One-year echocardiographic follow-up and two-year survival in 111 dogs undergoing mitral transcatheter edge-to-edge repair

INTRODUCTION/OBJECTIVES: Short-term results of mitral transcatheter edge-to-edge repair (TEER) with the canine V-Clamp device have been promising; however, longer-term outcome data are needed. This prospective study evaluated survival and echocardiographic outcomes in dogs with severe mitral regurgitation (MR) following TEER performed at one referral center. ANIMALS, MATERIALS AND METHODS: Dogs in American College of Veterinary Internal Medicine stages B2, C, and D meeting criteria for severe MR were treated by TEER. The procedure was performed via transapical approach and guided by transesophageal echocardiography and fluoroscopy. RESULTS: One hundred eleven dogs underwent TEER between January 2021 and January 2025. Technical feasibility for placing one clamp was 97.3%, with a single clamp placed in 80 of 108 / (74%) and two clamps placed in 28 of 108 (26%) dogs. In-hospital mortality was 6.3%, and 3-month survival was 86.4%. Freedom from all-cause and cardiac-related mortality was 75% and 80% at one year and 67% and 78% at two years, respectively. Mean (standard deviation) regurgitant fraction decreased from 60.6 (13.3)% to 35 (23)% post procedure and was 30.7 (24.1)% at one year. Normalized left ventricular diastolic dimension decreased from 2.07 (0.24) to 1.84 (0.3) and short-axis left atrial-to-aortic ratio decreased from 2.31 (0.41) to 2.08 (0.45) immediately post procedure; these variables remained decreased at 1.79 (0.28) and 1.94 (0.46), respectively, at 1-year follow-up (P < 0.001). STUDY LIMITATIONS: Follow-up echocardiograms were obtained by multiple centers. CONCLUSIONS: Intermediate outcomes after TEER demonstrated a likely benefit in dogs with severe MR as adjunct to medical therapy. Future goals include improving consistency of MR reduction, decreasing procedural complications through experience and refined case selection, and prospectively comparing to medical therapies.