Department of Mechanical Engineering, University of Texas at Austin, 204 E Dean Keeton Street, Austin, TX, 78712, USA.
Department of Biomedical Engineering, University of Texas at Austin, 107 W Dean Keeton Street, Austin, TX, 78712, USA.
Ann Biomed Eng. 2020 Dec;48(12):2911-2923. doi: 10.1007/s10439-020-02586-x. Epub 2020 Aug 6.
Tricuspid valve regurgitation is associated with significant morbidity and mortality. Its most common treatment option, tricuspid valve annuloplasty, is not optimally effective in the long-term. Toward identifying the causes for annuloplasty's ineffectiveness, we have previously investigated the technique's impact on the tricuspid annulus and the right ventricular epicardium. In our current work, we are extending our analysis to the anterior tricuspid valve leaflet. To this end, we adopted our previous strategy of performing DeVega suture annuloplasty as an experimental methodology that allows us to externally control the degree of cinching during annuloplasty. Thus, in ten sheep we successively cinched the annulus and quantified changes to leaflet motion, dynamics, and strain in the beating heart by combining sonomicrometry with our well-established mechanical framework. We found that successive cinching of the valve enforced earlier coaptation and thus reduced leaflet range of motion. Additionally, leaflet angular velocity during opening and closing decreased. Finally, we found that leaflet strains were also reduced. Specifically, radial and areal strains decreased as a function of annular cinching. Our findings are critical as they suggest that suture annuloplasty alters the mechanics of the tricuspid valve leaflets which may disrupt their resident cells' mechanobiological equilibrium. Long-term, such disruption may stimulate tissue maladaptation which could contribute to annuloplasty's sub-optimal effectiveness. Additionally, our data suggest that the extent to which annuloplasty alters leaflet mechanics can be controlled via degree of cinching. Hence, our data may provide direct surgical guidelines.
三尖瓣反流与重大发病率和死亡率相关。其最常见的治疗选择，三尖瓣瓣环成形术，在长期内并非最佳有效。为了确定瓣环成形术无效的原因，我们之前研究了该技术对三尖瓣环和右心室心外膜的影响。在我们目前的工作中，我们将分析扩展到前瓣。为此，我们采用了我们之前的策略，即进行 DeVega 缝线瓣环成形术作为一种实验方法，使我们能够在瓣环成形术中外部控制收紧程度。因此，在十只羊中，我们连续收紧瓣环，并通过结合超声心动描记术和我们成熟的力学框架，量化了心动周期中瓣叶运动、动力学和应变的变化。我们发现，瓣膜的连续收紧会导致更早的对合，从而减少瓣叶运动范围。此外，瓣叶在打开和关闭过程中的角速度减小。最后，我们发现瓣叶应变也减小了。具体而言，随着瓣环的收紧，径向应变和面积应变减小。我们的发现至关重要，因为它们表明缝线瓣环成形术改变了三尖瓣瓣叶的力学特性，这可能破坏它们固有细胞的机械生物学平衡。从长远来看，这种破坏可能会刺激组织适应性不良，这可能导致瓣环成形术的效果不理想。此外，我们的数据表明，瓣环成形术改变瓣叶力学的程度可以通过收紧程度来控制。因此，我们的数据可能提供直接的手术指导。
