Renoportal anastomosis in pediatric living donor liver transplantation: a case report

Abstract

In children with biliary atresia, recurrent episodes of cholangitis often lead to portal vein (PV) phlebosclerosis. We report a case of pediatric living donor liver transplantation (LDLT) for biliary atresia with PV occlusion and a large splenorenal shunt. A 3-year-5-month-old girl was diagnosed with syndromic biliary atresia and polysplenia. Because the patient’s condition progressively deteriorated with worsening jaundice, we opted to perform LDLT using a left lateral section graft from her father. The recipient’s native PV was severely atrophic and completely occluded, and the collateral veins around the hepatoduodenal ligament were too small to serve as a viable source of portal inflow. Consequently, renoportal anastomosis (RPA) was selected as an alternative approach. Iliac vein interposition was performed to provide a new portal inflow source, and anatomy-compliant PV reconstruction was performed. The patient recovered from transplant surgery, but PV conduit stenosis occurred with the development of ascites 2 months posttransplant. This RPA-related vascular complication was resolved through percutaneous balloon angioplasty of the PV conduit. The patient has been doing well for 6 months posttransplantation. This case demonstrates that RPA can represent a viable reconstructive option for PV inflow in liver transplantation for pediatric patients with phlebosclerotic PV and prominent splenorenal shunt.

HIGHLIGHTS
Renoportal anastomosis can serve as a viable reconstructive option for portal vein inflow in liver transplantation for pediatric patients with a phlebosclerotic portal vein and prominent splenorenal shunt.

INTRODUCTION

Liver transplantation (LT) is the definitive treatment for patients with end-stage liver disease. However, portal vein (PV) thrombosis or obliteration poses a significant surgical challenge, particularly in pediatric patients. In children with biliary atresia (BA), the leading indication for pediatric LT, recurrent episodes of cholangitis often lead to PV phlebosclerosis. This vascular abnormality complicates PV reconstruction during transplantation. To address this issue, various surgical strategies have been developed, including PV patch venoplasty, the use of interposition grafts, and mesenteric jump graft techniques [1].

Renoportal anastomosis (RPA), first introduced in 1997, is a vascular reconstruction technique that connects the PV of a liver graft to the recipient’s left renal vein (LRV) via an interposition graft. This approach may be considered in cases of extensive PV thrombosis accompanied by a significant splenorenal shunt (SRS). Although RPA has been used occasionally in adult LT [2], its application in pediatric recipients remains rare [3–5]. Here, we present a case of pediatric living donor liver transplantation (LDLT) using a left lateral section graft in which RPA was performed to manage severe PV phlebosclerosis and a large SRS.

CASE REPORT

The study was approved by the relevant Institutional Review Board of Asan Medical Center (IRB No. 2025-1028), and informed consent was obtained from the patient’s parent.

A 2-year-old girl was referred to our center for LT. She had been delivered at full term via cesarean section. At 2 months of age, she underwent Kasai portoenterostomy for BA, along with surgical repair of a left inguinal hernia. By 12 months of age, progressive jaundice had developed, and she experienced recurrent episodes of cholangitis, necessitating multiple hospital admissions for intravenous antibiotic therapy. Although she was placed on the deceased donor LT waiting list at 3 years of age, she did not receive an organ offer due to the limited availability of deceased donors.

Computed tomography (CT) revealed findings consistent with biliary cirrhosis secondary to syndromic BA with polysplenia, along with intestinal malrotation. The PV was barely visible (Fig. 1A), whereas the hepatic arteries appeared markedly engorged (Fig. 1B). Prominent paraesophageal, gastric, and rectal varices were identified (Fig. 1C), along with the development of a large SRS (Fig. 1D), indicating significant portal hypertension. Additionally, the ascending colon, ileocecal valve, and appendix were located to the right of the midline, with most of the small intestine positioned on the right side, suggesting intestinal malrotation. The patient had intermittent episodes of melena, prompting endoscopic gastroduodenoscopy. This revealed esophageal varices classified as L1Cb—large, tortuous varices with red color signs—although no active bleeding was observed.

Fig. 1.

Pretransplant computed tomography findings of the recipient. (A) The portal vein was barely visualized. (B) The hepatic arteries were markedly engorged. (C) Numerous collateral veins were present. (D) A large splenorenal shunt was identified (arrow).

As the patient’s condition progressively deteriorated with worsening jaundice, the decision was made to proceed with LDLT using a left lateral section graft from her father. At the time of transplantation, she was 3 years and 5 months old, measured 89 cm in height (<3rd percentile), and weighed 13 kg (10th percentile). Preoperative laboratory tests revealed a total bilirubin level of 16.9 mg/dL, a prothrombin time of 37.7% (international normalized ratio, 1.95), a serum albumin level of 2.7 g/dL, and a creatinine level of 0.27 mg/dL. These values corresponded to a pediatric end-stage liver disease score of 25.8.

