Hepatic venous outflow obstruction in pediatric liver transplantation: technical considerations in prevention, diagnosis, and management

Venous outflow obstruction in pediatric left lateral segment split liver transplantation

BACKGROUND

Venous outflow obstruction (VOO) is a known cause of graft and patient loss after pediatric liver transplantation (LT). We analyzed the incidence, risk factors, diagnosis, management, and outcome of VOO in a large, consecutive series of left lateral segment (LLS) split LT with end-to-side triangular venous anastomosis.

METHODS

We evaluated data collected in our prospective databases relative to all consecutive pediatric liver transplants performed from January 2006 to December 2021. We included in this study children undergoing LLS split liver transplant with end-to-side triangular anastomosis. Diagnosis of VOO was based on clinical suspicion and radiological confirmation.

RESULTS

VOO occurred in 24/279 transplants (8.6%), and it was associated with lower graft weight (p = .04), re-transplantation (p = .008), and presence of two hepatic veins (p < .0001). In presence of two segmental veins' orifices, the type of reconstruction (single anastomosis after venoplasty or double anastomosis) was not significantly related to VOO (p = .87). Multivariable analysis indicated VOO as a risk factor for graft lost (hazard ratio 3.21, 95% confidence interval 1.22-8.46; p = .01). Percutaneous Transluminal Angioplasty (PTA) was effective in 17/22 (77%) transplants. Surgical anastomosis was redone in one case. Overall six grafts (25%) were lost.

CONCLUSION

VOO after LLS split LT with end-to-side triangular anastomosis is an unusual but critical complication leading to graft loss in a quarter of cases. The occurrence of VOO was associated with lower graft weight, re-transplantation, and presence of two hepatic veins. PTA was safe and effective to restore proper venous outflow in most cases.

Understanding Local Hemodynamic Changes After Liver Transplant: Different Entities or Simply Different Sides to the Same Coin?

Liver transplantation is an extremely complex procedure performed in an extremely complex patient. With a successful technique and acceptable long-term survival, a new challenge arose: overcoming donor shortage. Thus, living donor liver transplant and other techniques were developed. Aiming for donor safety, many liver transplant units attempted to push the viable limits in terms of size, retrieving smaller and smaller grafts for adult recipients. With these smaller grafts came numerous problems, concepts, and definitions. The spotlight is now aimed at the mirage of hemodynamic changes derived from the recipients prior alterations. This article focuses on the numerous hemodynamic syndromes, their definitions, causes, and management and interconnection with each other. The aim is to aid the physician in their recognition and treatment to improve liver transplantation success.

Outflow reconstruction of left lateral graft with two widely spaced hepatic veins in pediatric living donor liver transplantation

BACKGROUND

Living donor liver transplantation using the left lateral segment of the liver is the most common type of pediatric liver transplantation. An appropriate surgical approach is crucial for decreasing the risk of vascular complications using these grafts with anatomical variations.

METHODS

Between January 2017 and December 2020, 631 living donor liver transplantations using left lateral segment grafts were performed at Tianjin First Central Hospital. The grafts from 162 (25.7%) donors have 2 hepatic vein openings. A total number of 21 transplantations using left lateral segment grafts with 2 widely spaced hepatic vein openings were performed. In group 1, the unification venoplasty technique with interposition vein graft was used at the back table for the reconstruction of hepatic vein from grafts. In group 2, dual hepatic vein reconstructions were performed, in which venoplasty of recipients' left hepatic vein, middle hepatic vein, and inferior vena cava was performed to create a large orifice for anastomosis with segment Ⅱ hepatic vein from the graft. Segment III hepatic vein from the graft was anastomosed with the recipient's right hepatic vein. The incidence, treatment, and outcomes of hepatic venous outflow obstruction were compared between the 2 groups.

RESULTS

The median follow-up time was 12.8 months. There was no significant difference in the incidence of hepatic venous outflow obstruction between the 2 groups.

