Directed Epicardial Assistance in Ischemic Cardiomyopathy: Flow and Function Using Cardiac Magnetic Resonance Imaging

Abstract

Background Heart failure after myocardial infarction (MI) is a result of increased myocardial workload, adverse left ventricular (LV) geometric remodeling, and less efficient LV fluid movement. In this study we utilize cardiac magnetic resonance imaging to evaluate ventricular function and flow after placement of a novel directed epicardial assist device. Methods Five swine underwent posterolateral MI and were allowed to remodel for 12 weeks. An inflatable bladder was positioned centrally within the infarct and secured with mesh. The device was connected to an external gas exchange pump, which inflated and deflated in synchrony with the cardiac cycle. Animals then underwent cardiac magnetic resonance imaging during active epicardial assistance and with no assistance. Results Active epicardial assistance of the infarct showed immediate improvement in LV function and intraventricular flow. Ejection fraction significantly improved from 26.0% ± 4.9% to 37.3% ± 4.5% (p < 0.01). End-systolic volume (85.5 ± 12.7 mL versus 70.1 ± 11.9 mL, p < 0.01) and stroke volume (28.5 ± 4.4 mL versus 39.9 ± 3.1 mL, p = 0.03) were also improved with assistance. End-diastolic volume and regurgitant fraction did not change with treatment. Regional LV flow improved both qualitatively and quantitatively during assistance. Unassisted infarct regional flow showed highly dis-coordinate blood movement with very slow egress from the posterolateral wall. Large areas of stagnant flow were also identified. With assistance, posterolateral wall blood velocities improved significantly during both systole (26.4% ± 3.2% versus 12.6% ± 1.2% maximum velocity; p < 0.001) and diastole (54.3% ± 9.3% versus 24.2% ± 2.5% maximum velocity; p < 0.01). Conclusions Directed epicardial assistance can improve LV function and flow in ischemic cardiomyopathy. This novel device may provide a valuable alternative to currently available heart failure therapies.

Individualized Biventricular Epicardial Augmentation Technology in a Drug-Induced Porcine Failing Heart Model

“…The latter may be of particular importance as McGarvey et al observed velocity profiles that indicated the most notable effect on blood velocity was seen during diastolic deflation in pigs. 15 In the current study, the device was used in both uni-and biventricular support modes. As shown, epicardial augmentation with subsystemic augmentation pressures in BiVAD mode and in LVAD mode increased EF from baseline in both ventricles ( Figure 7C).…”

Early Assistance With Left Ventricular Assist Device Limits Left Ventricular Remodeling After Acute Myocardial Infarction in a Swine Model

“…Firstly, the left main trunk flow and collateral vessels circulation were not directly measured. Additionally, we utilized a left circumflex artery ligation model with relatively stable hemodynamics to evaluate postinfarction remodeling , which may differ from left anterior descending artery ligation models. Furthermore, although myocardial scintigraphy can accurately provide ischemia and infarction information such as the size and location of the myocardial infarction, myocardial viability, and the area at risk, it was not applied in this experiment because of technical limitations.…”

Injectable Microsphere Gel Progressively Improves Global Ventricular Function, Regional Contractile Strain, and Mitral Regurgitation After Myocardial Infarction

“…With a trend towards less-invasive treatment modalities, localized ventricular restraint/stiffening devices and injectable biomaterials have gained considerable clinical and research interest in the secondary prevention of heart failure [5,10,11,14,33,34]. While this study focuses on a single treatment, our group and others are actively involved in the development of other catheter-based therapeutics which are designed to alter the biochemical milieu and/or LV material properties [15–18,35,36].…”