Mitral TEER: Patient Selection, Imaging and Workflow

1. How should patient selection for mitral TEER be approached across different MR aetiologies?

Prof Tobias Geisler: My name is Professor Tobias Geisler. I am an interventional cardiologist at the University Hospital Tuebingen in Germany, and I am involved in transcatheter mitral and tricuspid therapies.

It is important to clarify the mechanism of mitral regurgitation before starting a procedure. Of course, you can classify patients according to the aetiology of mitral regurgitation.

One group includes patients with secondary ventricular mitral regurgitation. In these patients, the MR is mostly not caused by structural deterioration of the leaflets, but by problems of the left ventricle, including left ventricular remodelling, tethering of the leaflets or impaired approximation of the papillary muscles.

In these patients, it is important to identify how much of the symptoms are really caused by the mitral regurgitation and how much of the symptoms are caused by impaired left ventricular function. This is sometimes challenging because you also have to take care of guideline-adherent medical therapy, and you also have to think about other ways to improve left ventricular function, such as cardiac resynchronisation therapy.

Then we have degenerative mitral regurgitation, which is caused by a primary leaflet problem. In these patients, you sometimes have issues with multiple jets, prolapse or flail segments, and this may be more challenging with regard to procedural planning.

Then you have a special form of functional mitral regurgitation, which is atrial functional mitral regurgitation. In most cases, this can be treated quite well with TEER. However, here it is also a multimodal approach. We still do not understand very well the effects of other interventions, for example rhythm control, in these patients. Many of these patients also have atrial fibrillation, so this can sometimes be challenging.

2. What are the key workflow adaptations required when moving between more and less complex cases?

Prof Tobias Geisler: The treatment of ventricular functional MR, and maybe also atrial functional MR, is sometimes straightforward. Sometimes you can treat the MR quite well by placing a TEER device in a central position, such as A2-P2. This can be a very straightforward case.

It becomes more challenging when you have complex situations, for example ventricular MR with heavy calcification, short leaflets, clefts or defects in the leaflets. This requires more sophisticated planning of the procedure and also more intense communication between the implanter and the imager.

These are more complex cases that require more sophisticated planning.

3. Where does imaging most critically influence procedural success in mitral TEER?

Prof Tobias Geisler: Imaging plays a role at all stages of mitral TEER. It is important in the planning phase, where you really have to identify the mechanism of MR and anticipate the challenges of the procedure.

During the procedure, imaging plays a role in determining the transseptal puncture height. It also helps with guiding the system, aligning the system, positioning the device and supporting the grasping process.

Imaging also plays a role in the evaluation of procedural success, including the evaluation of residual MR. Sometimes you need three-dimensional modalities to evaluate residual MR.

It also plays a role in evaluating the residual orifice area and the transmitral gradient.

4. What are the most common procedural challenges and how can they be mitigated?

Prof Tobias Geisler: The most common procedural challenges include low transseptal puncture height. With some systems, you can compensate for this quite well, but it is still a challenge.

Depending on the mechanism and the aetiology of the MR, you can encounter challenges in situations with leaflet calcification, or in patients with reduced baseline mitral valve orifice area.

Then it is always an individualised decision what you accept as procedural success, both with regard to MR reduction and with regard to the residual transmitral gradient.

Normally, we aim to reduce the MR as much as we can. Our goal should be to achieve MR 0 or 1+. Sometimes we can only achieve this with increased gradients. Then the question is how much gradient we accept.

Normally, we are now more tolerant of gradients up to 6 to 7 mmHg. But above this value, I think there is a risk of relevant stenosis in these patients.

Imaging can also be a challenge when you have artefacts, for example from the device itself, from intracardiac structures, from calcified lesions, or from other prostheses or devices. These factors can make the procedure more challenging.

5. What are your take-home messages for heart valve teams looking to optimise their TEER workflow?

Prof Tobias Geisler: As mentioned, you should have good planning of the procedure. You should identify the mechanism of MR in order to anticipate potential challenges.

You should standardise what can be standardised. There can be easy, straightforward cases, but there can also be challenging cases. In these cases, you need individualised procedural planning.

It is also important to have close communication between the implanter and the echocardiographer. They should work as a team. The echocardiographer is not only an observer, but is a procedural partner.

This is quite crucial, particularly in challenging cases. You should act as a team.

Finally, it is important to define what procedural success means in these patients, particularly in challenging patients.