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Mechanical Circulatory Support in COVID-19: When to Consider, What to Expect?

Soltesz E, Surgical Director of Cleveland of the Kaufman Center for Heart Failure and Recovery, from a recent Tall Rounds online CME activity from Cleveland Clinic covering COVID-19 and the heart published online In Consult QD.

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Key Points:

This summary describes the uses and potential limitations of Extracorporeal membrane oxygenation (ECMO) as well as other mechanical Circulatory (MCS) Devices.

  • Circulatory support in COVID – 19 patients is likely most effective for single organ system disease such as acute respiratory distress syndrome (ARDS) and/or cardiogenic shock.
  • Limitations involve patients with cytokine-mediated myocardial dysfunction plus severe respiratory failure, who despite support have a limited prognosis.
  • VV-ECMO and ARDS. (Extracorporeal Life Support Organization – ELSO).
    • Notes:
  • Contraindications include: older age, mechanical ventilations >7days; multiorgan failure.
  • VV-ECMO Oxygen indications focus on the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2:FiO2)
  • VV ECMO indicated if PaO2:FiO2 ≥ 150 mmHg and
    • pH < 7.25 with PaCO2 ≥ 60 mmHg for > 6 hours.
  • For those with PaO2:FiO2 < 150 mmHg and
    • PaO2:FiO2 < 80 mmHg for > 6 hours  
    • PaO2:FiO2 < 50 mmHg for > 3 hours
    • pH < 7.25 with PaCO2 >60 mmHg for > 6 hours.
  • Challenges to VV-ECMO include:
    • Prolonged ECMO support requires – up to 3 weeks due to slow lung healing.
    • Systemic inflammation producing a prothrombotic state requiring large heparin and/or bivalirudin dosages.
    • Potential ECMO induced advancement of of COVID – 19 to other organ systems.
  • Hemodynamic Support for the Management of Cardiogenic Shock
    • Optimal for left ventricular failure from a viral myocarditis – as an isolated organ problem.
  • Goals of Support
    • To provide adequate tissue perfusion (To break the shock spiral)
    • Unload the injured ventricle serving as a bridge to recovery, transplant or a permanent device.
  • Potential Devices:
    • Veno-arterial ECMO (VA-ECMO)
  • Advantages – can be implanted at bedside and provides full, biventricular support
  • Disadvantages – Lack of ventricular unloading adversely effecting left ventricular recovery (LV) while increasing risk of lung injury, risk of aortic/LV thrombosis as well as hemolysis. Lastly, it is unable to uncouple the left and right ventricles challenging the ability to predict next requirements. Ambulation generally not possible.
    • Impella
  • Advantages – Completely unloads the LV, protecting the lungs. Long term support is possible beyond one month with the larger devices. In addition, it has a low rate of hemolysis Ambulation is feasible with axillary cannulation (often surgical).
  • Disadvantages – Surgical implantation requires surgery and transesophageal echocardiogram for placement which possibly increases increased risk to personnel.
    • Temporary right-ventricular assist devices (RVADs)
  • Device types – ProtekDuo/TandemHeart, CentriMag and Impella RP
  • An oxygenator can be spliced in to provide an oxy-RVAD configuration.
  • Specific management:
    • Combined devices – Frequently beneficial – VA ECMO with combined Impella for unloading.
    • Heart Team Decisions critical
  • Summary
    • In appropriately selected patients, particularly with COVID – 19, these devices can be lifesaving.