Patient-specific finite element modeling of the Cardiokinetix Parachute(®) device: effects on left ventricular wall stress and function.

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.

Percutaneous left ventricular partitioning in patients with chronic heart failure and a prior anterior myocardial infarction: Results of the PercutAneous Ventricular RestorAtion in Chronic Heart failUre PaTiEnts Trial.

OBJECTIVES: The aim of this study was to assess the feasibility, safety, and preliminary efficacy of a novel percutaneous left ventricular partitioning device (VPD) in patients with chronic heart failure (HF) and a prior anterior myocardial infarction. BACKGROUND: Anterior myocardial infarction is frequently followed by left ventricular remodeling, HF, and increased long-term morbidity and mortality. METHODS: Thirty-nine patients were enrolled in a multinational, nonrandomized, longitudinal investigation. The primary end point was an assessment of safety, defined as the successful delivery and deployment of the VPD and absence of device-related major adverse cardiac events over 6 months. Secondary (exploratory) efficacy end points included changes in hemodynamics and functional status and were assessed serially throughout the study. RESULTS: Ventricular partitioning device placement was not attempted in 5 (13%) of 39 subjects. The device was safely and successfully implanted in 31 (91%) of the remaining 34 patients or 79% of all enrolled patients. The 6-month rate of device-related major adverse cardiac event occurred in 5 (13%) of 39 enrolled subjects and 5 (15%) of 34 treated subjects, with 1 additional event occurring between 6 and 12 months. For patients discharged with the device to 12 months (n = 28), New York Heart Association class (2.5 ± 0.6 to 1.3 ± 0.6, P < .001) and quality-of-life scores (38.6 ± 6.1 to 28.4 ± 4.4, P < .002) improved significantly; however, the 6-minute hall walk distance (358.5 ± 20.4 m to 374.7 ± 25.6 m, P nonsignificant) only trended toward improvement. CONCLUSIONS: The left VPD appears to be relatively safe and potentially effective in the treatment for patients with HF and a prior anterior myocardial infarction. However, these limited results suggest the need for further evaluation in a larger randomized controlled trial.

Percutaneous implantation of an intraventricular device for the treatment of heart failure: experimental results and proof of concept.

BACKGROUND: A percutaneous system to implant a ventricular partitioning device (VPD) has been developed to partition the left ventricular (LV) cavity for treating regional wall motion abnormalities associated with post-left anterior descending (LAD) infarction, dilated left ventricle, and systolic dysfunction. The hemodynamic effects of this novel approach were evaluated in an ovine model with an anteroapical infarction created by a coil placed in the LAD. METHODS AND RESULTS: LV anteroapical infarction (MI) was induced in 10 animals. The VPD device was implanted at 6 weeks after MI in 5 animals. The hemodynamic status of each animal was evaluated at 30 weeks post-MI in treated ("VPD+MI" group, n=5) and nontreated ("MI" group, n=5). The comparison of end-point hemodynamic variables shows a significantly smaller end-systolic LV volume in the animals receiving the implant (70.1+/-9.0 mL in "VPD+MI" group vs. 102.9+/-10.3 mL in "MI" group, P < .02), improved ejection fraction (46.9+/-5.2% in "VPD+MI" group vs. 34.7+/-6.8% in "MI" group, P < .04) and preserved cardiac output (5.2+/-0.7 L/min in "VPD+MI" group vs. 5.0+/-1.8 L/min in "MI" group, P=NS), suggesting more efficient mechanical performance of the LV with the implanted VPD. CONCLUSIONS: A significant reduction in LV volumes and corresponding improvement in LV function occurred after device implantation indicating a potential beneficial effect of this new device in treatment of post MI LV dilation.

First-in-man implantation of left ventricular partitioning device in a patient with chronic heart failure: twelve-month follow-up.

BACKGROUND: The ventricular partitioning device (VPD) (Cardiokinetix Inc., Redwood City, Calif) is a novel device that is deployed percutaneously in the left ventricle in patients with anteroapical regional wall motion abnormalities after a myocardial infarction (MI) to partition the ventricle and segregate the dysfunctional region. In this case report we present the first implantation of the VPD in a human, with a 12-month efficacy and safety follow-up. METHODS AND RESULTS: A 48-year-old man had an anterior MI in 2004. A coronary angiogram showed an occlusion of the proximal segment of the left anterior descending artery with no stenosis on other major epicardial vessels. Echocardiography revealed a dilated left ventricle (62 mm) with anteroapical wall motion abnormalities, no apical thrombus, a calculated ejection fraction of 26.8% (by Simpson biplane formula), and an end-systolic volume index (ESVi) of 76.8 mL/m(2). The VPD implant was delivered percutaneously from the femoral artery by the standard techniques for left-sided heart catheterization. The postimplantation course was uneventful. Echocardiography on discharge showed the VPD implanted at the apex, with a left ventricular ejection fraction of 30.9% and an ESVi of 57.2 mL/m(2). Left ventricular ejection fraction and ESVi remained improved during the 12-month follow-up. CONCLUSION: This case report demonstrates that VPD implantation in this particular patient was feasible and that it may provide a nonsurgical approach to prevent or reverse left ventricle remodeling.