Because the LDLT procedure required a fresh vein homograft, surgery was postponed for 2 weeks until a suitable graft became available from our institutional tissue bank. The living donor was the patient’s 37-year-old father. Preoperative CT volumetry estimated the left lateral section volume at 250 mL. The graft was harvested and weighed 220 g on the back table, yielding a graft-to-recipient weight ratio (GRWR) of 1.69. Two hepatic vein outflows were present and were unified using venoplasty to create a single outflow orifice. A 10-cm cold-preserved fresh iliac vein homograft was obtained from the tissue bank, and the semilunar valves were meticulously removed on the back table to prepare it for use.

During the recipient operation, careful dissection of the hepatic hilum was performed to identify adequate venous structures. However, the native PV trunk was severely atrophic and completely occluded, and the collateral veins around the hepatoduodenal ligament and mesentery were too small to serve as a viable source of portal inflow. Consequently, RPA was selected as an alternative approach.

The duodenum was mobilized using the Kocher maneuver, enabling exposure of the infrahepatic inferior vena cava (IVC) and LRV. After mobilization and encirclement of the LRV, the native PV trunk was confirmed to be completely thrombosed, prompting early hepatectomy to secure a wider operative field for dissection of the retroperitoneal structures (Fig. 2). Once fully exposed, the proximal and distal portions of the LRV were clamped (Fig. 3A). A 2 cm-long longitudinal venotomy was created (Fig. 3B), and the prepared iliac vein homograft was anastomosed in an end-to-side configuration using continuous 6-0 polydioxanone (PDS) sutures (Fig. 3C and D). Upon temporary clamping of the distal renal vein near its junction with the IVC, robust blood flow through the interposed conduit was observed. The distal segment of the LRV draining into the IVC was then stapled using a TA stapler, followed by reinforcement with over-and-over running 5-0 polypropylene sutures to prevent potential recanalization (Fig. 3E and F).

Fig. 2.

Intraoperative photographs showing (A) engorged collateral veins in the mesentery and (B) isolation of the inferior vena cava after removal of the native liver.

Fig. 3.

Intraoperative photographs showing attachment of an iliac vein homograft to the left renal vein. (A) The proximal and distal portions of the left renal vein were clamped, and the incision site was marked with a surgical pen. (B) A 2-cm longitudinal venotomy was created, and the orifice was spread with stay sutures. (C) An iliac vein homograft was anastomosed in an end-to-side configuration using continuous 6-0 polydioxanone sutures. (D) The anastomotic site expanded after release of the renal vein clamps. (E) The distal portion of the left renal vein draining into the inferior vena cava was stapled using a TA stapler (arrow), followed by reinforcement with over-and-over running 5-0 polypropylene sutures. (F) The interposed vein homograft was fully expanded.

The recipient hepatic vein orifices at the IVC were unified to create a single large orifice (Fig. 4A and B). The graft hepatic vein was then anastomosed to this unified orifice using continuous 5-0 PDS sutures (Fig. 4C and D). Subsequently, the liver graft was positioned in the right subphrenic fossa, with careful attention to alignment of the RPA axis. A surgical marking pen was used to mark the 3 o’clock position on the graft PV to guide axial orientation (Fig. 5A). The graft PV was then anastomosed to the iliac vein conduit using 6-0 PDS sutures (Fig. 5B and C). After graft reperfusion, the alignment of the RPA was assessed to ensure the absence of axial torsion (Fig. 5D–F). The collateral veins associated with the SRS were preserved, whereas the rectal varices were selectively ligated. The splenic artery was left intact to maintain adequate portal venous inflow.

Fig. 4.

Intraoperative photographs of outflow vein reconstruction. (A, B) The recipient hepatic vein orifices at the inferior vena cava were unified to create a single, large outflow orifice. (C, D) The graft hepatic vein was then anastomosed to this unified orifice using continuous 5-0 polydioxanone sutures.

Fig. 5.

Intraoperative photographs of portal vein reconstruction. (A) After the liver graft was positioned in the right subphrenic fossa, the vein conduit was marked longitudinally to guide the anastomotic orientation. (B, C) The graft portal vein stump was anastomosed to the iliac vein conduit using 6-0 polydioxanone sutures. (D–F) After graft reperfusion, the alignment of the renoportal anastomosis was assessed to ensure the absence of axial torsion.

