Aims: The indication for transcatheter aortic valve implantation (TAVI) has evolved from inoperable patients to patients at increased surgical risk. In low-risk patients, surgical aortic valve replacement (SAVR) remains the standard of care. The aim of this study was to explore the outcomes of TAVI and SAVR in patients with a Society of Thoracic Surgeons (STS) predicted risk of mortality (PROM) score below 3% in the SURTAVI trial.
Methods and results: In SURTAVI, patients at intermediate surgical risk based on Heart Team consensus were randomised to TAVI or SAVR. We stratified the overall patient population into quintiles based on the STS PROM score; the one-year mortality was correlated with the mean STS PROM score in each quintile. The quintiles were regrouped into three clinically relevant categories of STS score: less than 3%, 3 to <5%, and >5%. All-cause mortality or disabling stroke in each risk stratum was compared between TAVI and SAVR. Linear regressions between mean values of STS PROM in each quintile and observed all-cause mortality at one year showed great association for the global population (r2=0.92), TAVI (r2=0.89) and SAVR cohorts (r2=0.73). All-cause mortality or disabling stroke of TAVI vs. SAVR was 1.5% vs. 6.5% (p=0.04), 6.5% vs. 7.6% (p=0.52) and 13.5% vs. 11.0% (p=0.40) in the <3%, 3-5%, and ≥5% STS score strata, respectively.
Conclusions: Among patients at intermediate surgical risk but with an STS PROM <3%, TAVI may achieve superior clinical outcomes compared to SAVR. These findings support the need for an adequately powered randomised trial to compare TAVI with SAVR in patients at low operative risk.