Impact of the SYNTAX score in patients with acute coronary syndromes undergoing medical therapy

Aims: We sought to investigate the prognostic impact of the SYNTAX (Synergy between PCI with TAXUS and Cardiac Surgery) score (SS) on 1-year clinical outcomes in patient with non ST-segment elevation acute coronary syndromes (NSTE-ACS) undergoing medical therapy only. The SS has been shown to be a strong predictor of adverse ischaemic events after PCI. However, its predictive capacity among patients undergoing medical therapy only remains unexplored. Methods and results: Among the 13,819 patients enrolled in the ACUITY trial and undergoing coronary angiogram, 4,491 patients were treated with medical therapy as the initial strategy. From them, baseline SS and complete angiographic analysis were available in 1,275 patients. Patients were divided in four groups, based on the presence or absence of coronary artery disease (CAD), and subsequently, among patients with CAD, in tertile of SS. Composite ischaemic end-points and its individual components (death, MI, and unplanned revascularisation) were compared between groups. Among the 1,275 patients, the mean SS was 3.5±7.0, ranging from 0 to 45. SS was 0 in 842 patients, >0 and ≤5 in 170, (tertile 1), >5 and ≤11 in 119, (tertile 2), and >11 in 144 patients (tertile 3). Reasons leading to medical treatment were the absence of CAD (66.0%), physician preference (26.5%), coronary anatomy unsuitable for revascularisation (12.5%), patient preference (1.6%), and others (10.0%). Patients with CAD and higher baseline SS were more frequently older, male and presented with a history of diabetes, hyperlipidaemia, prior myocardial infarction, prior PCI, and renal insufficiency, and with ST depression than patients with no CAD or lower SS. The 1-year rates of all ischaemic adverse events were higher in patients with presence of CAD and higher SS (1-year MACE 4.5%, 6.1%, 14.9%, 14.8%, p<0.0001; 1-year mortality, 1.9%, 2.5% 7.4%, 5.2%, p=0.0048, for SS=0, tertile 1, tertile 2, and tertile 3, respectively). By multivariate analysis, the SS was a strong predictor of all adverse ischaemic events, including mortality (hazard ratio 1.04, 95% CI 1.01 -1.07, p=0.015). By ROC analysis, a cut-off of 9 showed the best prognostic accuracy for death and MACE. Conclusions: In patients with NSTE-ACS undergoing medical therapy, the SS was shown to be a strong predictor of 1-year adverse ischaemic events, including mortality. This finding has important clinical implications for risk stratification of patients with NSTE-ACS undergoing medical therapy after an initial angiogram.