A new type of aortic valved stent with good stability and no influence on coronary artery

BACKGROUND: To evaluated the feasibility and safety of new aortic valved stents in transcatheter aortic valve implantation (TAVI) using retrograde approach by in vitro testing and animal implantation. MATERIALS AND METHODS: The fluid passing test, expanding and releasing tests, static and releasing tests in tube were performed for new valved stents. Transvalvular pressure gradient, effective orifice area, pre-implantation and post-implantation regurgitant volume for the new stents were detected. Then, the new stents were implanted in six pigs using retrograde approach. These pigs were euthanized 12 h after the implantation for anatomic evaluation. RESULTS: In vitro tests showed that the closure of the new stents leaflets were effective, and stents could be released through catheter, then expanded completely and fixed fast in the tube. The coronary artery flow rates did not changed significantly after implantation (P > 0.05), while aortic regurgitant volumes were obviously reduced (P < 0.05). No significant difference in the transvalvular pressure gradient and effective orifice area of the new stents implanted within or above the valve leaflets was found (P > 0.05). In vivo experiments indicated that TAVI was successfully performed in six pigs using retrograde approach. However, one pig was died 10 h after the implantation since the stent was not expanded completely. The leaflets in stents were opening well and no valvular regurgitation was observed in the other five pigs. And thrombosis was not found. DISCUSSION AND CONCLUSION: The new type of aortic valved stent designed in this study was characterized with good stability and could avoid the impact caused by valve leaflets on the coronary artery.