EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Expanded polytetrafluoroethylene grafts are widely used for middle hepatic vein reconstruction during living-donor liver transplant because they have comparable patency to autologous or cryopreserved vessels. Mechanical complications like gastric or duodenal penetration by expanded polytetrafluoroethylene grafts have been infrequently reported. We recently experienced a case of duodenal penetration by the expanded polytetrafluoroethylene graft. The patient was a 57-year-old man who had undergone a living-donor liver transplant for cryptogenic liver cirrhosis. At an annual follow-up computed tomography scan performed 3 years after transplant, the expanded polytetrafluoroethylene graft appeared to have penetrated into the first to the second portion of the duodenum, and abnormal air shadow and partial thrombus were identified within the expanded polytetrafluoroethylene graft. The patient underwent exploratory laparotomy, the expanded polytetrafluoroethylene graft was removed, and the perforated duodenum was repaired. Pyloric exclusion with gastrojejunostomy and feeding jejunostomy was additionally performed because of a wide defect in the duodenum. Adjacent organ injuries such as duodenal or gastric penetration by the expanded polytetrafluoroethylene graft after living-donor liver transplant is rare but not uncommon. Because the use of expanded polytetrafluoroethylene grafts is essential when an adequate vessel allograft is unavailable, we can consider transposition of the omental flap between the expanded polytetrafluoroethylene graft and the stomach or duodenum to reduce this unexpected complication.

Key words : Allograft, Living-donor, Liver transplant

Middle hepatic vein reconstruction with an interposition vessel graft has been established as a standard procedure for living-donor liver transplant using a right lobe graft when the donor’s middle hepatic vein trunk is preserved in the donor’s remnant liver.^1-4 Sizable vein allografts are suitable for middle hepatic vein reconstruction regarding long patency and infection resistance, but the supply is often limited in most Asian countries because of scarcity in deceased-donor organ donation. Because of the easy availability of synthetic grafts, expanded polytetrafluoroethylene (ePTFE) grafts have been used instead of cryopreserved vessel allografts. Moreover, the early patency rate of the ePTFE graft is good, and the outcome of ePTFE grafts is comparable to allografts as the interposition graft for middle hepatic vein reconstruction in living-donor liver transplant using a right lobe graft.^3,4 Several studies have reported on the patency and outcome of ePTFE grafts for middle hepatic vein reconstruction,^3,4 but few mechanical complications such as adjacent organ penetration have been reported.^5,6 Here, we report a complication, namely, the duodenal penetration of a ringed ePTFE graft.

The patient was a 57-year-old man with cryptogenic liver cirrhosis and a Model for End-Stage Liver Disease score of 18. The patient underwent living-donor liver transplant using a modified right lobe graft donated by his son. We used a ringed ePTFE graft (GORE-TEX) with an internal diameter of 10 mm for the reconstruction of both hepatic vein branch segments 5 and 8 in a modified right lobe graft. We also used a greater saphenous vein patch for end-to-side anastomosis between the ePTFE graft and the middle hepatic vein branches, and closed the distal end of the ePTFE graft with a large clip Hem-o-Lok clip (Weck; TELEFLEX MEDICAL, Research Triangle Park, NC, USA). The postoperative period was uneventful, and the patient was discharged on the 30th postoperative day.

On an annual follow-up computed tomography scan 3 years after transplant, we found that the ePTFE graft penetrated into the first to the second portion of the duodenum, with abnormal air shadow and partial thrombus within the ePTFE graft (Figure 1). However, the patient did not complain of significant symptoms; therefore, esophagogastroduodenoscopy and another follow-up computed tomography scan were performed after 2 months. The scan showed that the ePTFE graft was more deeply buried in the duodenum, and esophagogastroduodenoscopy revealed that the ePTFE graft was freely exposed in the duodenal lumen (Figure 2). We decided to perform laparotomy (Figure 3) and removed the ePTFE graft from the recipient’s inferior vena cava and then repaired the perforated duodenum. In addition, we performed pyloric exclusion with gastrojejunostomy and feeding jejunostomy because of concerning duodenal leakage or stenosis caused by a wide defect of duodenum. Fortunately, the patient recovered without complications and was discharged on the 15th postoperative day. One year after surgery, the patient is doing well, and his liver graft function is preserved.

