Upgrading extra corporeal life support to ECMELLA using Impella 5.0 in rescued INTERMACS 1 patients, lactate level matters!

Background: Venoarterial extra corporeal life support (ECLS) is the treatment of choice of Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) class 1 patients, but left ventricle (LV) overload is a complication of ECLS. Unloading the LV by adding Impella 5.0 to ECLS in Impella used in combination with venoarterial extracorporeal membrane oxygenation (ECMELLA) configuration is recommended only in patients with acceptable prognosis. We investigated whether serum lactate level, a simple biological parameter, could be used as a marker to select candidates for bridging from ECLS to ECMELLA. Methods: Forty-one consecutive INTERMACS 1 patients under ECLS were upgraded to ECMELLA using Impella 5.0 pump implantation to unload the LV and were followed-up for 30 days. Demographic, clinical, imaging, and biological parameters were collected. Results: The time between ECLS and Impella 5.0 pump implantation was 9 [0-30] hours. Among these 41 patients, 25 died 6 +/- 6 days after implantation. They were older (53 +/- 12 vs. 43 +/- 12 years, P=0.01) with acute coronary syndrome as the primary etiology (64% vs. 13%, P=0.0007). In univariate analysis, patients who died exhibited a lower mean arterial pressure (74 +/- 17 vs. 89 +/- 9 mmHg, P=0.01), a higher level of troponin (24,000 +/- 38,000 vs. 3,500 +/- 5,000 mg/dL, P=0.048), a higher level of serum lactate (8.3 +/- 7.4 vs. 4.2 +/- 3.8 mmol/L, P=0.05) and more frequent cardiac arrest at admission (80% vs. 25%, P=0.03). In multivariate Cox regression analysis, a serum lactate level of >7.9 mmol/L (P=0.008) was found to be an independent predictor of mortality. Conclusions: In INTERMACS 1 patients who require urgent ECLS for restoring hemodynamics and organ perfusion, an upgrade from ECLS to ECMELLA is relevant if the serum lactate level is <= 7.9 mmol/L.