The MCV-US-2009-01 study randomised 797 surgical high-risk patients at 45 United States (US) centres 1:1 to undergo TAVR with a self-expanding bioprosthesis or SAVR. The primary endpoint was Extreme Risk (all-cause death or major stroke) in TAVR patients and High-Risk Surgical (all-cause mortality) for SAVR patients; both measured in the 1st-year and according to the Valve Academic Research Consortium I (VARC-1) criteria. Severe hemodynamic SVD was defined as a mean gradient ≥40 mm Hg, a change in gradient ≥20 mm Hg, or new onset severe aortic regurgitation. The preplanned analysis of the mid-term 5-year outcomes focussed on safety, performance, and durability.

Among the 797 patients randomised, the mean age was 83 years and the Society of Thoracic Surgeons (STS) score was 7.4%. Ninety-four per cent (N=750) underwent an attempted implant (TAVR: N=391; SAVR: N=359). The all-cause mortality rates at 5-years for TAVR vs SAVR were 55.3% vs 55.4%, respectively. No differences in mortality for subgroups were identified. The major stroke rates at 5-years for TAVR vs SAVR were 12.3% vs 13.2%, respectively. The mean aortic valve gradients were 7.1 ± 3.6 mm Hg (TAVR) and 10.9 ± 5.7 mm Hg (SAVR). The authors did not report any clinically significant valve thrombosis.

Finally, 99.2% of TAVR patients and 98.3% of SAVR patient remained free from severe SVD (p = 0.32). Moreover, 97.0% and 98.9% of patients were free from VR (p = 0.04), for TAVR and SAVR respectively. A third of TAVR patients had received a pacemaker at the 5-year follow-up vs 19.8% of SAVR patients.