Formation of a left atrial thrombus during percutaneous mitral valve edge-to-edge repair induced by acute reduction of mitral regurgitation.

Percutaneous mitral valve repair (PMVR) using the MitraClip system (Abbott, Abbott Park, IL, USA) is an innovative method allowing treatment of mitral regurgitation (MR) for patients that are not accessible by conventional operation. Thrombogenicity in the left atrium (LA) in general is increased in the presence of atrial fibrillation and mitral valve disease. We observed in a patient who underwent PMVR an acute change in thrombogenicity in the LA with thrombus formation in the left atrial appendix (LAA) immediately after clip placement. Thrombus formation occurred under verified therapeutic anticoagulation using unfractionated heparin. To our knowledge this is the first patient with documented acute and solid intra-interventional thrombus formation. The observation implies that acute reduction of mitral valve regurgitation and changes in hemodynamics within the LA enhances the risk of thrombus formation. <Learning objective: Percutaneous mitral valve repair is associated with acute changes in the thrombogenicity within the left atrium despite adequate periinterventional anticoagulation.>.