This content is only for readers outside of the US as it discusses a device that is not FDA approved.
Until recently, the tricuspid valve had the reputation for being the “forgotten valve”. According to Jörg Hausleiter (Medizinische Klinik und Poliklinik I, Klinikum der Universität München, Munich, Germany), there are limited therapy options available for managing patients with clinically significant tricuspid regurgitation. In this interview, Hausleiter discusses with Cardiovascular News the Cardioband tricuspid system as an important new treatment option for these patients.
Why, historically, has the tricuspid valve been seen as the “forgotten valve”?
It is mainly because treatment options have been limited for the majority of patients with severe tricuspid regurgitation. One option is pharmacological therapy, which can relieve some of the symptoms of tricuspid regurgitation but does not treat the underlying disease. Therefore, when not treated directly, tricuspid regurgitation can worsen over time. As an alternative, surgery is an option for some patients but surgical mortality is often high. Large American and European registries report an associated risk of mortality of 10%, which is still high.1
How do the origins of tricuspid regurgitation compare to those for mitral regurgitation?
Unlike mitral regurgitation, the majority of patients have secondary tricuspid regurgitation, which is due to annular dilatation. Therefore, the tricuspid leaflets are not typically diseased themselves. For example, a patient with heart failure develops right ventricular dilatation, which leads to severe annular dilatation. The tricuspid leaflets become “too small” for the annulus, resulting in tricuspid regurgitation. This type of tricuspid regurgitation is a secondary condition. This is the reason why tricuspid regurgitation is often seen in combination with left-sided disease such as aortic stenosis or mitral regurgitation, and in patients with dilated cardiomyopathies. Since the mortality rate for isolated tricuspid valve surgery remains relatively high, surgery on the tricuspid valve is frequently postponed until it can be performed in combination with another surgery. For example, if a patient with tricuspid regurgitation needs to undergo mitral valve surgery, the tricuspid valve can often be addressed during the same procedure. European guidelines currently recommend the tricuspid valve should be repaired at the same time as the mitral valve if the tricuspid regurgitation is severe or if it is moderate in the presence of annular dilatation.
What is the role of imaging in identifying the severity of tricuspid regurgitation?
Transthoracic echocardiography (TTE) imaging is the main diagnostic tool for tricuspid regurgitation. However, transoesophageal echocardiography TOE) is the most used imaging resource for interventional therapy. Of note, TOE imaging for the tricuspid valve is much more complicated and challenging than for the mitral valve. The two major hurdles are the anatomy itself and the ability to obtain good quality images. The tricuspid valve is further away from the oesophagus than the mitral valve, which makes imaging inherently more difficult.
Hahn et al have called for a new system for grading tricuspid regurgitation.2 Why is this?
The current echocardiographic criteria for grading tricuspid regurgitation only considers three grades of severity: mild, moderate and severe. However, there is huge variability among patients within the severe category. Of these patients, there is a spectrum of high-to-very high severity categorised as “severe”, “massive”, and “torrential”. Echocardiographers such as Rebecca Hahn (Columbia University Medical Center, New York-Presbyterian Hospital, New York, USA) have suggested the three-grade scale of “mild, moderate and severe” could be improved by using an extended five-grade scale of “mild, moderate, severe, massive, and torrential” to accommodate the large variability amongst patients. These additional grades might become important in the future because early reports indicate significant improvements in clinical outcome after interventional tricuspid repair, even when the tricuspid regurgitation was “only” reduced from “torrential” to “severe”. Such an improvement by two grades in the new grading system would not be considered a successful procedure when the conventional scale is applied.
Given the limitations of traditional management options (i.e. medical management or surgery), I presume an obvious advantage of a transcatheter device is more patients would be able to undergo treatment—is that true?
The risk for interventional tricuspid valve procedures is low; the procedural mortality risk is under 5%.3 That makes a big difference in terms of expanding the patient population who can undergo treatment. Also, the rehabilitation of these patients is much easier and faster than for those who have undergone surgery because they are not having to deal with trauma of the chest.
At present, the only CE-marked transcatheter option for tricuspid regurgitation is the Cardioband tricuspid system. How does the device work?
The Cardioband tricuspid system is a transcatheter valve reconstruction system designed to reduce tricuspid regurgitation through annular reduction. The Cardioband implant is affixed in a stepwise manner along the annulus using a series of anchors and then contracted with the use of a size-adjustment tool to reduce the tricuspid annular diameter. Throughout the procedure, both TOE and fluoroscopy play integral roles to guide the procedure, verify and confirm proper placement and adjustments.
How long does it take to implant?
We are still in the early stages of using the Cardioband tricuspid system, but we usually only need to allow between two and three hours depending on the imaging. The time taken is to ensure the proper location of each anchor, and we consider this a good investment considering the excellent results.
What data are available for the system?
I was an investigator for TRI-REPAIR study, which was a single arm, multicentre and prospective CE-mark study that evaluated the safety and performance of the Cardioband tricuspid system on 30 patients. The system is a feasible and safe approach for managing patients with severe tricuspid regurgitation.4 The technical success rate was 100%. At the six-month mark, we saw significant reductions in the annular size of the septal-lateral diameter. When we looked at the echocardiographic measurements, there was a significant reduction in the severity of tricuspid regurgitation. Furthermore, at least 80% of patients saw improvement in their New York Heart Association (NYHA) classification and almost 90% were in NYHA Class I or II at six months. At baseline, all of the patients were in Class III or IV. We also saw statistically significant improvements in the six-minute walk test and quality of life score, and interestingly, in oedema.
These data show that the Cardioband tricuspid system is associated with a considerable improvement in echocardiographic, functional, and clinical outcomes.
What do you think will be the future of transcatheter therapies for tricuspid regurgitation?
More approaches will become available and these will more likely be repair devices than replacement devices. In my opinion, we will end up with an interventional procedure that is standardised and associated with good outcomes. I expect this treatment will become the mainstay treatment for reducing tricuspid regurgitation, and many patients will benefit from this new treatment option.
References
- Sung et al. European Journal of Cardio-Thoracic Surgery 2009; 36: 825–29.
- Hahn et al. Eur Heart J Cardiovasc Imaging 2017; 18(12): 1342–43.
- Asmarats et al. JACC 2018; 71(25) 2935–56.
- Nickenig et al. JACC 2019; In Press.
