Mitral valve edge-to-edge repair under scrutiny: what can we learn from transoesophageal echocardiographic follow-up?

itral valve transcatheter edge-to-edge repair (M-TEER) has emerged as a safe and effective guideline-recommended treatment approach for patients with primary (PMR) and secondary mitral regurgitation (SMR) 1 .As demonstrated by several randomised clinical trials 2,3 and data from large real-world registries 4 , procedural mitral regurgitation (MR) reduction to 2+ can be achieved in 80% to 95% of patients, depending on MR aetiology and M-TEER experience of the implanting centre.Regular follow-up visits after MR treatment are key to monitoring long-term therapeutic success and enabling early intervention in case of relevant MR recurrence.Possible mechanisms for relevant MR after M-TEER are, among others, single leaflet device attachment (SLDA) and recurrent or newly developing structural defects of the valvular apparatus (e.g., prolapse or flail).Whether follow-up assessments which are nowadays usually performed using transthoracic echocardiography (TTE) can detect all relevant changes or whether regular transoesophageal echocardiography (TOE) might provide additional benefits in detecting recurrent MR is currently unclear.In this issue of EuroIntervention, the study by Bartkowiak and colleagues helps to fill the respective knowledge gap 5 .In their study, elective TOE follow-up was performed in 128 out of 373 (34.4%) patients who underwent M-TEER at a single heart valve centre in Switzerland.The study covers several important aspects including (1) detection of relevant MR recurrence after M-TEER and the underlying mechanism, (2) TOE assessment of mitral valve inflow gradients and its impact on prognosis, and (3) changes in mitral valve (MV) geometry after M-TEER.