P109: Influence of Body Surface Area, and Ventricular Dimensions on Impella 5.5 Outcomes

Background: There has been an increase in the use of the Impella 5.5 pump for patients with refractory cardiogenic shock in a number of different patient scenarios. There is a scarcity of data on the influence of patient Body Surface Area (BSA) and ventricular dimensions prior to implant on overall pump efficiency, safety, and outcomes. Methods: Patients undergoing Impella 5.5 implantation at a single institution between August 2020 and November 2022 were included. Patient BSA was collected at the time of pump implantation, as well as ventricular dimensions from the pre-Impella echocardiography or cardiac MRI. Other clinical data included death within 30 days, and other demographic variables, as well as suspected hemolysis defined as an LDH value of over 1000 IU/L. Left Ventricular Diastolic and Systolic Dimensions (LVEDD, LVESD) were indexed by dividing them by the BSA as iLVEDD and iLVESD, respectively. Results: One hundred patients with complete data were reviewed, of which, the analysis was limited to patients with chronic heart failure (n=75). The median LVESD was 5.8 cm (IQR 4.5, 6.2), and LVEDD 6.3 cm (5.3, 6.8). 17 patients (23%) died within 30 days of Impella implantation, with no difference in gender, age, BSA, or occurrence of hemolysis in those that died vs alive at 30 days. Patients that died within 30 days had smaller indexed LVEDD (2.6 vs 2.93, p=0.01), and smaller indexed LVESD (2.14 vs 2.79, p=0.002). Conclusion: Patients with smaller indexed LVEDD and indexed LVESD at time of Impella implantation have a higher risk of 30 day mortality that appears to be independent of hemolysis risk. This maybe due to less efficient pump function in small ventricles in higher BSA individuals requiring higher levels of forward flow.