Patient-specific in silico prediction of outcomes of partial continuous-flow LVAD treatment in peripartum cardiomyopathy

Patients with severe peripartum cardiomyopathy (PPCM) often receive mechanical circulatory support with good outcomes. However, mechanisms underlying the functional improvements are poorly understood for patients with different PPCM characteristics. This study investigated effects of partial, continuous-flow left ventricular assist device (LVAD) support on cardiac function and mechanics in patients with different PPCM severity. Patient-specific biventricular finite element models of six patients with different PPCM severity were developed from magnetic resonance images and combined with a circulatory system model, including variable LVAD support. Ventricular function and myocardial mechanics were predicted and changes due to LVAD support were quantified. The LVAD support decreased LV myofiber stress and increased ejection fraction (EF). EF increased steadily (two patients), fluctuated (two patients), or peaked before a steady decrease (two patients) with increasing LVAD speed. Improvement due to LVAD support was greater for PPCM patients with higher disease severity than those with lower disease severity. The LVAD and native LV jointly generated stroke volume (SV) in four patients, and the LV contribution diminished with increasing LVAD speed. In the two patients with the lowest EF, the LVAD was the sole source of SV. The improvement of cardiac function and mechanics due to LVAD support in PPCM exceeds that reported for chronic heart failure due to ischemia. However, the predicted variability of the LVAD benefits with PPCM severity and mechanical support level suggests the need and potential for further studies to guide clinicians in selecting personalised treatment parameters required for optimised LVAD therapy for each PPCM patient.