Prosthesis-patient mismatch following transcatheter aortic valve replacement with supra-annular and intra-annular prostheses

Selected in JACC: Cardiovascular Interventions by R. Didier , S. Feliachi

The results of this study suggest that the use of self-expandable valves could help reduce the incidence of post-procedural PPM after TAVI, especially in the population with large body size...

Reviewers

Romain Didier

Interventional cardiologist / Cardiologist

CHRU BREST SITE HOPITAL CAVALE BLANCHE - Brest, France

Souheib Feliachi

CHRU - Brest, France

Our Comment

Why this study – the rationale/objective?

According to the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy registry, the incidence of severe prosthesis-patient mismatch (PPM) after TAVI is around 12% and led to higher mortality and higher heart failure rehospitalization at 1-year follow-up.

The supra-annular position of self-expanding prostheses could potentially allow a larger effective orifice area, and we can speculate to reduce the occurrence of PPM after TAVI with self-expanding valves as compared to balloon-expandable valves with annular position. The present study aims to compare the incidence of post-procedural PPM between the two types of valves.

How was it executed – the methodology?

All patients undergoing TAVI at Bern university hospital with self-expandable valves (CoreValve and Evolut R, MedtronicÒ, Minneapolis, Minnesota) or BEV (SAPIEN THV/XT and SAPIEN 3, Edwards LifesciencesÒ, Irvine, California) were included. Baseline clinical data, procedural characteristics, echocardiographic features and follow-up data at 30 days and 1-year were collected from Swiss TAVI registry.

The choice of valve type and size was guided by CT and clinical characteristics. Regarding the statistical methodology, a propensity score matching method was used to overcome the confounding baseline bias through a multivariate logistic regression model based on clinical, echocardiographic and tomographic variables. The variables were selected based on their presumed association with prosthesis selection and hemodynamic outcomes.

What is the main result?

Overall, 757 patients were included in the present analysis, and finally, 420 patients were treated with Balloon Expandable Valves and 337 with self-expandable valves. The propensity score matching resulted in 224 matched pairs with no difference in the baseline characteristics between the matched population.

The main results were:

• Self-expandable valves were significantly associated with a lower rate of PPM compared with Balloon expandable valves (33.5% vs. 46.9%, p= 0.004; respectively). The difference between the two types of valves was largely driven by the patients with larger body sizes (BSA >1.83 m2 ). In addition, the balloon-expandable valves were associated with higher rate of PPM as compared with SEV even in patients with relatively larger annulus area (≥ 430 mm2).

• No difference was found in cumulative mortality rate at 1 year between patients with severe and/or moderate PPM and patients without PPM.

Critical reading and relevance for clinical practice

The results of this study suggest that the use of self-expandable valves could help reduce the incidence of post-procedural PPM after TAVI, especially in the population with large body size (BSA>1,83 m²). However, this study failed to demonstrate any benefit in term of mortality, functional status or valve deterioration in patients without post-procedural PPM as compared to patients with PPM.

Although all the potential factors influencing the selection of the prosthesis in clinical practice such as annulus size, aortic valvular complex calcium, and annulus eccentricity have been adjusted in propensity score matching analysis, we cannot exclude potential confounders that could affect the results. Moreover, the lack of core lab for echocardiographic assessment of valve function is another relevant limitation.

Nevertheless, in daily practise, we cannot put the PPM aside, and we must put all our efforts into planning the TAVI procedure to further reduce the risk of PPM occurrence. Finally, further studies will be required especially in a younger population with longer follow-up to confirm the translation of these results into clinical relevant events.