Management of vascular complications after pediatric liver transplantation

Vascular Complications After Liver Transplantation

OBJECTIVES

Vascular complications after liver transplant can be lethal. High levels of suspicion and aggressive use of diagnostic tools may help with early diagnosis and treatment. Here, we share our experiences regarding this topic.

MATERIALS AND METHODS

Adult and pediatric patients who had liver transplant between February 1997 and June 2018 in our clinic were included in the study. Patients were grouped according to age (pediatric patients were those under 18 years old), male versus female, indication for transplant, type of liver transplant, type of vascular complication, treatment, and survival aftertreatment.We analyzed the statistical incidence of vascular complications according to age, male versus female, and type of liver transplant.

RESULTS

Our analyses included 607 liver transplant procedures, including 7 retransplants, with 349 (57.4%) from living donors and 258 (42.6%) from deceased donors. Of total patients, 539 were adults (89.8%) and 61 were children (10.2%). Vascular complications occurred in 25 patients (4.1%), with hepatic artery complications seen in 13 patients (2.1%) (10 adults [1.8%] and 3 children [4.9%]), portal vein complications seen in 9 patients (1.5%) (6 adults [1.1%] and 3 children [4.9%]), and hepatic vein complications seen in 3 patients (0.5%) (2 adults [0.36%] and 1 child [1.6%]). Rate of vascular complications was statistically higher in pediatric patients (11.4% vs 3.3%; P = .007) and higher but not statistically in recipients of livers from living donors (5.2% vs 2.7%; P = .19). Twelve patients (48.8%) were treated with endovascular approach, and 11 (0.44%)required surgicaltreatment. Two patients underwent immediate retransplant due to hepatic artery thrombosis.

CONCLUSIONS

Because vascular complications are the most severe complications afterlivertransplant,there must be close follow-up of vascular anastomoses, particularly early postoperatively, with radiologic methods. In cases of vascular complications, emergent treatment, including endovascular interventions, surgery, and retransplant, must be performed.

Hepatic artery reconstruction in pediatric liver transplantation: Experience from a single group

BACKGROUND

The reconstruction of hepatic artery is a challenging part of the pediatric liver transplantation procedure. Hepatic artery thrombosis (HAT) and stenosis are complications which may result in ischemic biliary injury, causing early graft lost and even death.

METHODS

Two hundred and fifty-nine patients underwent liver transplantation in 2017 in a single liver transplantation group. Among them, 225 patients were living donor liver transplantation (LDLT) and 34 deceased donor liver transplantation (DDLT).

RESULTS

In LDLT all reconstructions of hepatic artery were microsurgical, while in DDLT either microsurgical reconstruction or traditional continuous suture technique was done depending on different conditions. There were five (1.9%) HATs: four (4/34, 11.8%) in DDLT (all whole liver grafts) and one (1/225, 0.4%) in LDLT (P = 0.001). Four HATs were managed conservatively using anticoagulation, and 1 accepted salvage surgery with re-anastomosis. Until now, 3 HAT patients remain in good condition, whereas two developed biliary complications. One of them needed to be re-transplanted, and the other patient died due to biliary complications.

CONCLUSIONS

Microsurgical technique significantly improves the reconstruction of hepatic artery in pediatric liver transplantation. The risk for arterial complications is higher in DDLT. Conservative therapy can achieve good outcome in selected HAT cases.

Current state of the art in management of vascular complications after pediatric liver transplantation

Vascular complications by compromising the blood flow to the allograft can have significant and sometimes life-threatening consequences after pediatric liver transplantation. High level of suspicion and aggressive utilization of diagnostic modalities can lead to early diagnosis and salvage of the allograft. This review will summarize the current trends in management of vascular complications after pediatric liver transplantation.

Frequency of and factors associated with vascular complications after pediatric liver transplantation

OBJECTIVE

to evaluate the frequency and factors associated with vascular complications after pediatric liver transplantation.

