一种新型介入瓣膜脉动流性能的初步研究

Preliminary Study of a New Heart Valve Prostheses Implanted with Minimally Invasive Techniques: Pulsatile-flow Testing in Vitro

本文对一种国产新型介入瓣膜(HVPMIT)的体外脉动流性能进行了初步评价,并就该方法对HVPMIT的适用性进行了初步探索。试验中以国产HVPMIT为试验样品、进口的常规生物瓣为对照样品,根据ISO5840-2005和GB 12279-2008标准列出的方法,采用人工心脏瓣膜脉动流测试仪测定了试样的脉动流参数(包括平均跨瓣压差、返流百分比和有效开口面积)。结果显示,在模拟心输出量为5L/min时,HVPMIT的返流百分比高达13%,显著高于对照瓣,显示其发生了瓣周漏。进一步分析可以发现因为HVPMIT在植入体内时不需缝合,因此在HVPMIT支架外侧没有缝合环。当将HVPMIT夹持在试验仪器上时夹持垫片和HVPMIT支架间有明显缝隙,所以导致瓣周漏的发生。这说明,HVPMIT在外形、结构、在心脏上的固定方式、临床的手术方法等方面和传统的心脏瓣膜有明显的区别。必须根据其自身的特点,设计和建立适用的检测方法来科学客观地评价HVPMIT的性能。

The aim of this study was to investigate the pulsatile-flow performance in vitro of a new heart valve pros- theses implanted with minimally invasive techniques （HVPMIT）. Three HVPMITs were tested valves and another three original biological heart valve prostheses acted as reference valves. The pulsatile-flow parameters （including mean pressure drop, regurgitant percentage of stroke volume, and effective orifice area） were tested in a pulse dupli- cator according to the methods listed in ISO5840-2005 and GB 12279-2008. The results demonstrated that the regur- gitant percentage of stroke volume of tested valves was up to 13%. It was significantly higher than that of the refer- ence valves. This result suggested that paravalvular leakage had occurred in the tested valves. It was found in the further analysis that because HVPMIT was not sewn into the heart tissue when the HVPMIT was implanted in vivo and there was not a sewing ring in the HVPMIT, when tested valves were fixed in the pulse duplicator, some gaps might exist between the stent of HVPMIT and the fix gasket, and the paravalvular leakage could therefore take place through these gaps. This study demonstrated that there are significant differences in the shape, structure, fixation in vivo and clinical operational methods between HVPMIT and original biological heart valve prostheses. It is necessary to establish new test methods which adapt for HVPMIT to evaluate its pulsatile-flow performance according to its own features.