Circulatory unloading during VA-ECMO

  • ECMO treatment is often responsible for an elevation of LV afterload caused by the blood flow from the ECMO arterial return cannula
  • In cases of compromised LV function, the heart cannot eject against the additional afterload, leading to LV distention and pulmonary congestion
  • Pulmonary congestion can lead to irreversible pulmonary failure
  • LV distention results in a positive feedback loop, which may cause degradation of LV function and subsequent progression of heart failure
  • Blood stagnation in a nonejecting ventricle can lead to the formation of a ventricular or aortic thrombus

How to unload?

  • the first course of unloading is to use partial ECMO flow + inotropes to promote LV ejection
  • this can be ineffective in severe LV dysfunction and other mechanical methods of circulatory unloading are used

Mechanical methods

  • (transeptal balloon/blade septostomy or sheath)
  • IABP
  • partial VADs (Impella CP, Impella 2.5)
  • temporary VADs (CentriMag, TandemHeart)
  • Impella 5.0
  • catheter interventions such as LV/left atrial (LA)/pulmonary artery (PA) vents, which connect in parallel to the ECMO drainage circuit
  • each technique comes with associated risks and may be contraindicated depending on disease etiology