Effect of percutaneous ventricular assisted device on post-cardiac arrest myocardial dysfunction in swine model with prolonged cardiac arrest.

BACKGROUND: It remains unclear if percutaneous left ventricular assist device (pLVAD) reduces post-cardiac arrest myocardial dysfunction. METHODS: This is a prespecified analysis of a subset of swine that achieved return of spontaneous circulation (ROSC) in a study comparing pLVAD, transient aortic occlusion (AO), or both during cardiopulmonary resuscitation (CPR). Devices were initiated after 24 minutes of ventricular fibrillation cardiac arrest (8 min no-flow and 16 min mechanical CPR). AO was discontinued post-ROSC, and pLVAD support or standard care were continued. Beginning 60 minutes post-ROSC, pLVAD support was weaned to < 1.0 L/min and subsequently removed at 240 minutes. The primary outcome was cardiac index (CI), stroke volume index (SVI), and left ventricular ejection fraction (LVEF) at 240 minutes post-ROSC. Data are shown as mean (standard error). RESULTS: Seventeen swine achieved ROSC without complication and were included in this analysis (pLVAD group, n = 11 and standard care group, n = 6). For the primary outcomes, the pLVAD group had significantly higher CI of 4.2(0.3) vs. 3.1(0.4) L/min/m2 (p = 0.043) and LVEF 60(3) vs. 49(4) % (p = 0.029) at 240 minutes after ROSC when compared with the standard care group, while SVI was not statistically significantly different (32[3] vs. 23[4] mL/min/m2, p = 0.054). During the first 60 minutes post-ROSC, the pLVAD group had significantly higher coronary perfusion pressure, lower LV stroke work index, and total pulmonary resistance index. CONCLUSION: These results suggest that early pLVAD support after ROSC is associated with better recovery myocardial function compared to standard care after prolonged cardiac arrest.

Percutaneous left ventricular assist devices in refractory cardiac arrest: The role of chest compressions.

Background: Recent studies describe an emerging role for percutaneous left ventricular assist devices such as Impella CP® as rescue therapy for refractory cardiac arrest. We hypothesized that the addition of mechanical chest compressions to percutaneous left ventricular assist device assisted CPR would improve hemodynamics by compressing the right ventricle and augmenting pulmonary blood flow and left ventricular filling. We performed a pilot study to test this hypothesis using a swine model of prolonged cardiac arrest. Methods: Eight Yorkshire swine were anesthetized, intubated, and instrumented for hemodynamic monitoring. They were subjected to untreated ventricular fibrillation for 5.75 (SD 2.90) minutes followed by mechanical chest compressions for a mean of 20.0 (SD 5.0) minutes before initiation of percutaneous left ventricular assist device. After percutaneous left ventricular assist device initiation, mechanical chest compressions was stopped (n = 4) or continued (n = 4). Defibrillation was attempted 4, 8 and 12 minutes after initiating percutaneous left ventricular assist device circulatory support. Results: The percutaneous left ventricular assist device + mechanical chest compressions group had significantly higher percutaneous left ventricular assist device flow prior to return of spontaneous heartbeat at four- and twelve-minutes after percutaneous left ventricular assist device initiation, and significantly higher end tidal CO2 at 4-minutes after percutaneous left ventricular assist device initiation, when compared with the percutaneous left ventricular assist device alone group. Carotid artery flow was not significantly different between the two groups. Conclusion: The addition of mechanical chest compressions to percutaneous left ventricular assist device support during cardiac arrest may generate higher percutaneous left ventricular assist device and carotid artery flow prior to return of spontaneous heartbeat compared to percutaneous left ventricular assist device alone. Further studies are needed to determine if this approach improves other hemodynamic parameters or outcomes after prolonged cardiac arrest.