Abstract
A 70-year-old male underwent mitral transcatheter valve-in-valve implantation for a failed bioprosthesis implanted 11 years earlier. In the first days following the procedure, he developed thrombosis of the new bioprosthesis with restricted cusp motion. The transmitral mean gradient increased significantly despite effective anticoagulation therapy using unfractionated heparin infusion. Low dose and slow infusion of alteplase resulted in resolution of the thrombus and normalisation of cusp motion. Thereafter long-term anticoagulation using a vitamin K antagonist was instituted and the patient remained asymptomatic.