The impact of residual coronary lesions on clinical outcomes after percutaneous coronary intervention: Residual SYNTAX score after percutaneous coronary intervention in patients from the Efficacy of Xience/Promus versus Cypher in rEducing Late Loss after stENTing (EXCELLENT) registry

Background The SYNTAX score (SS) is used in preprocedural evaluation for percutaneous coronary intervention (PCI); it assesses the complexity of coronary lesions and predicts PCI outcome. However, the usefulness of the residual SS (rSS), which can be calculated after PCI and may reflect the completeness of revascularization, has not been fully investigated in an enriched PCI population. Methods and Results The baseline SS and rSS were determined in 5,088 patients (3,046 everolimus-eluting stents and 2,042 sirolimus-eluting stents) from the EXCELLENT registry. The primary end point was 1-year patient-oriented composite end point (POCE), comprising all-cause death, myocardial infarction, and repeat revascularization. The mean baseline SS was 13.6 +/- 9.1 and rSS was 4.7 +/- 6.5. Residual SS tertiles were defined as rSS = 0 (42.7%), 0 < rSS < 7 (29.9%), and rSS >= 7 (27.4%). Increasing rSS tertiles had increasing 1-year POCE rates (5.2%, 8.1%, 12.4%; P < .001) mainly caused by the increase in repeat revascularization. Also, rSS was an independent predictor of 1-year POCE after multivariate analysis (P for trend < .001) and had better predictability in simple coronary lesions (baseline SS < 16). The clinical rSS, calculated by multiplying the rSS to a modified age, creatinine clearance, and ejection fraction score (age/ ejection fraction + 1 for each 10 mL the creatinine clearance <60 mL/min), was also associated with 1-year POCE, with predictability similar to rSS (area under curve 0.610 vs 0.607, P = .634). Conclusion Greater residual coronary lesions after PCI with "limus" drug-eluting stent, as quantified by the rSS and the clinical rSS, are associated with increased risk of adverse cardiac events.