ViV TAVR For Failing Surgical Valves Shows Promising Longer-Term Data
PARTNER II ViV results presented at TCT Connect 2020 raises expectations and questions in difficult patient group
PARTNER II ViV investigators presented promising five-year data on valve-in-valve (ViV) transcatheter aortic valve replacement (TAVR) for severe aortic stenosis patients with failing surgical bioprosthetic valves (SBV) at TCT Connect 2020 this year to raise confidence in the procedure but still leaving low-risk groups up in the air.
The five-year data may serve as the latest catalyst for shifting the rate of physician selection for ViV TAVR over redo surgery and patient preference for bioprosthetic valves in what is becoming an increasingly complex decision-making process for patients with aortic stenosis.
ViV TAVR – in earlier studies1 – was associated with acceptable mortality, improved valve hemodynamics, and excellent quality of life outcomes at three years for patients with failing surgical valves, but lacked data attesting to longer-term clinical outcomes, valve function, and durability.
Rebecca T. Hahn, MD (NewYork-Presbyterian/Columbia University Irving Medical Center), who presented the results of the PARTNER II ViV study on Oct. 17 at TCT Connect 2020, explained that the lack of long-term data spurred investigators to conduct a five-year follow-up study of the prospective, multicenter PARTNER aortic ViV registries.
And the team found, Hahn said, ViV TAVR mortality in high-risk patients at five years was comparable to that of native TAVR mortality in intermediate-risk patients. Early improvement in functional status and quality of life were maintained throughout five years among survivors and valve hemodynamics were stable over five years. Rates of hemodynamic valve deterioration (HVD) and bioprosthetic valve failure (BVF) were also consistent with those reported for native SAPIEN XT valves in intermediate-risk patients.
PARTNER 2 ViV raises TAVR confidence, leaves low-risk patients in grey zone
The prospective, multicenter PARTNER II ViV trial pulled 365 patients from two ViV registries – Nested Registry (NR3) and Continued Access Nested Registry (CANR) – that were nested in the PARTNER II trial.
Investigators included patients with symptomatic severe stenosis or regurgitation of a surgical aortic bioprosthetic valve and a high- and extreme-risk for re-operation (estimated surgical mortality or major morbidity ¡Ă50 percent). Patients with surgical bioprostheses smaller than 21-mm were excluded, and instead included patients eligible for treatment with a 23-mm or 26-mm SAPIEN XT THV. Mean patient age was 79 years old and 64 percent were male.
Between studies, the five-year all-cause mortality rate was 50.6 percent, which was significantly lower than the 73.0 percent of inoperable patients treated with native valve TAVR in PARTNER II cohort B (P<0.0001). No significant mortality difference was found between patients in the PARTNER 2 ViV trial and those in the PARTNER 2 cohort A trial (50.6% vs. 45.9%, P=0.06).
¡°These outcomes are likely related to the numerous differences in baseline characteristics and echocardiographic parameters – and most importantly, the 23-mm valve was implanted more in males with a higher STS score, lower BMI, and greater incidence of important CAD,¡± Hahn said. ¡°These patients also had a significantly smaller baseline EOA and a higher baseline mean gradient, as well as a suggestion of more right heart disease, such as tricuspid regurgitation.¡±
Early improvement in functional status and quality of life – quantified by improvements in mean gradients, Doppler Velocity Index, and total aortic regurgitation – held up for five years.
Valve hemodynamics were also stable over the five years, with the rate of structural valve deterioration being 5.9 percent. Structural valve deterioration resulting in bioprosthetic valve failure occurred only in 2.3 percent at five years whereas bioprosthetic valve failure due to either structural valve deterioration or re-intervention was 4.7 percent at five years. The additional 14 patients requiring re-intervention included seven who underwent surgical valve replacement, five who had a second TAVR, and two who had a balloon aortic valvuloplasty for either valve stenosis or restenosis.
¡°There was a dramatic improvement in the Kansas City Cardiomyopathy Questionnaire (KCCQ) of nearly 30 points from 43.1 at baseline to 74.2 at 5 years - this is greater than what any native TAVR trials have seen – and this improvement remained stable throughout the follow-up period,¡± Hahn said. ¡°In conclusion, ViV TAVR mortality at five years in high-risk patients was comparable to that of native TAVR in intermediate-risk patients, while early improvement in functional status and quality of life was maintained throughout five years for survivors.¡±
When asked about the need for a randomized controlled trial for low-risk patients, Hahn responded by saying,
We do have more confidence in the procedure itself as well as its durability with these more longitudinal outcomes but I agree that in low-risk patients, we are looking for much longer-term results than five years. Conducting a randomized trial for low-risk patients would be an interesting prospect that would definitely inform patients before their first procedure to consider mechanical valves.