Dylan Smoot

Background: Utilization of microaxial pumps for temporary mechanical circulatory support in children has increased in recent years. However, data on patient selection, implantation techniques, and outcomes remain limited. Methods: A systematic literature search was conducted in July 2025 to identify case reports and case series reporting the use of microaxial pumps in patients aged 18 years or less. Forty‐four studies comprising 100 patients were identified, and patient‐level data were extracted for analysis. Results: The median age of the patients was 14 [IQR, 11.5–16] years, with a median weight of 52 [40–73] kg and median body surface area of 1.59 [1.35–1.85] m ² . The most common diagnoses were cardiomyopathy (29%), heart allograft rejection (26%), and myocarditis (21%). Impella CP was the most frequently used device (48%), followed by Impella 2.5 and Impella 5.5 (each 21%). Access was predominantly obtained via the femoral artery (47%). Percutaneous implantation was performed in 47% of patients. Patients were weaned from microaxial support for cardiac recovery (42%) or heart transplantation (31%). Fourteen patients (14%) died prior to discharge, with significantly higher mortality among patients supported with ECPella (29%) compared with microaxial pump alone (6%; p = 0.01). The median duration of support was 6 [4–13] days. At the median follow‐up of 119 [23–180] days overall survival was 84%. Conclusion: Microaxial pumps represent an important addition to temporary mechanical circulatory support in pediatric patients and can serve as an alternative to VA‐ECMO in selected cases. Outcomes were less favorable when used in tandem configurations such as ECPella, reflecting the greater severity of illness in these patients.

Background: Conventional mechanical circulatory support offers limited options for patients with small or restrictive left ventricles. Left atrial inflow (LA–Ao) ventricular assist device (VAD) configuration represents an alternative to conventional apical left ventricular assist device (LVAD). However, outcomes data remain limited. To address this, we evaluated patient characteristics, procedural details, and outcomes of LA–Ao VAD configuration in this population. Methods: A systematic search was conducted to identify case reports and series of patients with small or restrictive left ventricles who underwent LA–Ao LVAD implantation. A total of 21 reports, representing 27 patients, were included. Patient‐level data were extracted for analysis. Results: Thirteen adult and 14 pediatric patients underwent LA–Ao VAD implantation. Median age was 57 [46–62] years in adults and 3.5 [0.8–9] years in children. Hypertrophic cardiomyopathy and restrictive cardiomyopathy were the predominant diagnoses in both adults and children, accounting for 54% (7/13) and 29% (4/14), and 46% (6/13) and 43% (6/14), respectively. Median left ventricular ejection fraction was 44% [39–53] in adults and 45% [36–61] in children, and median left ventricular end‐diastolic diameter was 42 [35–42] mm in adults and 33 [29–34] mm in children. The most used devices were HeartWare HVAD (46%, 6/13) in adults, and Berlin Heart (64%, 9/14) in children. Overall pulmonary capillary wedge pressure decreased from 23 [19–27] to 7 [0–9] mmHg ( p = 0.02), and cardiac index increased from 2.0 [1.3–2.8] to 3.1 [2.7–3.7] L/min/m ² ( p = 0.04). In‐hospital mortality included one fatal case (7.7%) in each group. Overall survival was 85% (11/13) in adults at median follow‐up of 6.7 [4.4–19.9] months and 86% (12/14) in children at 2.3 [1.2–8.1] months. Conclusion: The LA–Ao configuration of VAD is a viable strategy for mechanical circulatory support in patients with small or restrictive left ventricles. It offers effective unloading of the left atrium and improved cardiac index, supporting its role as an alternative to the conventional LVAD approach.