Abstract P237: The Society of Thoracic Surgeons Risk Score Is Superior to the EuroSCORE in Discriminating Long-Term Mortality in Patients Undergoing Nonemergent Unprotected Left Main Stenting

Abstract

Background: Prior observational studies have demonstrated the ability of the EuroScore to discriminate long-term outcomes following unprotected left main (ULM) percutaneous coronary intervention (PCI). No studies have assessed the discriminatory ability of the Society of Thoracic Surgeons (STS) risk score in this context, nor have any compared the two scores. Methods: The study population consisted of 101 consecutive patients undergoing non-emergent ULM PCI. The discriminatory abilities of the EuroScore and STS scores to predict one year mortality were compared using area under the receiver operator characteristic curves (AUC). Optimal partitions of high and low risk were determined separately for the EuroScore and STS scores, and the net reclassification index (NRI) was computed after initial classification with the EuroScore. Results: The STS score provided superior discrimination for one year mortality than did the logistic EuroScore: AUC 0.78 (0.63 - 0.93) v. 0.68 (0.52 - 0.84), P = 0.04 and the additive EuroScore: AUC 0.78 (0.63 - 0.93) v. 0.67 (0.51-0.83), P = 0.01. Using an STS score of > 4 to reclassify all patients initially classified as high risk for death with EuroScore > 10 resulted in an NRI of 0.29 (95% CI 0.08-0.47, P = 0.004); NRI for events 0.16 (95% CI -.03 -.32) NRI for non-events 0.13 (95% CI .04-.22). Conclusions: The STS score provides superior discrimination of long-term mortality in patients undergoing non-emergent ULM PCI than does the EuroScore. The STS score is a useful tool to assess risk in patients eligible for ULM PCI, and may be an important covariate in future comparative effectiveness studies comparing PCI and bypass surgery.