Maurizio Taramasso (Department of Cardiac Surgery, University Hospital of Zurich, University of Zurich, Zurich, Switzerland) and colleagues write in EuroIntervention that transcatheter mitral valve repair and transcatheter mitral valve replacement (TMVR) “will most likely be complementary rather than competitive” therapies, adding that a “repair-first” (followed by TMVR if needed) “seems the most appropriate approach”.
Taramasso et al note that transcatheter mitral valve therapies “have great potential to address unmet clinical needs for patients with symptomatic severe mitral regurgitation who are inoperable or high surgical risk”, adding that several approaches—including both repair and replacement devices—are commercially available or under investigation. However, they add: “We are still far from having an unbiased and evidence-supported process to select the best treatment for each patient, and direct comparisons between transcatheter repair and replacement methods are not available so far”.
Despite the lack of evidence for repair vs. replacement therapies, according to Taramasso et al, the general consensus is that the therapies “will be completely rather than mutually exclusive”. “This will happen for both degenerative (primary) and functional (secondary) mitral regurgitation,” the authors write.
They comment that there are a number of reasons why a “repair-first strategy” may be preferable to a replacement-first strategy. These include that 30-day mortality seems to be higher with replacement than with repair, that repair is “more respectful of the physiology of the mitral valve as the impact of the implant is minimal”, and that life expectancy of a patient who undergoes replacement (because of valve-related events) is reduced. Furthermore, the authors note that the lack of a TMVR device on the market leads to “obvious logistical reasons favouring a repair-first strategy”. They explain that the screening process to get a patient into a clinical trial of a TMVR device—the only way a patient can undergo TMVR at present—is relatively long and that this “may create discomfort or even be dangerous in the case of severely symptomatic patients, especially if an alternative is immediately available”.
According to lead author Taramasso, the “repair-first” strategy will apply when/if a TMVR receives marketing approval. He tells BIBA Briefings that the “mitral valve is not the aortic valve” (and thus, replacement is not necessarily the best option). However, he adds there will be some patients for whom TMVR is a more suitable approach. In EuroIntervention, he and his colleagues comment that replacement “has to be considered as an alternative” if the likelihood of a good repair is reduced because of unsuitable anatomy. The authors say that another reason for not performing repair is insufficient institutional experience, noting that the outcomes of repair procedures are linked to institutional volume (i.e. more experienced centres have better outcomes). Taramasso, though, does observe that operator/centre experience will “absolutely” be as important for performing TMVR as it appears to be for performing repair.
Another argument in favour of a repair-first strategy, Taramasso et al write, is that some repair techniques “keep the option for subsequent valve replacement open”. Therefore, the choice of repair device has to take into account the effect of that device on the potential to perform valve replacement at a later date. “In cases where TMVR is anatomically feasible, leaving a ‘bad clip’ should be avoided, although the feasibility of TMVR has been reported even after edge-to-edge repair”, Taramasso et al observe. But, ultimately, the authors argue: “Keeping in mind that residual mitral regurgitation has an impact on outcomes even in the short term, if a ‘bad repair’ is expected, the best option is to consider the patient for replacement, avoiding the risk of two procedures.”
In the paper, he and his colleagues conclude: “Finding the sweet spot in mitral valve treatment requires a tailor-made approach for each patient with an accurate evaluation of valve disease anatomy and clinical presentation. In addition, the treatment should be performed in a dedicated valve centre with a high level of expertise in mitral valve interventions.”