Patient-specific finite element modeling of the Cardiokinetix Parachute® device: effects on left ventricular wall stress and function
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The Parachute® (Cardiokinetix, Inc., Menlo Park, California) is a catheter-based device intended to reverse left ventricular (LV) remodeling after antero-apical myocardial infarction. When deployed, the device partitions the LV into upper and lower chambers. To simulate its mechanical effects, we created a finite element LV model based on computed tomography (CT) images from a patient before and 6 months after Parachute® implantation. Acute mechanical effects were determined by in silico device implantation (VIRTUAL-Parachute). Chronic effects of the device were determined by adjusting the diastolic and systolic material parameters to better match the 6-month post-implantation CT data and LV pressure data at end-diastole (ED) (POST-OP). Regional myofiber stress and pump function were calculated in each case. The principal finding is that VIRTUAL-Parachute was associated with a 61.2 % reduction in the lower chamber myofiber stress at ED. The POST-OP model was associated with a decrease in LV diastolic stiffness and a larger reduction in myofiber stress at the upper (27.1 %) and lower chamber (78.4 %) at ED. Myofiber stress at end-systole and stroke volume was little changed in the POST-OP case. These results suggest that the primary mechanism of Parachute® is a reduction in ED myofiber stress, which may reverse eccentric post-infarct LV hypertrophy.
KeywordsMyocardial infarction Remodeling Finite element method Surgical ventricular restoration
This study was supported by an unrestricted gift from Cardiokinetix and NIH grants R01-HL-084431 (Dr. Ratcliffe), R01-HL-077921 and R01-HL-118627 (Dr. Guccione).
Supplementary material 1 (MPG 1003 kb)
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