Visualization of fiber structure and calcification of porcine and human aortic valve and pericardium tissue via optical coherence tomography

Calcific aortic valve disease, the most treated heart valve pathology, is characterized by leaflet fibrosis and calcification. Diseased aortic valves (AV) are replaced by bio-prostheses fabricated from glutaraldehyde-fixed xenogeneic pericardium. Material degeneration and tissue calcification of these prostheses result in a limited durability of 10-15 years and, thus, the need of surgical reintervention. To improve both treatment of native aortic valve disease and prostheses durability, non-invasive monitoring of tissue remodeling and calcification via optical coherence tomography (OCT) is envisioned for the characterization of in vitro model systems. Application of OCT technology is planned for the investigation of in vivo models in AV research up to a clinical application. Extra cellular matrix (ECM) structure of AV and pericardium tissue could be visualized as well as a diffuse microcalcification in human pathological AV tissue. A nondirectional fiber orientation was verified in porcine pericardium and AVs. The three-layered AV structure can be imaged by the means of different optical densities identified by OCT. Microcalcification was correlated to subsequent histology of fibrotic tissue. Large calcification nodules of human AV tissue exhibit inhomogeneous OCT intensities. In summary, OCT facilitates not only the non-invasive definition and quantification of fibrotic matrix remodeling but also the detection of tissue calcification in pericardium or AV tissues. The presented preliminary dataset reveals the applicability of OCT for visualization of aortic valve or pericardium tissue remodeling and calcification and allows to point out tasks for development of OCT monitoring and quantitative analysis adopted for tissue culture in a microphysiological system.