Thrombotic complication of severe COVID-19 pneumonia: stroke due to atypical paradoxical embolism

Introduction. Severe infection by SARS-CoV-2 has shown to entail an increased risk of thrombotic, especially venous, events. Central venous catheters have also been associated with an increased risk of thrombotic complications. Paradoxical embolism as an aetiological mechanism of ischaemic stroke should be considered in a highly prothrombotic context, where it may be more frequent. Case report. A 40-year-old woman with a central venous catheter, with a large vessel ischaemic stroke, treated with mechanical thrombectomy for an atypical paradoxical embolism while in intensive care for bilateral COVID-19 pneumonia. In the aetiological study, analysis highlighted an elevation of the D-dimer and right-left shunt with massive passage of contrast directly from the central peripheral access pathway in the left upper extremity to the left atrium in the transoesophageal echocardiogram. Thoracic tomographic angiography showed an anomalous venous structure with its origin in the subclavian vein and drainage to the segmental vein of the left upper lobe with direct emptying into the left atrium. Treatment consisted in anticoagulation until removal of the central venous catheter and simple anti-aggregating medication on discharge. Conclusions. Paradoxical embolism due to intra- or extra-cardiac shunt should be considered in patients with COVID-19, given the high associated risk of venous thromboembolism. Further studies are needed to be able to define optimal prophylactic and therapeutic management.