Microsurgical techniques were used to reconstruct the left hepatic artery of the graft. Biliary reconstruction was performed using a Roux-en-Y hepaticojejunostomy. Right inguinal herniorrhaphy and appendectomy were also performed. The abdominal wound was closed primarily. The pathology report of the explant liver showed biliary cirrhosis with a 2-cm regenerating nodule in segments VI and VII (Fig. 6).

Fig. 6.

Gross photograph of the explant liver showing biliary cirrhosis with a regenerating nodule.

Liver function recovered early following LDLT. A CT scan obtained 10 days posttransplant showed a patent PV conduit with an engorged and tortuous SMV, with some flow draining into the SRS and some draining directly into the suprarenal IVC (Fig. 7). However, the volume of ascites drained from the abdominal drain was 300–500 mL/day, and this persisted for 2 months. A CT scan obtained 2 months posttransplant showed a partial PV thrombus with a decreased PV conduit diameter, increased diameters of the splenic vein, SMV, and SMV-splenic vein collaterals, and mildly aggravated splenomegaly. These findings suggested a portal flow steal phenomenon, with diversion of SMV flow toward the spleen and relatively decreased hepatopetal PV flow to the liver (Fig. 8).

Fig. 7.

Posttransplant computed tomography findings at 10 days after transplantation. (A) The cross-sectional image and (B, C) three-dimensional reconstructed images of the interposed vein conduit (arrows) show a streamlined configuration. (D) The mesenteric collateral veins remained engorged.

Fig. 8.

Posttransplant computed tomography findings at 2 months after transplantation. (A–C) The portal vein conduit became narrowed with partial intraluminal thrombus formation (arrows). (D) Collateral veins persisted along the splenic vein and superior mesenteric vein, with mildly aggravated splenomegaly.

At 2 months posttransplant, balloon angioplasty was performed to dilate the PV conduit. Percutaneous transhepatic access was achieved through the segment III PV. The portogram showed mild stenosis of the PV conduit with persistence of multiple collaterals via the lumbar vein. Pressures at the LRV and intrahepatic PV were 21 mmHg and 18 mmHg, respectively. Balloon dilatation with a 10-mm balloon was performed for the mild stenosis at the PV conduit and the LRV anastomosis. Thereafter, venography showed improved stenosis and hepatopetal flow in the transplanted liver, with disappearance of the pressure gradient; the pressure at the PV conduit was 19 mmHg (Fig. 9). Soon after balloon angioplasty, the volume of drained ascites decreased to less than 100 mL/day. The abdominal drain was removed 17 days after angioplasty. The patient has received anticoagulation with warfarin since 2 months posttransplant. She was discharged 3 months after LDLT. At the 6-month follow-up, she had been doing well, with stable graft function and no complications.

Fig. 9.

Percutaneous balloon angioplasty performed at 2 months after transplantation. (A) Portography reveals mild stenosis of the portal vein conduit with persistence of multiple collaterals (arrows) via the lumbar vein. (B) Balloon dilatation with a 10-mm balloon (arrow) was performed for mild stenosis of the portal vein conduit and the left renal vein anastomosis. (C) Thereafter, venography showed improved stenosis (arrow). (D) Multiple collaterals (arrows) via the lumbar vein were still visible.

DISCUSSION

RPA is a specialized vascular reconstruction technique used in complex cases of extensive PV thrombosis accompanied by a prominent SRS. It involves connecting the graft PV to the recipient’s LRV using an interposition vein graft. RPA has been reported as a feasible option for adult LDLT [6,7]; however, only a few cases have been reported in pediatric LDLT [3–5,7]. To our knowledge, our case represents one of the youngest pediatric LDLT recipients to undergo RPA using a left lateral section graft and the first pediatric RPA case in Korea.

PV phlebosclerosis is commonly observed in patients with BA, largely due to recurrent episodes of cholangitis [8]. To address the challenges posed by a sclerotic or thrombosed PV, several surgical strategies have been explored, including PV patch venoplasty, interposition grafting from the PV stump or collateral veins, and jump grafts originating from the superior mesenteric vein [1]. RPA can be considered a variant of interposition grafting that utilizes collateral venous pathways.

In the present patient, the native PV was completely occluded, prompting an extensive search for alternative sources of portal inflow. However, no suitable collateral veins were identified, making RPA the only feasible option. In previous pediatric cases with congenital absence of the PV, we explored all available reconstruction strategies, including interposition grafting to large portosystemic shunt vessels [9,10].

