Long Extending Thrombus Formation Around a Transseptal Puncture Site After Transcatheter Edge-to-Edge Mitral Valve Repair.

right atrium around the transseptal puncture (TSP) site (Figure C). The patient had no history of coagulation disorders and oral anticoagulation was not prescribed; however, dual antiplatelet therapy was administered because of recent coronary stenting. The active clotting time was maintained over 200 s during TEER. The following day, transthoracic echocardiography (TTE) revealed a wriggling, long structure extending from the TSP site to the right ventricle (Figure D; Supplementary Movie). We suspected A 90-year-old woman was transferred to Nagoya Heart Center because of cardiogenic shock with severe mitral valve regurgitation. The mitral valve regurgitation was caused by chordal elongation, which led to anterior central scallop prolapse (Figure A). Transcatheter edge-to-edge mitral valve repair (TEER) was successfully performed without complications (Figure B). After TEER, transesophageal echocardiography showed a newly developed small mass not found previously in the