METHOD

risk factors were evaluated in 99 patients under 18 years of age with chronic liver disease who underwent deceased donor liver transplantation (DDLT) between March of 1995 and November of 2009 at the Hospital de Clínicas de Porto Alegre, Brazil. The variables analyzed included donor and recipient age, gender, and weight; indication for transplant; PELD/MELD scores; technical aspects; postoperative vascular complications; and survival.

RESULTS

vascular complications occurred in 19 patients (19%). Arterial events were most common, occurred earlier in the postoperative period, and were associated with high graft loss and mortality rates. In the multivariate analysis, the following factors were identified: portal vein diameter ≤ 3mm, donor-to-recipient body weight ratio (DRWR), prolonged ischemic time, and use of arterial grafts.

CONCLUSION

the choice of treatment depends on the timing of diagnosis; however, in this study, surgical revision or correction produced worse outcomes than percutaneous angioplasty. The reduction of risk factors and early detection of vascular complications are key elements to a successful transplantation.

Stent placement versus angioplasty for hepatic artery stenosis after liver transplant: a meta-analysis of case series

BACKGROUND

Hepatic artery stenosis (HAS) is a serious complication of liver transplantation but data on the most effective endovascular management are lacking. We aimed to compare percutaneous balloon angioplasty (PBA) with stent placement.

METHODS

We searched MEDLINE, Cochrane, Web of Science, EMBASE, SCOPUS, and Biosis Previews between 1970 and December 2011 and performed meta-analysis of short-term (procedural success, complications) and long-term outcomes (liver function, arterial patency, survival, re-intervention, re-transplantation). Random effects models were used for the analysis and meta-regression performed for the year of study.

RESULTS

A total of 263 liver transplants in 257 patients [age 43 (±8) years] underwent 147 PBAs and 116 stents. Transplanted livers were from deceased donors in 240 (91 %). Follow-up was 1 month to 4.5 years (median 17 months). PBA and stent had similar procedural success (89 % vs. 98 %), complications (16 % vs. 19 %), normal liver function tests (80 % vs. 68 %), arterial patency (76 % vs. 68 %), survival (80 % vs. 82 %), and requirement for re-intervention (22 % vs. 25 %) or re-transplantation (20 % vs. 24 %) (P non-significant). In the most recent studies re-transplantation was reported less compared to older series (P = 0.04).

CONCLUSION

Both PBA and stent offer comparable results for HAS. These techniques have contributed to a recent decline in re-transplantation.

KEY POINTS

• Interventional radiological procedures are often used to treat post-transplant hepatic artery stenosis. • Meta-analysis shows that percutaneous balloon angioplasty and stent placement are both efficacious. • Percutaneous balloon angioplasty and stent placement appear to have similar complication rates. • Re-transplantation rates have declined, partly due to interventional management for arterial stenosis.

Can Doppler sonography discern between hemodynamically significant and insignificant portal vein stenosis after adult liver transplantation?

OBJECTIVE

The purpose of our study was to determine whether Doppler sonography, using a strict reference standard, can specifically identify hemodynamically significant portal vein anastomotic stenosis after liver transplantation in adults.

MATERIALS AND METHODS

The duplex and color Doppler examinations of 13 consecutive adult patients who underwent portal venography for suspected portal vein stenosis after liver transplantation were retrospectively examined. Peak systolic velocity (PSV) and change in PSV (ΔPSV) along the portal vein were correlated with portal venography. Stenoses above 50% on the basis of strict venographic criteria were considered hemodynamically significant. The Doppler studies before and after intervention were also assessed. Fourteen randomly chosen subjects with transplants without suspicion of portal anastomotic stenosis acted as controls.

RESULTS

Six patients had significant portal vein stenosis (> 50%) and seven had stenosis below 50%. PSV and ΔPSV were significantly greater for patients with > 50% stenosis in comparison with those with ≤ 50% stenosis and control subjects. Optimal threshold values for PSV and ΔPSV were 80 and 60 cm/s, respectively, with either value alone yielding sensitivity of 100% and specificity of 84% for significant stenosis. Threshold values also included cases of stenosis below 50%. Five of six patients with > 50% stenosis underwent stenting, with poststent PSV and ΔPSV significantly declining to match that of control subjects. Three of seven with stenosis below 50% had stents placed but no significant change in the Doppler examination.