CONCLUSION

Dual hepatic vein reconstruction is an alternate surgical option for grafts with 2 widely spaced hepatic veins, and it is associated with ideal graft recovery and vascular condition. However, long-term follow-up is still needed to verify the efficacy and safety of this approach.

Pediatric Hepatobiliary Interventions in the Setting of Intrahepatic Vascular Malformations, Portal Hypertension, and Liver Transplant

Within the broad spectrum of pediatric hepatobiliary disorders, hepatic vascular malformations, portal hypertension, and hepatic transplant interventions pose numerous challenges. The role of interventional radiology within each of these conditions is discussed herein, beginning with endovascular management of high flow hepatic vascular malformations. Next, while becoming less common in adult populations, surgical portoportal and portosystemic shunts remain prevalent in many pediatric centers. Shunt anatomy is reviewed along with endovascular management techniques for shunt dysfunction. Next, the growing experience with pediatric transjugular intrahepatic portosystemic shunt placement is reviewed along with tips for success in pediatric patients. Finally, pediatric hepatic transplant interventions are discussed with technical notes pertinent to split liver anatomy.

Efficacy of repeated balloon venoplasty for treatment of hepatic venous outflow obstruction after pediatric living-donor liver transplantation: A single-institution experience

HVOO is a rare complication after LT and an important cause of graft failure. Balloon venoplasty is the first-line treatment for HVOO, but the effect of repeated balloon venoplasty and stent placement for HVOO recurrence after pediatric LDLT remains unclear. Between 1998 and 2016, 147 pediatric patients underwent LDLT in our institution. Among them, the incidence of HVOO and the therapeutic strategy were retrospectively reviewed. Ten patients were diagnosed with HVOO. All the patients underwent LLS grafts. Median age at the initial endovascular intervention was 2.7 years (range, 5 months-8 years). The median interval between the LDLT and the initial interventional radiology was 2.7 months (range, 29 days-35.7 months). Four patients experienced no recurrence after a single balloon venoplasty; 6 underwent balloon venoplasty more than 3 times because of HVOO recurrence; and 2 underwent stent placement due to the failure of repeated balloon venoplasty. All patients are alive with no symptoms of HVOO. The HVOO recurrence-free period after the last intervention ranged from 20 days to 15.5 years (median, 8.9 years). Repeated balloon venoplasty may prevent unnecessary stent placement to treat recurrent HVOO after pediatric LDLT.

Aggressive prevention and preemptive management of vascular complications after pediatric liver transplantation: A major impact on graft survival and long-term outcome

Vascular complications are a major cause of patient and graft loss after LTs. The aim of this study was to evaluate the effect of a multimodal perioperative strategy aimed at reducing the incidence of vascular complications. A total of 126 first isolated LTs-performed between November 2008 and December 2015-were retrospectively analyzed. A minimum follow-up period of 24 months was analyzable for 124/126 patients (98.4%). The aggressive preemptive strategy consisted of identifying and immediately managing any problem and any abnormality in the vascular flow, in any of the hepatic vessels, and at any time after the liver graft revascularization. As a result, with a median follow-up of 57 months (3-112 months), not a single graft has been lost from vascular or biliary problems. The actuarial 8-year graft survival is 96.5%. These results have shown that a combination of technical attention, medical prevention, an early diagnosis, and rapid interventions reduced the negative impact of vascular problems on the outcome of both grafts and patients.

Doppler ultrasound predictors of transplant hepatic venous outflow obstruction in pediatric patients

OBJECTIVE

To investigate Doppler US and catheter venogram correlates to improve detection of transplant HVOO and avoid unnecessary invasive imaging procedures.

MATERIALS AND METHODS

A retrospective review was performed in all pediatric OLT patients undergoing catheter venography of the hepatic veins between 2007 and 2017 at a single large tertiary pediatric liver transplant institution.

