Emergent coronary artery bypass grafting was performed in a 73-year-old male patient due to an interventional left main stem coronary artery dissection. Following the operation the patient had to be put on femoral extracorporeal membrane oxygenation (ECMO) due to postcardiotomy cardiogenic shock. ECMO flow was adjusted according to measurements of the mixed venous or central venous saturation of oxygen (target 70 %; 4–4.5 l/min ECMO flow). Anticoagulation with intravenous heparin was guided by the activated clotting time (ACT), which was kept strictly above 140 s throughout the whole period of treatment resulting in partial thromboplastin time levels of between 44 and 65 s. Additionally, the thrombocyte count was between 35 and 75 Gyl throughout the whole period of treatment. A heparin-induced thrombocytopenia was ruled out by testing for platelet factor 4–heparin complexes. Three days later, after failed weaning from ECMO, echocardiography showed severe biventricular failure and thrombosis of the entire aortic root and the proximal part of the ascending aorta (Fig. 1). The patient died as a consequence of long-lasting myocardial ischemia and secondary multiple organ failure. If left ventricular output is not