Month: November 2024

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

Gen Thorac Cardiovasc Surg Cases. 2023 Aug 29;2(1):87. doi: 10.1186/s44215-023-00108-4.

ABSTRACT

BACKGROUND: Left ventricular (LV) pseudo-false aneurysm is a rare and fatal complication secondary to myocardial infarction. Sometimes, it may perforate the right ventricle (RV) and lead to acute heart failure. We experienced 2 cases of surgical repair of an LV pseudo-false aneurysm perforating the RV.

CASE PRESENTATION: Case 1: A 76-year-old man was referred to our hospital due to dyspnea. Echocardiography revealed an LV pseudo-false aneurysm (25 mm × 20 mm) that had perforated the RV. Via LV incision, the two small orifices communicating to the RV were detected and closed by direct suture. A double patch of bovine pericardium and a dacron sheet was sutured around the aneurysm with everting mattress. Case 2: A 51-year-old man, who had undergone percutaneous coronary intervention 1 month before, was referred to our hospital due to an LV aneurysm perforating the RV. Via LV incision, a double-layered patch was sutured around the aneurysm with everting mattress. The communicating hole to RV was closed by bovine pericardium patch with a running suture via an RV incision. Postoperative course was uneventful in both cases.

CONCLUSIONS: An LV pseudo-false aneurysm perforating the RV should be considered for urgent repair before serious complications arise and the patient’s general condition deteriorates.

PMID:39516980 | DOI:10.1186/s44215-023-00108-4

Gen Thorac Cardiovasc Surg Cases. 2024 Aug 31;3(1):39. doi: 10.1186/s44215-024-00164-4.

ABSTRACT

BACKGROUND: Calcified amorphous tumor (CAT) of the heart is a rare, non-neoplastic cardiac mass with mitral valves and annuli being the most common sites. The presence of mitral annular calcification (MAC) is associated with an increased risk of stroke or other systemic embolisms. Here, we report a case of CAT showing rapid growth with MAC and investigate the link between the two.

CASE PRESENTATION: A 71-year-old man presented at our hospital with dyspnea and had been undergoing hemodialysis for 26 years for chronic glomerulonephritis. Transthoracic echocardiography (TTE) revealed moderate mitral stenosis with bulky MAC. Two months later, the patient developed progressive dyspnea, and follow-up TTE revealed a highly mobile mass (8 × 5 mm) attached to the left ventricular (LV) side of the posterior MAC. He underwent surgery because of congestive heart failure and a high risk of embolization. Surgical inspection revealed that the tumor was attached beneath the P3 segment of the mitral valve on the LV side and was removed. When removing the MAC, toothpaste-like contents drained from the encapsulated mass inside the MAC at the P3 segment, where the tumor was located. After reconstructing the posterior mitral annulus defect with a bovine pericardial patch, mitral valve replacement with a mechanical prosthesis, a maze procedure, and left appendage closure were performed. Histopathological examination revealed that the excised tumor contained fibrin and calcium deposits. The mass was diagnosed as a CAT.

CONCLUSIONS: CAT may be one of the causes of stroke induced by MAC. Routine follow-up echocardiography should be recommended for patients with MAC, especially those undergoing hemodialysis.

PMID:39517092 | PMC:PMC11533609 | DOI:10.1186/s44215-024-00164-4