SYNTAX score and Clinical SYNTAX score as predictors of very long-term clinical outcomes in patients undergoing percutaneous coronary interventions: a substudy of SIRolimus-eluting stent compared with pacliTAXel-eluting stent for coronary revascularization (SIRTAX) trial

Aims To investigate the ability of SYNTAX score and Clinical SYNTAX score (CSS) to predict very long-term outcomes in an all-comers population receiving drug-eluting stents. Methods and results The SYNTAX score was retrospectively calculated in 848 patients enrolled in the SIRolimus-eluting stent compared with pacliTAXel-Eluting Stent for coronary revascularization (SIRTAX) trial. The CSS was calculated using age, and baseline left ventricular ejection fraction and creatinine clearance. A stratified post hoc comparison was performed for all-cause mortality, cardiac death, myocardial infarction (MI), ischaemia-driven target lesion revascularization (TLR), definite stent thrombosis, and major adverse cardiac events (MACE) at 1- and 5-year follow-up. Tertiles for SYNTAX score and CSS were defined as SS(LOW) <= 7, 7 < SS(MID) <= 14, SS(HIGH) > 14 and CSS(LOW) <= 8.0, 8.0 < CSS(MID) <= 17.0 and CSS(HIGH) > 17.0, respectively. Major adverse cardiac events rates were significantly higher in SS(HIGH) compared with SSLOW at 1- and 5-year follow-up, which was also seen at 5 years for all-cause mortality, cardiac death, MI, and TLR. Stratifying outcomes across CSS tertiles confirmed and augmented these results. Within CSS(HIGH), 5-year MACE increased with use of paclitaxel-compared with sirolimus-eluting stents (34.7 vs. 21.3%, P = 0.008). SYNTAX score and CSS were independent predictors of 5-year MACE; CSS was an independent predictor for 5-year mortality. Areas-under-the-curve for SYNTAX score and CSS for 5-year MACE were 0.61 (0.56-0.65) and 0.62 (0.57-0.67), for 5-year all-cause mortality 0.58 (0.51-0.65) and 0.66 (0.59-0.73) and for 5-year cardiac death 0.63 (0.54-0.72) and 0.72 (0.63-0.81), respectively. Conclusion SYNTAX score and to a greater extent CSS were able to stratify risk for very long-term adverse clinical outcomes in an all-comers population receiving drug-eluting stents. Predictive accuracy for 5-year all-cause mortality was improved using CSS. Trial Registration Number: NCT00297661.