Caudate lobe-sparing subtotal hepatectomy as treatment for extensive intrahepatic arterioportal fistula

Rui Tang, Guang-Dong Wu, Ang Li, Li-Han Yu, Xuan Tong, Jun Yan, Qian Lu

Hepatopancreatobiliary Center, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Institute for Precision Medicine, Tsinghua University,Beijing 102218, China

Intrahepatic arterioportal fistulas (APFs) are abnormal hepatic artery and portal vein (PV) communications that develop as a result of congenital malformation, trauma, ruptured hepatic aneurysm, cirrhosis, tumor-related changes, biopsy, chemotherapy or iatrogenic causes [ 1 , 2 ].The most common symptoms are gastrointestinal bleeding and ascites secondary to portal hypertension; other symptoms include abdominal pain, pyrexia, edema,back pain and jaundice [3].The main goal of therapy is to decrease the portal pressure with variceal bleeding being the absolute indication for surgical management.Transarterial embolization (TAE)should be the first choice to treat APFs, while resection, portocaval shunt and even transplantation may cure APFs in the case of TAE failure [4].In previous reports, caudate lobe-sparing subtotal hepatectomy (CLSSH) has been applied for the treatment of primary hepatolithiasis and hepatocellular carcinoma [ 5 , 6 ].As far as we know, this is the first report describing CLSSH as treatment for an extensive intrahepatic APF, which involved segments 2 to 8, with corresponding hypertrophy of the caudate lobe.

A 45-year-old female was admitted to our hospital with a twoweek history of epigastric discomfort.Physical examination was normal except for a large, palpable spleen.Laboratory tests revealed normal liver and coagulation functions.Viral hepatitis panels were negative.Preoperative hepatic ultrasound revealed an artery flow rate of 217 cm/s and mixed blood flow and pulsatility in the PV.Enhanced computed tomography (CT) imaging of the arterial phase revealed widening of the proper hepatic artery(PHA), enhancement of the PV and APFs causing blood reflux to the PV ( Fig.1 A).Enhanced CT of the PV phase revealed that both the left and right lobe of the liver were reduced in size, the volume of the caudate lobe was significantly increased, and that multiple cysts were present in the liver ( Fig.1 B).Preoperative magnetic resonance cholangiopancreatography (MRCP) indicated that the common hepatic duct and the left and right hepatic ducts were compressed, with various degrees of bile duct narrowing and dilatation.Hepatic artery angiography confirmed hepatic APFs in the liver parenchyma and liver99mtechnetium-diethylenetriaminepentaacetic acid-galactosyl human serum albumin (99mTc-GSA) single photon emission computed tomography (SPECT)/CT imaging suggested a normal function of the caudate lobes and atrophy of segments 2 to 8.The patient’s standard liver volume was 1125 mL and the caudate lobe volume was 1128 mL, which accounted for 100% of the standard liver volume.The indocyanine green 15 min retention test (ICG R15) was 1.2%.There were no significant abnormalities in preoperative laboratory tests.Hepatectomy of segments 2 to 8 was chosen, which involved preservation of the caudate lobe’s vasculature, and virtual surgical planning was performed with the slice plane located on the dorsal side of the three hepatic veins ( Fig.1 C).

Fig.1.Preoperative findings.A: Preoperative enhanced CT of the arterial phase showing a widening of the PHA and enhancement of the PV, which were considered as regurgitation of contrast agent into the main PV.Extensive APF can be seen involving the left and right liver, but no APF was visible in the CL.B: Preoperative enhanced CT of the PV phase showing CL hyperplasia.C: Three-dimensional reconstruction of liver and blood vessels based on enhanced CT.CT: computed tomography; PHA: proper hepatic artery; PV: portal vein; APF: arterioportal fistula; CL: caudate lobe; HA: hepatic artery; LHV: left hepatic vein; MHV: middle hepatic vein; RHV: right hepatic vein.

Mild abdominal adhesions and liver atrophy with caudate lobe hyperplasia were visible ( Fig.2 A) with no obvious ascites.The hepatic artery was thickened and blood flow was increased; a branch of the superior mesenteric vein was then identified in the mesentery.Portal pressure in that area was 41 cmH2O and there was a pulsatile aspect in the vein.The liver was then mobilized and the gallbladder removed.The Pringle maneuver following the surface of the caudate lobe and the atrophic boundary of the liver was applied during parenchymal transection.The hepatic veins were identified and used as a transection landmark.Injuries to the caudate lobe vascular pedicles were avoided by dividing the Glisson pedicle at the ventral side of Arantius’ ligament and the hilar plate.Fig.2 B shows the caudate lobe structure after APF excision.The liver remnant was negative for bile leakage and active hemorrhage on examination.Ultrasound confirmed that the hepatic artery and PV blood flow of the caudate lobe were well preserved.Portal pressure was measured again with a value of 27 cmH 2 O recorded, with significantly decreased pulsatility.Fig.2 C shows the surgical specimen after excision with the three main hepatic veins.