RESULTS

Forty-four transplant hepatic venograms in 32 OLT patients were included (mean 1.38, range 1-4 venograms per patient). All venograms were preceded by an independent Doppler US examination. Twenty-one (47.7%) venograms were performed for the investigation of suspected HVOO based on Doppler US alone, 19 (43.2%) were performed for TJLB without suspected HVOO, 4 (9.1%) were performed for both. Sixteen (36.3%) instances of >50% anastomotic stenosis were identified. Mean peak anastomotic velocities were 208 cm/s and 116 cm/s in the presence and absence of a >50% venographic stenosis, respectively (P < 0.004). In all cases where there was a monophasic waveform seen on Doppler US, there was a > 50% stenosis seen on hepatic vein venogram. In all cases where a triphasic waveform was seen on Doppler US, there was no stenosis seen on hepatic vein venogram.

CONCLUSION

While a Doppler US velocity threshold providing both high sensitivity and specificity has yet to be identified, increasing peak anastomotic velocity and decreasing intrahepatic venous velocity correlate strongly with venographic outflow stenosis. The presence of a triphasic intrahepatic waveform provides good NPV.

Modified triangular hepatic vein reconstruction for preventing hepatic venous outflow obstruction in pediatric living donor liver transplantation using left lateral segment grafts

HVOO can be a critical complication in pediatric LDLT. The aim of this study was to evaluate a modified triangular technique of hepatic vein reconstruction for preventing HVOO in pediatric LDLT. A total of 298 pediatric LDLTs were performed using a left lateral segment graft by 2 methods for reconstruction of the hepatic vein. In 177 recipients, slit-shaped anastomosis was indicated with partial clamp of the IVC. A total of 121 recipients subjected to the modified triangular anastomosis with total clamp of the IVC. We compared the incidence of hepatic vein anastomotic complications between these 2 methods. Nine of the 177 cases (5.3%) treated with the conventional technique were diagnosed with outflow obstruction. All 9 cases underwent hepatic vein reconstruction with the slit-shaped hepatic vein anastomosis. In contrast, there were no cases of outflow obstruction in the 121 cases treated with the modified triangular anastomosis. The modified triangular technique of hepatic vein reconstruction with total clamping of the IVC was useful for preventing HVOO in pediatric LDLT.

Diagnosis, treatment and outcome of hepatic venous outflow obstruction in paediatric liver transplantation: 24-year experience at a single centre

BACKGROUND

Hepatic venous outflow obstruction after paediatric liver transplantation is an unusual but critical complication.

OBJECTIVES

To review the incidence, diagnosis and therapeutic modalities of hepatic venous outflow obstruction from a large national liver transplant unit.

MATERIALS AND METHODS

During the period from October 1992 to March 2016, 917 liver transplant procedures were performed with all types of grafts in 792 children. Transplants suspected to have early or delayed venous outflow obstruction were confirmed by percutaneous venography or surgical revision findings. Therapeutic intervention, recurrence and outcome were evaluated.

RESULTS

Twenty-six of 792 children (3.3%) experienced post-transplant hepatic venous outflow obstruction. These patients had been diagnosed from 1 day to 8.75 years after transplantation. Six occurred during the early post-transplant period; in three of them, the graft was lost. Seventeen patients were initially treated by balloon angioplasty with success; 11 of these experienced recurrences. Four stents were implanted; one was complicated by definitive occlusion. Three of the five surgical revisions were successful. The initial stenosis involved the inferior vena cava in 10 grafts, in isolation or associated with hepatic vein involvement. Mean follow-up was 79 months after transplantation. Eight grafts were lost.

CONCLUSION

Acute postoperative hepatic venous outflow obstruction was associated with poor prognosis. Diagnostic venography should be performed if there is any suspicion of venous outflow obstruction, even if first-line examinations are normal. Stenosis frequently involved the inferior vena cava. Angioplasty was a safe and efficient treatment for venous outflow obstruction despite frequent recurrence.

