Bioprosthetic aortic valve durability in the era of transcatheter aortic valve implantation

Abstract

The main limitation of bioprosthetic valves is their limited durability, which exposes the patient to the risk of aortic valve reintervention. Transcatheter aortic valve implantation (TAVI) is considered a reasonable alternative to surgical aortic valve replacement (SAVR) in patients with intermediate or high surgical risk. TAVI is now rapidly expanding towards the lower risk populations. Although the results of midterm durability of the transcatheter bioprostheses are encouraging, their long-term durability remains largely unknown. The objective of this review article is to present the definition, mechanisms, incidence, outcome and management of structural valve deterioration of aortic bioprostheses with specific emphasis on TAVI. The structural valve deterioration can be categorised into three stages: stage 1: morphological abnormalities (fibrocalcific remodelling and tear) of bioprosthesis valve leaflets without hemodynamic valve deterioration; stage 2: morphological abnormalities and moderate hemodynamic deterioration (increase in gradient and/or new onset of transvalvular regurgitation); and stage 3: morphological abnormalities and severe hemodynamic deterioration. Several specifics inherent to the TAVI including valve oversizing, manipulation, delivery, positioning and deployment may cause injuries to the valve leaflets and increase leaflet mechanical stress, which may limit the long-term durability of transcatheter bioprostheses. The selection of the type of aortic valve replacement and bioprosthesis should thus take into account the ratio between the demonstrated durability of the bioprostheses versus the life expectancy of the patient. Pending the publication of robust data on long-term durability of transcatheter bioprostheses, it appears reasonable to select SAVR with a bioprosthesis model that has well-established long-term durability in patients with low surgical risk and long life expectancy.

Glycation and Serum Albumin Infiltration Contribute to the Structural Degeneration of Bioprosthetic Heart Valves

“…Glycation is established as a functional mechanism of tissue degeneration in various diseases 8,13,40 . This study is the first description of the involvement of glycation in the degeneration of BHVs.…”

“…Further, recent observation suggests that calcification might be associated with SVD without necessarily being functionally causative 5 . Several noncalcific mechanisms have been proposed to contribute to SVD, including inflammatory oxidation, tissue thickening, and collagen network degeneration 4,8 . however, technologies to address known mechanisms thus far have not significantly improved valve durability, suggesting that additional key mechanisms remain unidentified 9,10 .…”

Durability of bioprosthetic aortic valves in patients under the age of 60 years – rationale and design of the international INDURE registry

“…The primary objectives (Table 1) are to 1) determine the time-related valve safety at 1-year (composite endpoint according to the VARC-2 criteria) depicted as freedom from events [23] and 2) determine freedom from stage 3 SVD following the Salaun definition at 5 years [23,24]. Events include SVD (either valve-related dysfunction, defined by haemodynamic parameters or the need for repeat procedure), prosthetic valve endocarditis, prosthetic valve thrombosis, thromboembolic events (e.g., stroke) and valve-related bleeding.…”

“…Clinical outcomes of interest are NYHA functional class compared to baseline and freedom from valve-related hospitalisation. Quality-of-life will be assessed using the Kansas City Cardiomyopathy Questionnaire (KCCQ) and Short Form-12 Health Survey (SF-12) [24]. Various additional exploratory analyses regarding rehospitalisation, costs and safety will also be performed.…”

Using Soft Robotic Technology to Fabricate a Proof‐of‐Concept Transcatheter Tricuspid Valve Replacement (TTVR) Device

“…The premise motivating this method is that surgical valves are known to be significantly more robust than transcatheter stented valves . This is partially due to the fact that surgical valves have a solid ring of material that has less stress concentration and is substantially thicker such that they are more durable than transcatheter metallic stents.…”