Asian Cardiovasc Thorac Ann 2006;14:e6-e8
© 2006 Asia Publishing EXchange Ltd
A Pitfall in Ligation of Intrahepatic Shunting after Fontan Type Operation
Akihiko Ikeda, MD,
Yuji Hiramatsu, MD,
Hitoshi Horigome, MD1,
Tetsuo Hori, MD2,
Mio Noma, MD,
Yuzuru Sakakibara, MD
Department of Cardiovascular Surgery
1 Department of Pediatric Cardiology
2 Department of Pediatric Surgery, University of Tsukuba, Tsukuba, Japan
For reprint information contact: Yuji Hiramatsu, MD, Tel: 81 29 853 3096, Fax: 81 29 853 3096, Email: yuji3{at}md.tsukuba.ac.jp, Department of Cardiovascular Surgery, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan.
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ABSTRACT
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An 8-year-old boy experienced progressive cyanosis after a Fontan type operation. Under the guidance of intraoperative color Doppler we performed a transabdominal ligation of the accessory hepatic veins which drained into a common atrium. Reoperation was needed through a median sternotomy to eliminate residual shunting. Although intraoperative Doppler is useful to aid in the ligation of accessory veins while portal hypertension is monitored, intraoperative angiogram serves better to ensure the elimination of intrahepatic shunting in a transabdominal approach.
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INTRODUCTION
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Great variation exists in systemic venous connections in patients with heterotaxy, and hepatic veins may drain separately from the inferior vena cava. An unanticipated accessory hepatic vein may result in massive intrahepatic shunting after a Fontan type operation. We report the case of a boy with heterotaxy who experienced progressive cyanosis after an extracardiac total cavopulmonary connection (TCPC). A pitfall of the transabdominal approach in ligation of the accessory hepatic veins is described.
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CASE STUDY
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The patient was diagnosed at birth with heterotaxy syndrome, asplenia, single atrium, single ventricle, common atrioventricular valve, pulmonary stenosis and bilateral superior venae cavae. He underwent a right modified Blalock-Taussig shunt at 3 months of age, and subsequent bilateral bidirectional cavopulmonary anastomoses at 2 years. At 8 years of age, he underwent an extracardiac TCPC using a 16 mm polytetrafluoroethylene graft without fenestration. The patient experienced gradually increasing cyanosis, and systemic oxygen saturation levels decreased from 90% to 65% within 3 weeks of surgery. Cardiac catheterization demonstrated marked desaturation at the atrial level while the mean pulmonary artery pressure was 13 mm Hg. Angiography revealed that contrast medium from the left superior vena cava flowed retrogradely down the conduit toward the inferior vena cava (Figure 1
). An angiogram of the inferior vena cava demonstrated intrahepatic shunting and large accessory hepatic veins draining into a common atrium (Figure 2). Since coil embolization of the wide vein trunk was considered a difficult option, we performed a surgical ligation of the accessory hepatic vein using a transabdominal suprahepatic approach. Intraoperative liver ultrasonography and color Doppler revealed that 2 dilated branches of the accessory hepatic vein immediately beneath the diaphragm flowed toward the left side common atrium. No other branches were found to be responsible for the intrahepatic shunting.
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Figure 1. A left superior vena caval angiogram showing that the contrast medium flowed retrogradely down the extracardiac conduit toward the inferior vena cava. LSVC = left superior vena cava; PA = pulmonary artery.
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Figure 2. An inferior vena caval angiogram showing a network of intrahepatic shunting and a large accessory hepatic vein draining into a common atrium. IVC = inferior vena cava; AHV = accessory hepatic vein.
