Representativeness of surgical controls in aortic valve replacement trials: comparison with routine surgical cohorts

Randomised controlled trials (RCTs) comparing transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) have significantly influenced treatment guidelines for aortic stenosis, expanding the use of TAVI into lower risk populations. However, the patients enrolled in the SAVR arms of these trials may differ from those typically undergoing SAVR in routine clinical practice. This study aims to critically assess the representativeness of SAVR patients in these RCTs by comparing their characteristics and outcomes to those of patients undergoing SAVR in routine clinical practice.

A systematic literature review was conducted across PubMed, Embase, Web of Science, Emcare and the Cochrane Library, focusing on RCTs and large prospective studies (n≥500 SAVR patients), enrolling low-risk or intermediate-risk patients since 2010. Patient characteristics, early outcomes and 5-year survival were compared between RCT SAVR cohorts and those treated in routine clinical practice settings. Meta-analyses of pooled data and reconstructed Kaplan-Meier survival analyses were performed, with stratification by risk category.

Nineteen studies (9 RCTs and 10 studies describing routine clinical practice), encompassing 74 797 SAVR patients, were included. SAVR patients in routine clinical practice demonstrated comparable early mortality to SAVR patients in RCTs but experienced fewer periprocedural complications, including lower rates of stroke, pacemaker implantation and myocardial infarction. At 5 years, overall survival was notably higher in patients treated in routine clinical practice compared to those in the SAVR arms of RCTs, both for low-risk (HR 0.64, 95% CI 0.55 to 0.75) and intermediate-risk patients (HR 0.55, 95% CI 0.470.64).

Compared with typical SAVR patients treated in routine practice, RCT SAVR patients experienced higher complication rates and worse long-term survival, despite similar or lower surgical risk scores. These findings question the external validity of SAVR versus TAVI trials.