CONCLUSION

Doppler threshold criteria reliably exclude those without posttransplantation portal vein stenosis and have high sensitivity for detecting portal stenosis. However, these criteria cannot discern the extent of stenosis.

Vascular complications after deceased and living donor liver transplantation: a single-center experience

INTRODUCTION

Vascular complications (VC) after liver transplantation (OLT) are one of the most feared problems that frequently result in graft and patient loss. Herein we have reported our experience with VC after either deceased donor liver transplantation (DDLT) or living donor liver transplantation (LDLT).

PATIENTS AND METHODS

Between April 2001 and September 2009, we performed 224 OLT: 155 DDLT and 69 LDLT. The overall male/female ratio was 136/88 and the adult/pediatric ratio was 208/16. We retrospectively identified and analyzed vascular complications in both groups.

RESULTS

In the DDLT group, 11/155 recipients (7%) suffered vascular complications; hepatic artery thrombosis (HAT; n=5; 3.2%), portal vein thrombosis occurred (n=4; 2.6%); hepatic vein stenosis (n=1; 0.6%), and severe postoperative bleeding due to a slipped splenic artery ligature (n=1, 0.6%). In the DDLT group, 4/11 (36.4%) patients died as a direct result of the vascular complications. In the LDLT group, 9/69 recipients (13%) suffered vascular complications: HAT (n=3; 4.3%), portal vein problems (n=5; 7.2%), and hepatic vein stenosis (n=1; 1.5%). Among LDLT, 3/9 (33.3%) patients died as a direct result of the vascular complications. In both groups vascular complications were associated with poorer patient and graft survival.

CONCLUSIONS

In our experience, the incidence of vascular complications was significantly higher among the LDLT group compared with the DDLT group. Vascular complications were associated with poorer graft and patient survival rates in both groups.

Long-term results of urgent revascularization for hepatic artery thrombosis after pediatric liver transplantation

Hepatic artery thrombosis (HAT) after pediatric orthotopic liver transplantation (OLT) is a serious complication resulting in bile duct necrosis and often requiring retransplantation. Immediate surgical thrombectomy/thrombolysis has been reported to be a potentially successful treatment for restoring blood flow and avoiding urgent retransplantation. The long-term results of this strategy remain to be determined. In 232 pediatric liver transplants, we analyzed long-term outcomes after urgent revascularization for early HAT. HAT developed in 32 patients (13.7%). In 16 children (50%), immediate surgical thrombectomy was performed in an attempt to salvage the graft. Fourteen patients (44%) underwent urgent retransplantation, and 2 (6%) died before further intervention. Immediate thrombectomy resulted in long-term restoration of the hepatic artery flow in 6 of 16 patients (38%) and in 1- and 5-year graft and patient survival rates of 83% and 67%, respectively. In 10 patients, revascularization was unsuccessful, and retransplantation was inevitable. The 1- and 5-year patient survival rates in this group decreased to 50% and 40%, respectively. After immediate retransplantation, the 5-year patient survival rate was 71%. In conclusion, immediate surgical thrombectomy for HAT after pediatric OLT results in long-term graft salvage in about one-third of patients. However, when thrombectomy is unsuccessful, long-term patient survival is lower than the survival of patients who underwent immediate retransplantation.

