Collagen fibre-mediated mechanical damage increases calcification of bovine pericardium for use in bioprosthetic heart valves.

In cases of aortic stenosis, bioprosthetic heart valves (BHVs), with glutaraldehyde-fixed bovine pericardium leaflets (GLBP), are often implanted to replace the native diseased valve. Widespread use of BHVs, however, is restricted due to inadequate long-term durability, owing specifically to premature leaflet failure. Mechanical fatigue damage and calcification remain the primary leaflet failure modes, where glutaraldehyde treatment is known to accelerate calcification.

Bovine Pericardium of High Fibre Dispersion Has High Fatigue Life and Increased Collagen Content; Potentially an Untapped Source of Heart Valve Leaflet Tissue.

Bioprosthetic heart valves (BHVs) are implanted in aortic valve stenosis patients to replace the native, dysfunctional valve. Yet, the long-term performance of the glutaraldehyde-fixed bovine pericardium (GLBP) leaflets is known to reduce device durability. The aim of this study was to investigate a type of commercial-grade GLBP which has been over-looked in the literature to date; that of high collagen fibre dispersion (HD).

The impact of implantation depth of the Lotus™ valve on mechanical stress in close proximity to the bundle of His.

It has been proposed that inappropriate positioning of transcatheter aortic valves (TAVs) is associated with procedural complications and decreased device durability. Second-generation TAVs allow for repositioning giving greater control over the final deployment position. However, the impact of positioning on the tissue surrounding these devices needs to be better understood, in particular for the interleaflet triangle in which the conductance system (bundle of His) resides.

Total ellipse of the heart valve: the impact of eccentric stent distortion on the regional dynamic deformation of pericardial tissue leaflets of a transcatheter aortic valve replacement.

Transcatheter aortic valve replacements (TAVRs) are a percutaneous alternative to surgical aortic valve replacements and are used to treat patients with aortic valve stenosis. This minimally invasive procedure relies on expansion of the TAVR stent to radially displace calcified aortic valve leaflets against the aortic root wall. However, these calcium deposits can impede the expansion of the device causing distortion of the valve stent and pericardial tissue leaflets.

Simulation of self expanding transcatheter aortic valve in a realistic aortic root: implications of deployment geometry on leaflet deformation.

Self expanding Transcatheter Aortic Valve Replacements (TAVR) can conform to the geometry of the aortic annulus and the calcified leaflet complex, which may result in leaflet distortion and altered leaflet kinematics, but such changes have not yet been characterized. In this study we developed a computational model to investigate the deployment of a self expanding TAVR in a realistic aortic root model derived from multi-slice computed tomography (MSCT) images. We simulated TAVR crimping/deployment in realistic and idealized aortic root models, followed by diastolic loading of the TAVR leaflets in its final deployed configuration.

An in vitro evaluation of the impact of eccentric deployment on transcatheter aortic valve hemodynamics.

Patients with aortic stenosis present with calcium deposits on the native aortic valve, which can result in non-concentric expansion of Transcatheter Aortic Valve Replacement (TAVR) stents. The objective of this study is to evaluate whether eccentric deployment of TAVRs lead to turbulent blood flow and blood cell damage. Particle Image Velocimetry was used to quantitatively characterize fluid velocity fields, shear stress and turbulent kinetic energy downstream of TAVRs deployed in circular and eccentric orifices representative of deployed TAVRs in vivo.