High-flow microaxial mechanical circulatory support using the Impella 5.5: clinical outcomes and analysis of complications during implantation, support and device exchange

Abstract Introduction and Purpose The Impella 5.5® is a high-flow circulatory support device approved for up to one month of use, representing a valuable option in advanced heart failure. We evaluated the clinical outcomes and complication profile of patients treated with this device at our centre. Methods This was a retrospective, single-centre study encompassing all Impella 5.5® implants performed between 2022 and 2024. Demographic variables, clinical outcomes according to the indication for implantation, duration of support, and complications occurring during implant, support, and device exchange were collected. Results A total of 21 Impella 5.5® devices were implanted in 17 patients (mean age 61 years, 10% were women). The underlying cardiomyopathy etiology was chronic ischemic (n=6), idiopathic (n=5), acute ischemic (n=2), hypertrophic (n=2), and other causes (n=2). INTERMACS classification at implantation was level 2 in 8 patients and level 3 in 9 patients. Complications related to implantation (24 hours), device support, and device exchange are detailed in Table 1. The total cumulative support duration was 421 patient-days, with a median of 17 days per patient (range 1–81). In 5 devices, the certified technical support period was exceeded (median post-certification duration 48 days; range 36–59). Device exchange was required in 4 patients due to accidental removal (day 9), purge line rupture (day 24), and thrombotic dysfunction (days 39 and 59). During device exchange, 2 patients (50%) experienced ischemic stroke—one underwent successful thrombectomy, whereas the other developed intracranial hemorrhage and died. Only one patient (25%) underwent device exchange without complications. During support, the incidence of ischemic-hemorrhagic complications (major bleeding, tamponade, intestinal ischemia) was 19 events per 1000 patient-days, and device-related complications (malposition, access issues, dysfunction, hemolysis) were 23.7 events per 1000 patient-days. Seven patients (41%) experienced no complications during support, and six (35%) had none during either implantation or support. Regarding therapeutic intent, there were 11 successful transplants (3 after achieving transplant eligibility), 1 case of myocardial recovery, 1 bridge to long-term mechanical circulatory support (following exchange to another Impella), and 4 deaths during support (24%) due to multiple organ failure (n=3) and ischemic stroke (n=1). Conclusions High-flow mechanical circulatory support with the Impella 5.5® achieved the intended therapeutic goal in 76% of patients in this real-world patient cohort. Device-related complications occurred in 65% of patients, with severe adverse events observed in 75% of those undergoing device exchange.Impella-associated complications