A modified right lobe graft in living-donor liver transplant was introduced for the purpose of preventing anterior sectoral congestion in conventional right lobe graft by interposing vessel grafts between middle hepatic vein tributaries and the recipient’s inferior vena cava or middle-left hepatic vein trunk.^1,2 For the interposition vessel grafts required for this technique, the recipient’s autologous vein grafts or cryopreserved vessel grafts are used.^7-9 However, additional time is spent harvesting autologous vein grafts such as the greater saphenous vein, portal vein, or paraumbilical vein from the recipient, and the surgical procedure is complicated. Allografts are also insufficiently available in Eastern countries where organ or tissue donations from deceased donors are scarce. For these reasons, artificial vessel grafts such as ePTFE are considered useful substitutes to overcome the shortage of vessel allografts.^3,4 The infection resistance and long-term patency of cryopreserved allografts are superior to synthetic vessel grafts such as ePTFE grafts. The recipient’s operative field is not contaminated because spillage of gastrointestinal contents is uncommon during operation, and duct-to-duct anastomosis is preferred for biliary reconstruction. In addition, ePTFE grafts are believed to be more suitable in a contaminated field because they are inert, nonthrombogenic, and impervious compared with other artificial vessel grafts.^3,10 Moreover, it is known that the long-term patency of the interposing vessel for anterior section drainage is not important in living-donor liver transplant because intrahepatic venous collateral can be expected to develop by day 7 after transplant.^2,3 For this reason, if the patency of ePTFE grafts is warranted during the first 1 to 2 weeks after transplant, it is well worthy as a good alternative to allografts. Currently, ePTFE grafts are used for interposing vessels for anterior section drainage in modified right lobe grafts in many centers.

There are a few studies on the patency of ePTFE grafts compared with cryopreserved vessel grafts, but reports on the migration or mechanical complications of ePTFE such as adjacent organ penetration are scarce. There are 3 influencing factors on the development of ePTFE-related organ injuries according to a report by Kim and associates.⁶ The factors are (1) interventional treatments for biliary strictures or drainage of perihepatic fluid or hematoma, (2) bowel wall adhesion to the ePTFE grafts, and (3) patency of the ePTFE grafts. In many cases with biliary complications, repeated percutaneous or endoscopic interventional treatments may be performed, and these could distort the shape and location of the ePTFE grafts. Also, adhesion of the bowel or common bile duct to the ePTFE grafts is a potential cause of adjacent organ injury because the stiff grafts might cause erosion, inflammation, and thickening of the adjacent bowel wall, leading to perforation. The grafts are external to the liver surface and can be incorporated into perihepatic seroma or hematoma, which would subsequently become organized perihepatic fibrosis. Therefore, early occlusion of the ePTFE grafts could be an indicator of perihepatic inflammation or complications, although early occlusion of the ePTFE grafts in living-donor liver transplant does not compromise the function of the modified right lobe graft.

In the present case, the patient had no history of interventional percutaneous or endoscopic treatment for biliary stricture or bleeding. Due to the above influencing factors, the ePTFE graft was very close to the duodenum and stomach wall; therefore, frequent erosion from the stiff ePTFE graft led to penetration of the duodenal wall. If we had not used a ringed ePTFE graft, duodenal penetration would not have happened. We have always used ringed ePTFE grafts for interposing vessel grafts in modified right lobe grafts because the outer rings are helpful for maintaining the contour and preventing occlusion by extrinsic forces such as the stomach, fluid collection, or a hematoma.⁴ However, per previous studies, the incidence of ePTFE graft-associated complications is 0.46% (1/215) to 1.96% (4/204), which is low and acceptable.^5,6 Considering these possible influencing factors, there is no way we can avoid performing interventional treatments in cases of biliary strictures, which significantly reduces early occlusion of ePTFE grafts. However, we can try to minimize the adhesion of the bowel to the ePTFE grafts. In left hemihepatectomy, we sometimes experience delayed gastric emptying due to duodenal adhesion to the liver cut surface. Therefore, we spray antiadhesive agents over the liver cut surface or the interposed omental flaps between the cut surface and the duodenum or stomach to prevent or reduce adhesion. We can expect less adhesion of the ePTFE grafts to adjacent organs such as the duodenum and stomach by applying these methods.

In conclusion, the comparable patency rate of ePTFE grafts to cryopreserved allografts has already been reported; therefore, an ePTFE graft is a good alternative when allograft vessel grafts are unavailable for modified right lobe grafts. Mechanical complications related to ePTFE grafts such as the penetration of adjacent organs are very uncommon. However, relaparotomy, for our patient, was necessary to remove the ePTFE graft; therefore, the use of an antiadhesive agent to reduce adhesion or interpose the omentum between the ePTFE graft and the duodenum or stomach to avoid direct adherence should be considered.

Volume: 16 Issue: 4 August 2018

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