Intraoperative Doppler sonogram in pediatric liver transplants: a pictorial review of intraoperative and early postoperative complications

A spectrum of vascular complications can be seen in pediatric liver transplant patients, including occlusion and hemodynamically significant narrowing of the vessels that provide inflow to or outflow from the graft. Intraoperative Doppler ultrasound (US) has the potential benefit of identifying vascular complications in pediatric liver transplant patients prior to abdominal closure. Importantly, intraoperative Doppler US can be used as a problem-solving tool in situations such as position-dependent kinking of the portal or hepatic veins, or in suspected vasospasm of the hepatic artery. Furthermore, this technique can be used for real-time reassessment after surgical correction of vascular complications. This pictorial review of intraoperative Doppler US in pediatric liver transplant patients illustrates normal findings and common vascular complications, including examples after surgical correction, in the perioperative period.

Optimizing hepatic venous outflow reconstruction for hepatic vein stenosis with indwelling stent in living donor liver retransplantation

The patient was a boy of 7 years and 5 months of age, who underwent LDLT for acute liver failure at 10 months of age. HV stent placement was performed 8 months after LDLT because of intractable HV stenosis. At 7 years of age, his liver function deteriorated due to chronic rejection. The patient therefore underwent living donor liver retransplantation from his father. The HV was transected with the stent in situ. The IVC was resected due to stenosis. The pericardial cavity was opened and detached around the IVC to elongate the IVC. The divided ends of the IVC were joined by suturing to the posterior wall of the IVC. A new triangular orifice was made by adding an incision on the anterior wall of the IVC. The graft HV was then anastomosed to the new orifice with continuous sutures in the posterior wall and interrupted sutures in the anterior wall using 5-0 non-absorbable sutures. Doppler ultrasound showed a triphasic waveform. We successfully performed HV reconstruction without a vascular graft. This is a feasible procedure for overcoming HV stenosis in LDLT patients with an indwelling stent.

Risk Factors for Hepatic Venous Outflow Obstruction in Piggyback Liver Transplantation: The Role of Recipient's Pattern of Hepatic Veins Drainage into the Inferior Vena Cava

Background

The recipient’s pattern of hepatic veins (HVs) drainage into the inferior vena cava (IVC) (drainage pattern, for short) may influence outflow reconstruction and thus hepatic venous outflow obstruction (HVOO) in piggyback liver transplantation (PBLT). However, no previous study has investigated this association.

Material/Methods

A retrospective analysis of 202 PBLT (2000–2016) was conducted. Based on drainage patterns, the patients were divided into Group A (common trunk of left and middle HVs), Group B (common trunk of right and middle HVs), and Group C (common trunk of 3 HVs). Patients’ demographic and surgical data were compared within the 3 groups, and risk factors for HVOO were tested using a multiple logistic regression model.

Results

A chi-square test revealed a significantly higher HVOO incidence in Group 1 compared with the other groups (23.5% vs. 9.6% vs. 7.1%, p=0.047). The demographics and surgical data except angle∠AOB between the reconstructed outflow and IVC in cross-section of 3D image (∠AOB), ratio of the length of reconstructed outflow and ∠AOB (LRO/∠AOB ratio), and types of HV ligation did not differ significantly within the 3 groups. ∠AOB and LRO/∠AOB ratio were used to assess the level of anastomosis twisting and compression, respectively. Among the 3 groups, the largest ∠AOB and highest LRO/∠AOB ratio were observed in Group A and B, respectively. In addition, multivariate analysis indicated that the ∠AOB (OR=1.016, 95%CI: 1.006–1.027) and LRO/∠AOB ratio (OR=2.254, 95% CI: 1.041–5.519) were risk factors for HVOO.

Conclusions

This study demonstrated that drainage patterns were associated with HVOO. The best choice for outflow reconstruction is Group C. The patients in Group A and B were likely to develop HVOO due to anastomosis twisting and compression, respectively.

