Echocardiographic imaging of the Medtronic Micro Vascular Plug^™ during off label placement in the premature infant with patent ductus arteriosus

Objectives: To report the usefulness of harmonic imaging in echocardiography to visualize and direct the implantation of the Medtronic micro vascular plug (MVP). Background: Off label use of the MVP was reported for transcatheter occlusion of patent ductus arteriosus (PDA) in premature infants. The device is poorly visible on fluoroscopy and echocardiography. Methods: In 9 consecutive premature infants, the MVP was used for transcatheter closure of the PDA. In each, the ability of conventional echocardiographic imaging was compared to harmonic imaging, and the device was deployed in the PDA using echocardiography. Results: In each subject, harmonic imaging proved superior to conventional echocardiography to visualize the MVP in premature infants using 12 and 8 MHz probes. Once the delivery, catheter was across the PDA into the descending aorta, and the MVP advanced to the catheter tip, positioning, and deployment of the device was possible without fluoroscopy. All devices were deployed appropriately with immediate occlusion and no obstruction to the left pulmonary artery or aorta. Conclusions: The MVP can be accurately imaged using harmonic imaging, even in the near field in premature infants. Precise implantation of the MVP in the PDA of premature infants is possible with echocardiographic imaging of the device and vascular structures.