Multiscale Multimodal Characterization and Simulation of Structural Alterations in Failed Bioprosthetic Heart Valves

Abstract

Calcific degeneration is the most frequent type of heart valve failure, with rising incidence due to the ageing population. The gold standard treatment to date is valve replacement. Unfortunately, calcification oftentimes re-occurs in bioprosthetic substitutes, with the governing processes remaining poorly understood. Here, we present a multiscale, multimodal analysis of disturbances and extensive mineralisation of the collagen network in failed bioprosthetic bovine pericardium valve explants with full histoanatomical context. In addition to highly abundant mineralized collagen fibres and fibrils, calcified micron-sized particles previously discovered in native valves were also prevalent on the aortic as well as the ventricular surface of bioprosthetic valves. The two mineral types (fibers and particles) were detectable even in early-stage mineralisation, prior to any macroscopic calcification. Based on multiscale multimodal characterisation and high-fidelity simulations, we demonstrate that mineral occurrence coincides with regions exposed to high haemodynamic and biomechanical indicators. These insights obtained by multiscale analysis of failed bioprosthetic valves may serve as groundwork for the evidence-based development of more durable alternatives.

On the role of aortic valve architecture for physiological haemodynamics and valve replacement. Part II: spectral analysis and anisotropy

“…3 In regards to the fluctuating enstrophy intensity I ω ′2 , the time-averaged value for the VLth30 valvular case is thrice that of the stenotic case and the Ulth0 BioAV case. The elevated levels of fluctuating enstrophy in the VLth30 case arise from the non-axisymmetric and more pronounced leaflet motion, with a displacement magnitude of approximately 2 mm during systole 27,9 . This finding is consistent with the higher levels of streamwise instantaneous vorticity highlighted in the first part of the study 9 .…”

“…Previous studies have extensively explored the haemodynamic performance of aortic valves made from biological materials like porcine or bovine pericardium 2,4,6,13,27,29 . However, the correlation between the kinetic energy (KE) present within the valve components (i.e.…”

Instability mechanisms initiating laminar–turbulent transition past bioprosthetic aortic valves

“…A BHV creates a more physiological flow field and exhibits lower thrombogenicity. Nevertheless, turbulent flow during the systolic phase of the cardiac cycle is observed (Becsek, Pietrasanta & Obrist 2020), possibly triggering leaflet calcification and eventually leading to structural valve deterioration (Dvir et al 2018;Gomel, Lee & Grande-Allen 2019;Li 2019;Tsolaki et al 2023) or causing bioprosthetic leaflet thrombosis (Egbe et al 2015;Holmes & Mack 2017;Puri, Auffret & Rodés-Cabau 2017). Therefore, turbulent blood flow after BHVs is detrimental to valve performance and may be a factor for their limited durability of less than 20 years, which prevents their usability for younger patients (Kheradvar et al 2015).…”

“…2018; Gomel, Lee & Grande-Allen 2019; Li 2019; Tsolaki et al. 2023) or causing bioprosthetic leaflet thrombosis (Egbe et al. 2015; Holmes & Mack 2017; Puri, Auffret & Rodés-Cabau 2017).…”