Dynamic Fontan Operation With Skeletal Muscle Conduit For Single Ventricle With Pulmonary Hypertension

目的：本实验旨在探讨一种新的外科手术方法-“动态Fontan手术”-电起搏骨骼肌心室（SMV）或线性骨骼肌管道移植术治疗单心室（SV）合并肺动脉高压（PH）的可行性，以获得Fontan手术高危患者的可能替代物。研究方法：作为初步研究，用33只狗在模拟循环系统中刺激背阔肌构建的SMV，以测试（1）电预处理对胸内SMV的收缩特性和抗疲劳性的影响以及（2）机械功能。这些研究表明：（1）电预处理从肌纤维转化和代谢向有氧代谢的转变产生高度的抗疲劳性，（2）静息体积为2 ml/kg的胸内SMV具有足够的机械性能，最大SWI为0.7±0.06gm/ml，可替代总RI。 ...更多信息 右心室作功在此基础上，对13只幼犬用带蒂左背阔肌（LD）瓣构建的骨骼肌心室（SMV）（n = 5）和骨骼肌管道（n=8），在左胸内进行电预适应6周。在体外循环（CPB）条件下，通过右心室腔闭塞，同时关闭三尖瓣和右肺动脉，建立单心室肺动脉高压模型。动态Fontan是通过（1）在右心房和肺动脉之间闭合一个同种主动脉移植物并合并胸内SMV或（2）在右心房和肺动脉干之间闭合线性收缩管道来建立的。体外循环结束后，用训练脉冲（25 Hz）刺激骨骼肌移植物。结果如下：在存在肺血管阻力增加的情况下（11±3.2 Wood单位，CPB前值的412±34%），在没有骨骼肌移植物刺激的情况下观察到严重的右心衰竭，而管道刺激显示在CVP的生理范围（13.2±0.7mmHg）下平均肺流量显著增加68±23%，主动脉收缩压显著增加33±5%。右心功能曲线分析证实动态Fontan手术可明显改善右心功能，即使合并肺动脉高压，肺循环也基本恢复正常。结论：动态Fontan手术是治疗单心室合并肺动脉高压的一种可行的手术方法，但不能作为Fontan手术的选择。少

Purpose : The purpose of this experimental study is to test the feasibility of a new surgical procedure "dynamic Fontan operation" with skeletal muscle ventricle (SMV) or linear skeletal muscle conduit constructed by the electrically paced skeletal muscle grafts for single ventricle (SV) with pulmonary hypertension (PH) to obtain a possible proxy for high risk patients for Fontan procedure. Methods : As the preliminary studies using 33 dogs, SMVs constructed with latissimus dorsi were stimulated in a mock-circulation system to test (1) the effects of electrical preconditioning on contractile properties and fatigue resistance and (2) mechanical function of intrathoracic SMV.These studies showed that (1) electrical preconditioning produced highly fatigue resistance from muscle fiber transformation and metabolic shift to aerobic metabolism, and (2) an intrathoracic SMV with a resting volume of 2ml/kg showed sufficient mechanical property as maximum SWI of 0.7±0.06gm/ml to replace total ri … More ght ventricular work. Base on these pilot studies, skeletal muscle ventricles (SMV) (n-5) and skeletal muscle conduit (n=8) constructed by a pedicled left lattissimuss dorsi (LD) flap in 13 puppies, was electrically precondtioned for 6 weeks within the left thorax. The surgical model of the single ventricle with pulmonary hypertension was made by obliteration of the right ventricular cavity with concomittent closure of the tricuspid valve and the right pulmonary artery by using a cardiopulmonary bypass (CPB). Dynamic Fontan was established by (1) an aortic homograft anastomosed between the right atrium and pulmonary artery incorporated with intra-thoracic SMV or (2) the linear contractile conduit anastomosed between the right atrium and pulmonary trunk. After the termination of CPB, skeletal muscle grafts were stimulated with a trained-pulse (25 Hz). Results : Profound right heart failure was noted without skeletal muscle graft stimulation at the presence of increased pulmonary vascular resistance (11±3.2 Wood units, 412±34% of pre CPB values), whereas conduit stimulation showed significant augmentation of the mean pulmonary flow by 68±23% and the systolic aortic pressure by 33±5% at a physiological range of CVP (13.2±0.7mmHg). Right heart function curve analysis confirmed dramatical augmentaion of right heart performance by dynamic Fontan, restoring almost normal pulmonary circulation even with pulmonary hypertension.Conclusion : Dynamic Fontan procedure may be a viable surgical option for the single ventricle with pulmonary hypertension, which can not be a Fontan candidate. Less