Is it feasible to implant transcatheter A tissue engineered pulmonary heart valve without tissue distorsion?

Objective: Today glutaraldehyde fixed pulmonary valves are implanted in clinics, however limited by absence of regeneration, remodeling and growth potential. This feasibility study was performed to evaluate delivery-related tissue distortion of tissue engineered (TE) heart valves during implantation.

Methods: The used injectable TE heart valve was mounted on a self-expanding nitinol stent (n=7) and delivered into the pulmonary position of seven pigs, (weight 26 to 31kg), performing a sternotomy or limited lateral thoracotomy. Prior to implantation, the injectable TE heart valve was crimped using an applicator. The positioning of the implant was guided by fluoroscopy. Hemodynamic measurements were performed by epicardial echocardiography, angiography and invasive pressure measurements. Finally, the animals were sacrificed and the injectable TE heart valves were inspected by groß examination, and histology.

Results: Orthotropic delivery of the injectable TE heart valves (all 19mm diameter) were successfully performed in all, expect in one due to valve migrated become of size discrepancy. Angiographically all other valve (n=6) showed normal valve function, supported by epicardial echocardiography in which no increase flow velocity was measured, neither valve regurgitation. Invasive pressure measurements showed a mean pressure gradient of 5mm Hg. Histological evaluation demonstrated no integrity changes of the extracellular matrix and absence of collagen and elastin distortion.

Conclusions: Transcatheter implantation of an injectable TE heart valve seems to be possible without tissue distortion due to the delivery system.