Biologically-engineered Pediatric Tri-tube Valved Conduit Evaluated 52 Weeks in the Growing Lamb. (9th April 2021)

• Record Type: Journal Article
• Authors: Syedain, Zeeshan; Haynie, Bee; Johnson, Sandra; Lahti, Mathew; Berry, James; Carney, John; Lee, Jirong; Hill, Ryan; Hansen, Kirk; Nair, Greeshma; Bianco, Richard; Tranquillo, Robert
• Is Part Of: Structural heart. Volume 5(2021)Supplement 1
• Page Start: 42
• Page End: 42
• Publication Date: 2021-04-09
• Subjects: Heart -- Diseases -- Periodicals; Congenital heart disease -- Periodicals; Cardiovascular system -- Diseases -- Periodicals; Cardiovascular Diseases; Cardiovascular system -- Diseases; Congenital heart disease; Heart -- Diseases; Periodicals; 616.12
• DOI: 10.1080/24748706.2021.1901474
• Languages: English
• ISSNs: 2474-8706

Abstract

Abstract : Objective : There is a dire need for a heart valve that can grow with children. We fabricated tubes of biologically-engineered matrix that have been shown to regenerate and grow as a pulmonary artery replacement in lambs, and implemented a novel design for a valved conduit made from sewing three of these tubes together with degradable suture that confers valve growth potential. The study was to assess valve function and growth potential over a one-year period in the lamb model. Methods : Seven lambs were implanted with tri-tube valved conduits in sequential cohorts and compared to bioprosthetic conduits using longitudinal echocardiography and histological and mechanical characterization post-explantation. Results : Valves implanted in two lambs of the first cohort of four animals functioned with only mild regurgitation and systolic pressure drops <10 mmHg up to 52 weeks post-implantation, during which the valve diameter increased from 19 mm to a normal ~25 mm. In a second cohort of three animals, an additional tube was used to create a sleeve around the tri-tube valve to counteract faster root growth relative to the leaflets. Two valves exhibited only trivial-to-mild regurgitation at 52-weeks with similar diameter increase and systolic pressure drops of < 5 mm Hg. The same was true for the third animal until moderate regurgitation at 52 weeks correlating to hyper-increase of the valve diameter. In all explanted valves, the leaflets remained thin and pliable with only sparse, punctate microcalcification at most, and they contained interstitial cells and an endothelium progressing from the base of the leaflets. Conclusions : These results are demonstrably improved in terms of calcification and hemodynamic function compared to reported studies for clinically-used pediatric bioprosthetic valves tested in the same model. The results demonstrate the potential for long-term valve growth of this "off-the-shelf" tri-tube valved conduit in children.