At present, as in surgical practice, two main transcatheter strategies are available for the treatment of mitral regurgitation: transcatheter edge-to-edge repair (TEER, predominantly using the MitraClip® system) and transcatheter mitral valve replacement (TMVR, mainly with the Tendyne® system). TMVR represents a conceptually attractive alternative, offering near-complete abolition of regurgitation; however, its application remains constrained by significant anatomical, technical, and safety limitations.

Severe mitral regurgitation (MR) continues to be associated with substantial prognostic and symptomatic burden, and a considerable proportion of patients are not suitable candidates for conventional surgery. Within this context, transcatheter repair techniques have evolved over little more than a decade from niche technologies reserved for highly selected cases to effective, minimally invasive therapeutic options with real-world applicability.

Pivotal trials such as EVEREST established the foundations of TEER, enrolling patients with either primary or secondary MR under strict anatomical selection criteria. These criteria were progressively broadened following favorable results from registries such as EXPAND G4, which demonstrated acceptable outcomes even in more complex anatomies. Nevertheless, subsequent studies have emphasized the critical importance of procedural success, defined by the achievement of a non-significant transmitral gradient (<5 mmHg) and residual MR <2+, as failure to meet these thresholds has been associated with increased mortality in later analyses.

Focusing specifically on secondary mitral regurgitation (SMR), the positive findings of the COAPT trial were not replicated in the MITRA-FR study, although the clinical and anatomical profiles of enrolled patients differed substantially. More recent trials, including RESHAPE-HF2 and MATTERHORN, have contributed additional nuance to the field. In selected populations, TEER demonstrated non-inferiority to surgery at 1 year, with a more favorable safety profile and fewer major adverse events. Together with the overall consistency of published data, these findings have led to a class I recommendation for TEER in ventricular SMR with a left ventricular ejection fraction of 20–50% despite optimized medical therapy in the most recent European guidelines.

However, the authors of the review caution that the primary risk of such recommendations is not limited to procedural failure, but also includes the generation of unrealistic expectations in patients with advanced structural disease. Regarding atrial SMR, they argue that surgery provides a more comprehensive correction by restoring annular geometry and enabling concomitant treatment of atrial fibrillation, tricuspid regurgitation, and left atrial appendage closure. Consequently, TEER should be reserved for symptomatic, non-surgical patients after optimized medical therapy.

With respect to TMVR, the overarching message is that eliminating mitral regurgitation does not automatically translate into improved prognosis when achieved at the cost of a complex, high-risk procedure applicable only to highly selected anatomies. Although early studies are encouraging, reporting procedural success rates approaching 95% and sustained symptomatic improvement at 1-year follow-up, the overall experience remains limited. Most procedures are still performed via a transapical approach, early complications are not negligible, and anatomical requirements are stringent, excluding approximately 65–70% of patients during initial screening in major studies.

The review clearly conveys that, at present, TMVR should not be regarded as a “more powerful” alternative to TEER, but rather as a distinct option reserved for patients in whom repair is clearly unfeasible or has failed.

A particularly relevant contribution of the manuscript is its insistence that TEER and TMVR should not be viewed as competing technologies. The review challenges the narrative of technological replacement and instead proposes a framework of complementarity. From a clinical standpoint, this implies recognizing that, in some patients, an imperfect repair may be preferable to a high-risk replacement, whereas in others, accepting residual regurgitation may be less reasonable than pursuing a more aggressive intervention. The value of the article lies in its reminder that these decisions cannot be reduced to simplistic protocols.

In its final sections, the focus shifts from devices to the clinical environment. The authors emphasize that the outcomes described are achievable only in centers with adequate experience, procedural volume, and a genuinely multidisciplinary Heart Team capable of offering both surgical and percutaneous alternatives without bias.

COMMENTARY:

In my view, this article fulfills a role that, while uncomfortable, is necessary: it acts as an editorial counterbalance to the growing inertia toward extending edge-to-edge repair beyond the boundaries where a true clinical benefit is likely to exist. This warning is timely. Expanding indications should not be equated with normalizing suboptimal outcomes, clinically relevant residual mitral regurgitation, or the early need for reintervention.

In secondary mitral regurgitation, the manuscript adopts a more balanced tone, although it retains a somewhat reductive perspective that tends to downplay the role of the valve in favor of the ventricle, which remains the primary determinant of prognosis. Nevertheless, the message that improving MR should not create false prognostic expectations is crucial and should be extended to emphasize that such therapies must not delay or compromise eligibility for other advanced options, including heart transplantation.

The discussion surrounding TMVR is characterized by a commendable degree of clinical realism. Enthusiasm is deliberately tempered, and the current limitations of the technique are clearly highlighted: strict anatomical selection, procedural complexity, and a non-negligible early risk profile. This approach is both honest and necessary to avoid generating unrealistic expectations. That said, the same realism should also be applied when interpreting the developmental stage of the technology. TMVR is currently at a phase comparable to that of transcatheter aortic valve implantation in its early years, and demanding the same level of maturity, safety, and reproducibility as TEER—despite the latter having more than a decade of advantage—may not be entirely fair from a historical or technological perspective.

It is likely that the true inflection point for TMVR will arise not from further conceptual arguments, but from tangible technical advances. A shift toward transfemoral access has the potential to radically alter the procedural profile, expanding eligibility to frail patients who are currently excluded, reducing procedural burden, and potentially redefining the role of TMVR within therapeutic algorithms.

Overall, the article offers a valuable and timely perspective, particularly as a reminder not to trivialize functional failure. The key will lie in adopting a forward-looking approach capable of distinguishing genuine structural limitations from transient constraints inherent to a technology that remains in evolution.

REFERENCE:

Fiocco A, Besola L, De Carlo M, Whitlock RP, Colli A. Transcatheter Mitral Valve Repair and Replacement. A Critical Review of Current Real-World Practice. Eur J Cardiothorac Surg. 2025 Nov 2;67(11):ezaf373. doi: 10.1093/ejcts/ezaf373.