Performance of EuroSCORE II and Society of Thoracic Surgeons risk scores in elderly patients undergoing aortic valve replacement surgery

Abstract

Background: In cardiac surgery, risk is estimated with models such as EuroSCORE II and the Society of Thoracic Surgeons (STS) score. Performance of these scores may vary across various patient age ranges.

Aim: To assess the effect of patient age on performance of the EuroSCORE II and STS scores, regarding postoperative mortality after surgical aortic valve replacement.

Methods: In a prospective cohort of patients, we assessed risk stratification of EuroSCORE II and STS scores for discrimination of in-hospital mortality with the area under the receiver operating characteristic curve (AUROC) and calibration with the Hosmer-Lemeshow test. Two groups of patients were compared: elderly (aged>75years) and younger patients.

Results: Of 1229 patients included, 635 (51.7%) were elderly. Mean EuroSCORE II score was 3.7±4.4% and mean STS score was 2.1±1.5%. Overall in-hospital mortality was 4.8% and was higher in the elderly compared with younger patients (6.6% vs. 2.8%; log-rank P=0.014). AUROC for the EuroSCORE II score was lower in elderly than in younger patients (0.731 vs. 0.784; P=0.025). Similarly, AUROC for the STS score was lower in elderly versus younger patients (0.738 vs. 0.768; P=0.017). In elderly patients, EuroSCORE II and STS scores were not adequately calibrated and significantly underestimated mortality. Age was independently associated with mortality, regardless of EuroSCORE II or STS score.

Conclusions: In this cohort, EuroSCORE II and STS scores did not perform as well in elderly patients as in younger patients. Elderly patients may be at increased postoperative risk, regardless of risk score.

Keywords: Aortic valve replacement; Chirurgie cardiaque; Elderly; EuroSCORE II; Gériatrie; Risk stratification; Scores de risque; Society of Thoracic Surgeons; TAVI.