Fig.2.Intraoperative findings.A: Atrophy of the left and right hepatic parenchyma and caudate lobe hyperplasia.B: The caudate lobe structure was retained after APF excision.C: The surgical specimen after excision: the three main hepatic veins are indicated.APF: arterioportal fistula; CBD: common bile duct; PHA: proper hepatic artery;PV: portal vein; RHA: right hepatic artery; RHV: right hepatic vein; LHV: left hepatic vein; MHV: middle hepatic vein.

Postoperative pathology revealed mild mixed steatosis, central venous dilatation and fibrous tissue in the vascular wall, with partial intraluminal thrombosis.The operative time was 490 min and the intraoperative blood loss was 20 0 0 mL.The patient received 4 units of packed red blood cells, 600 mL of plasma, and 600 mL of Cell SaverTM.There were no major postoperative complications and no significant abnormalities in postoperative laboratory tests.The drainage tube was removed on postoperative day 5 and the patient was discharged 11 days after surgery in good physical condition.The patient was followed-up for 1 year.Ultrasound performed one week after the surgery showed that the hepatic artery flow ratewas 47 cm/s with a resistance index of 0.58.The PV was tortuous and dilated with a main flow velocity of around 30 cm/s, while there was no obvious abnormality in the hepatic veins.Abdominal CT angiography revealed that the hepatic artery in the arterial phase was thickened and that there were multiple areas of tortuosity and small tubular enhancements on the edge of the residual liver, which were significantly reduced compared with the preoperative examination.MRCP showed no significant dilatation of the intrahepatic bile ducts and three-dimensional (3D) reconstruction suggested that the residual liver volume was about 1216 mL and ICG R15 was 0.6%.One year after surgery, repeated ultrasound showed that the hepatic artery systolic velocity was 41 cm/s, the resistance index 0.67, the PV width about 1.1 cm and the flow rate 23.8 cm/s, with a normal pulse wave spectrum.Abdominal CT angiography revealed a decreased thickness of the hepatic artery, as well as multiple thin tubular enhancement images at the edge of the residual liver.PV enhancement during the arterial phase obviously improved.MRCP showed no significant bile duct dilatation and ICG R15 was 0.5%.

Hypertrophy of the caudate lobe based on the theory of atrophy-hypertrophy mechanism can lead to a sufficient remnant liver volume for safe CLSSH [5].It has been shown in patients with hepatolithiasis that the caudate lobe has a separate biliary system, and our report further demonstrated that the caudate lobe possessed an integrated arterial, portal venous inflow, as well as hepatic venous outflow [7].However, rigorous preoperative evaluation is necessary for safe performance of this procedure [8]and anatomical assessment, 3D reconstruction, functional assessment and other preoperative examinations must be performed to ensure that remnant segment 1 has an integrated biliary tract, vascular inflow and outflow, and a sufficient functional liver remnant [9].The transection plane is the largest among the types of anatomical liver resections and all three hepatic veins need to be dissected with a high risk of hemorrhage, while the Glisson system of the caudate lobe must be preserved with the transection more toward the atrophic parenchyma.Hepatic pedicles of segments 2 and 3, segment 4, and the right anterior and posterior liver segments should be transected separately.There was no specific difference between the postoperative management of CLSSH compared to that of other liver resections.Ultrasound examination for evaluation of vascular flow and ascites, as well as enhanced CT and MRCP may be necessary postoperatively to detect stenosis or embolism.

In conclusion, this study is the first on CLSSH as a treatment for an extensive intrahepatic APF.Our findings further demonstrated that the caudate lobe possesses an independent arterial and portal venous inflow, as well as a hepatic venous outflow.

Acknowledgments

None.

CRediT authorship contribution statement

Rui Tang:Conceptualization, Data curation, Formal analysis, Validation, Visualization, Writing - original draft, Writing -review & editing.Guang-Dong Wu:Data curation, Formal analysis, Validation, Visualization, Writing - original draft.Ang Li:Conceptualization, Formal analysis, Validation, Visualization, Writing - original draft, Writing - review & editing.Li-Han Yu:Formal analysis, Validation, Visualization, Writing - review & editing.Xuan Tong:Data curation, Formal analysis, Validation, Visualization, Writing - review & editing.Jun Yan:Data curation, Validation, Visualization, Writing - review & editing.Qian Lu:Conceptualization, Funding acquisition, Project administration, Supervision,Validation, Visualization, Writing - review & editing.

Funding

This study was supported by a grant from the National Natural Science Foundation of China ( 81930119 ).

Ethical approval

This study was approved by the Ethics Committee of Beijing Tsinghua Changgung Hospital (20311-0-01).Written informed consent for publication was obtained from the reported patient.

Competing interest

No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.