Patient size parameters to guide use of the Impella device in pediatric patients

Objectives: To define patient and ventricular size parameters to guide Impella device (Abiomed, Inc., Danvers, MA) placement for mechanical circulatory support (MCS) in small pediatric patients (10–30 kg). Background: There are few options for MCS in children, and there are no data on minimum patient size requirements for placement of the Impella 2.5 device. Methods: This was a multicenter study of echocardiographic and magnetic resonance imaging (MRI) derived dimensions of the left ventricle (LV) length and ascending aorta used to define minimum size parameters that are necessary for the placement of the Impella catheter. Results: Data were collected from 44 cardiac MRIs conducted in healthy pediatric patients and 39 echocardiograms performed in pediatric patients with cardiomyopathy prior to surgical ventricular assist device (VAD) placement. The Impella 2.5 catheter is 7.5 cm from the pigtail to the aortic annulus marker, thus requiring an LV apical length of 7.5 cm to allow the device to function in an unconstrained fashion. In the cohort of patients undergoing consideration for VAD placement, a minimum LV length of 7.5 cm corresponded to a height of 122 cm, weight of 23 kg, and body surface area (BSA) of 0.89 m². In the MRI cohort, this corresponded to a height of 121 cm, weight of 23.9 kg, and BSA of 0.89 m². Conclusion: MCS with Impella devices is feasible in pediatric patients. This study defines anthropomorphic and anatomic measurements to guide providers in patient selection for MCS using the Impella devices.