This is the case of a 59-year-old man admitted due to bilateral pulmonary thromboembolism in the deep shock and refractory hypoxemia setting. Veno-arterial extracorporeal membrane oxygenation (ECMO) under emergency intubation was implanted. Although the right ventricular function improved, the patient required bailout percutaneous thrombectomy followed by an efferent cannula via right jugular access to improve oxygenation. While on venous-arteriovenous ECMO, a few centimeters of the femoral cannula were removed towards the inferior vena cava to prevent recirculation. Fig. 1 (and video 1 too) show the suction cannula on a transesophageal ultrasound with a persistent isoechogenic cylindrical image attached to the interatrial septum after its removal (Fig. 2; video 2). While on systemic anticoagulation, the control ultrasound performed 13 days later confirmed that the image was gone and it was interpreted as a fibrin mold. Fibrin sheaths are structures made of smooth muscle cells, detritus, extracellular matrix, and thrombotic material. They are created around a foreign body and persist after its removal. They have been described as associated with endovascular material like pacemakers, catheters, ECMO cannulae or the Impella device. This phenomenon is important since a substrate for thromboembolic events or endocarditic vegetation is possible.

Figure 1

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Figure 2

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