Three-Year SYNTAX Data Support Global Risk to Evaluate PCI

June 20, 2012—Patrick W. Serruys, MD, et al published 3-year data from the SYNTAX trial in the Journal of the American College of Cardiology: Cardiovascular Interventions (2012;5:606–617). The aim of this study was to assess the additional value of Global Risk—a combination of the SYNTAX score and EuroSCORE—in the identification of a low-risk population who could safely and efficaciously be treated with coronary artery bypass graft surgery (CABG) or percutaneous coronary intervention (PCI).

Within the SYNTAX (Taxus Drug-Eluting Stent Versus Coronary Artery Bypass Surgery for the Treatment of Narrowed Arteries) trial, all-cause death and major adverse cardiac and cerebrovascular events (MACCE) were analyzed at 36 months in low to high Global Risk groups, with Kaplan-Meier, log-rank, and Cox regression analyses.

As detailed in the Journal of the American College of Cardiology: Cardiovascular Interventions, the investigators reported that within the randomized left main stem population (n = 701), comparisons between Global Risk groups demonstrated a significantly lower mortality with PCI compared with CABG (1.2% vs 7.5%; hazard ratio [HR], 0.16; 95% confidence interval [CI], 0.03–0.7; P = .0054) and a trend toward reduced MACCE (15.8% vs 23.1%; HR, 0.64; 95% CI, 0.39–1.07; P = .088). Similar analyses within the randomized three-vessel disease population (n = 1,088) demonstrated no statistically significant differences in mortality (5.8% vs 5.2%; HR, 1.14; 95% CI, 0.57–2.3; P = .71) or MACCE (24.7% vs 19%; HR, 1.35; 95% CI, 0.95–1.92; P = .1). Risk-model performance and reclassification analyses demonstrated that the inclusion of Global Risk enhanced the risk stratification of all PCI patients.

In comparison with the SYNTAX score, Global Risk (with a simple treatment algorithm), substantially enhances the identification of low-risk patients who could safely and efficaciously be treated with CABG or PCI, concluded the investigators.

Also in the Journal of the American College of Cardiology: Cardiovascular Interventions, the SYNTAX investigators published data on the risk profile and 3-year outcomes from the SYNTAX PCI and CABG nested registries (2012;5:618–625). The aim of this study was to evaluate the use of PCI and CABG in “real-world” patients who are unsuitable for the alternative treatment.

The background of the second study, advised the SYNTAX investigators, is that no data are available on the risk profile and outcomes of patients who can only undergo PCI or CABG. In the SYNTAX trial, a multidisciplinary heart team reached a consensus on whether PCI and CABG could result in clinical equipoise; if so, the patient was randomized; if not, the patient was enrolled in a CABG-ineligible PCI registry or PCI-ineligible CABG registry. A proportion of patients (60%) in the CABG registry was randomly assigned to be followed up for 5 years. No statistical comparisons were performed between randomized and registry patients. MACCE rates are presented as observational only.

As summarized in the Journal of the American College of Cardiology: Cardiovascular Interventions, a total of 3,075 patients were treated in the SYNTAX trial: 198 (6.4%) and 1,077 (35%) patients were included in PCI and CABG registries, respectively. The main reason for inclusion in the CABG registry was complex coronary anatomy (70.9%), and the main reason for inclusion in the PCI registry was high surgical risk (70.7%). The 3-year MACCE rate was 38% after PCI and 16.4% after CABG. Stratification by SYNTAX score terciles demonstrated a step-wise increase of MACCE rates in both PCI and CABG registries.

The SYNTAX heart team concluded that PCI and CABG remained the only treatment options for 6.4% and 35% of patients, respectively. Inoperable patients with major comorbidities who underwent PCI had high MACCE rates. In patients who were not suitable for PCI, surgical results were excellent, stated the investigators in the Journal of the American College of Cardiology: Cardiovascular Interventions.