(235) Impact of Heparin Versus Sodium Bicarbonate Impella Purge Solutions on Renal Outcomes

Introduction: The percutaneous ventricular assist Impella® device (Abiomed, Inc; Danvers, MA) requires a purge solution to run countercurrent to blood flow through the device’s microaxial pump. While heparin-based purge solutions (HBPS) are considered standard of care, in June 2022, Abiomed issued a recommendation to utilize sodium bicarbonate-based purge solutions (BBPS) when alternatives to heparin were required. Acute hemolysis secondary to shear stress is a known complication of Impella® support and may precipitate the development of acute kidney injury (AKI). Additionally, there is limited literature supporting widespread utilization of BBPS. The objective of this study was to determine if BBPS compared to HBPS resulted in differences in renal and clinical outcomes among adult patients requiring Impella® support.

Methods: This retrospective cohort study included adult patients (≥19 years) receiving Impella® support from October 2015 to August 2023. Patients were included if they received device support for ≥ 48 hours and excluded if they received prior renal replacement therapy. The primary outcome was incidence of AKI utilizing the 2012 KDIGO definition after receiving 24 consecutive hours of purge solution during the first 14 days of device support. Secondary outcomes included incidence of pump thrombosis, major bleeding, supratherapeutic activated partial thromboplastin time (aPTT) > 85s, and ICU/hospital length of stay (LOS).

Results: A total of 26 patients receiving BBPS and 49 patients receiving HBPS patients were included. The median duration of Impella® support was longer in the BBPS group compared to the HBPS group (median [IQR] 6.9 days [2.1-36.7] vs. 4.7 days [2-30], p=0.04). There was no difference in the primary outcome rate of AKI during the first 14 days of pVAD support comparing BBPS to heparin (19.2% vs. 34.7%, p=0.19). There was also no difference in incidence of pump thrombosis (p=0.35), major bleeding (p=0.07), and ICU LOS (p=0.11) or hospital LOS (p=0.15). Patients in the HBPS group had a higher incidence of aPTT > 85s compared to BBPS (69.4% vs. 38.5%, p=0.01).

Conclusions: There was no difference in renal outcomes comparing BBPS to HBPS. This study may guide future investigations assessing safety and clinical outcomes of BBPS.