Injectable Tissue-Engineered Pulmonary Heart Valve Implantation Into the Pig Model: A Feasibility Study

BACKGROUND: Transcatheter pulmonary valve replacement is currently performed in clinical trials, but is limited by the use of glutaraldehyde-treated bioprostheses. This feasibility study was performed to evaluate delivery-related tissue distortion during implantation of tissue-engineered (TE) heart valves.
MATERIAL AND METHODS: The injectable TE heart valve was mounted on a self-expanding nitinol stent (n=7) and delivered into the pulmonary position in 7 pigs, (weight 26 to 31 kg), performing a sternotomy or limited lateral thoracotomy. Prior to implantation, the injectable TE heart valves were crimped and inserted into an applicator. Positioning of the implants was guided by fluoroscopy, and after careful deployment, angiographic examination was performed to evaluate the correct delivered position. Hemodynamic measurements were performed by epicardial echocardiography. Finally, the animals were sacrificed and the injectable TE heart valves were inspected by gross examination and histological examination.
RESULTS: Orthotopic deliveries of the injectable TE heart valves were all successful performed, expect in 1 where the valve migrated due to a discrepancy between pulmonary valve annulus size and injectable TE valve size. Angiographic evaluation (n=6) showed normal valve function, supported by epicardial echocardiography in which no increased flow velocity was measured, neither trans- nor paravalvular regurgitation. Histological evaluation demonstrated absence of tissue damage from the delivery process.
CONCLUSIONS: Transcatheter implantation of an injectable TE heart valve seems to be possible without tissue distortion due to the delivery system.

Keywords: Animals, Alloys, Feasibility Studies, Fluoroscopy, Heart Valve Diseases - surgery, Heart Valve Prosthesis Implantation - methods, Hemodynamics, Stents, Swine, Tissue Engineering - methods