ECMO
Treatment options for COVID-19 myocarditis are still evolving. However, mechanical circulatory support devices and life support therapies such as veno-venous ECMO (VV-ECMO) and VA-ECMO may be beneficial in select cases.
The mortality in COVID-19 patients who require mechanical ventilation is high. Extracorporeal membrane oxygenation can be lifesaving in patients with severe forms of ARDS, or refractory cardio-circulatory compromise. While accepting that resource scarcity may be the overwhelming concern for healthcare systems during this pandemic, VA-ECMO can be considered in highly selected cases of refractory CS and biventricular failure. The decision to initiate this therapy should take into consideration the availability of resources, perceived benefit, and risks of transmitting disease to patients and staff.
The Extracorporeal Life Support Organization (ELSO) recommends consideration of VA-ECMO in refractory CS that persists despite adequate fluid resuscitation, inotropes, and vasopressor support.[24] Contraindications to VA-ECMO include advanced age, life- threatening noncompliance, and significant medical comorbidities.[24]
The Society of Critical Care Medicine guidelines for the management of COVID-19 patients recommends the use of ECMO when conventional management fails.[25] Due to the intensive hospital resource utilization, substantial staff training, and multidisciplinary needs associated with starting an ECMO program, ELSO recommends against starting new ECMO centres for the sole purpose of treating patients with COVID-19. During the COVID-19 surge, it is reasonable to concentrate those patients with the greatest chance of benefit from receiving ECMO in a hospital where an experienced ECMO team is available.
Patient selection for VA-ECMO in the setting of COVID-19 infection is a challenging task. However, a multidisciplinary CS team that includes representation of cardiac surgery, cardiology, intensive care, anaesthesia, and advanced heart failure/transplant physicians may facilitate decision-making.
Although patients with COVID-19 infection are in a proinflammatory and prothrombotic state, coagulopathy occurs in up to one-fifth of cases.[26] Thus, vigilant monitoring for both thrombotic complications (intracardiac thrombi, aortic root/aortic valve thrombi, cannula thrombi, thrombosis of oxygenator) is necessary. Severe cases of COVID-19 tend to present with multi-organ failure. The use of VA-ECMO in such patients may be considered a futile resource-intensive endeavour. Use of validated prognostic scores such as the Sequential Organ Failure Assessment and Survival after Veno-arterial ECMO scores together with clinical judgment may identify those who are more likely to recover.[27]
The provision of ECMO, also is dependent on local institution and regional policies. ECMO requires specialized equipment, training (of physicians, nursing staff, and perfusionists), and delivery of care in specialized critical care units. MacLaren et al.[28] suggest, resources may well be better concentrated to ensure that enough ICU beds, ventilators, and personal protective equipment are available to deal with the influx of patients encountered during the pandemic. Providing this level of care should be considered dynamically on a case-by-case basis as the local situation and resource availability changes (ie, critical care beds, healthcare personnel, equipment).
Many factors could affect the outcomes of ECMO treatment, including the duration of mechanical ventilation, the severity of underlying disease, the experience of trained medical staff, and ECMO equipment. Use of ECMO in patients with a combination of advanced age, multiple co-morbidities, or multiple organ failure should be avoided.
Not all patients will improve with ECMO support. As is standard with usual ECMO care, clinicians should be continuously evaluating when ECMO no longer provides a positive benefit:risk ratio and should at that point return to conventional management. As prognosis is worse with time on invasive mechanical ventilation, patients on mechanical ventilation greater than 7 days can probably be excluded and observing no lung or cardiac recovery after approximately 21 days on ECMO can be considered futile.
In the present time of global uncertainty with limited evidence to guide care, we must be mindful of balancing resource scarcity. We anticipate that Extracorporeal Membrane Oxygenation for 2019 Novel Coronavirus Acute Respiratory Disease (ECMO-CARD), an ongoing multicentre prospective observational study of ECMO use in COVID-19, will inform practice for both VV-ECMO and VA-ECMO use when published.[29] For now, it seems reasonable to reserve VA-ECMO for highly selected cases of COVID-19 where there is a perceived reasonable probability of recovery.