Clot Formation in Cardiopulmonary Bypass Circuit After Application of Factor XI Concentrate

A 60-year-old patient was scheduled for CABG after suffering from symptomatic angina pectoris. His medical history included severe FXI deficiency (activity 1%), hypertension, and colitis ulcerosa. He did not report a significant bleeding history other than bleeding complication after tooth extraction. His tonsillectomy was uneventful. Specific laboratory results include factor IX 148% (50-150), FXI <5% (50-150), and factor XII 138% (50-150). The baseline activated partial thromboplastin time was 115 seconds, which could be corrected after mixing with normal serum to 290 seconds. Treatment with double antiplatelet therapy had been started after the diagnosis of non-ST-elevation myocardial infarction. Along with acetylsalicylic acid, his clopidogrel was continued during surgery. Preoperatively, the hematologist was consulted and pretreatment with FXI concentrate isolated from human plasma (Hemoleven) was advised.