This article is based on an interview with Dr Isida Byku on the evolving evidence for mitral transcatheter edge-to-edge repair (TEER) and the implications of the 2025 ESC/EACTS Guidelines for the Management of Valvular Heart Disease.[1]

Key Take-home Messages

• The 2025 ESC/EACTS guidelines formally distinguish ventricular functional mitral regurgitation (MR) from atrial functional MR, creating a more precise framework for diagnosis, referral and treatment selection.[1,2]
• Mitral TEER now has a Class I, Level A recommendation for selected patients with symptomatic ventricular functional MR despite guideline-directed medical therapy, reflecting a strengthened evidence base for reducing heart failure hospitalisations and improving quality of life.[1–3]
• Advanced imaging, haemodynamic assessment and multidisciplinary Heart Team review remain essential to identifying patients most likely to benefit from TEER and achieving durable clinical outcomes.[1,2]

A Guideline Update With Practical Consequences for Valve Teams

The 2025 ESC/EACTS Guidelines for the Management of Valvular Heart Disease represent an important evolution in the management of mitral regurgitation, particularly for patients with secondary MR.[2] Rather than treating functional MR as a single clinical entity, the guidelines distinguish between ventricular functional MR and atrial functional MR, reflecting differences in mechanism, patient phenotype and treatment strategy.[1–3]

Speaking to Transcatheter Academy, Dr Isida Byku described this distinction as one of the most clinically meaningful aspects of the guideline update.[1] For Heart Teams, the change is more than semantic: it encourages more careful evaluation of the underlying mechanism of MR and supports more tailored decisions around medical therapy, transcatheter intervention and surgical referral.[1,2]

“The most important message from the 2025 European guidelines is the recognition of functional ventricular MR and functional atrial MR as distinct clinical entities, with corresponding upgrades in treatment recommendations,” said Dr Isida Byku.[1]

For interventional cardiologists, structural heart specialists, heart failure physicians, cardiac surgeons and imaging experts, the updated classification reinforces the importance of aligning intervention with disease mechanism rather than relying on MR severity alone.[1,2]

Mitral TEER Gains a Stronger Position in Ventricular Functional MR

One of the most notable changes in the 2025 guidelines is the upgrade of mitral TEER to a Class I, Level A recommendation for carefully selected patients with symptomatic ventricular functional MR who remain symptomatic despite guideline-directed medical therapy.[1–3] This positions TEER as an established component of management for an appropriately selected subgroup of patients with ventricular secondary MR.[1,2]

According to Dr Isida Byku, the recommendation reflects an evidence base showing reductions in heart failure hospitalisations, improvements in quality of life and favourable clinical outcomes in selected patients.[1] She noted that two randomised controlled trials since the previous guideline update have contributed to the strengthened recommendation by demonstrating improvements in quality of life and reductions in heart failure hospitalisation rates.[1]

“Positioning mitral TEER alongside guideline-directed medical therapy as a core treatment option reflects the therapy’s proven ability to reduce heart failure hospitalisations and mortality while improving quality of life,” she said.[1]

The guideline update therefore signals a shift from considering TEER mainly as a procedural option for selected complex cases to recognising it as an evidence-supported therapy within contemporary heart failure and valve disease pathways.[1–3] For clinicians, the practical implication is the need for earlier identification and referral of patients who remain symptomatic despite optimised medical therapy and who may meet anatomical and physiological criteria for TEER.[1,2]

Atrial Functional MR: An Emerging but More Nuanced Evidence Base

The 2025 guidelines also refine recommendations for atrial functional MR, although the evidence base remains less mature than for ventricular functional MR.[1–3] In the interview, Dr Isida Byku noted that the recommendation for atrial functional MR has been strengthened to Class IIb, reflecting growing clinical experience in this patient group.[1]

She described emerging data suggesting that selected patients with atrial functional MR may benefit from TEER, including reductions in heart failure hospitalisations and meaningful improvements in Kansas City Cardiomyopathy Questionnaire scores.[1] However, compared with ventricular functional MR, the evidence base remains more limited and patient selection requires particular caution.[1,3]

This distinction is important for expert audiences. Atrial functional MR often occurs in the setting of left atrial enlargement, atrial fibrillation and annular dilatation, rather than primary leaflet pathology or left ventricular remodelling.[1–3] As a result, treatment decisions may involve different trade-offs, including rhythm management, surgical considerations and transcatheter repair in patients who are high risk or unsuitable for surgery.[2,3]

Collectively, the guideline changes reflect growing confidence in TEER for selected patients across the functional MR spectrum, while preserving an appropriately cautious approach where evidence remains evolving.[1–3]

Degenerative and Functional MR Require Distinct Treatment Pathways

Dr Isida Byku emphasised that accurate classification of MR remains central to treatment selection.[1] In degenerative, or primary, MR, surgical mitral valve repair remains the preferred strategy for patients who are appropriate surgical candidates and have favourable anatomy.[1,2] This reflects the established durability and outcomes of surgical repair in suitable patients.[2]

TEER, by contrast, continues to play an important role in degenerative MR for patients who are at high or prohibitive surgical risk.[1,2] In this setting, the value of TEER lies in providing a less invasive treatment option for patients who may otherwise have limited procedural alternatives.[1]

