Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, Mass 01609, USA.
J Thorac Cardiovasc Surg. 2013 Jan;145(1):285-93, 293.e1-2. doi: 10.1016/j.jtcvs.2012.03.009. Epub 2012 Apr 7.
Patients with repaired tetralogy of Fallot account for most cases of late-onset right ventricle failure. The current surgical approach, which includes pulmonary valve replacement/insertion, has yielded mixed results. A new surgical option of placing an elastic band in the right ventricle is proposed to improve right ventricular cardiac function as measured by the ejection fraction.
A total of 20 computational right ventricular/left ventricular/patch/band combination models using cardiac magnetic resonance imaging from a patient with tetralogy of Fallot were constructed to investigate the effect of band material stiffness variations, band length, and active contraction. These models included 4 different band material properties, 3 band length, 3 active contracting band materials, and models with patch and scar replaced by contracting tissue.
Our results indicated that the band insertion, combined with active band contraction and tissue regeneration techniques that restore right ventricular myocardium, has the potential to improve right ventricular ejection fraction by 7.5% (41.63% ejection fraction from the best active band model to more than 34.10% ejection fraction from baseline passive band model) and 4.2% (41.63% from the best active band model compared with cardiac magnetic resonance imaging-measured ejection fraction of 37.45%).
The cardiac magnetic resonance imaging-based right ventricular/left ventricular/patch/band model provides a proof of concept for using elastic bands to improve right ventricular cardiac function. Band insertion, combined with myocardium regeneration techniques and right ventricular remodeling surgical procedures, has the potential to improve ventricular function in patients with repaired tetralogy of Fallot and other similar forms of right ventricular dysfunction after surgery. Additional investigations using in vitro experiments, animal models, and, finally, patient studies are warranted.
法洛四联症患者是晚期右心室衰竭的主要病例。目前的手术方法包括肺动脉瓣置换/植入，但效果不一。有人提出在右心室放置弹性带的新手术方案，以改善射血分数等右心室心功能。
共构建了 20 个使用法洛四联症患者心脏磁共振成像的右心室/左心室/补片/带组合模型，以研究带材硬度变化、带长和主动收缩对右心室功能的影响。这些模型包括 4 种不同的带材特性、3 种带长、3 种主动收缩带材，以及用收缩组织替代补片和瘢痕的模型。
我们的结果表明，带插入术结合主动带收缩和组织再生技术，可恢复右心室心肌，有潜力将右心室射血分数提高 7.5%（从最佳主动带模型的 41.63%提高到基线被动带模型的 34.10%以上）和 4.2%（从最佳主动带模型的 41.63%提高到心脏磁共振成像测量的 37.45%）。
基于心脏磁共振成像的右心室/左心室/补片/带模型为使用弹性带改善右心室心功能提供了概念验证。带插入术结合心肌再生技术和右心室重塑手术，有潜力改善法洛四联症等手术后其他类似右心室功能障碍患者的心室功能。需要进一步进行体外实验、动物模型和最终的患者研究。
