Predictors and clinical impact of thrombosis after transcatheter mitral valve implantation using balloon-expandable bioprostheses.

Aims: The aim of this study was to report the predictors and clinical impact of transcatheter heart valve (THV) thrombosis in patients undergoing transcatheter mitral valve implantation (TMVI).
Methods and Results: We included 130 patients who consecutively underwent TMVI. Transoesophageal echocardiography (TOE) and/or computed tomography (CT) were performed in 91.7% of patients at discharge, in 73.3% at three months and in 72% beyond three months. THV thrombosis was defined as the presence of at least one thickened leaflet with restricted motion confirmed by TOE or contrast CT and classified as immediate, early, or late according to the timing of diagnosis. THV thrombosis was observed in 16 (12.3%) patients: immediate in 43.7%, early in 37.5% and late in 18.8%. Most of these thromboses were subclinical (93.7%) and non-obstructive (87.5%). No thromboembolic event occurred. After optimisation of antithrombotic treatment, THV thromboses resolved in all but one patient. Predictors were shock for immediate (p<0.001), male sex for early (p=0.045) and absence of anticoagulation for both early (p=0.018) and late (p=0.023) THV thromboses.
Conclusions: THV thrombosis is frequent after TMVI, occurs mainly within the first three months, is mostly subclinical and resolves after optimisation of antithrombotic treatment. An anticoagulation therapy for at least three months after the procedure is mandatory.