Left ventricular decompression on Veno-arterial extracorporeal membrane oxygenation with intra-aortic balloon Counterpulsation

Temporary Mechanical Circulatory Support after Cardiac Surgery

Postcardiotomy shock in the cardiac surgical patient is a highly morbid condition characterized by profound myocardial impairment and decreased systemic perfusion inadequate to meet end-organ metabolic demand. Postcardiotomy shock is associated with significant morbidity and mortality. Poor outcomes motivate the increased use of mechanical circulatory support (MCS) to restore perfusion in an effort to prevent multiorgan injury and improve patient survival. Despite growing acceptance and adoption of MCS for postcardiotomy shock, criteria for initiation, clinical management, and future areas of clinical investigation remain a topic of ongoing debate. This article seeks to (1) define critical cardiac dysfunction in the patient after cardiotomy, (2) provide an overview of commonly used MCS devices, and (3) summarize the relevant clinical experience for various MCS devices available in the literature, with additional recognition for the role of MCS as a part of a modified approach to the cardiac arrest algorithm in the cardiac surgical patient.

Steady Flow Left Ventricle Unloading Is Superior to Pulsatile Pressure Augmentation Venting During Venoarterial Extracorporeal Membrane Oxygenation Support

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) shunts venous blood to the systemic arterial circulation to provide end-organ perfusion while increasing afterload that may impede left ventricle (LV) ejection and impair cardiac recovery. To maintain flow across the aortic valve and reduce risk of lethal clot formation, secondary mechanical circulatory support (MCS) devices are increasingly used despite limited understanding of their effects on cardiac function. This study sought to quantify the effects of VA-ECMO and combined with either intraaortic balloon pump (IABP) or percutaneous ventricular assist device (pVAD) on LV physiologic state and perfusion metrics in a porcine model of acute cardiogenic shock. Shock was induced through serial left anterior descending artery microbead embolization followed by initiation of VA-ECMO support and then placement of either IABP or pVAD. Hemodynamic measurements, LV pressure-volume loops, and carotid artery blood flow were evaluated before and after institution of combined MCS. The IABP decreased LV end-diastolic pressure by a peak of 15% while slightly increasing LV stroke work compared with decreases of more than 60% and 50% with the pVAD, respectively. The pVAD also demonstrated increased coronary perfusion and systemic pressure gradients in comparison to the IABP. Combined support with VA-ECMO and pVAD improves cardiovascular state in comparison to IABP.

Left Ventricular Unloading With an IABP in Patients Undergoing Ventricular Tachycardia Ablation With ECMO Support

OBJECTIVE

The authors investigated the preprocedural predictors of postprocedural intra-aortic balloon pump (IABP) need in patients undergoing transcatheter ventricular tachycardia (VT) ablation on venoarterial (VA) extracorporeal membrane oxygenation (ECMO).

DESIGN

Observational study.

SETTING

Hybrid operating room and intensive care unit of a teaching hospital.

PATIENTS

Participants were 121 consecutive patients with unstable VT undergoing transcatheter ablation with VA-ECMO.

INTERVENTIONS

In patients with postprocedural echocardiographic, radiographic, or hemodynamic signs of increased left ventricle afterload, an IABP was positioned.

MEASUREMENTS AND MAIN RESULTS

Patients in the IABP group were more frequently on angiotensin-converting enzyme inhibitors (58% v 37%; p = 0.03) and had lower median baseline ejection fraction (25% v 28% p = 0.05), larger end-diastolic diameter (69.7 mm ± 13.0 v 65.7 mm ± 11.3; p = 0.03), and more frequent ischemic etiology as the reason for dilated cardiomyopathy (76% v 47%; p = 0.04,) when compared with patients not requiring IABP. Postoperatively, the IABP group required longer mechanical ventilation (24 hours [20-56.5] v 23 hours [15-28]; p = 0.003), intensive care unit stay (78 hours [46-174] v 48 hours [24-72]; p < 0.001), and continuous renal replacement therapy (13.3% v 1.3%; p = 0.006). By multivariate analysis, end-diastolic diameter (odds ratio [OR]:1.08; confidence interval [CI]: 1.00-1.16; p = 0.049), ischemic dilated cardiomyopathy (OR: 8.40; CI: 2.15-32.88; p = 0.002), and more-than-moderate mitral regurgitation (OR: 4.83; CI: 1.22-19.22; p = 0.025) were independent predictors of need for IABP.

CONCLUSIONS

The need for an IABP to unload the left ventricle can be predicted by ventricular size, medium-severe mitral valvular defect, and ischemic etiology of the dilated cardiomyopathy.

Left ventricle unloading strategies in ECMO: A single-center experience

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is a life-saving technology capable of restoring perfusion but is not without significant complications that limit its realizable therapeutic benefit. ECMO-induced hemodynamics increase cardiac afterload risking left ventricular distention and impaired cardiac recovery. To mitigate potentially harmful effects, multiple strategies to unload the left ventricle (LV) are used in clinical practice but data supporting the optimal approach is presently lacking.

MATERIALS & METHODS

We reviewed outcomes of our ECMO population from September 2015 through January 2019 to determine if our LV unloading strategies were associated with patient outcomes. We compared reactive (Group 1, n = 30) versus immediate (Group 2, n = 33) LV unloading and then compared patients unloaded with an Impella CP (n = 19) versus an intra-aortic balloon pump (IABP, n = 16), analyzing survival and ECMO-related complications.

RESULTS

Survival was similar between Groups 1 and 2 (33 vs 42%, P = .426) with Group 2 experiencing more clinically-significant hemorrhage (40 vs. 67%, P = .034). Survival and ECMO-related complications were similar between patients unloaded with an Impella versus an IABP. However, the Impella group exhibited a higher rate of survival (37%) than predicted by their median SAVE score (18%).

DISCUSSION

Based on this analysis, reactive unloading appears to be a viable strategy while venting with the Impella CP provides better than anticipated survival. Our findings correlate with recent large cohort studies and motivate further work to design clinical guidelines and future trial design.