Management of Peripheral Venoarterial Extracorporeal Membrane Oxygenation in Cardiogenic Shock

OBJECTIVES

Cardiogenic shock is a highly morbid condition in which inadequate end-organ perfusion leads to death if untreated. Peripheral venoarterial extracorporeal membrane oxygenation is increasingly used to restore systemic perfusion despite limited understanding of how to optimally titrate support. This review provides insights into the physiologic basis of extracorporeal membrane oxygenation support and presents an approach to extracorporeal membrane oxygenation management in the cardiogenic shock patient.

DATA SOURCES, STUDY SELECTION, AND DATA EXTRACTION

Data were obtained from a PubMed search of the most recent medical literature identified from MeSH terms: extracorporeal membrane oxygenation, cardiogenic shock, percutaneous mechanical circulatory support, and heart failure. Articles included original articles, case reports, and review articles.

DATA SYNTHESIS

Current evidence detailing the use of extracorporeal membrane oxygenation to support patients in cardiogenic shock is limited to isolated case reports and single institution case series focused on patient outcomes but lacking in detailed approaches to extracorporeal membrane oxygenation management. Unlike medical therapy, in which dosages are either prescribed or carefully titrated to specific variables, extracorporeal membrane oxygenation is a mechanical support therapy requiring ongoing titration but without widely accepted variables to guide treatment. Similar to mechanical ventilation, extracorporeal membrane oxygenation can provide substantial benefit or induce significant harm. The widespread use and present lack of data to guide extracorporeal membrane oxygenation support demands that intensivists adopt a physiologically-based approach to management of the cardiogenic shock patient on extracorporeal membrane oxygenation.

CONCLUSIONS

Extracorporeal membrane oxygenation is a powerful mechanical circulatory support modality capable of rapidly restoring systemic perfusion yet lacking in defined approaches to management. Adopting a management approach based physiologic principles provides a basis for care.

Selective implantation of durable left ventricular assist devices as primary therapy for refractory cardiogenic shock

OBJECTIVE

Surgical therapy for refractory primary cardiogenic shock is largely based on emergent placement of extracorporeal membrane oxygenation or short-term ventricular assist devices. We have adopted a strategy of routine implantation of durable left ventricular assist devices (LVAD) as initial therapy for refractory cardiogenic shock, in patients who are potential candidates for heart transplantation, and report our experience.

METHODS

Retrospective review of 43 consecutive patients with refractory shock caused by acute myocardial infarction (n = 21) or acute decompensated heart failure (n = 22) who were treated with primary implantation of a durable LVAD in a single institution.

RESULTS

All patients received durable LVAD (axial flow, n = 37; centrifugal, n = 4; pulsatile, n = 2), with concurrent placement of right ventricular assist device (RVAD) in 5 patients (12%). One patient had delayed RVAD implantation. Mean operative time was 362 minutes and mean cardiopulmonary bypass time was 94 minutes. Twenty patients underwent concurrent cardiac procedures. Major early adverse events included operative mortality 14% (6/43), reoperation for bleeding 7% (3/43), and stroke 4.7% (2/43). Median time on mechanical ventilation was 3.5 days, ICU stay 9 days, and hospital stay 25 days. Kaplan-Meier survival was 82.7 ± 6.0% at 6 months and 73.9 ± 8.0% at 12 months. Using competing analysis, the cumulative incidence of transplantation was 10.3 ± 5.0% at 6 months and 30.8 ± 7.9% at 1 year.

CONCLUSIONS

Our data challenge the notion that patients in refractory cardiogenic shock are best served by an initial period of stabilization with temporary devices. Primary implantation of durable LVADs in cardiogenic shock can yield good midterm outcomes and may have potential benefits.

Percutaneous cardiac support during myocardial infarction drastically reduces mortality: perspectives from a swine model

BACKGROUND/AIMS

Acute myocardial infarction (AMI) with cardiogenic shock (CS) remains the leading cause of in-hospital death in acute coronary syndromes. In the AMI-CS pig model we tested the efficacy of temporary percutaneous cardiorespiratory assist device (PCRA) in rescuing the failing heart and reducing early mortality.

METHODS

In open-chest pigs we induced AMI by proximal left anterior descending coronary artery (LAD) ligation. Eight animals without PCRA (C group) were compared with 12 animals otherwise treated with PCRA (T group), starting approximately at 60 minutes post-occlusion and lasting 120-180 minutes. In 3 animals of the T group, regional myocardial oxygen content was also imaged by two-dimensional near infrared spectroscopy (2D-NIRS) with and without PCRA, before and after LAD reperfusion.

RESULTS

All animals without PCRA died despite unrelenting resuscitation maneuvers (120 minutes average survival time). Conversely, animals treated with PCRA showed a reduction in life-threatening arrhythmia and maintenance of aortic pressure, allowing interruption of PCRA in all cases early in the experiments, with sound hemodynamics at the end of the observation period. During LAD occlusion, NIRS showed severe de-oxygenation of the LAD territory that improved with PCRA. After PCRA suspension and LAD reperfusion, the residual de-oxygenated area proved to be smaller than the initial risk area.

CONCLUSIONS

In AMI, PCRA initiated during advanced CS drastically reduced early mortality from 100% to 0% in a 4-5 hour observation period. PCRA promoted oxygenation of the ischemic area during LAD occlusion. Results support the use of PCRA as first line of treatment in AMI-CS, improving myocardial rescue and short-term survival.