Clinical outcome of asymptomatic severe aortic stenosis with medical and surgical management: Importance of STS score at diagnosis

Background The Society of Thoracic Surgeons (STS) score aims at predicting operative mortality in cardiac surgery. The value of this score in predicting short- and long-term survival with medical or surgical management in patients with asymptomatic severe aortic stenosis (AS) is unknown. Methods In a cohort of 694 patients (aged 71 ± 11 years) with isolated, asymptomatic severe AS (velocity <4 m/s), STS score was calculated at baseline and its link to survival analyzed. Patients were stratified by STS score less than 4%, 4% to 6.5%, and 6.5% or greater. Results The STS score showed no association with operative mortality within 1 year of diagnosis or any time (1%, 2.9%, and 6.1%, respectively, by strata; p = 0.08) and a weak association with 1-year survival (p = 0.04). Conversely, long-term survival (10-year) was strongly predicted by STS score strata (78%, 47%, and 16%, respectively; p < 0.0001). In multivariate analysis, STS score independently predicted mortality (hazard ratio/1%, 1.15 [1.12 to 1.18], p < 0.0001) or cardiac death (1.21 [1.17 to 1.25], p < 0.0001). Aortic valve replacement within 1 year of diagnosis markedly improved survival (adjusted hazard ratio, 0.58, p < 0.001). However, benefit of early surgery varied according to strata, with no overt benefit with low score (p = 0.83), whereas early surgery considerably improved survival in the intermediate strata (p < 0.001). Conclusions For patients with asymptomatic severe AS, STS score is a powerful tool for predicting long-term outcome and for selecting patients (particularly those at intermediate risk) who benefit markedly from early surgery. Hence, risk-scoring using STS score should be routinely performed in patients with AS to support the clinical decision-making process.