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BackgroundCongenital heart defects affect approximately 1% of births in the United States and Europe, with >1 million children in the United States living with congenital heart defects. Many experience abnormalities in the right ventricular outflow tract, often necessitating surgical intervention early in life. However, the initial repairs typically are temporary solutions as many patients will eventually need pulmonary valve replacement to address pulmonary valve regurgitation and prevent right ventricle failure. Addressing progressive pulmonary valve regurgitation, ideally in patients weighing 8 to 10 kg, is critical to prevent right ventricle dysfunction. Transcatheter pulmonary valve replacement currently treats patients weighing at least 20 kg. Unfortunately, smaller children must wait for valve replacement and risk right ventricular dilation. MethodsTo address this challenge, we have developed the IRIS Valve, a growth‐accommodating transcatheter pulmonary heart valve inspired by origami targeting implantation in at least 8 kg children. The valve stent underwent finite element analysis with validation by fracture testing. Using a 12‐Fr transcatheter system, the IRIS valve was implanted into 8 to 17 kg Yucatan mini pigs for 6 months. ResultsBenchtop fracture testing and finite element analysis confirmed the stent's ability to be crimped to a 3‐mm diameter for loading into a 12‐Fr transcatheter system and expanded to 20 mm without fracture. Animal studies successfully demonstrated excellent integration within the pulmonary valve annulus, intact valve integrity, and favorable tissue response. ConclusionsThe IRIS Valve offers a promising solution for earlier treatment of heart valve disease in pediatric patients with congenital heart defects, potentially improving outcomes in this vulnerable population.
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Hemodynamic evaluation of biomaterial-based surgery for Tetralogy of Fallot using a biorobotic heart, in silico, and ovine models
Tetralogy of Fallot is a congenital heart disease affecting newborns and involves stenosis of the right ventricular outflow tract (RVOT). Surgical correction often widens the RVOT with a transannular enlargement patch, but this causes issues including pulmonary valve insufficiency and progressive right ventricle failure. A monocusp valve can prevent pulmonary regurgitation; however, valve failure resulting from factors including leaflet design, morphology, and immune response can occur, ultimately resulting in pulmonary insufficiency. A multimodal platform to quantitatively evaluate the effect of shape, size, and material on clinical outcomes could optimize monocusp design. This study introduces a benchtop soft biorobotic heart model, a computational fluid model of the RVOT, and a monocusp valve made from an entirely biological cell-assembled extracellular matrix (CAM) to tackle the multifaceted issue of monocusp failure. The hydrodynamic and mechanical performance of RVOT repair strategies was assessed in biorobotic and computational platforms. The monocusp valve design was validated in vivo in ovine models through echocardiography, cardiac magnetic resonance, and catheterization. These models supported assessment of surgical feasibility, handling, suturability, and hemodynamic and mechanical monocusp capabilities. The CAM-based monocusp offered a competent pulmonary valve with regurgitation of 4.6 ± 0.9% and a transvalvular pressure gradient of 4.3 ± 1.4 millimeters of mercury after 7 days of implantation in sheep. The biorobotic heart model, in silico analysis, and in vivo RVOT modeling allowed iteration in monocusp design not now feasible in a clinical environment and will support future surgical testing of biomaterials for complex congenital heart malformations.
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- Award ID(s):
- 1847541
- PAR ID:
- 10550530
- Publisher / Repository:
- AAAS
- Date Published:
- Journal Name:
- Science Translational Medicine
- Volume:
- 16
- Issue:
- 755
- ISSN:
- 1946-6234
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1126/scitranslmed.adk2936
