Four-Year Outcomes from the EVOLUT Low Risk Trial
Reported from TCT 2023
Dejan Milasinovic provides his take on the EVOLUT Low Risk trial, presented by Michael I. Reardon at TCT Congress 2023. 4-year results reveal a continuing trend towards lower combined rates of all-cause mortality and disabling stroke with TAVI compared with surgical aortic valve replacement (SAVR)
4-year results of the EVOLUT Low Risk trial reveal a continuing trend towards lower combined rates of all-cause mortality and disabling stroke with TAVI compared with surgical aortic valve replacement (SAVR) (10.7% vs. 14.1%, p=0.05). Importantly, absolute difference between the groups rose from 1.8% in favour of TAVI at 2 years, to 3.4% at 4 years, implying a sustained benefit of the percutaneous procedure over surgery. Of note, EVOLUT Low Risk trial included 1 414 patients with the mean age of 74 and STS score of 2.0 and 1.9 in TAVI and SAVR group, respectively. 94.7% of patients treated with TAVI were available for follow-up at 4 years, compared with 89.2% in the SAVR group, in alignment with previous trials that have also showed a lower patient availability for follow-up following surgery.
The intuitive question following the release of 4-year EVOLUT Low Risk data is whether a more liberal approach to patient selection for TAVI, moving towards younger, lower risk patients, is now warranted. When pondering this question, at least the following two major issues may need to be considered.
First, given the mean age of 74, the awaited 10-year follow-up is still needed to provide crucial information on both the valve durability and performance, as well as on the clinical course of these patients including aortic valve reinterventions.
Second, the here described EVOLUT Low Risk 4-year results need to be contrasted with the PARTNER 3 5-year data. In the latter study, a balloon-expandable Sapien valve did not maintain an edge over SAVR over 5 years, i.e. there was an attenuation of the benefit seen in the first year. Moreover, all-cause mortality was numerically higher in the TAVI group (10.0%) vs. 8.2% in the SAVR group. However, this difference was reduced to 10.2% vs. 9.0% when additional vital status data were obtained from national databases, reflecting the need to achieve better follow-up rates in patients treated with SAVR. In an attempt to comparatively analyse both Low-Risk trials, further information may be required, to understand 1) the differences in the outcomes of the SAVR group across both trials, 2) causes of death after TAVI vs. SAVR and 3) the potentially differential impact of supra- vs. intra-annular devices in more complex anatomical subsets.
Overall, the higher rate of permanent pacemaker implantation (up to 25% in the TAVI arm of the EVOLUT Low Risk trial) notwithstanding, the favourable clinical outcomes and hemodynamic profile, reflected by low mean gradients at 4- to 5-year follow-up and low rate of moderate/severe PVL, seem reassuring. Hence, the promise of a durable percutaneous treatment for younger aortic stenosis patients appears to still hold, as we await the 10-year outcomes.
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