Left Versus Biventricular Assist Devices in Cardiac Arrest

Comparison of mechanical resuscitation by an LV Impella device to extracorporeal resuscitation using VAECMO in a large animal model

Extracorporeal cardiopulmonary resuscitation (ECPR) is an effective treatment for cardiac arrest (CA). Percutaneous left ventricular (LV) assist devices such as the Impella ECP (intravascular CPR [ICPR]) have been proposed as a less invasive alternative. The aim of this study was to explore the haemodynamic differences between ECPR and ICPR using a large animal model of electrically induced CA. Fourteen juvenile female German landrace pigs (72.4 ± 9.8 kg) were subjected to electrically induced CA for 5 mins followed by either ECPR (veno-arterial extracorporeal membrane oxygenation [VA-ECMO]) or ICPR (Impella ECP). Haemodynamic parameters and echocardiographic ventricular function indicators were monitored. Mechanical circulatory support (MCS) was continued until five hours after the return of spontaneous circulation (ROSC), when the devices were removed. Resuscitation outcomes and the haemodynamic effects of ECPR and ICPR were compared. The cannulation time for ECMO (469 ± 129 s) was significantly longer than the time for Impella device implantation (153 ± 64 s, p < 0.001). ECPR facilitated ROSC in 6/6 animals, whereas ICPR facilitated ROSC in 6/8 animals (p = 0.19). Echocardiography revealed no difference in LV or right ventricular (RV) dysfunction between the ECPR- and ICPR-treated animals after resuscitation (LV-global longitudinal strain [GLS] 3 h post-ROSC: ICPR: - 16.5 ± 5.6% vs. ECPR: - 13.7 ± 5.9%, p = 0.99; RV-GLS 3 h post-ROSC: ICPR: - 15.9 ± 3.3% vs. ECPR: - 17.3 ± 10.6%, p = 0.99). MCS using VA-ECMO and the Impella device both provided effective haemodynamic support during CA and post-ROSC in this large animal model. Despite LV unloading conferring a hypothetical advantage for ICPR, no significant differences in myocardial recovery were observed.

Biventricular Compared to Left Ventricular Impella and Norepinephrine Support in a Porcine Model of Severe Cardiogenic Shock

Contemporary management of cardiogenic shock (CS) with vasopressors is associated with increased cardiac workload and despite the use of unloading devices such as the Impella pump, concomitant vasopressors are often necessary. Therefore, we compared if cardiac workload could be reduced and end-organ perfusion preserved with biventricular support (Bipella) compared to ImpellaCP and norepinephrine in pigs with left ventricular (LV) CS caused by left main coronary microembolization. Cardiac workload was calculated from heart rate × ventricular pressure-volume area obtained from conductance catheters placed in the LV and right ventricle (RV), whereas organ perfusion was measured from venous oxygen saturation in the pulmonary artery (SvO 2 ) and the kidney- and the cerebral vein. A cross-over design was used to access the difference after 30 minutes of ImpellaCP and norepinephrine 0.1 µg/kg/min versus Bipella for 60 minutes. Bipella treatment reduced LV workload ( p = 0.0078) without significant difference in RV workload from ImpellaCP and norepinephrine, however a decrease in SvO 2 (49[44-58] vs . 66[63-73]%, p = 0.01) and cerebral venous oxygen saturations (62[48-66] vs . 71[63-77]%, p = 0.016) was observed during Bipella compared to ImpellaCP and norepinephrine. We conclude that Bipella reduced LV workload but did not preserve end-organ perfusion compared to ImpellaCP and norepinephrine in short-term LV CS.

