Transesophageal echocardiography as the sole guidance for occlusion of patent ductus arteriosus using the Amplatz® Canine Ductal Occluder in dogs: a preliminary study.

Transesophageal echocardiography (TEE) has proven useful in evaluating patent ductus arteriosus (PDA) morphology thereby guiding appropriate device selection. Additionally, TEE, in combination with fluoroscopy, has been used to guide the transcatheter coil embolization and for deployment of Amplatz Canine Ductal Occluder (ACDO) in dogs. Recently, we described the use of transthoracic echocardiography (TTE) guidance during transcatether PDA occlusion with ACDO without the use of fluoroscopy, but observed problems of deployment in patients with sub-optimal acoustic windows. However, TEE, can overcome issues of sub-optimal TTE acoustic windows and provides higher image resolution of cardiac and vascular regions. Therefore, we hypothesized that TEE could be used to successfully visualize the vascular structures and interventional devices to safely perform PDA occlusion with ACDO without requiring fluoroscopy.We recruited 5 dogs with patent ductus arteriosus (PDA) for TEE-guided percutaneous ductal occlusion with an ACDO. Dogs were anesthetized, positioned in right lateral recumbency and the right femoral artery was accessed percutaneously (modified Seldinger technique). The TEE probe was advanced to a midesophageal position with minimal force to obtain a long axis 4-chamber view (transverse plane). The probe was then retroflexed and withdrawn to a cranial esophageal position until a cross section of the descending aorta was seen. To visualize PDA to the probe was slightly straightened and turned counterclockwise, and the ultrasonic beam was oriented between 60 and 120 degrees.In all dogs, the guide wire and a long introducer-sheath were guided from the aorta through the PDA into the main pulmonary artery by TEE monitoring. The ACDO was advanced through the introducer-sheath until the flat distal disk was visualized within the main pulmonary artery by TEE monitoring. The distal disk was positioned against the pulmonic ostium and the coupled proximal disk was deployed within the ductal ampulla while being monitored by TEE visualization.The guide wires, long introducer-sheath and ACDO appeared hyperechoic on TEE images and TEE guidance provided images of sufficient quality to clearly monitor the procedures in real-time. Real-time monitoring also allowed for immediate corrections to guide wire, catheter or device positioning. The procedures were successful and without complications in all patients.We have demonstrated that TEE monitoring, like TTE monitoring, can guide every step of transcatheter ACDO embolization procedures without requiring fluoroscopy, thereby avoiding radiation exposure, and provides an alternative to TTE-based guidance, especially when TTE visualization of the PDA is insufficient for safe and timely ACDO deployment.