Publications by authors named "William Neethling"

A Phase II Clinical Trial reviewed the performance (morbidity and calcification) of the tissue-engineered ADAPT® bovine pericardial scaffold (CardioCel®) in pediatric patients ( = 30) with congenital cardiac defects. In that study, CardioCel® demonstrated no graft-related morbidity and mortality in 25 patients, over 12 months. Five patients died due to non-graft-related events.

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Objectives: Durability of bioscaffolds cross-linked with glutaraldehyde and used in cardiovascular surgery is limited by biomechanical instability, calcification and reduced biocompatibility. This study compares CardioCel®, a bovine pericardial scaffold engineered via the ADAPT® process to ensure optimized biostability and biocompatibility, with the commonly used bioscaffolds.

Methods: Bovine pericardial scaffolds, cross-linked with 0.

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Background: The purpose of this study was to provide a preliminary assessment of the performance of a decellularized pericardial patch in a trileaflet aortic valve reconstruction in a long-term juvenile sheep model.

Methods: A sheep surgical model was used to perform a complete trileaflet reconstruction (Ozaki technique) of the aortic valve with 3 separate pericardial patches. Valve function was assessed 1 week, 3 months, and 6 months after surgery via transthoracic echocardiography.

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The present study has evaluated a commercial pericardial material for its capacity to assist as a natural extracellular matrix (ECM) patch for the delivery and retention of mesenchymal stem cells for cardiac repair. The repair of cardiac tissue with cells delivered by an appropriate bioscaffold is expected to offer a superior, long-lasting treatment strategy. The present material, CardioCel®, is based on acellular pericardium that has been stabilized by treatments, including a low concentration of glutaraldehyde, that eliminate calcification after implantation.

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Objective: To conduct a test of noninferiority for CardioCel (Admedus, Brisbane, Australia), a chemically engineered bovine pericardium over autologous pericardium treated intraoperatively with glutaraldehyde in a chronic juvenile sheep model of pulmonary valve (PV) and mitral valve (MV) reconstruction.

Methods: We replaced the posterior leaflet of the MV and of 1 PV cusp with patches in ewes aged 10 months. There were 2 groups: CardioCel (n = 6) and control (n = 4).

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Objectives: Autologous pericardium rapidly fixed with glutaraldehyde (GA) in theatre is considered in many cardiac surgery centres the best material currently available for intracardiac, valvular or vascular repair. Implanted non-fixed autologous tissues suffer rapid degeneration, shrinkage and absorption whereas standard xenotypic fixed tissues cause local cytotoxicity and calcification. In the present study, using a subcutaneous rat model, we tested the biostability, durability and calcification potential of four different pericardium patches treated with GA and relevant to current clinical practice.

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Objectives: This study evaluated the safety, efficacy and clinical performance of the tissue-engineered ADAPT® bovine pericardial patch (ABPP) in paediatric patients with a range of congenital cardiac anomalies.

Methods: In this single-centre, prospective, non-randomized clinical study, paediatric patients underwent surgery for insertion of the ABPP. Primary efficacy measures included early (<30 day) morbidity; incidence of device-related complications; haemodynamic performance derived from echocardiography assessment at 6- and 12-month follow-up and magnetic resonance imaging findings in 10 randomly selected patients at 12 months.

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The history of using homologous cardiac valves dates back more than 30 years. Through the years emphasis was placed on the optimization of graft retrieval, preservation techniques and clinical application. A cardiac homograft valve bank was established at the Department of Cardiothoracic Surgery, University of the Free State, Bloemfontein in 1982.

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Background And Aims Of The Study: Implanted non-crosslinked tissues suffer rapid degeneration, shrinkage and absorption, whereas standard crosslinked tissues cause local cytotoxicity and calcification. Both approaches diminish implant capacity for long-term function. The study aim was to examine the tissue-engineered characteristics (cytotoxicity, calcification potential, biocompatibility) of bovine pericardium, crosslinked with a low concentration of glutaraldehyde (GA) followed by ADAPT anti-mineralization, following prolonged implantation in a subcutaneous rat model.

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Objective And Design: Tumor necrosis factor alpha (TNF-α) has been implicated in the pathogenesis of cardiovascular disease and sepsis-associated cardiac dysfunction. Although initially described solely as a lipopolysaccharide (LPS)-induced macrophage product, evidence exists that cardiac myocytes themselves produce substantial amounts of TNF-α in response to ischemia as well as LPS. The use of phosphodiesterase inhibitors has been shown to decrease LPS-induced TNF-α elaboration.

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Background And Aim Of The Study: Matrix preparation remains controversial due to incomplete cell removal, inflammatory responses, reabsorption and thrombocyte activation. Previously, crosslinked matrices have been considered unsatisfactory due to cytotoxicity. In the present study, the biostability, biocompatibility and calcification potential of a decellularized matrix crosslinked with a low concentration of monomeric glutaraldehyde (GA) and treated with the ADAPT anti-calcification process were examined.

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Background: Homograft valves offer advantages including avoidance of anticoagulation and less susceptibility to infection especially in the setting of endocarditis. However, there is concern about their durability and possible accelerated degeneration particularly in cases of second time replacement with homografts.

Aim: This study aimed to evaluate the pattern of homograft failure and the quality of life in patients after homograft implantation.

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Background: Glutaraldehyde-preserved bioprosthetic heart valve substitutes have limited performance and longevity due to tissue degeneration and calcification. The Freestyle valve (Medtronic Heart Valves, Inc, Minneapolis, MN) combines zero fixation pressure and proportional, variant-amino oleic acid (AOA) as antidegeneration and antimineralization measures. The aim of this study was to compare the calcification behavior of glutaraldehyde-preserved kangaroo aortic valves with Freestyle stentless bioprostheses in a juvenile sheep model.

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Background And Aim Of The Study: The study aim was to compare the crosslink stability and calcification behavior of porcine tissue (cusp and wall), treated with a new antimineralization process (ADAPT) with that of commercially prepared Freestyle and Prima Plus bioprosthetic tissues.

Methods: Porcine aortic roots were divided into two groups: (i) tissue zero pressure-fixed with 0.625% glutaraldehyde (GA) for seven days and stored in 0.

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Background And Aim Of The Study: The performance and longevity of bioprosthetic heart valves are limited by tissue calcification and degeneration after implantation. Experimental valve replacement in large animal models forms an important component of the preclinical evaluation of these bioprosthetic heart valves. The study aim was to assess the feasibility of a mitral model for stentless valves and to evaluate the calcification behavior of stentless glutaraldehyde-preserved kangaroo heart valves in the mitral position of a sheep model.

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