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Successful haemostatic management of replacement of the ascending aorta for type A acute aortic dissection in a patient with mild haemophilia B

The mortality from cardiovascular disease, particularly coronary artery disease, is reported to be lower in haemophilia patients than in age-matched male population [1]. While, comparison between haemophilia patients and healthy controls suggested only minimally reduced intima-media onto the femoral artery in individuals with bleeding tendency and hypocoagulability caused by the disorder has a limited effect on atherogenesis [2]. In recent decades, the treatment for haemophilia patients has been developing, consequently their life expectancy is close to that of normal male population. This change would attribute to an increased risk of developing age-related disorders such as acquired heart diseases. Only few hospitals can be performed the cardiac surgery for haemophilia patients, however [3]. We had a case with replacement of the ascending aorta for acute aortic dissection classified as Stanford type A for a 65 year-old haemophilia B patient admitted in our hospital, and now present the successful haemostatic management for the monitoring of factor IX activity (FIX:C) during the support of extracorporeal circulation with heparinization. The patient was previously diagnosed as mild haemophilia B, because FIX:C and FIX antigen were 13 and 37 IU dL , respectively. On August in 2014, he had a temporary faintness and was admitted to our hospital. Ultrasound and chest CT findings revealed the acute aortic dissection with Stanford type A (Fig.1), and he had to undergo an urgent surgery with arch replacement. The FIX:C level measured at our laboratory was 14 IU dL 1 prior to surgery. The prothrombin time was 11.3 s (reference 10.0–15.0 s), activated partial thromboplastin time was 33.9 s (reference 22.0–32.0 s), haemoglobin was 14.5 g dL . Since the FIX:C level was required to maintain ~100 IU dL 1 on the open cardiac surgery, he received 6000 IU of recombinant factor IX (rFIX) (BeneFIX ; Pfizer, peak FIX:C 83 IU dL ) at initial bolus infusion, showing the 70% recovery rate of expected value, although his FIX inhibitor was not detected (<0.3 BU mL ). He received additional 3000 IU of rFIX, followed by continuous infusion of rFIX at a rate of 6.7 IU kg 1 h 1 during the operation. A left radial artery catheter and a pulmonary artery catheter via right internal jugular vein were placed for continuous haemodynamic monitoring. He was anticoagulated with 10 000 U of heparin (~150 IU kg ) for extracorporeal circulation, resulting in significant prolongation (>400 s) of activated clotting time. Meanwhile, the presence of heparin at high level prevented to measure the FIX:C in onestage clotting assay. To solve this, we attempted to evaluate the FIX:C in his plasma by counteracting the heparin due to addition of heparinase (Hep-tem ; Pentapharm GmbH, Munich, Germany) into blood samples (v/v = 1:20) during the bypass. Just after the beginning of cardiopulmonary bypass, his FIX:C was 4.0 IU dL 1 in the absence of heparinase, while was 41 IU dL 1 in its presence, suggestive of the usefulness of heparinase for measurement of coagulation factor activity when heparinazation. Also, this result indicated the more requisition of rFIX than was anticipated, may be due to the hemodilution, and the successful assessment of FIX:C in this methodology. He had an additional bolus infusion of 5000 U rFIX, followed by continuous infusion with up to 13 IU kg 1 h . The replacement of the ascending aorta graft and a pacing wire were placed, and the atrial pacing was required to separation from cardiopulmonary bypass. When reversal of anticoagulation with protamine was achieved, FIX:C was 126 and 123 IU dL 1 in the absence or presence of heparinase, respectively. From this data, we decreased the rate of continuous infusion of rFIX to 6.7 IU kg 1 h . The operation was uneventfully successful. Total time using cardiopulmonary bypass for the operation was 2 h 58 min and the bleeding volume was 1320 mL. Correspondence: Keiji Nogami, MD, PhD, Department of Pediatrics, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan. Tel.: +81 744 29 8881; fax: +81 744 24 9222; e-mail: roc-noga@naramed-u.ac.jp