Growth adapting valve prosthesis

OBJECTIVES: The purpose of this study was to test whether adaptive or maladaptive remodeling is associated with survival in women and men after aortic valve replacement (AVR). BACKGROUND: Women with isolated aortic valve stenosis (AS) develop more concentric left ventricular hypertrophy (LVH) than men in similar disease states. We recently reported less up-regulation of profibrotic genes at AVR and faster LVH regression post-operatively in women than in men, suggesting that there are sex differences in the adaptation to pressure overload and its regression...

Currently available heart valve replacements are limited in long-term performance or fail due to leaflet thickening, lack of growth or remodeling potential. In order to address these issues, it is necessary to mimic multiple factors of the native valvular extracellular matrix (ECM) such as architecture, mechanical behavior and biochemical signals. Here, we successfully generated an electrospun PEGdma-PLA scaffold adapted to the structure and mechanical properties of native valve leaflets. Valvular interstitial cells (VICs) and valvular endothelial cells (VECs) were seeded on the scaffold and when cultured under physiological conditions in a bioreactor, the construct performed like a native leaflet...

Cardiac valvular pathologies are often caused by rheumatic fever in young adults, atherosclerosis in elderly patients, or by congenital malformation of the heart in children, in effect affecting almost all population ages. Almost 300,000 heart valve operations are performed worldwide annually. Tissue valve prostheses have certain advantages over mechanical valves such as biocompatibility, more physiological hemodynamics, and no need for life-long systemic anticoagulation. However, the major disadvantage of biological valves is related to their durability...

Using the principal of tissue engineering, several groups have demonstrated the feasibility of creating heart valves, blood vessels, and myocardial structures using autologous cells and biodegradable scaffold materials. In the current cardiovascular clinical scenario, the main medical need for a tissue engineering solution is in the field of pediatric applications treating congenital heart disease. In these young patients, the introduction of autologous viable and growing replacement structures, such as tissue engineered heart valves and vessels, would substantially reduce today's severe therapeutic limitations, which are mainly due to the need for repeat reoperations to adapt the current artificial prostheses to somatic growth...

Tissue-engineered heart valves (TEHVs) promise to be the ideal heart valve replacement: they have the potential to grow and repair within the host, to minimise inflammatory and immunological responses and to limit thromboembolism. Viable cells included in TEHVs can theoretically adapt to a growing and changing environment exactly as a native biological structure. This could be extremely important in case of paediatric applications, where reoperations are frequently required to replace failed valve substitutes or to accommodate the growth of the patient...

BACKGROUND: TGF-beta1 is involved in cardiac remodeling through an auto/paracrine mechanism. The contribution of TGF-beta1 from plasmatic source to pressure overload myocardial remodeling has not been analyzed. We investigated, in patients with valvular aortic stenosis (AS), and in mice subjected to transverse aortic arch constriction (TAC), whether plasma TGF-beta1 relates with myocardial remodeling, reflected by LV transcriptional adaptations of genes linked to myocardial hypertrophy and fibrosis, and by heart morphology and function...

Engineered heart valves promise to be the ideal heart valve replacement: they have the potential to grow and repair within the host, to minimize inflammatory and immunological responses and to limit thromboembolism. In particular, pediatric patients with congenital defects would greatly benefit from growing replacement materials by reducing the need for surgical reinterventions due to the lack of prosthetic material growth. In fact, viable cells included in engineered heart valves can theoretically adapt to a growing and changing environment exactly as a native biological structure...

Heart valve replacements composed of living tissue that can adapt, repair, and grow with a patient would provide a more clinically beneficial option than current inert replacements. Bioartificial valves were produced by entrapping human dermal fibroblasts within a fibrin gel. Using a mold design that presents appropriate mechanical constraints to the cell-induced fibrin gel compaction, gross fiber alignment (commissure-to-commissure alignment in the leaflets and circumferential alignment in the root) and the basic geometry of a native aortic valve were obtained...

Pulmonary valve autografts have proven to be valid aortic valve substitutes in children. The objective of this study is to evaluate the performance of the pulmonary autograft (PAG) in systemic position and its adjustment to growth in four infants who underwent a Ross operation. Between April 1998 and January 2000, four infants whose aortic valve anatomy and function were judged unsuitable for a valve-sparing operation underwent successful Ross operation. All patients were followed postoperatively with echocardiograms to evaluate the function and the dimensional changes of the PAG within the systemic circulation...

OBJECTIVES: Degeneration of bioprosthetic heart valves has been suggested to be at least partly an immunogenic reaction toward the xenogeneic tissue. An autologous endothelial lining has been proposed to overcome this problem. We examined in vitro endothelialization of such tissue and retention of endothelial cells after exposure to flow resembling the in vivo situation. METHODS: Cultured human saphenous vein endothelial cells were used to in vitro endothelialize photo-oxidized bioprosthetic heart valves...

PURPOSE: This study was aimed to demonstrate growth in the pulmonary autograft after transplantation to the aortic position. METHODS AND MATERIALS: In 20 piglets (weight 25.4 +/- 3.5 kg) (mean +/- standard deviation) a Ross operation was performed and in five piglets (weight 9.3 +/- 0.7 kg) (mean +/- standard deviation) the ascending aorta was replaced with a valveless pulmonary autograft. Animals were allowed to grow as much as possible. Postmortem explanted autografts were studied by direct measurements of the valve cusps in the Ross group and of the wall segments in the valveless autograft group...

Valve repair is often required to maintain haemodynamic performance in patients with infectious endocarditis. Localizations on the aortic valve are frequent and lead to rapid, often severe, deterioration, especially when the valve ring and the septum are also infected. Conduction disorders and rupture of the abscess into the heart cavities are formal indications for surgery. Mitral regurgitation requires surgical repair less often and has a slower clinical course. The tricuspid valve generally tolerates infection well and surgery is only exceptionally indicated...