"We are responsible for the pre-procedural screening and detection of the disease process, and obviously the intra-procedural imaging has become very intense. It requires a lot of training and expertise for a number of procedures where the procedure volumes are very small. Because of that, we really have started to dedicate ourselves to designing the training programs and required numbers of procedures that we think will be able to show us competence and proficiency, if not expert level care," Hahn said. 

She was one of the authors of the 2023 ASE guideline document outlining clear and uniform training standards for echocardiographers. This is the first guideline defining training requirements to help increase the number of skilled interventional echocardiographers and improve patient access to quality care.

Another growing role of the interventional echocardiographer is to follow structural heart patients out for several years to help track the long-term outcomes of the therapy and to monitor the implanted device. Hahn said this helps to better understand what is happening to the devices and the cardiac chambers over time. These serial follow-up exams also help monitor disease progression and detect  any complications with the devices as early as possible.

Multimodality imaging being embraced across structural heart 

One common TAVR complication is hypo-attenuating leaflet thickening (HALT), which is caused by thrombus formation on the valve leaflets. This can be detected on echo, but is an area most often monitored with CT. Hahn said this is a good example of why interventional echocardiographers also need to have a good understanding of multimodality imaging and where each modality has strengths or weaknesses.

"That is one of the newest developments where everyone is now embracing the fact that we need multimodality imaging and it cannot just be echo and it can't just be CT. Interventional echocardiographers really need to understand cardiac MRI, CT and nuclear imaging," Hahn explained. 

Imaging has been key to new transcatheter device development

Echocardiography has played a key role in the development of transcatheter structural heart procedures because it enables visualization of the soft tissues and landing zones for the devices. TAVR, mitral and tricuspid valve transcatheter edge-to-edge repair (TEER), left atrial appendage (LAA) occlusion, transcatheter pulmonary valves, septal occluders to seal holes in the heart, and transcatheter mitral and tricuspid valves in trials are all enabled because of echo.

"Part of the development of these new devices and the progress we have made toward approval of devices has really centered on on imaging," Hahn said.

She said this has led to development of new technologies in ultrasound to enhance transesphogeal each (TEE) and intra-cardiac echo (ICE). It also led to improvements or new imaging software for planning and guiding procedures. Live, procedural guidance and echo/angiography fusion technology like the Philips EchoNavigator system have been instrumental in advancing to more complex procedures and patient anatomies. 

These advances have enabled procedures in new areas of the heart. In particular, the tricuspid is now on the verge of seeing several FDA device approvals thanks to advances in echo imaging. Hahn said the tricuspid valve has traditionally been the most difficult valve to image, especially for live echo procedural guidance. But thanks to 3D/4D ICE and improvements in TEE imaging technology, tricuspid procedures are poised to become the next big expansion for structural heart programs over the next couple years. 

Hahn has been deeply involved with some of the tricuspid device trials because of the need for experienced, expert interventional echocardiographers to guide implantation of these devices.

"We are progressing with the equipment that has become available to us to image these really complex procedures and complex anatomies. And it really gives us greater confidence in the procedural and technical success," Hahn said. 

How do interventional echocardiographers get paid?

One issue with having a dedicated interventional echocardiographer is identifying enough procedures to pay for their full-time position using traditional relative value units (RVUs). However, it is critical to have a highly experienced echocardiographer who knows how to work as part of the heart team.

For these reasons, Hahn said most full-time interventional echocardiographers are now salaried by the hospital. 

"I may be the first interventional imager who was taken out of the echo lab and actually hired by the cath lab. I am fully salaried in the cath lab, and many of my colleagues around the country are all similarly salaried," Hahn explained. She added that some interventional echocardiographers are also hired as salaried employees of cardiac surgical departments. 

She said this is why it is so important that administrators understand the role of the interventional echocardiographers to support their pay in the budget outside of traditional RVU models.

"I can't think of a single operator that would feel comfortable doing a complex mitral clip, or a complex tricuspid valve device without an imager. So they have to understand that in order to do these procedures and offer these solutions to patients, they are going to need to support the interventional imager," she explained.

Role of 3D ICE in structural heart imaging

In just the past couple years, 3D/4D ICE has been introduced in the market with much better imaging capability than 2D ICE from a decade ago. Hahn said the new ICE catheters have much of the same imaging capability of 3D/4D TEE. However, ICE does not require general anesthesia, so one physician can be eliminated from the cath lab during procedures. And since ICE catheters are placed and manipulated by the interventional cardiologist or electrophysiologist, the question has been raised if ICE can replace the interventional echocardiographer as well. 

While Hahn said it is possible to use 4D ICE to perform a very straightforward LAA occlusion, most procedures require more expertise. Since the ICE systems offer the same functionality as TEE requiring the same 3D manipulation, multiplaner reconstruction, bi-plane imaging and the various bi-plane modes, those all require someone who really understands the equipment and the anatomy.  

"Something like a clip procedure with a complex cleft, or a lateral or commissural flail, these are things that require some nuances as to the procedure. And again, I feel most procedures are better off having more brains in the room than fewer," Hahn said.