A novel MRI-based finite element modeling method for calculation of myocardial ischemia effect in patients with functional mitral regurgitation.

BackgroundFunctional Mitral Regurgitation (FMR) affects nearly 3 million patients in the United States. Conventional indices are limited for predicting FMR response to coronary revascularization (REVASC). Uncertainty as to which patients will respond to REVASC alone impedes rational decision-making regarding FMR management. Determination of myocardial material parameters associated with ischemic myocardium will address knowledge gaps regarding the impact of ischemia on regional cardiac muscle.\n\nMethodWe proposed a novel MRI-based finite element (FE) modeling method to determine the effect of ischemia on myocardial contractility. The method was applied to two patients with multi-vessel coronary disease and FMR and one healthy volunteer. Cardiac MRI (CMR) included cine-MRI, gadolinium-enhanced stress perfusion, late gadolinium enhancement (LGE), and non-invasive tagged MRI (CSPAMM). The left ventricular (LV) FE model was divided into 17 sectors. Sector-specific circumferential and longitudinal end-systolic strain and LV volume from CSPAMM were used in a formal optimization to determine the sector based myocardial contractility, Tmax.\n\nResultsThe FE optimization successfully converged with good agreement between calculated and experimental end-systolic strain and LV volumes. Specifically, the optimized TmaxH for Patient 1, Patient 2, and the volunteer was 336.8 kPa, 401.4 kPa, and 259.4 kPa and for Patient 1 and Patient 2 was 0.44 and 0.\n\nConclusionWe developed a novel computational method able to predict the effect of myocardial ischemia in patients with FMR. This method can be used to predict the effect of ischemia on the regional myocardium and promises to facilitate better understanding of FMR response to REVASC.