Tubular heart valves: a new tissue prosthesis design--preclinical evaluation of the 3F aortic bioprosthesis.
Tubular heart valves: a new tissue prosthesis design--preclinical evaluation of the 3F aortic bioprosthesis.
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DOI：
10.1016/j.jtcvs.2004.12.054
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发表时间：
2005-08
期刊：
影响因子：
--
通讯作者：
J. Cox;N. Ad;K. Myers;M. Gharib;R. Quijano
中科院分区：
文献类型：
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作者：
J. Cox;N. Ad;K. Myers;M. Gharib;R. Quijano
背景：据推测，天然心脏瓣膜的功能就像简单的管道，当施加外部压力时，它们的侧面会塌陷。因为“形式服从功能”，这个假设理论上可以通过在任何一个天然心脏瓣膜的解剖位置植入一根简单的管子来证实，并证明在与天然瓣膜相同的解剖限制和生理条件下，管子会呈现出天然瓣膜的形状。如果这一假设得到证实，那么基于管状设计的组织阀将具有更好的流动动力学和应力分布，因此有望比目前可用的组织阀寿命更长。3F生物主动脉假体（3F Therapeutics, Inc ., Lake Forest, california）设计了这种管状组织瓣膜，并与市售的无支架主动脉生物假体进行了体外测试。方法采用最先进的测试设备，其中一些是专门为在体外测试这种真正的无支架生物假体而开发的，跨瓣梯度，有效孔面积，跨瓣层流程度，小叶应力分布的有限元分析，并对新型3F主动脉生物假体与St Jude Medical Toronto SPV主动脉生物假体（St Jude Medical, Inc ., St Paul, minnesota）的长期耐久性进行了加速磨损测试。结果在心脏输出量为2.0 ~ 7.0 L/min，平均灌注压为40 ~ 200 mm Hg，主动脉顺应性为4%和16%的条件下，3F生物主动脉假体在所有瓣膜尺寸和所有测试条件下，瓣膜梯度较低，有效孔面积较大。体外3F生物主动脉假体的经瓣血流在质量上是平滑的，周围漩涡最小。3F生物主动脉假体小叶的腹部应力最大，连接部位应力最小。在加速磨损试验中，3F主动脉生物假体优于多伦多SPV瓣膜。这些体外研究表明，在相同的体外条件下，与优质的市售组织主动脉瓣相比，基于形式服从功能的工程原理设计的组织主动脉瓣具有更好的血流动力学、血流动力学、应力分布和耐用性。
BACKGROUNDIt was hypothesized that native heart valves function as if they were simple tubes with sides that collapse when external pressure is applied. Because “form follows function,” this hypothesis could theoretically be confirmed by implanting a simple tube into the anatomic position of any native heart valve and documenting that under the same anatomic constraints and physiologic conditions as the native valve, the tube would assume the form of that native valve. If the hypothesis were thus proved, it would follow that a tissue valve based on a tubular design would have superior flow dynamics and stress distribution and would therefore be expected to outlast currently available tissue valves. Such a tubular tissue valve, the 3F Aortic Bioprosthesis (3F Therapeutics, Inc, Lake Forest, Calif) was designed and tested in vitro against a commercially available stentless aortic bioprosthesis.METHODSWith the use of state-of-the-art testing equipment, some of which had to be developed especially to test this truly stentless bioprosthesis in vitro, transvalvular gradients, effective orifice areas, degree of transvalvular laminar flow, finite element analysis of the distribution of leaflet stress, and accelerated wear testing for long-term durability were evaluated for the new 3F Aortic Bioprosthesis in comparison with the St Jude Medical Toronto SPV aortic bioprosthesis (St Jude Medical, Inc, St Paul, Minn).RESULTSThe valve gradients were lower and the effective orifice areas were greater for the 3F Aortic Bioprosthesis at all valve sizes and under all test conditions, including cardiac outputs ranging from 2.0 to 7.0 L/min, mean perfusion pressures from 40 to 200 mm Hg, and aortic compliances of 4% and 16%. The transvalvular flow across the 3F Aortic Bioprosthesis in vitro was qualitatively smooth, with a minimum of surrounding vortices. Maximum stress occurred in the belly of the leaflets of the 3F Aortic Bioprosthesis, with minimum stress at the commissural posts. The 3F Aortic Bioprosthesis was superior to the Toronto SPV valve in accelerated wear tests.CONCLUSIONSThese in vitro studies show that a tissue aortic valve designed on the basis of the proved engineering principle that form follows function has better hemodynamics, flow dynamics, stress distribution, and durability when compared under identical in vitro conditions with an excellent commercially available tissue aortic valve.