By Vinayat Bapat
The heart team is at the centre of the success of transcatheter aortic valve implantation (TAVI)—it is involved in patient selection, procedural planning, and post-procedure care. A strong heart team will be of paramount importance for the success of transcatheter mitral valve (TMV) interventions. In this commentary, Vinayak Bapat outlines transcatheter mitral valve interventions and reviews which specialists should comprise the optimal heart team for such procedures.
A heart team for transcatheter mitral valve interventions should reflect specialists who should be involved in patient selection, procedure and aftercare. Structurally, the mitral valve is more complex than the aortic valve—ie. it is larger, non-circular and closing pressures are higher. Furthermore, mitral valve pathology can be either “primary” (due to mitral valve disease) or “secondary” (due to left ventricular disease). Unlike aortic valve disease, in which replacement is the only option, mitral valve disease can be managed either with repair or with replacement. There are multiple repair strategies and, at present, they tend to focus on the mitral annulus, leaflets or the chordae. Also, repairs are usually done through a trans-septal approach and tend to be safer and result in reduction rather than elimination of mitral regurgitation. With replacement strategies, the aim is to eliminate the mitral regurgitation—irrespective of the pathology—but they are much more invasive procedures than repair procedures and are performed through a transapical approach. This is because repair devices are larger and the transapical approach provides a shorter and more direct approach to the mitral valve.
A major difference, which is often not highlighted, between TAVI and transcatheter mitral valve interventions is how the procedures are performed. While TAVI is done under fluoroscopy, mitral valve interventions are performed with echo guidance. Therefore, a heart team for transcatheter mitral valve interventions will need to include an operator who is skilled in interpreting and reacting to dynamic echo during the procedure. Ideally, such a heart team should also include a surgeon who is trained in mitral valve surgery, has good catheter skills, and can work in a hybrid operating room environment with imaging assistance and also understands echocardiography. Similarly, the team should comprise of an interventionist who has experience in trans-septal access and in TAVI procedures.
As transoesophageal echo is the main imaging modality used for the procedure, a good echocardiologist with understanding of mitral valve and transcatheter treatments will also be crucial. An imaging specialist will also be an important part of the team because transcatheter mitral valve replacement—with current devices for a given anatomy—will be predominantly based on multislice computed tomography (MSCT). Finally, early experience with mitral devices may lead to unexpected problems and (with patient safety in mind) bailout with circulatory support will be essential and will need to be provided by a perfusionist.
As with any new therapy area, the first cohort of patients in whom new transcatheter mitral valve interventions (repairs and replacements) will be used will be high-risk patients. These patients will be referred from either heart failure specialists or surgeons who specialise in mitral valve surgery. It is possible that neither of these specialists will have been involved in TAVI. Therefore, it will be important to engage heart failure specialists and mitral valve surgeons early when building heart teams for transcatheter mitral valve interventions to help choose the right patients and to exclude patients similar to Cohort C for TAVI—ie. patients who are too sick for the procedure and in whom, to attempt the procedure in these patients would be futile.
Thus to summarise, a transcatheter mitral valve intervention heart team should consist of a surgeon who has experience mitral valve surgery and is trained in transcatheter techniques, an interventionist who is familiar with trans-septal procedures and TAVI, an echo expert, imaging specialist for MSCT planning and a heart failure specialist. As the options could be repair or replacement, a strong heart team with broader understanding of strengths and weakness of rapidly evolving treatment options will be crucial for better patient selection and outcomes.
Vinayak Bapat, consultant cardiothoracic surgeon, Guys and St. Thomas’ Hospital, London, UK