Left atrial appendage thrombus on full-dose dabigatran treatment: a case report

Background Dabigatran is a direct competitive thrombin inhibitor approved for stroke prevention in non-valvular atrial fibrillation. At full-dose, dabigatran showed similar rates of bleedings and higher efficacy compared to warfarin. Case summary We report a case of acute ischaemic stroke in a patient treated with dabigatran 150 mg b.i.d. for atrial fibrillation. After an off-label treatment with idarucizumab, a humanized monoclonal antibody approved for dabigatran reversal, we performed a successful intravenous thrombolysis (IVT). Transoesophageal echocardiography showed a left atrial appendage (LAA) thrombus, despite full-dose dabigatran and an adequate therapy adherence. Discussion There are few cases of LAA thrombus during dabigatran treatment reported in literature till date. We analyse the possible pathogenetic mechanisms involved in dabigatran failure, including drug interactions and unexpected genetic variations interfering with dabigatran serum levels suggesting periodical assessment of direct Oral Anticoagulant levels. Furthermore, we confirm initial reports of safety and efficacy of intravenous thrombolysis after idarucizumab, in case of dabigatran failure.