5.3 / IAGS 2019
Session 5: Structural Session 2 – Mitral & Tricuspid
Percutaneous Tricuspid Valve Repair
Christopher Meduri, MD
Statement of problem or Issue
Tricuspid regurgitation (TR) has historically been overlooked and not often treated due to poor resulting outcomes. We know, however, that untreated tricuspid regurgitation (both moderate and severe) is associated with high mortality, up to 50% at 5 years. Surgical treatment has an extremely high reported mortality, but unfortunately there is a paucity of data on surgical treatment. This is the perfect scenario for a transcatheter treatment option, but the studies to date are all early feasibility studies, and they are slow to enroll. Imaging of the tricuspid valve continues to be a major challenge. Until recently there was only 2D/3D transesophageal echocardiography (TEE), which in the best of hands still results in difficulty in seeing the tricuspid valve clearly. Now we have 3D intracardiac echocardiography (ICE) that may greatly advance the field but is still limited to a minority of programs.
Gaps in knowledge
Finding suitable tricuspid regurgitation patients is difficult. There is not a natural referral process mainly due to lack of knowledge about the horrific outcomes of tricuspid regurgitation. Referring physicians generally do not identify this valve as a problem. A second issue is deciding what amount of tricuspid regurgitation is appropriate to treat. Both moderate and severe TR are associated with bad outcomes and we have yet to determine how much we need to reduce the TR. We do not even know how to quantify TR precisely by echo. Often patients feel better symptomatically even with only a modest reduction in TR but we do not know if this improvement translates into a mortality benefit. These are typically highly functional patients, and treating fluid retention and BP may help them as much as a device. How do we quantify our results? Do we look at quality of life metrics, biomarkers, both? Lastly, how do we customize the treatment options for each patient? How do we know when and in which patients to repair or replace the tricuspid valve, and does right ventricular function matter?
Possible solutions and future directions
There needs to be a paradigm shift in the best way to identify the TR patients that might benefit from treatment. Databases within our own systems need to be mined to collect data and to jumpstart the referral process. This will help educate the referring physicians on who to send, and help all providers learn who to treat and who to leave alone. This has built up some tricuspid programs already, and gives those institutions a robust program for data collection and analysis. Referring physicians need to be educated on the importance of this valve and to notice it in the echo reports. Establishing which are the best medicines to give for symptomatic relief is also important. For example, switching furosemide to torsemide may cause a better diuresis because torsemide works better in patients who have gut edema. It is well known that furosemide orally does not work in patients with gut edema because it is not absorbed as well. Referring physicians need to be shown and educated that transcatheter tricuspid technologies are relatively safe and should be tried in place of doing nothing.
The meaning of “significant reduction” in TR needs to be determined. Though a 50% reduction may make a patient feel better, it is probably not adequate for mortality benefit. Using 2D/3D ICE for the clip procedures for accurate leaflet grasping will most likely become the standard of care with or without TEE guidance. There is a much higher risk for single leaflet detachment than in mitral clip because the leaflets are much more delicate. New and improved technology helps in preventing this. Lastly, this technology needs to stay in high volume centers, at least until these questions above are answered. These TR procedures are difficult and require not only experienced operators but experienced imagers as well. We want to make sure that this technology does not go away just because of low volume and less experienced operators trying to perform procedures without appropriate guidance and training.