Model of magnetically guided fetal cardiac intervention: potential to avoid direct cardiac puncture

Fetal cardiac interventions are performed via direct cardiac puncture and are associated with significant fetal morbidity. The feasibility of utilizing magnetic navigation to maneuver a guide wire and balloon across a fetal aortic valve without direct cardiac puncture is tested.

A fetal heart model was manufactured and placed in a catheterization laboratory equipped with magnetic navigation. Magnetically steerable guide wires along with commercially available coronary balloons were inserted into the model at a site mimicking a hepatic vein.

Passage of the wire and balloon was achieved on every attempt. The model was suitable for testing although the structural characteristics of the model made wire passage from the right to the left atrium the most challenging aspect. Once the wire was positioned in the left ventricle, it was easily maneuvered 180 degrees towards the left ventricular outflow tract and then the descending aorta. Advancement of a coronary balloon over this wire was uncomplicated.

In a fetal heart model, it is feasible to deliver a wire and balloon from abdominal venous access antegrade across the aortic valve. Progression to fetal lamb models is planned and may advance fetal cardiac interventions by reduction of fetal morbidity.