Abstract:
"Analysis of Patient-specific Surgical Ventricular Restoration - Importance of an Ellipsoidal Left Ventricular Geometry for Diastolic and Systolic Function"
This study develops and applies patient-specific three-dimensional finite element (FE) models of the left ventricle (LV), reconstructed from pre- and post-surgical MR images of 12 ischemic cardiomyopathy patients undergoing surgical ventricular restoration (SVR) with coronary artery bypass grafting. Passive and active myocardial material parameters were calibrated to match measured end-diastolic and end-systolic volumes under assumed physiological pressures. Biomechanical simulations quantified changes in diastolic compliance via the end-diastolic pressure–volume relationship (EDPVR), systolic contractility via the end-systolic pressure–volume relationship (ESPVR), and global pump function through the Starling (stroke volume–end-diastolic pressure) curve. Results show that SVR reduces LV volume and peak myofiber stress by ~50%, enhancing systolic elastance (EES) by >1.5×, but simultaneously increases diastolic elastance (EED) by ~70%, thus depressing the overall Starling response in most patients. A parametric “virtual elongation” reducing LV sphericity by 30% restored both diastolic and systolic function, yielding a ~3.5 mL gain in stroke volume, underscoring the adverse biomechanical impact of postoperative LV spherical remodeling. These findings highlight the critical role of three-dimensional biomechanical modeling in resolving the trade-off between wall-stress reduction and impaired diastolic distensibility post-SVR, guiding geometry-based optimization of surgical strategies.
