Minimally Invasive Delivery of a Novel Direct Epicardial Assist Device in a Porcine Heart Failure Model

Abstract

<jats:sec><jats:title>Objective</jats:title><jats:p> Despite advances in design, modern ventricular assist device placement involves median sternotomy and cardiopulmonary bypass and is associated with infectious/embolic complications. In this study, we examine the feasibility and function of a novel minimally invasive, non–blood-contacting epicardial assist device in a porcine ischemic cardiomyopathy model. </jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p> Feasibility was first tested in an ex vivo thoracoscopic trainer box with slaughterhouse hearts. Five male Yorkshire swine underwent selective ligation of the circumflex artery to create a posterolateral infarct Twelve weeks after infarct, all animals underwent left minithoracotomy. A custom inflatable bladder was positioned over the epicardial surface of the infarct and firmly secured to the surrounding border zone myocardium with polypropylene mesh and minimally invasive mesh tacks. An external gas pulsation system actively inflated and deflated the bladder in synchrony with the cardiac cycle. All animals then underwent cardiac magnetic resonance imaging to assess ventricular function. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p> All subjects successfully underwent off-pump placement of the epicardial assist device via minithoracotomy. Ejection fraction significantly improved from 29.1% ± 4.8% to 39.6% ± 4.23% ( P &lt; 0.001) when compared with pretreatment. End-systolic volume decreased (76.6 ± 13.3 mL vs 62.4 ± 12.0 mL, P &lt; 0.001) and stroke volume increased (28.6 ± 3.4 mL vs 37.9 ± 3.1 mL, P &lt; 0.05) when assisted. No change was noted in end-diastolic volume (105.1 ± 11.4 vs 100.3 ± 12.7). On postmortem examination, mesh fixation and device position were excellent in all cases. No adverse events were encountered. </jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p> Directed epicardial assistance improves ventricular function in a porcine ischemic cardiomyopathy model and may provide a safe alternative to currently available ventricular assist device therapies. Further, the technique used for device positioning and fixation suggests that an entirely thoracoscopic approach is possible. </jats:p></jats:sec>

Development of Light-Responsive Liquid Crystalline Elastomers to Assist Cardiac Contraction

“…The final goal of this study was to follow the route of recently proposed epicardial contraction assist devices. 35 Because external ventricular compression is the most physiological way to improve pump function, 36,37 as proposed by recent preclinical investigations, 38 we tested our fittest material, M1CL1, in an experimental setting where cardiac muscle contraction was supported by the LCE working in parallel with a mouse cardiac trabecula ( Figure 5). The sum of the parallel forces compared with that developed by the muscle alone demonstrated that our LCE strips provided a significant systolic assistance.…”

Optimizing Epicardial Restraint and Reinforcement Following Myocardial Infarction: Moving Towards Localized, Biomimetic, and Multitherapeutic Options

“…Because local infarct restraint intends to prevent infarct expansion most of which occurs early post-MI, the majority of scaffolds, patches and devices evaluated have been implanted immediately post-MI [17,18,19,42,58,59,60,61,62]. However, some groups have seen benefits in cardiac function upon patch implantation at latter timepoints post-MI [63,64,65,66,67,68,69,70] ranging from four days to 12 weeks (Figure 3).…”

“…At implantation eight weeks into IMR, the adjustment of the device was done such that IMR was minimized and in a chronic study the group showed that this initial mechanical reinforcement led to a reduction of end-systolic and diastolic LV volumes. Another group pursued a study to test if the minimally invasive delivery of an inflatable localized device to treat ICM was feasible [70]. Their device was made of a heavy-duty 2.5 × 2.5 cm neoprene rubber inflatable bladder that was positioned centrally within the infarct and then secured to the surrounding border zone myocardium with polypropylene mesh.…”

“…Their device was made of a heavy-duty 2.5 × 2.5 cm neoprene rubber inflatable bladder that was positioned centrally within the infarct and then secured to the surrounding border zone myocardium with polypropylene mesh. They validated that a minithoracotomy insertion of such device in a pig model was possible and by providing active assistance to the infarct region showed dramatic improvements in systolic function using magnetic resonance imaging [70].…”