Are There Etiology-Specific Risk Factors for Adverse Outcomes in Patients on Impella 5.5 Support?

Objectives Identify possible etiology-specific differences in preoperative risk factors for major adverse events during Impella 5.5 support in patients with ischemic (ICM) and non-ischemic cardiomyopathy (NICM). Methods From 10/2019-1/2023, 228 Impella 5.5s were inserted at our institution. Patients were stratified into ICM (n=124) and NICM (n=104) cohorts. The primary outcome was a composite of death/stroke/new-onset dialysis while actively receiving Impella 5.5 support. Random forests identified preoperative factors predictive of the primary outcome separately for each cohort, with ranking by variable importance. Results The primary outcome occurred in 42 (34%) ICM and 35 (34%) NICM patients. Twenty-one (17%) ICM and 21 (20%) NICM patients died on Impella 5.5; stroke occurred in 12 (9.7%) ICM and 3 (2.9%) NICM patients, and new-onset dialysis was initiated in 23 (19%) ICM and 24 (23%) NICM patients while actively receiving Impella 5.5 support. Risk factors reflecting systemic and myocardial cellular injury, end-organ and cardiopulmonary failure, right ventricular dysfunction, and smaller left ventricular dimensions were most predictive of adverse outcomes in both cohorts. Indication for Impella 5.5 and device strategy (bridge to recovery, advanced therapies, or decision) were not top risk factors in either cohort. Conclusions Risk factors related to preoperative stability, right ventricular dysfunction and left ventricular size were more predictive of adverse outcomes while actively receiving Impella 5.5 support than indication or device strategy. These factors could help identify high risk patients who may benefit from additional tailored management to reduce their risk for these impactful adverse outcomes while on Impella 5.5 support.