Surgical anterior cavoplasty for managing a case of early acute outflow obstruction after liver transplantation

HVOO following liver transplantation is rarely treated surgically because it tends to debut subacutely. However, acute HVOO is a surgical emergency that compromises the viability of the graft. We report a case of HVOO diagnosed intra-operatively during surgical revision for a suspected arterial thrombosis in a 10-month-old male recipient of a second graft (segments II-III) for familial intrahepatic cholestasis. HVOO was related to a stenosis at the first transplant hepato-caval anastomosis, left in place to obtain longer venous cuffs for retransplantation. An anterior cavoplasty was necessary to resolve the issue. The new anastomosis was created under total vascular exclusion after gaining control of the supradiaphragmatic vena cava, because the inferior vena cava was unsuitable for further surgery. This approach (normally used as a means to avoid sternotomy in patients with hepatic or renal tumours associated with venous thrombosis) allows adequate vascular control and, in selected cases, offers a surgical alternative for treating HVOO.

Long-term outcome of endovascular intervention in hepatic venous outflow obstruction following pediatric liver transplantation

The purpose of our study was to address the long-term outcome of angioplasty and stent placement for hepatic venous outflow obstruction following pediatric liver transplantation. From October 1999 to December 2011, 20 stenotic lesions were confirmed to constitute hepatic venous outflow obstruction in 18 pediatric patients (13 boys, 5 girls) among 152 pediatric patients following liver transplantation and were managed with endovascular intervention. Stent placement was favored over additional angioplasty in patients of preadolescent or adolescent age (>8 years old), after 1 or 2 sessions of balloon angioplasty. The primary patency and assisted primary patency were estimated using the Kaplan-Meier method. A total of 32 procedures (24 balloon angioplasties, 8 stent placements) were conducted. The technical success rate was 90.6% (29/32). Clinical success was achieved in 15 of 18 patients (clinical success rate of 83.3%). Major complications did not occur in our study. Median follow-up was 91.5 months (interquartile range, 54.7-137.3 months) for the 18 patients. The 1-year, 3-year, 5-year, and 10-year primary patencies of the 20 treated lesions were 63.5%, 57.8%, 57.8%, and 57.8%, respectively. The 1-year, 3-year, 5-year, and 10-year assisted-primary patencies of the lesions were 100%, 100%, 100%, and 100%, respectively. Of the 6 patients of preadolescent or adolescent age, 5 patients underwent stent placement procedures, and the stents were patent during the follow-up period of 57.3-162.5 months (median, 72.7 months). In conclusion, endovascular intervention is very effective in hepatic venous outflow obstruction following pediatric liver transplantation. In addition, early stent placement in patients of preadolescent or adolescent age can provide a safe and favorable long-term outcome.

Technique advance to avoid hepatic venous outflow obstruction in pediatric living-donor liver transplantation

HVOO represents a serious critical complication of pediatric living-donor liver transplantation because open surgical repair is virtually impossible. Currently, despite several technical innovations and the introduction of triangulated anastomosis for hepatic vein reconstruction, the reported incidence of HVOO is still considerable. The aim of this study was to propose a new technique for hepatic venous reconstruction that avoids the original orifice of the recipient hepatic veins. Instead, anastomosis is performed in a newly created wide longitudinal orifice in the anterior wall of the recipient inferior vena cava. A total of 210 living related-donor liver transplantations were performed using two methods for reconstruction of the hepatic vein. Group 1 included 69 patients subjected to direct anastomosis of the orifice of the graft hepatic vein and a wide orifice created in the recipient inferior vena cava by the confluence of the orifices of the right, left, and middle hepatic veins. Group 2 included 141 patients in whom the original orifices of the recipient hepatic veins were closed, the inferior vena cava was widely opened, and a long longitudinal anastomosis was performed using two lines of continuous sutures. Diagnosis of HVOO was suspected based on clinical findings and ultrasound studies and then confirmed by liver biopsy and interventional radiology examinations. Among the 69 recipients in group 1, 16 patients died due to graft problems during the postoperative period and eight of the survivors (15.1%) presented with HVOO. In group 2 (141 patients), 21 patients died, and there were no cases of HVOO. A comparison of the incidence of HVOO between groups revealed a significant difference (p = 0.01). Hepatic venous reconstruction during pediatric living-donor liver transplantation should be performed using a wide longitudinal incision in the anterior wall of the recipient inferior vena cava because this technique eliminated anastomosis complications.