Abstract P223: Direct Mechanical Ventricular Actuation of the Acutely Failing Heart Attenuates Maladaptive Cell Signaling
Purpose: Cardiogenic shock refractory to medical therapy can be treated with blood pumps that serve as ventricular assist devices (VADs). Mechanical “unloading” by VADs during severe heart failure (HF) can attenuate ventricular remodeling and improve myocardial recovery. Direct mechanical ventricular actuation (DMVA) is a non-blood contacting VAD that can be rapidly applied. The device attaches atraumatically and augments both systolic and diastolic ventricular pump function. The purpose of this study was to determine how DMVA’s mechanical forces affect maladaptive cell signaling in the acutely failing heart.
Methods: New Zealand white rabbits (n=40) underwent sternotomy and were instrumented for hemodynamic monitoring. Esmolol (a short-acting beta-adrenergic blocker) was titrated for a cardiac output of 50% baseline. Phenylephrine was used to maintain baseline systemic pressures. Animals received either DMVA vs no support for 30, 60, or 120 min of HF. A sham group received no Esmolol or DMVA. Hearts were recovered for 15 min and then rapidly frozen. Immunoblotting and enzyme assays were performed on LV & RV cell homogenates. Results were compared between groups using a non-paired t-test.
Results: See Table⇓
Conclusion: DMVA has previously proven effective to support the failing or asystolic heart. The present study demonstrates DMVA attenuates myocardial signals known to be associated with maladaptive processes during progressive HF. These effects were noted as early as 30 min and reached statistical significance at 2 hours. The findings most likely relate to DMVA reducing myocardial stretch, which has favorable implications on myocardial recovery & remodeling. In summary, DMVA can be rapidly applied to improve ventricular pump function while reducing the detrimental myocardial stress associated with HF. DMVA’s absence of blood-contact and relative ease of installation are also pertinent to its potential clinical efficacy for resuscitative support.