Six-Year Outcomes After Transcatheter vs Surgical Aortic Valve Replacement in Low-Risk Patients With Aortic Stenosis

Abstract

Background: The Evolut Low Risk trial enrolled patients with severe aortic stenosis at low surgical risk. Annual follow-up is planned for 10 years, evaluating the composite of all-cause mortality or disabling stroke and key secondary endpoints.

Objectives: Our prespecified objective was to report the 6-year clinical outcomes of transcatheter aortic valve replacement (TAVR) vs surgery from the Evolut Low Risk trial. Given an increase in reintervention rates at 6 years, we performed additional analyses in available 7-year data.

Methods: Low-risk patients with severe symptomatic aortic stenosis were randomized to TAVR or surgery from 2016-2019. Prespecified analyses at 6 years included annual follow-up of clinical outcomes reported as Kaplan-Meier estimates with log-rank test. Because the trial enrolled patients over several years, at the time of data lock, a majority of patients had completed 7-year follow-up. Given an increased reintervention rate at 6 years in the TAVR arm, we performed additional analysis of 7-year data available at the time of the database lock. Reintervention rates are reported as cumulative incidence.

Results: A total of 1,414 patients underwent an attempted implantation (730 TAVR, 684 surgery). At 6 years, the composite endpoint of all-cause mortality or disabling stroke was 23.3% for TAVR and 20.4% for surgery (difference: 2.8% [95% CI: -1.9% to 7.6%]; P = 0.43). All-cause mortality with vital status sweep at 6 years was 23.3% (95% CI: 20.6%-26.4%) for TAVR and 20.2% (95% CI: 17.4%-23.3%) for surgery (P = 0.24). The reintervention rate at 6 years was 5.5% for TAVR and 3.3% for surgery (sHR: 1.66 [95% CI: 0.96-2.86]; P = 0.07). Using available 7-year follow-up (555 TAVR and 480 surgery), the reintervention rate for TAVR was 9.8% and for surgery was 6.0% (sHR: 1.68 [95% CI: 1.10-2.58]; P = 0.02). In the TAVR and surgery groups, the rate of reintervention for regurgitation was 5.6% vs 1.6% (sHR: 3.39 [95% CI: 1.62-7.07]; P < 0.001) and the rate of reintervention for stenosis was 3.6% vs 3.5% (sHR: 1.14 [95% CI: 0.61-2.15]; P = 0.70).

Conclusions: The 6-year results from the Evolut Low Risk trial show no significant difference in the composite endpoint of all-cause mortality or disabling stroke. At 6 and 7 years, the TAVR arm had a higher reintervention rate compared with surgery, driven by an increased incidence of aortic regurgitation. (Medtronic Evolut Transcatheter Aortic Valve Replacement in Low Risk Patients; NCT02701283).

Keywords: TAVR; aortic stenosis; low-risk; supra-annular self-expanding; surgery.