Evaluation of transventricular placement of porcine small intestinal submucosa stent valves in the pulmonary position in juvenile sheep model.

OBJECTIVES: We assessed the transventricular placement of porcine small intestinal submucosa (SIS) stent valves in a juvenile sheep model at the 3-month follow-up evaluation.

METHODS: We constructed a pulmonary stent valve by suturing a porcine SIS bicuspid valve into a bell-shaped 'Z' nitinol stent and implanted 7 SIS stent valves transventricularly in the pulmonary position in 7 sheep. The function of the stent valves was assessed using a pulsatile flow simulation system in vitro. Haemodynamic, angiographic, echocardiographic, histologic and radiographic examinations were carried out before, immediately after implantation and 3 months after implantation.

RESULTS: All SIS stent valves were successfully implanted in the pulmonary position in 7 sheep. Angiographic, echocardiographic, haemodyamic and macroscopic studies confirmed firm anchoring and good positioning of the stents immediately after implantation and at 3-month follow-up. All stent valves had good function immediately after implantation and at the end of the protocol, with the exception of 1 stent valve with mild stenosis detected at the end of the protocol. All SIS valves were free of calcifications and thrombus formation, and all stents were intact with no fractures and migration based on postmortem examination and X-radiography.

CONCLUSIONS: We demonstrated successful implantation of porcine SIS stent valves in the pulmonary position in sheep with excellent valve function at the 3-month follow-up evaluation. Porcine SIS has potential superiority as a pulmonary stent bioprosthetic valve material, and the bell-shaped nitinol stent has potential superiority as a frame for pulmonary stent valves.