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Bioprinting of living aortic valve
Published in Ali Khademhosseini, Gulden Camci-Unal, 3D Bioprinting in Regenerative Engineering, 2018
D.Y. Cheung, S. Wu, B. Duan, J.T. Butcher
The Ross procedure, also known as the pulmonary autograph, replaces the diseased aortic valve with the healthy pulmonary valve. Generally, a bioprosthetic will be placed in the less hemodynamically demanding pulmonary position. This procedure has shown great potential due to enhanced hemodynamic and kinematic performance and lack of anticoagulation therapy (Stelzer 2011). However, the success of this procedure biases the adult population (Sharabiani et al. 2016). One long-term study of the Ross procedure in adults showed a 90.7% 10-year survival rate and high freedom from autograph and pulmonary graft reoperations up to 10 years (Karaskov et al. 2016). However, in younger patients (median age of 4.8 years) had a lower rate of freedom from RVOT intervention, dropping to 59% at 15 years (Karaskov et al. 2016). Similarly, the performance of bioprosthetics in the pulmonary position is dependent on age. In a recent study, bioprosthetics implanted in the pulmonary position in patients with congential heart disease showed excellent short-term outcomes, but children showed a fivefold greater risk of reintervention than adults (Nomoto et al. 2016). Despite the successes of the operation, the operation turns a one-valve procedure into two valves, increasing operational risks and complexity. There are still concerns about the growth and remodeling potential of the pulmonary autograft in the aortic position. Furthermore, there are still concerns about using bioprosthetics in the pulmonary position, particularly in younger patients with increased rate of reoperations (Kallio et al. 2015).
A human pericardium biopolymeric scaffold for autologous heart valve tissue engineering: cellular and extracellular matrix structure and biomechanical properties in comparison with a normal aortic heart valve
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Frantisek Straka, David Schornik, Jaroslav Masin, Elena Filova, Tomas Mirejovsky, Zuzana Burdikova, Zdenek Svindrych, Hynek Chlup, Lukas Horny, Matej Daniel, Jiri Machac, Jelena Skibová, Jan Pirk, Lucie Bacakova
All currently available forms of valve replacements have several inherent problems in their design. Mechanical prostheses are composed of pyrolytic carbon or titanium, and have an estimated lifespan of 25 years. Biological heart valve replacements are made from chemically crosslinked bovine pericardium, porcine aortic heart valves or allogeneic cadaveric cryopreserved valves, and have an estimated functional lifespan of around 15 years. These valve prostheses are predisposed to infection, thrombus formation, calcification, fibrosis, degenerative changes and deterioration [3,4]. At the present time, only autologous pulmonary heart valve implantation into the aortic position (the Ross procedure) has produced a functional autologous heart valve replacement in humans [5]. However, this is a difficult operation with a high early mortality rate (up to 10%). It involves a concomitant pulmonary heart valve replacement procedure, and is complicated by valve stenosis of the homograft in long-term follow-up [5].