Category: General

J Mech Behav Biomed Mater. 2024 Dec;160:106741. doi: 10.1016/j.jmbbm.2024.106741. Epub 2024 Sep 11.

ABSTRACT

Transcatheter aortic valve replacement (TAVR) has become today the most attractive procedure to relieve patients from aortic valve disease. However, the procedure requires crimping biological tissue within a metallic stent for low diameter catheter insertion purpose. This step induces specific stress in the leaflets especially when the crimping diameter is small. One concern about crimping is the potential degradations undergone by the biological tissue, which may limit the durability of the valve once implanted. The purpose of the present work is to investigate the mechanical damage undergone by bovine pericardium tissue during compression and analyze how this degradation evolves with time under fatigue testing conditions. Pericardium 500 μm thick pericardium ribbons (5 mm large, 70 mm long) were crimped down to 12 Fr for 30 and 50 min within a metallic stent to replicate the heart valve crimping configuration. After crimping, samples underwent cyclic fatigue flexure and pressure loading over 0.5 Mio cycles. Samples were characterized for mechanical performances before crimping, after crimping and after fatigue testing in order to assess potential changes in the mechanical properties of the tissue after each step. Results bring out that the ultimate tensile strength is not modified through the process. However an increase in the modulus shows that the crimping step tends to stiffen the pericardium. This may have an influence on the lifetime of the implant.

PMID:39276437 | DOI:10.1016/j.jmbbm.2024.106741

J Mech Behav Biomed Mater. 2024 Dec;160:106741. doi: 10.1016/j.jmbbm.2024.106741. Epub 2024 Sep 11.

ABSTRACT

Transcatheter aortic valve replacement (TAVR) has become today the most attractive procedure to relieve patients from aortic valve disease. However, the procedure requires crimping biological tissue within a metallic stent for low diameter catheter insertion purpose. This step induces specific stress in the leaflets especially when the crimping diameter is small. One concern about crimping is the potential degradations undergone by the biological tissue, which may limit the durability of the valve once implanted. The purpose of the present work is to investigate the mechanical damage undergone by bovine pericardium tissue during compression and analyze how this degradation evolves with time under fatigue testing conditions. Pericardium 500 μm thick pericardium ribbons (5 mm large, 70 mm long) were crimped down to 12 Fr for 30 and 50 min within a metallic stent to replicate the heart valve crimping configuration. After crimping, samples underwent cyclic fatigue flexure and pressure loading over 0.5 Mio cycles. Samples were characterized for mechanical performances before crimping, after crimping and after fatigue testing in order to assess potential changes in the mechanical properties of the tissue after each step. Results bring out that the ultimate tensile strength is not modified through the process. However an increase in the modulus shows that the crimping step tends to stiffen the pericardium. This may have an influence on the lifetime of the implant.

PMID:39276437 | DOI:10.1016/j.jmbbm.2024.106741

J Mech Behav Biomed Mater. 2024 Dec;160:106741. doi: 10.1016/j.jmbbm.2024.106741. Epub 2024 Sep 11.

ABSTRACT

Transcatheter aortic valve replacement (TAVR) has become today the most attractive procedure to relieve patients from aortic valve disease. However, the procedure requires crimping biological tissue within a metallic stent for low diameter catheter insertion purpose. This step induces specific stress in the leaflets especially when the crimping diameter is small. One concern about crimping is the potential degradations undergone by the biological tissue, which may limit the durability of the valve once implanted. The purpose of the present work is to investigate the mechanical damage undergone by bovine pericardium tissue during compression and analyze how this degradation evolves with time under fatigue testing conditions. Pericardium 500 μm thick pericardium ribbons (5 mm large, 70 mm long) were crimped down to 12 Fr for 30 and 50 min within a metallic stent to replicate the heart valve crimping configuration. After crimping, samples underwent cyclic fatigue flexure and pressure loading over 0.5 Mio cycles. Samples were characterized for mechanical performances before crimping, after crimping and after fatigue testing in order to assess potential changes in the mechanical properties of the tissue after each step. Results bring out that the ultimate tensile strength is not modified through the process. However an increase in the modulus shows that the crimping step tends to stiffen the pericardium. This may have an influence on the lifetime of the implant.

PMID:39276437 | DOI:10.1016/j.jmbbm.2024.106741

ACS Appl Mater Interfaces. 2024 Nov 13. doi: 10.1021/acsami.4c14256. Online ahead of print.

ABSTRACT

Valve replacement is the most effective means of treating heart valve diseases, and transcatheter heart valve replacement (THVR) is the hottest field at present. However, the durability of the commercial bioprosthetic valves has always been the limiting factor restricting the development of interventional valve technology. The chronic inflammatory reaction, calcification, and difficulty in endothelialization after the implantation of a glutaraldehyde cross-linked porcine aortic valve or bovine pericardium often led to valve degeneration. Improving the biocompatibility of valve materials and inducing endothelialization to promote in situ regeneration can extend the service life of valve materials. Herein, inspired by the hardening process of butterfly wings, this study proposed a dopamine-metal-phenol strategy to modify decellularized porcine pericardium (DPP). This is a strategy to make dopamine (DA) coordinate trivalent metal chromium ions (Cr(III)) with antiplatelets (PLTs) and anti-inflammatory properties, and then cross-link it with tea polyphenols (TP) to generate a valve scaffold that is mechanically comparable to glutaraldehyde-cross-linked scaffolds but avoids the cytotoxicity of aldehyde and presents better biocompatibility, hemocompatibility, anticalcification, and anti-inflammatory response properties.

PMID:39535147 | DOI:10.1021/acsami.4c14256