LEFT VENTRICULAR REMODELING IN AORTIC INSUFFICIENCY

导言。在过去的九年里，我们的实验室通过评估体内心肌的收缩和舒张期应力-应变关系，帮助开发和验证了临床评估心脏功能所必需的数学建模能力。这项建议将扩大这些临床工具的应用，以全面评估与严重主动脉瓣关闭不全相关的病理性左心室(LV)重构，以及主动脉瓣置换(AVR)后这种重构逆转的时间进程、程度、持久性和预后意义。左心室重构及其逆转的准确特征将与大量临床上有意义的疾病过程直接相关。简要研究概述。基于磁共振成像(MRI)的3D双室几何数据集可以结合双室负荷条件和有限元分析来构建准确的、特定于患者的心脏收缩和舒张期数学(应力-应变)模型。严重主动脉瓣关闭不全的患者将在手术前接受MRI扫描和导管术，以确定临床表现时出现的左心室病理重构的程度。3D LV收缩末期应力(有限元分析)和收缩期应变(在多巴酚丁胺刺激下和不在刺激下)将被量化，并在适当的时间间隔与术后数据进行比较。手术后左室收缩末期应力的变化将反映由于主动脉瓣关闭不全而导致的几何结构的改变(反向重构)。AVR发生重塑逆转的时间进程、程度和持久性将根据临床结果进行分析。术前舒张期材料特性的特征也将与术后重塑逆转和临床结果相关。

Introduction. Over the last nine years, our laboratory has helped develop and validate the mathematical modeling capabilities that are necessary to clinically evaluate the function of the heart by assessing the systolic and diastolic stress-strain relationships of the in vivo myocardium. This proposal would extend the application of these clinical tools to the comprehensive evaluation of the pathological left ventricular (LV) remodeling associated with severe aortic valvular insufficiency and the time course, degree, durability and prognostic significance of the reversal of this remodeling that occurs after aortic valve replacement (AVR). The accurate characterization of left ventricular remodeling and its reversal would have direct clinical relevance to a large number of clinically significant disease processes. Brief Study Overview. Magnetic resonance imaging (MRI)-based, 3D biventricular geometrical data-sets can be combined with biventricular loading conditions and finite element analysis to construct accurate, patient-specific systolic and diastolic mathematical (stress-strain) models of the heart. Patients with severe aortic insufficiency will undergo MRI scanning and catheterization prior to surgery to characterize the degree of left ventricular pathological remodeling that is present upon clinical presentation. 3D LV end-systolic stress (finite element analysis) and systolic strains (with and without Dobutamine stimulation) will be quantified and compared to post-operative data obtained at appropriate intervals. The change in LV end-systolic stress following surgery will reflect the interval change in geometry (reverse remodeling) that has occurred as a result of elimination of the aortic insufficiency by AVR. The time course, degree and durability of reversal of remodeling that occurs that AVR will be analyzed with respect to clinical outcomes. Preoperative characterization of diastolic material properties will also be related to subsequent postoperative reversal of remodeling and clinical outcomes.