Department of Surgery, University of California, San Francisco, Department of Veterans Affairs Medical Center, San Francisco, California 94121, USA.
Ann Thorac Surg. 2011 Sep;92(3):935-41. doi: 10.1016/j.athoracsur.2011.04.089.
Infarcted regions of myocardium exhibit functional impairment ranging in severity from hypokinesis to dyskinesis. We sought to quantify the effects of injecting a calcium hydroxyapatite-based tissue filler on the passive material response of infarcted left ventricles.
Three-dimensional finite element models of the left ventricle were developed using three-dimensional echocardiography data from sheep with a treated and untreated anteroapical infarct, to estimate the material properties (stiffness) in the infarct and remote regions. This was accomplished by matching experimentally determined left ventricular volumes, and minimizing radial strain in the treated infarct, which is indicative of akinesia. The nonlinear stress-strain relationship for the diastolic myocardium was anisotropic with respect to the local muscle fiber direction, and an elastance model for active fiber stress was incorporated.
It was found that the passive stiffness parameter, C, in the treated infarct region is increased by nearly 345 times the healthy remote value. Additionally, the average myofiber stress in the treated left ventricle was significantly reduced in both the remote and infarct regions.
Overall, injection of tissue filler into the infarct was found to render it akinetic and reduce stress in the left ventricle, which could limit the adverse remodeling that leads to heart failure.
心肌梗死区域表现出从运动减弱到运动障碍不等的功能损害。我们试图量化注射基于羟基磷灰石的组织填充物对梗死左心室被动材料反应的影响。
利用来自患有经治疗和未经治疗的心尖前壁梗死的绵羊的三维超声心动图数据，建立左心室的三维有限元模型，以估计梗死区域和远隔区域的材料特性（刚度）。这是通过匹配实验确定的左心室容积，并使经治疗的梗死区域的径向应变最小化来实现的，径向应变表明运动不能。舒张期心肌的非线性应力-应变关系相对于局部肌纤维方向是各向异性的，并纳入了活性纤维应力的弹性模型。
发现在经治疗的梗死区域，被动刚度参数C增加到健康远隔区域值的近345倍。此外，经治疗的左心室中远隔区域和梗死区域的平均肌纤维应力均显著降低。
总体而言，向梗死区域注射组织填充物可使其运动不能，并降低左心室的应力，这可能会限制导致心力衰竭的不良重塑。