Effects of Add-On Left Ventricular Assist Device to Extracorporeal Membrane Oxygenation During Refractory Cardiac Arrest in a Porcine Model

This study evaluated the effects of extracorporeal membrane oxygenation (ECMO) in combination with a percutaneous adjunctive left ventricular assist device (LVAD) in a porcine model during 60 minutes of refractory cardiac arrest (CA). Twenty-four anesthetized swine were randomly allocated into three groups given different modes of circulatory assist: group 1: ECMO 72 ml/kg/min and LVAD; group 2: ECMO 36 ml/kg/min and LVAD; and group 3: ECMO 72 ml/kg/min. During CA and extracorporeal cardiopulmonary resuscitation (ECPR), mean left ventricular pressure (mLVP) was lower in group 1 (p = 0.013) and in group 2 (p = 0.003) versus group 3. Mean aortic pressure (mAP) and coronary perfusion pressure (CPP) were higher in group 1 compared with the other groups. In group 3, mean pulmonary artery flow (mPAf) was lower versus group 1 (p = 0.003) and group 2 (p = 0.039). If the return of spontaneous circulation (ROSC) was achieved after defibrillation, up to 180 minutes of unsupported observation followed. All subjects in groups 1 and 3, and 5 subjects in group 2 had ROSC. All subjects in group 1, five in group 2 and four in group 3 had sustained cardiac function after 3 hours of spontaneous circulation. Subjects that did not achieve ROSC or maintained cardiac function post-ROSC had lower mAP (p < 0.001), CPP (p = 0.002), and mPAf (p = 0.004) during CA and ECPR. Add-on LVAD may improve hemodynamics compared with ECMO alone during refractory CA but could not substitute reduced ECMO flow. Increased mAP and CPP could be related to ROSC rate and sustained cardiac function. Increased mLVP was related to poor post-ROSC cardiac function.

Balanced Biventricular Assist Versus Extracorporeal Membrane Oxygenation in Cardiac Arrest

Mechanical assist devices in refractory cardiac arrest are increasingly employed. We compared the hemodynamics and organ perfusion during cardiac arrest with either veno-arterial extracorporeal membrane oxygenation (ECMO) or biventricular assisted circulation combining left- and right-sided impeller devices (BiPella) in an acute experimental setting. Twenty pigs were randomized in two equal groups receiving circulatory support either by ECMO or by BiPella during 40 minutes of ventricular fibrillation (VF) followed by three attempts of cardioversion, and if successful, 60 minute observation with spontaneous, unsupported circulation. Hemodynamic variables were continuously recorded. Tissue perfusion was evaluated by fluorescent microsphere injections. Cardiac function was visualized by intracardiac echocardiography. During VF device output, carotid flow, kidney perfusion, mean aortic pressure (AOPmean), and mean left ventricular pressure (LVPmean) were all significantly higher in the ECMO group, and serum-lactate values were lower compared with the BiPella group. No difference in myocardial or cerebral perfusion was observed between groups. In 15 animals with sustained cardiac function for 60 minutes after return of spontaneous circulation, left ventricular subendocardial blood flow rate averaged 0.59 ± 0.05 ml/min/gm during VF compared with 0.31 ± 0.07 ml/min/gm in five animals with circulatory collapse (p = 0.005). Corresponding values for the midmyocardium was 0.91 ± 0.06 vs. 0.65 ± 0.15 ml/min/gm (p = 0.085). Both BiPella and ECMO could sustain vital organ function. ECMO provided a more optimal systemic circulatory support related to near physiologic output. Myocardial tissue perfusion and sustained cardiac function were related to coronary perfusion pressure during VF, irrespective of mode of circulatory support.

Impella use in acute myocardial infarction complicated by cardiogenic shock and cardiac arrest: Analysis of 10 years registry data

AIMS

To assess characteristics and outcome of patients treated with Impella for acute myocardial infarction (AMI) complicated by severe cardiogenic shock (CS) or cardiac arrest (CA).

METHODS AND RESULTS

From 2008 through 2017, 92 patients with AMI complicated by CS were treated with Impella. Survival varied according to clinical presentation. Patients in cardiogenic shock without CA had a 75% 30-day survival. Patients with CA and return of spontaneous circulation (ROSC) had a 43% survival and those with CA and ongoing cardio-pulmonary resuscitation (CPR) had a 6% 30-day survival. Age, pre-existing hypertension, coronary disease, ventilatory support and use of adrenergic agents were associated with worse prognosis. Complications were predominantly access site related.

CONCLUSIONS

In this registry of patients with AMICS treated with Impella, hypertension and older age were found to be negatively predictive for survival. Patients without CA had the highest 30-day survival. In patients with ROSC, survival was strongly related to age and comorbidity. Patients with ongoing CPR had very high mortality.