Eur J Cardiothorac Surg 2001;19:525-527
© 2001 Elsevier Science NL
Budd–Chiari syndrome and heparin-induced thrombocytopenia
Thierry Carrel,
Pascal Berdat,
Jürg Schmidli,
Erich Gygax
Clinic for Cardiovascular Surgery, University Hospital, CH-3010 Berne, Switzerland
Received 3 November 2000;
received in revised form 31 January 2001;
accepted 16 February 2001.
Corresponding author. Tel.: +41-31-632-2375; fax: +41-31-632-4443
e-mail: thierry.carrel{at}insel.ch
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Abstract
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We report on a patient suffering from Budd–Chiari disease who developed heparin-induced thrombocytopenia preoperatively. Dorsocranial liver resection and hepatoatrial anastomosis were performed with the extracorporeal circulation and perioperative anticoagulation was achieved with r-hirudin. Surprisingly, thrombus formation was observed in the venous reservoir although ACT was 590 s and aPTT 55 s. An additional bolus of hirudin and rinsing the reservoir allowed unproblematic discontinuation of the cardiopulmonary bypass.
Key Words: Budd–Chiari • Thrombocytopenia • Perioperative anticoagulation
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1. Introduction
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Recombinant hirudin has been recommended as an alternative anticoagulant for cardiopulmonary bypass in patients with heparin-induced thrombocytopenia type II [1,2]. This treatment carries the risk of potentially life-threatening hemorrhage, because the anticoagulant properties of hirudin cannot be neutralized at the end of cardiopulmonary bypass; however, the short duration of plasma half time of hirudin compensates in part the lack of an inhibitor. The risk of postoperative bleeding might be increased in patients with renal dysfunction, which preclude rapid elimination of this substance [3]. In addition, hirudin requires specialized intraoperative monitoring which is still not completely elucidated and not widely available. We report on a patient requiring cardiopulmonary bypass to treat obstruction of inferior vena cava and hepatic veins in whom perioperative anticoagulation was rendered difficult because of heparin-induced thrombocytopenia.
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2. Case report
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A 26-year-old, North-African patient was transferred to our institution with a subacute Budd–Chiari syndrome (including hepatic veins as well as intrahepatic inferior vena cava obstruction). Previous medical history did not reveal any special pathology. He had demonstrated a loss of 12 kg within 6 weeks despite gross accumulation of ascites fluid. Body weight was 58 kg at admission. Renal function was slightly impaired with a plasma creatinine level of 145 µmol/l. During hospitalization, the patient developed heparin-induced thrombocytopenia (HIT) type II with minimal platelet count of 40x103/mm3. Heparin-induced thrombocytopenia antibody concentration was determined by an enzyme-linked immunosorbent assay that uses complexes of heparin and platelet factor 4 as the capture antigen (not commercially available). Preoperative anticoagulation was achieved by continuous intravenous infusion of recombinant hirudin (0.15 mg/kg per h Refludan, Hoechst, Frankfurt, Germany) with dose adjustments to maintain aPTT 1.5 to 3.0 times the mean of the normal laboratory aPTT range (40 to 60 s).
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3. Surgical technique
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The indication to proceed with transcaval liver resection and hepatoatrial anastomosis was found to be the best option for this young patient (Fig. 1)
[4,5]. Surgical approach was performed through a midline sternotomy combined to a right subcostal incision. The pericardium was opened through a T-incision, followed by a vertical incision of the diaphragm in the midline.
Standard canulation of the ascending aorta, superior vena cava and right extern iliac vein were performed and cardiopulmonary bypass conducted in moderate hypothermia (32°C). Ventricular fibrillation was induced to prevent air embolism and the right atrium was opened vertically above the orifice of the inferior vena cava. Thrombotic material was removed from the right atrium and the completely obstructed inferior vena cava was desobliterated with a dissector. Following reopening of the inferior vena cava, the venous return was excellent and had to be blocked by balloon catheter. The vertical incision was extended through the orifice of the inferior vena cava. The liver parenchyma was generously resected on both sides of this incision, staying carefully into the liver capsula. The orifices of the hepatic veins were resected en bloc with the liver parenchyma until brisk bleeding appeared from the decompressed hepatic veins. The liver showed a visible shrinking and changed rapidly to a healthy pink color in contrast to the cyanotic appearance at the begin of the operation. After completion of the resection, the right atrium was sutured to the liver capsula with a running 4.0 polypropylene, creating a rhomboid-shaped large confluence for the hepatic veins and the liver tissue. A small patch of xenopericardium was sutured to prevent tension when closing the atrial incision.
