Hemodynamic Support With the Impella 5.5 Acute Mechanical Circulatory Support Device

The Impella 5.5 is increasingly used as a bridge to recovery or heart replacement therapies despite lack of clinical trial evidence. We report real-world outcomes and hemodynamic effects of 150 consecutive patients from a single, high-volume center. Primary outcome was incidence of recovery, durable left ventricular assist device (LVAD), or heart transplant compared with incidence of death at 90 days. Secondary outcomes included hemodynamic trends and upgrade to veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support. The composite endpoint occurred in 59.3% and death in 18.8% of patients (incidence rate ratio: 8.1 [95% confidence interval {CI}: 5.4-12.2], p < 0.001). Decreases in pulmonary artery diastolic pressure (PADP) (p = 0.026), estimated pulmonary effective arterial elastance (Ea) (p < 0.001), and vasoactive-inotropic score (VIS) (p < 0.001) occurred during Impella 5.5 support. Pulmonary artery diastolic pressure correlated with estimated Ea (p < 0.001), suggesting improved right ventricle (RV) afterload with left ventricle (LV) unloading. Veno-arterial extracorporeal membrane oxygenation upgrade occurred in 11.3% of patients who had higher baseline right atrial pressure (RAP) (16.0 [9.0-20.5] vs. 9.0 [7.0-12.0], p = 0.022), PADP (28.5 [25.0-31.0] vs. 23.0 [18.0-28.0], p = 0.011), and lower pulmonary artery pulsatility index (PAPi) (1.45 [0.82-3.45] vs. 2.5 [1.65-3.86], p = 0.029). Upgrade patients had higher repeated measures trends in RAP (p < 0.001) and PADP (p = 0.015). The Impella 5.5 improved hemodynamics and effectively bridged to recovery or heart replacement therapies. Co-existing RV dysfunction can be supported on Impella 5.5 with careful hemodynamic trend monitoring.