CVD recently conducted an interview with Rebecca T. Hahn, MD, Professor of Medicine at Columbia University Irving Medical Center, Chief Scientific Officer of the echo core lab at the Cardiovascular Research Foundation (CRF), and Director of Interventional Echocardiography at the Columbia Structural Heart and Valve Center. In it, she discusses some of the trends in the growing use of interventional cardiac ultrasound guidance in transcatheter structural heart procedures, the growing number of tricuspid valve procedures, the rising use of 3D intracardiac echo (ICE) and the need for training interventional sonographers. She spoke with Cardiovascular Business at the 2022 Transcatheter Valve Therapies (TVT) Structural Heart Summit.

"At TVT, one of the main focuses is on imaging, because the imager is guiding the procedure so they are an essential part of the team and a big part of the technical success of these devices," Hahn said. It was noted in numerous TVT sessions that the interventional cardiac ultrasound guidance is what makes these minimally invasive structural heart procedures possible.

Transesophageal echo (TEE) has been used to guide most transcatheter structural heart cases over the past decade, but recently 3D ICE catheters have become available and it is changing how many centers image these procedures, Hahn said. The advantage of ICE is that it can eliminate the need for an anesthesiologist. It also offers views inside the heart that can sometimes be difficult to get, especially in areas that are more difficult to visualize on TEE.  But, she said TEE offers a wider field of view, deeper tissue imaging and can obtain views that ICE cannot. For these reasons, she said ICE is often used in conjunction with TEE in complex procedures. However, some speakers at TVT said they have moved mainly to ICE only for some procedures, most notably left atrial appendage (LAA) occlusions.

There has been a growing number of transcatheter procedures to treat tricuspid valve regurgitation and it is widely believed that the U.S. Food and Drug Administration (FDA) will clear some of these devices for commercial use before new mitral valve technologies. This has led to a concentration on tricuspid valve in sessions at conferences like TVT and TCT. Hahn confirmed there is a growing need to image the tricuspid valve as the number of these procedures grow, but its position in the heart has made it more difficult to image using TEE. 

"We are doing more and more imaging in the tricuspid side, where the imaging is indeed challenging. We do find that the 3D ICE images, since they are intracardiac, are going to help us get those procedures done and have the technical success we expect," Hahn said. "The way we do it is the imager is still in charge of the ultrasound machine generating the images, because the software is similar to TEE and the images still need to be manipulated, even though the interventional cardiologist is controlling the probe." 

Hahn said the new pre-procedural imaging for TEE image acquisition guidelines (Recommended Standards for the Performance of Transesophageal Echocardiographic Screening for Structural Heart Intervention: From the American Society of Echocardiography) outline how to overcome some of the difficulties imaging the tricuspid valve and other structural heart anatomy. The document describes the additional TEE views that can be used to image the tricuspid valve.

"The tricuspid valve is sitting on the diaphragm, so the lower you go in the esophagus the closer you get to the right heart and the tricuspid valve, and in addition you eliminate imaging through any left heart structures. So when you have mechanical valves or a lot of acoustic shadowing from the intra-atrial septum, you can avoid all those structures by just going a little deeper and/or using the transgastric views."

Hahn said training and specialization for interventional imagers to provide transcatheter structural heart procedure guidance is also important. She said core competencies have been better defined in the 2019 ACC/AHA/ASE Advanced Training Statement on Echocardiography and in the Core Competencies in Echocardiography for Imaging Structural Heart Disease Interventions: An Expert Consensus Statement.

Learn more about the Guidelines and Review of Tricuspid and Interatrial Septum/LAA Imaging Protocols in this American Society of Echocardiography (ASE) video.