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Ligation of the two branches immediately increased oxygen saturation to over 90%, without liver congestion. Direct monitoring of the portal vein pressure showed little change. Although oxygen saturation levels were stabilized at 90% during the proceeding few days, they gradually dropped again into the 70 percentile range by 2 weeks after the ligation. An angiogram of the inferior vena cava revealed residual intrahepatic shunting through one large unligated branch of the accessory hepatic veins. Reoperation was carried out through a median sternotomy and the main trunk of the accessory hepatic vein was ligated above the diaphragm. Intraoperative angiography confirmed complete elimination of the intrahepatic shunting and oxygen saturation was stabilized at 95%. After complete ligation of the shunting, the inferior vena caval pressure and the mean pulmonary artery pressure were equivalent at 13 mm Hg.
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DISCUSSION
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Since indications for a Fontan type operation have been extended to include resolution of heterotaxy syndrome, complications related to hepatic vein anomalies should be recognized. In heterotaxy, anomalous drainage of the hepatic veins was found in 28% of cases with an intact inferior vena cava.1 Accessory hepatic veins draining from the left side of the liver are an extremely rare anatomic condition, and this situation associated with Fontan type operations has been described only in several case studies.2–5 Although the presence of accessory hepatic veins alone is of no hemodynamic significance, the higher systemic venous pressure after a Fontan type operation may stimulate rapid formation of large intrahepatic channels. It is difficult to detect the accessory hepatic veins preoperatively by angiography or color Doppler echocardiography as there is little pressure gradient between the systemic venous channel and the common atrium.2–3 Extracardiac TCPC is our preferred option in a Fontan type operation since it has been demonstrated as the procedure of choice for children with heterotaxy syndrome6, although lifetime anticoagulation therapy is recommended to prevent thrombotic complications related to prosthetic grafts. If accessory hepatic veins are detected before or during the operation, one possible option is incorporation of the accessory hepatic vein channel into the systemic venous route using an intracardiac baffle or conduit rather than an extracardiac route. Ligation of the accessory hepatic veins risks excessive hepatic congestion and portal hypertension unless a considerable amount of intrahepatic shunting is detected.4 Previous reports2–5 as well as our own experience suggest that surgical ligation of the accessory hepatic veins is practical and safe when performed after a significant intrahepatic shunt has been confirmed. Transcatheter approach is another option but not always a solution, as complete occlusion is rather difficult.3–5
The transabdominal surgical approach has the advantage of monitoring hepatic congestion and portal vein pressure directly, and avoids risks related to sternal re-entry.5 In the transabdominal approach, more than one hepatic vein branch should be detected beneath the diaphragm, and a small diaphragmatic incision may be needed to mobilize a sufficient length of each branch.5 Although intraoperative color Doppler is useful to aid in ligating accessory veins while portal hypertension is monitored simultaneously, one has to make every effort to eliminate any tiny venous flow because this can dilate and cause cyanosis in the future. One significant pitfall in the transabdominal ligation approach with Doppler guide is the possibility of flow direction change of each branch during liver manipulation as the pressure gradient between the systemic venous side and the common atrium is very small. Therefore, intraoperative angiogram of the inferior vena cava is a superior visualization method to ensure complete elimination of intrahepatic shunting when the transabdominal approach has been selected in this rare condition.
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REFERENCES
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- Rubino M, Van Praagh S, Kadoba K, Pessotto R, Van Praagh R. Systemic and pulmonary venous connections in visceral heterotaxy with asplenia: diagnostic and surgical considerations based on seventy-two autopsied cases. J Thorac Cardiovasc Surg 1995;110:641–50.[Abstract/Free Full Text]
- Fernandez-Martorell P, Sklansky MS, Lucas VW, Kashani IA, Cocalis MW, Jamieson SW, et al. Accessory hepatic vein to pulmonary venous atrium as a cause of cyanosis after the Fontan operation. Am J Cardiol 1996;77:1386–7.[Medline]
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- Nakano T, Kado H. Long-term surgical results of total cavopulmonary connection in children with visceral heterotaxy syndrome; comparison between lateral tunnel method and extracardiac conduit method. Kyobu Geka 2003;56:299–303.[Medline]
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