3D histopathology of stenotic aortic valve cusps using ex vivo microfocus computed tomography

Camille Pestiaux; Grzegorz Pyka; Louise Quirynen; David De Azevedo; Jean-Louis Vanoverschelde; Benoît Lengelé; David Vancraeynest; Christophe Beauloye; Greet Kerckhofs

doi:10.3389/fcvm.2023.1129990

3D histopathology of stenotic aortic valve cusps using ex vivo microfocus computed tomography

Front Cardiovasc Med. 2023 Apr 25:10:1129990. doi: 10.3389/fcvm.2023.1129990. eCollection 2023.

Authors

Camille Pestiaux^{1

2}, Grzegorz Pyka^{1

2}, Louise Quirynen¹, David De Azevedo^{3

4}, Jean-Louis Vanoverschelde^{3

4}, Benoît Lengelé², David Vancraeynest^{3

4}, Christophe Beauloye^{3

4}, Greet Kerckhofs^{1

2

5

6}

Affiliations

¹ Mechatronic, Electrical Energy and Dynamic Systems, Institute of Mechanics, Materials and Civil Engineering, UCLouvain, Louvain-la-Neuve, Belgium.
² Pole of Morphology, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium.
³ Pole of Cardiovascular Research, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium.
⁴ Division of Cardiology, University Hospital Saint-Luc, Brussels, Belgium.
⁵ Department of Materials Engineering, KU Leuven, Heverlee, Belgium.
⁶ Prometheus, Division for Skeletal Tissue Engineering, KU Leuven, Leuven, Belgium.

Abstract

Background: Calcific aortic stenosis (AS) is the most prevalent heart valve disease in developed countries. The aortic valve cusps progressively thicken and the valve does not open fully due to the presence of calcifications. In vivo imaging, usually used for diagnosis, does not allow the visualization of the microstructural changes associated with AS.

Methods: Ex vivo high-resolution microfocus computed tomography (microCT) was used to quantitatively describe the microstructure of calcified aortic valve cusps in full 3D. As case study in our work, this quantitative analysis was applied to normal-flow low-gradient severe AS (NF-LG-SAS), for which the medical prognostic is still highly debated in the current literature, and high-gradient severe AS (HG-SAS).

Results: The volume proportion of calcification, the size and number of calcified particles and their density composition was quantified. A new size-based classification considering small-sized particles that are not detected with in vivo imaging was defined for macro-, meso- and microscale calcifications. Volume and thickness of aortic valve cusps, including the complete thickness distribution, were also determined. Moreover, changes in the cusp soft tissues were also visualized with microCT and confirmed by scanning electron microscopy images of the same sample. NF-LG-SAS cusps contained lower relative amount of calcifications than HG-SAS. Moreover, the number and size of calcified objects and the volume and thickness of the cusps were also lower in NF-LG-SAS cusps than in HG-SAS.

Conclusions: The application of high-resolution ex vivo microCT to stenotic aortic valve cusps provided a quantitative description of the general structure of the cusps and of the calcifications present in the cusp soft tissues. This detailed description could help in the future to better understand the mechanisms of AS.

Keywords: 3D histopathology; aortic stenosis; ex vivo imaging; microfocus computed tomography; microstructural characterization.

Grants and funding

CP, BL and GK acknowledge the Action de Recherche Concertée (ARC 19/24-097)-Fédération Wallonie-Bruxelles and acknowledge the support from ASBL Jean Degroof-Marcel Van Massenhove funding and the Foundation Saint-Luc (RM2A project). GP and GK acknowledge the support from the SBO project of the Research Foundation Flanders (FWO; grant S007219N). DDA acknowledges the grant support from the Fondation Nationale de la Recherche Scientifique of the Belgian Government (FRSM PDR T.0237.21). Avizo 2022.1 (ThermoFisher Scientific, France) software acquisition was supported by the Fonds de la Recherche Scientifique – (FNRS - EQP - Tomo4D-U.N069.20).