EuroPCR 2023: Timing of Active LV Unloading in Patients on VA ECMO

In this EuroPCR 2023 presentation, Dirk Westermann, MD, discusses data supporting the use of Impella® in combination with VA ECMO, a combination known as ECMELLA or ECpella. In particular, he looks at the timing for adding Impella support to VA ECMO support. Dr. Westermann is chief of cardiology at University Heart Center, Freiburg Bad Krozingen.

“When you have ECMO, you increase afterload, and that’s the last thing you want to do in heart failure patients, especially in acute heart failure patients,”Dr. Westermann states. Due to retrograde flow, VA ECMO can lead to complications such as aortic thrombus, LV thrombus, and volume overload. Adding Impella support to VA ECMO helps unloading the left ventricle. “When you add an Impella device to that scenario,” Dr. Westermann explains, “you reduce the LV size to normal in a matter of seconds. It can be at a very normal and healthy LVEDP in seconds.”

Dr. Westermann reviews retrospective data demonstrating the benefits of LV unloading in patients supported with ECMO. He describes an analysis from a retrospective database of roughly 700 patients in Europe and the US, in which the addition of Impella to VA ECMO reduced all-cause mortality by roughly 20% compared to VA ECMO alone. He also discusses an ELSO registry dataset of 12,000 patients treated with ECMO, in which a reduction in mortality in patients who received unloading from an Impella device was shown.

To address the lack of prospective data for ECMELLA, Dr. Westermann describes the UNLOAD-ECMO randomized controlled trial currently underway in up to 14 centers in Germany and Europe. This trial is enrolling patients in severe cardiogenic shock who require ECMO support. Patients are randomized to the intervention arm with VA ECMO and Impella or the control arm with VA ECMO alone. He explains that he often starts unloading the heart during VA ECMO treatment with the Impella CP® with SmartAssist® and then upgrades to an Impella 5.0® or Impella 5.5® with SmartAssist® to stop VA ECMO as soon as possible. 

Dr. Westermann also discusses recently published data from a database with 750 ECMELLA patients, highlighting the benefits of LV unloading in a timely manner with ECMO. “I think it’s important to add the Impella concomitantly, so as soon as possible,” he states, explaining that the hazard ratio increases as you wait to add Impella. It is easier to prevent complications, such as thrombus and LV distention, he emphasizes, than to address them after they have occurred.

After his presentation, Dr. Westermann addresses a question about how Impella compares to the intra-aortic balloon pump (IABP) for LV unloading with VA ECMO. “I think the IABP might not be strong enough, in view of afterload reduction, to have that beneficial effect.” He also explains that with ECMELLA, a low level of Impella support, P2 or P3, is sufficient at first to “vent” the LV, and then, in the next few hours, Impella support is increased while VA ECMO flow is reduced to wean the patient from ECMO support as soon as possible.