Vena cava as autologous tissue for pulmonary valve substitute.

In this study, we report on our first experience with the construction of a valve using autologous vena cava tissue for right ventricular outflow tract reconstruction. Simulating the clinical situation valves were built from tubular pieces of porcine inferior vena cava placed in a PTFE tube and investigated in a pulsatile flow simulator. Based on the given vena cava dimensions, conduits were constructed with diameters of 19 mm in bicuspid or tricuspid and 22 mm and 24 mm in bicuspid configuration. The lowest pressure gradients were observed in the 22 mm vena cava valves in bicuspid configuration (8.6+/-0.5 mmHg) compared to 24 mm valves (10.6+/-0.9 mmHg, P=0.0004) and 19 mm valves (13.4+/-1.5 mmHg, P=0.005). No differences could be found between 19 mm bicuspid and tricuspid valves. Concerning valve opening movements, a complete opening in the 19 mm and a nearly unhindered opening in 22 mm valves were registered. In 24 mm valves opening was incomplete. Leakage was increased in 19 mm bicuspid valves due to leaflet prolapse. In conclusion, construction of a valve mechanism from vena cava tissue is feasible. The in-vitro hemodynamic results are encouraging, animal experiments are ongoing to investigate the midterm function of these valves.