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4. Perioperative anticoagulation
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Intraoperative anticoagulation consisted of an intravenous bolus of 0.25 mg/kg hirudin before canulation in addition to 0.25 mg/kg hirudin in the priming volume (1500 ml human albumine 5%, 2x106 KIU aprotinin and 20 g mannitol) of the bypass circuit. The preoperative continuous hirudin infusion (0.15 mg/kg per h) was maintained throughout the operation.
Perioperative anticoagulation was monitored using the kaolin activated clotting time (ACT) which showed values between 450 and 1000 s and aPTT which varied between 45 and 70 s. (Table 1). Surprisingly, thrombus formation was observed in the venous reservoir after 40 min of CPB; at that time ACT was 590 s and aPTT 55 s. An additional bolus of 0.25 mg/kg hirudin was injected and the venous reservoir was rinsed with 1 l of ringer lactate. The patient was rewarmed, the heart defibrillated and cardiopulmonary bypass could be discontinued after 61 min without any additional thrombotic event.
Immediate postoperative anticoagulation was accomplished with intravenous infusion of hirudin (0.1 to 0.15 mg/kg per h) to achieve an aPTT between 50 and 70 s. Warfarin (Coumadin) was started on the 2nd postoperative day, the INR being targeted between 3.0 and 4.0. One week postoperatively, a significant stenosis of the intrahepatic vena cava – due to massive hypertrophy of segment I – was successfully stented with a 22 mm self-expandable stent. No residual pressure gradient was detected invasively following stenting. Abdominal ultrasound showed a normal flow pattern of the hepatic veins into the right atrium and CT-scan demonstrated a patent inferior vena cava with normalized hepatic veins size. The patient recovered well and was discharged 2 weeks after the operation.
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5. Comment
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This case report demonstrates a complex anticoagulation management in a patient suffering from Budd–Chiari syndrome and heparin-induced thrombocytopenia operated with the aid of extracorporeal circulation.
We were surprised to observed thrombus formation in the cardiotomy reservoir despite adequate hirudin-dosage (continuous infusion 0.15 mg/kg per h, intravenous bolus prior to CPB 0.25 mg/kg and additional bolus in the circuit 0.25 mg/kg); also surprising was the fact that thrombus formation appeared when ACT values were largely in the range of therapeutical intraoperative anticoagulation (>480 s) and aPTT values between 40 and 70 s. Both monitoring methods are recommended in reports dealing with the management of patients suffering from HIT and requiring cardiopulmonary bypass [1,2].
However, more recently monitoring of hirudin blood levels has been recommended by simultaneous measurements of aPTT and ecarin clotting time (ECT) [6]. Since ECT was not available in our institution at that time, we opted for an additional bolus of 0.25 mg/kg hirudin in the circuit and rinsage of the cardiotomy reservoir. This additional precaution allowed for safe discontinuation of cardiopulmonary bypass after 61 min and did not compromise hemostasis at the end of the procedure.
From this experience we conclude that intraoperative monitoring of anticoagulation with hirudin should not only include various anticoagulation tests but also continuous observation of all components of the extracorporeal circulation. Our observation shows further that hirudin still requires more specific intraoperative monitoring which is not completely elucidated. Looking at the controversial discussion in the literature, we believe that there is still no universally accepted method for monitoring short-term intraoperative hirudin treatment.
In those patients in whom emergency surgical treatment is not required, the alternative option might be to wait until the antigenic assay becomes negative for the HIT-antibodies [7], since antibody-negative patients may undergo safe CPB with established heparin protocols.
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References
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Pötzsch B., Madlener K., Seelig C., et al. Monitoring of r-hirudin anticoagulation during cardiopulmonary bypass: assessment of the whole blood ecarin clotting time. Thromb Haemost 1997;77:920-925.[Medline]
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Abstract
1. Introduction