Functional MR requires a different framework. In ventricular functional MR, the regurgitation is closely linked to left ventricular remodelling and systolic dysfunction, making optimisation of guideline-directed medical therapy a prerequisite before intervention is considered.[1,2] In atrial functional MR, atrial remodelling and annular dilatation may be more prominent, requiring a different clinical discussion around rhythm, haemodynamics and procedural suitability.[1–3]

For Dr Isida Byku, distinguishing degenerative MR, ventricular functional MR and atrial functional MR is therefore essential before a treatment pathway is selected.[1]

Imaging and Haemodynamics Remain Central to Patient Selection

As guideline recommendations for TEER strengthen, the need for rigorous patient assessment becomes even more important.[1,2] Dr Isida Byku highlighted high-quality imaging as fundamental to determining whether a patient is likely to benefit from TEER.[1]

Important anatomical factors include leaflet motion, coaptation gap, leaflet tethering, left ventricular size and function, and left atrial dimensions.[1] These features help determine procedural feasibility, the likelihood of achieving effective MR reduction and the potential durability of repair.[1,2]

The 2025 ESC/EACTS guidelines similarly emphasise the central role of advanced imaging in contemporary valvular heart disease management, including three-dimensional echocardiography, cardiac computed tomography and cardiac magnetic resonance imaging where appropriate.[2] The guidelines also reinforce the importance of correctly assessing the cause and mechanism of valve disease, because these factors directly influence management.[2]

Physiological assessment is equally important. Dr Isida Byku noted that pulmonary pressures, invasive haemodynamics obtained through right-heart catheterisation, volume status and overall haemodynamic compensation all contribute to decision-making.[1] These measures help identify patients in whom TEER is likely to provide meaningful clinical benefit and those in whom advanced disease or competing haemodynamic factors may limit response.[1,2]

Heart Team Review Helps Navigate Areas of Clinical Uncertainty

The 2025 ESC/EACTS guidelines reinforce the importance of multidisciplinary Heart Teams and experienced Heart Valve Centres for complex valve disease.[2] This is particularly relevant in functional MR, where multiple interacting factors — including ventricular function, atrial remodelling, pulmonary pressures, surgical risk, anatomy and patient preference — may influence the final recommendation.[1,2]

Dr Isida Byku described a structured Heart Team process involving structural heart specialists, cardiac surgeons, heart failure physicians and imaging experts.[1] In her practice, patients are first assessed and counselled in clinic before imaging and clinical data are reviewed in a multidisciplinary meeting.[1] The consensus recommendation is then discussed with the patient at follow-up.[1]

“Being able to explain that the treatment strategy has been reviewed and agreed upon by experts from multiple disciplines provides reassurance for both the physician and the patient,” she said.[1]

This model is particularly important when there is clinical uncertainty or when competing treatment options may be reasonable.[1,2] It also supports continuity beyond the procedure itself, as durable benefit depends on ongoing optimisation of guideline-directed medical therapy, surveillance and management of the underlying pathophysiology driving MR.[1,2]

Device Iteration and Procedural Experience Continue to Enhance Outcomes

In parallel with stronger clinical evidence, mitral TEER technology continues to evolve.[1] Dr Isida Byku highlighted that newer-generation systems have become more user-friendly, predictable and reliable, helping improve procedural confidence and shorten the learning curve for operators.[1]

She also noted that comparisons between third- and fourth-generation systems suggest that favourable outcomes are being maintained and, in some cases, improved as devices evolve.[1] For structural heart programmes, device iteration may support broader adoption of TEER by improving procedural efficiency and expanding the range of anatomies that can be treated safely and effectively.[1]

The wording here is important: device advances should be viewed as enabling better procedural execution rather than replacing the need for careful patient selection.[1,2] Imaging quality, haemodynamic assessment, operator experience and Heart Team decision-making remain critical determinants of success.[1,2]

Earlier Recognition and Referral May Improve Patient Outcomes

For Dr Isida Byku, one of the key practical implications of the 2025 guideline update is the importance of earlier recognition and referral of appropriate patients with functional MR.[1] The distinction between ventricular and atrial functional MR creates a more precise treatment framework, while the strengthened TEER recommendation for ventricular functional MR reflects a more mature evidence base.[1–3]

Earlier evaluation may help identify patients before recurrent hospitalisations, advanced remodelling or worsening haemodynamics limit the potential benefit of intervention.[1,2] For clinicians managing patients with heart failure and significant MR, the updated recommendations support more proactive collaboration with specialist valve teams and structural heart programmes.[1,2]

The central message is not that all patients with functional MR should undergo TEER, but that the right patients should be recognised, assessed and referred earlier within a multidisciplinary pathway.[1,2] As the evidence base and device platforms continue to evolve, the challenge for clinicians will be to integrate these recommendations into routine practice while maintaining careful attention to anatomy, physiology, comorbidity and patient goals.[1–3]

References

[1] Byku I. Mitral TEER: New Evidence Shaping Patient Selection. Transcatheter Academy. Available at: View video interview.

[2] Praz F, Borger MA, Lanz J, et al. 2025 ESC/EACTS Guidelines for the Management of Valvular Heart Disease. European Society of Cardiology / European Heart Journal. 2025. Available at: ESC valvular heart disease guideline page.

[3] Adamo M, Massussi M, Ajmone Marsan N, et al. 2025 ESC/EACTS valvular heart disease guidelines: practical updates on mitral and tricuspid regurgitation. European Heart Journal Supplements. 2026;28(Suppl 4):iv83–iv96. Available at: Oxford Academic article.