Butterfield M, Fisher J, Davies G A, Kearney J M
Cardiac Research Unit, Killingbeck Hospital, Leeds, UK.
Eur J Cardiothorac Surg. 1991;5(1):27-32; discussion 33. doi: 10.1016/1010-7940(91)90079-y.
The leaflet geometry and hydrodynamic function of five porcine bioprostheses have been studied and compared to a fresh tissue porcine valve. The neutral leaflet geometries in two high pressure fixed valves (Carpentier Edwards and Hancock) and two low pressure fixed valves (Carpentier Edwards Supra-Annular and Hancock 2) had been modified during fixation and mounting. The leaflets were extended or displaced downwards towards the base of the valve, producing a higher ratio of circumferential leaflet length to inter-commissural spacing than in the fresh tissue valve. This produced high bending strains in the commissural area of the open leaflet in hydrodynamic tests. The leaflet geometry of the fresh tissue porcine valve studied was defined by a cylindrical shell inclined at approximately 27 degrees to the base of the valve and showed reduced open leaflet bending strains. Leaflet opening at low flows was dependent on leaflet geometry. Geometrical changes which are induced during mounting and fixation produced higher bending strains in the commissural area of the open leaflets. These may be contributing factors to tissue degeneration and calcification in this area.
研究了五个猪生物瓣膜的瓣叶几何形状和流体动力学功能，并与新鲜组织猪瓣膜进行了比较。两个高压固定瓣膜（卡朋蒂埃·爱德华兹和汉考克）和两个低压固定瓣膜（卡朋蒂埃·爱德华兹超环瓣和汉考克2号）的中性瓣叶几何形状在固定和安装过程中发生了改变。瓣叶向瓣膜基部延伸或向下移位，导致瓣叶圆周长度与瓣间间距的比值高于新鲜组织瓣膜。在流体动力学测试中，这在开放瓣叶的连合区域产生了高弯曲应变。所研究的新鲜组织猪瓣膜的瓣叶几何形状由一个与瓣膜基部成约27度角倾斜的圆柱形壳定义，并且显示出开放瓣叶弯曲应变降低。低流量时瓣叶开放取决于瓣叶几何形状。在安装和固定过程中引起的几何变化在开放瓣叶的连合区域产生了更高的弯曲应变。这些可能是该区域组织退变和钙化的促成因素。
