Shapiro, Anna

The Impella 5.5 is an axillary mechanical circulatory support device used in patients with cardiogenic shock, but those with small left ventricular (LV) cavities may be at risk for suction events, hemolysis, malpositioning, hypoperfusion, and LV injury. Informally accepted guidelines, extrapolated from durable LVAD studies, suggest a minimum left ventricular internal dimension in diastole (LVIDd) of 58 mm, with some clinical practices using a more stringent ≤52 mm cutoff. We retrospectively analyzed 154 consecutive patients supported with Impella 5.5 between January 2020 and December 2024. Overall, 38 patients had an LVIDd ≤58 mm, and 116 had an LVIDd >58 mm; a key subgroup of 21 patients presented with a very small LVIDd of ≤52 mm]. Baseline demographics, comorbidities, body mass index, and renal function were similar [across groups], although those with larger LVIDd had lower ejection fractions (16% vs. 24%, p = 0.001). Median support duration was 24 days in all groups, and pre- and post-implant hemodynamic and laboratory improvements were comparable. Rates of transplantation (79% vs. 90%, p = 0.088) and LVAD implantation (2% vs. 6%, p = 0.159) did not differ significantly in the ≤58 mm cohort. Notably, within the ≤52 mm subgroup, 90-day survival remained high at 90.5% ( p = 0.336), with significant improvements in right atrial pressure (17 to 10 mmHg, p = 0.041), mean pulmonary artery pressure (36 to 26 mmHg, p = 0.008), and eGFR (45 to 57 mL/min/1.73m 2 , p = 0.003). Remarkably, native cardiac recovery was observed exclusively in the smaller LV cohorts, occurring in 11% of the ≤58 mm group ( p = 0.003 vs. 0%, p = 0.003) and reaching 19% in the ≤52 mm group (vs. 0% in larger cavities, p < 0.001), while durable LVAD escalation was entirely avoided in the ≤52 mm cohort (0% vs. 6%). Ninety-day event-free survival was excellent across all cohorts 92% vs. 96% in the primary analysis, with no major device-related complications, suction events, clinically significant hemolysis, bleeding, stroke, or escalation to Bi-VAD support. These findings strongly support the safety and feasibility of Impella 5.5 in extremely constrained, small LV cavities.

Prehabilitation with Impella 5.5 offers hemodynamic support while allowing early mobilization, yet its overall effect on post-transplant recovery remains unclear. The aim was to assess recovery during Impella 5.5–supported prehabilitation and determine its association with early post-heart transplant outcomes, including a potential dose–response relationship with ambulatory activity. We conducted a single-center retrospective cohort study of adults bridged to transplant with Impella 5.5 between April 1, 2022 and September 30, 2024. Daily walking distance, recorded by nursing staff, served as the intervention. Primary outcome was postoperative hospital length of stay (LOS); the secondary outcome was time to extubation. Fine–Gray competing-risk models, adjusted for age, Sequential Organ Failure Assessment (SOFA) score, New York Heart Association (NYHA) class, and days of Impella support, assessed associations. Longitudinal recovery trajectories were analyzed with linear mixed-effects models incorporating restricted cubic splines. Among 82 eligible patients, 65 met the inclusion criteria. Patients who walked farther during Impella 5.5 support in the intensive care unit (ICU) had shorter hospital stays and were taken off the ventilator sooner after transplantation. The overall recovery peaked during the first 2–3 weeks of support, with smaller recovery thereafter, indicating that most functional recovery occurred early during prehabilitation.