Transcatheter edge-to-edge repair with DragonFly^TM system and ‘stepless self-locking’ strategy in a patient with mixed mitral regurgitation: a case report

Transcatheter edge-to-edge repair (TEER) has emerged as an alternative treatment for severe mitral regurgitation (MR). However, complex anatomical features of mitral valve pose significant technical and procedural challenges for TEER. In patients whose effective regurgitation reduction requires multiple clips, a small mitral valve area (MVA) limits TEER by increasing the risk of post-procedural elevated transvalvular gradients and iatrogenic stenosis.

A 90-year-old man presented with progressive tightness of breath that remained refractory to drug-based medical therapy. Echocardiography revealed severe mixed mitral regurgitation characterized by C1 segment prolapse and atrial functional mitral regurgitation with a small MVA of 4.09 cm². Given his advanced age and prohibitive surgical risk (Society of Thoracic Surgeons [STS] score for repair: 10.49%), the multidisciplinary Heart Team elected to perform TEER using the DragonFly^TM system. The procedure was successfully performed under transoesophageal echocardiographic (TEE) guidance with the sequential implantation of two clips. The second clip utilized a ‘Stepless self-locking’ strategy to carefully balance the reduction of regurgitation against the transmitral pressure gradient elevation. Regurgitation was reduced from grade 4 + to 1 + with a final mean gradient of 4 mmHg and no evidence of significant mitral stenosis. The patient experienced a marked improvement in functional status during the follow-up period.

This case highlights the importance of individualized anatomical assessment and tailored device selection in managing patients with MR and complex, challenging structure. Precise clip sizing and stepwise deployment strategies can successfully balance MR reduction while preserving MVA. Such tailored approaches are essential to prevent iatrogenic complications and optimize clinical outcomes in high-risk populations.