The importance of tissue science and valve design in relation to durability and hemodynamics of the DurAVR aortic heart valve

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  Figure 1. Aortic valve disease. (A) Age-related calcification and congenital heart defects can lead to severe aortic valve conditions including regurgitation and stenosis. If left untreated, conditions can lead to heart failure with increased mortality rates. Patients with aortic valve disease typically have two treatment options, surgical valve replacement or TAVR. (B) SVD occurs due to several interrelated mechanisms that increase inflammation, calcification, and impair valve hemodynamics. Contextual factors such as a young host with a strong immune response can increase the risk of developing SVD. The origin of the biomaterial can also carry added risk, with xenografts from bovine or porcine origin being recognized by the host as a foreign tissue. In addition, commonly applied chemical glutaraldehyde treatment of the implanted material is ineffective at removing cellular antigens and can exacerbate calcification. The ADAPT™ tissue engineering process aims to mitigate or abolish key risk factors leading to SVD (identified in black boxes). TAVR, transcatheter aortic valve replacement; SVD, structural valve deterioration.

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  Figure 2. ADAPT™ tissue engineering process. BSE-free bovine pericardium is decellularized to remove all cellular antigens known to initiate inflammation and interrelated calcification mechanisms. The ADAPT™ cross linking treatment with a modified monomeric glutaraldehyde at a low concentration enables maintenance and stabilization of strength and elasticity to improve mechanical resistance. The cytotoxicity is further reduced using detoxification and sterilization processes, as well as a anti-calcification methodology to remove and bind aldehydes and enable safe storage in a non-glutaraldehyde solution. Post-implantation, ADAPT™ tissue provides a scaffold for cell migration to create the optimal environment. Migrated cells can stimulate site-specific remodeling, repair, and enable the formation of new blood vessels to improve hemodynamic function. The ADAPT™ tissue engineering process minimizes risk factors known to cause structural valve deterioration and creates a durable biomaterial optimized for a TAVR application. TAVR, transcatheter aortic valve replacement; SVD, structural valve deterioration.