Transcatheter Pulmonary Valve Replacement from Autologous Pericardium with a Self-Expandable Nitinol Stent in an Adult Sheep Model

This protocol demonstrates an autologous pulmonary valve with specific characteristics, such as self-repair, regeneration, and growth capacity, to ensure physiological performance and long-term functionality in our patients requiring TPVR. The autologous pulmonary valve can prevent tissue rejection, enable regenerative potential due to living endogenous cells, and does not require any medication intake. This method will provide a longer life expectancy of the implanted heart valve in the treatment of younger patients with right ventricular outflow tract that is dysfunctional.

The autologous heart valve can be modified for transcatheter aortic valve implantation, which can benefit millions of patients suffering from aortic valve disease. To test the autologous pulmonary valve before implantation, hold the stented valve with a surgical tweezer. Lift and leave the valve in 0.9%sodium chloride to test the commissures for sufficient opening and closing of the orifice.

Next, evaluate the degree of native valvular regurgitation in the vena contracta by intra-cardiac echocardiography. Using fluoroscopy via a portable C-arm, perform angiography of the right ventricle and pulmonary artery to guide the implantation. Also, perform functional screen by measuring the diameters of the right ventricular outflow tract, native pulmonary valve annulus, pulmonary bulb, sino-tubular junction, and supervalvular pulmonary artery and identify the landing zone.

Then, advance the loaded delivery system via the pre-shaped guide wire through the right ventricular inflow tract and the right ventricular outflow tract to the position of the native pulmonary valve. Retract the cover tube of the delivery system and deploy the autologous pulmonary valve slowly and directly over the native pulmonary valve in the landing zone at the end of the diastolic phase under fluoroscopic guidance After deployment, carefully retract the tip of the delivery system into the cover tube and retrieve it from the sheep. Repeat intra-cardiac echocardiography and post-implantation angiography for the right ventricle and pulmonary artery.

Follow up post-implantation by performing cardiac-computed tomography to evaluate the stent position and the deformation of the right heart throughout the entire cardiac cycle. Also, assess the relationship between the pulmonary artery and left coronary artery from the final computed tomography. Autologous pulmonary valves were successfully implanted in adult sheep.

Stable hemodynamics throughout the left antero-lateral mini-thoracotomy and after implantation indicated the well-being of the animals. Intra-cardiac echocardiography and angiography assessment immediately after valve deployment showed no signs of paravalvular leak, no pulmonary valve insufficiency, and no valve migration. Post-implantation cardiac-computed tomography showed that implanted stent was anchored in the targeted position without migration.

Final CT analysis showed that blood flow in the left anterior descending artery and left circumflex artery was unaffected throughout the cardiac cycle. The implanted stented autologous pulmonary valve demonstrated favorable function and hemodynamics in the right cardiac system, with only a 5 to 10%regurgitation fraction in follow-up magnetic resonance flow measurements and intra-cardiac echocardiography. For this procedure, it's crucial to harvest the autologous tissue, manufacture a 3D-shaped autologous heart valve, and implant it to the native pulmonary position.

This method will pave the way for the development of a regenerative autologous pulmonary valve replacement that provides a lifetime solution for children with a congenital heart defect.