Early Outcomes of the First 200 US Patients Treated with Impella 5.5: A Novel Temporary Left Ventricular Assist Device

Objective To report the initial clinical experience with the Impella 5.5 ® with SmartAssist ® , a temporary left ventricular assist device that provides up to 6.2 L/min forward flow, with recent FDA approval for up to 14 days. Methods From October 2019 to March 2020, 200 patients at 42 US centers received the Impella 5.5 and entered into the IQ registry, a manufacturer-maintained quality database that captures limited baseline/procedural characteristics and outcomes through device explant. Post hoc subgroup analyses were conducted to assess the role of baseline and procedural characteristics on survival, defined as successful device weaning or bridge to durable therapy. Results Median patient age was 62 years (range, 13 to 83 years); 83.4% were male. The device was most commonly used for cardiomyopathy (45.0%), acute myocardial infarction complicated by cardiogenic shock (AMICS; 29.0%), and post cardiotomy cardiogenic shock (PCCS; 16.5%). Median duration of support was 10.0 days (range, 0.001 to 64.4 days). Through device explant, overall survival was 74.0%, with survival of 80.0%, 67.2%, 57.6%, and 94.7% in cardiomyopathy, AMICS, PCCS, and others (comprising high-risk revascularization, coronary artery bypass graft, electrophysiology/ablation, and myocarditis), respectively. Patients requiring extracorporeal membrane oxygenation and Impella support (35 patients, 17.5%) had significantly lower survival (51.4% vs 78.8%, P = 0.002). Conclusions In the first 200 US patients treated with the Impella 5.5, we observed overall survival to explant of 74%. Survival outcomes were improved compared to historic rates observed with cardiogenic shock, particularly PCCS. Prospective studies assessing comparative performance of this device to conventional strategies are warranted in future.