanded to treat patients with increasingly complex disease, such as multivessel and left main coronary disease.

The optimum method for revascularisation of these patients has been a matter of debate, with many published trials comparing outcomes of CABG and PCI with drug-eluting stents (DES). Most of these trials have been limited by non-randomised patient selection, inclusion of less complex disease, or insufficient statistical power. The SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery (SYNTAX) trial assessed the optimum revascularisation treatment for patients with de novo left main coronary disease or three-vessel disease (or both), by randomly assigning patients to either PCI with a first-generation paclitaxel-eluting stent or CABG. 

In this study, ‘Coronary artery bypass graft surgery versus percutaneous coronary intervention in patients with three-vessel disease and left main coronary disease: 5-year follow-up of the randomised, clinical SYNTAX trial’, the authors present the final results of the SYNTAX trial after five years of follow-up, with the aim to confirm the one-year and three-year findings.

The SYNTAX trial with nested registries took place in 85 centres in the US and Europe. Patients were randomly assigned (1:1) to either PCI with a first-generation paclitaxel-eluting stent or to CABG. Patients suitable for only one treatment option were entered into either the PCI-only or CABG-only registries. A composite rate of major adverse cardiac and cerebrovascular events (MACCE) at five-year follow-up was determined by Kaplan-Meier analysis on an intention-to-treat basis.

There were 1,800 patients randomly assigned to CABG (n = 897) or PCI (n = 903). More patients who were assigned to CABG withdrew consent than did those assigned to PCI (50 versus 11). 

After five year’s follow-up, Kaplan-Meier estimates of MACCE were 26.9% in the CABG group and 37.3% in the PCI group (p < 0.0001). 

Estimates of myocardial infarction (3.8% in the CABG group versus 9.7% in the PCI group; p < 0.0001) and repeat revascularisation (13.7% versus 25.9%; p < 0.0001) were significantly increased with PCI versus CABG. 

All-cause death (11.4% in the CABG group versus 13.9% in the PCI group; p = 0.10) and stroke (3.7% versus 2.4%; p = 0.09) were not significantly different between groups. 

Some 28.6% of patients in the CABG group with low SYNTAX scores had MACCE versus 32.1% of patients in the PCI group (p = 0.43); and 31.0% in the CABG group with left main coronary disease had MACCE versus 36.9% in the PCI group (p = 0.12). 

However, in patients with intermediate or high SYNTAX scores, MACCE was significantly increased with PCI (intermediate score, 25.8% of the CABG group versus 36.0% of the PCI group; p = 0.008; high score, 26.8% versus 44.0%; p < 0.001).

CABG should remain the standard of care for patients with complex lesions (high or intermediate SYNTAX scores). For patients with less complex disease (low SYNTAX scores) or left main coronary disease (low or intermediate SYNTAX scores), 

PCI is an acceptable alternative. All patients with complex multivessel coronary artery disease should be reviewed and discussed by both a cardiac surgeon and interventional cardiologist to reach consensus on optimum treatment.

Reference

1. Mohr FW, Morice MC, Kappetein AP et al, Lancet 2013; 381: 629-638