In this case, the RPA configuration initially resembled an end-to-side anastomosis. Following ligation of the distal LRV, the anastomosis functioned as an end-to-end type. Our experience with adult LDLT cases involving RPA has shown the evolution of this technique [6]. Early attempts using direct end-to-end anastomosis between the interposition graft and the LRV were associated with anastomotic stenosis. This led to the development of an end-to-side technique incorporating a T-shaped incision on the LRV to enlarge the orifice, combined with distal LRV ligation. Ultimately, a more refined approach involves end-to-end anastomosis between the interposition graft and an IVC cuff attached to the LRV. Two key technical considerations in RPA are prevention of anastomotic stenosis and avoidance of recanalization at the ligated distal LRV. In the present case, we opted for the end-to-side configuration due to the congenitally anomalous course of the LRV, which would have compromised anastomotic alignment if a standard end-to-end technique had been used. To ensure a wide and unobstructed anastomosis, a long longitudinal incision was made in the LRV, an approach previously demonstrated effective in pediatric cases with congenital PV absence [9,10].

The presence of large portosystemic collaterals, such as a prominent SRS, can result in portal flow steal, potentially leading to graft hypoperfusion, atrophy, and even graft failure, particularly in LDLT involving a small-for-size partial graft. To prevent this phenomenon, ligation of the SRS or distal LRV may be necessary [11]. We previously reported both short- and long-term outcomes of LRV ligation in adult LDLT recipients [12,13]. Simple ligation of the distal LRV is not advisable because it carries a significant risk of recanalization over time [13]. In the present case, to ensure durable occlusion, we used a linear vascular stapler in combination with reinforcing running sutures.

Although RPA functionally diverts flow from the SRS, it does not completely resolve portal hypertension. In our previous study involving 40 adult LDLT recipients who underwent LRV ligation, complete resolution of the SRS was observed in only half of the cases, while the remaining patients exhibited persistent, variably sized SRS on long-term follow-up or at the time of death [13]. Other reports have indicated that some patients undergoing RPA may require proximal splenic artery embolization to regulate hepatic inflow and manage ascites resulting from unresolved portal hypertension [2]. Additionally, transient posttransplant ascites and hyperbilirubinemia have been described after RPA, consistent with graft overperfusion syndrome, a condition resembling small-for-size graft syndrome [7].

In contrast, the present case did not show signs of graft overperfusion, likely because the graft was adequately sized, with a GRWR of 1.69. Splenic artery ligation was not performed intraoperatively because portal inflow appeared to be well balanced. Importantly, splenic artery embolization via interventional radiology remains a viable postoperative option. A Japanese pediatric case previously advocated the benefits of intraoperative splenic artery ligation in RPA [5]; however, we believe that the clinical value of this surgical procedure in that case remains uncertain.

Concern exists regarding potential impairment of left renal function due to venous congestion following LRV ligation [7]. In our previous studies, some patients experienced transient renal dysfunction in the early postoperative period; however, all cases resolved spontaneously without long-term consequences [12,13]. No significant impairment of renal function was observed in the present case.

RPA is reported to be vulnerable to anastomotic stenosis. In the present case, narrowing of the PV conduit with a partial PV thrombus occurred 2 months posttransplant, resulting in a portal flow steal phenomenon and the production of large-volume ascites. The stenotic PV conduit was dilated by percutaneous balloon angioplasty, and portal inflow improved, with a progressive decrease in ascites. Anticoagulation therapy with warfarin was continued to prevent PV thrombus formation. In our previous RPA study of 15 adult LDLT cases [6], the incidence of RPA-related complications was 42.9% (three of seven patients) before technical standardization of RPA, and it decreased markedly to 12.5% (one of eight patients) after technical standardization. The RPA surgical technique used in the present case was compliant with our institutional standardized technique.

The availability of a suitable vein graft is a critical factor in interposition vein grafting. In a previously reported Japanese pediatric case of RPA, the donor’s superficial femoral vein was used. In adult LDLT cases requiring RPA, a range of graft materials have been employed, including the recipient’s internal jugular vein, external iliac vein, and ringed polytetrafluoroethylene grafts [7,14,15]. Based on our experience, a fresh external iliac vein homograft represents an ideal substitute for the PV in pediatric patients. We do not recommend cryopreserved iliac vein homografts because they are prone to degeneration over time and may necessitate endovascular stenting—an approach that is generally unsuitable in pediatric recipients, unlike in adults. In the present case, a cold-preserved fresh iliac vein homograft was obtained from our institutional tissue bank, but its availability required a 2-week waiting period.

In conclusion, this case demonstrates that RPA can serve as a viable reconstructive option for PV inflow in LT in BA patients with a phlebosclerotic PV and a prominent SRS. Successful PV reconstruction in pediatric BA patients requires a tailored, case-specific approach based on comprehensive preoperative and intraoperative anatomical evaluations.