Hepatic artery reconstruction in pediatric living donor liver transplantation under 10 kg, without microscope use

Arterial reconstructions are pivotal, particularly in pediatric LDLT. We describe microsurgical reconstruction technique with 6x loupes and the clinical course of the first 23 less than 10 kg recipients in an initial LDLT program at a developing country. From March 2002 to October 2008, 286 liver transplantation were performed in 279 patients at our unit. There were 73 children and 206 adults. Among the children, 23 weighing less than 10 kg were recipients from living donors. Arterial reconstructions were with end-to-end interrupted suture using a 6x magnification loupe, according to the untied suture technique. All patients were prospectively followed by color Doppler ultrasound protocol. In our initial experience there were no arterial complications. With mean 24 months of follow-up, 19 patients (82%) are alive with good graft function. Hepatic artery in LDLT can be safely reconstructed with microsurgical techniques without microscope using, with 6x loupe magnification, and can achieve good results in patients under 10 kg.

Early hepatic artery thrombosis after liver transplantation: a systematic review of the incidence, outcome and risk factors

To clarify inconsistencies in the literature we performed a systematic review to identify the incidence, risk factors and outcome of early hepatic artery thrombosis (eHAT) after liver transplantation. We searched studies identified from databases (MEDLINE, EMBASE, Science Citation Index) and references of identified studies. Seventy-one studies out of 999 screened abstracts were eligible for this systematic review. The incidence of eHAT was 4.4% (843/21, 822); in children 8.3% and 2.9% in adults (p < 0.001). Doppler ultrasound screening (DUS) protocols varied from 'no routine' to 'three times a day.' The median time to detection was at day seven. The overall retransplantation rate was 53.1% and was higher in children (61.9%) than in adults (50%, p < 0.03). The overall mortality rate of patients with eHAT was 33.3% (range: 0-80%). Mortality in adults (34.3%) was higher than in children (25%, p < 0.03). The reported risk factors for eHAT were, cytomegalovirus mismatch (seropositive donor liver in seronegative recipient), retransplantation, arterial conduits, prolonged operation time, low recipient weight, variant arterial anatomy, and low volume transplantation centers. eHAT is associated with significant graft loss and mortality. Uniform definitions of eHAT and uniform treatment modalities are obligatory to confirm these results and to obtain a better understanding of this disastrous complication.

Endovascular diagnosis and intervention in patients with isolated hyperammonemia, with or without ascites, after liver transplantation

Hyperammonemia with or without ascites with normal synthetic liver functions after liver transplantation might indicate the presence of anastomotic stenosis of the portal or hepatic vein or the existence of a patent portosystemic shunt. The authors describe six patients, three children after split-liver transplantation and three adults after cadaver liver transplantation, who presented with hyperammonemia. Three patients had ascites. All lesions were successfully treated percutaneously; stents were placed in patients with anastomotic stenoses and coil embolization was performed in patients with patent portosystemic shunts--with either transhepatic or transjugular approaches according to the site of the abnormality. Ammonia levels returned to normal, and ascites had regressed completely for at least 3 months.

Percutaneous transhepatic venous angioplasty and stenting in a 9-month-old patient with hepatic vein obstruction after partial liver transplantation

Hepatic venous outflow obstruction is a rare but serious complication after liver transplantation. We report ultrasound-guided percutaneous transhepatic stent placement in a 9-month-old infant with a left lateral split liver transplantation with near-complete hepatic vein obstruction.

Intraoperative stent placement in the portal vein during or after liver transplantation

The purpose of this research was to evaluate the intermediate effectiveness of intraoperative portal vein stent placement for portal venous stenosis in liver transplantation. We attempted intraoperative portal vein stent placement in 44 portal venous anastomotic stenoses in 36 patients. All patients underwent stent placement via either the inferior or superior mesenteric vein. A total of 22 patients underwent portal vein stent placement simultaneously with liver transplantation, and 14 patients underwent stent placement 1-25 days (mean 5.93 days) after liver transplantation. Of the 22 patients, there was portal vein occlusion in 3 patients and small portal vein (<6 mm) in 10 patients (2.5-5.7 mm; mean size 3.9 mm). Patient follow-up included clinical and laboratory data collection, Doppler ultrasonography (US), and computed tomography (CT). Intraoperative portal vein stent placement was technically successful in all of our study patients, even in 6 patients with total occlusion of the portal vein. A total of 10 study patients underwent thrombectomy of the portal vein, 1 underwent patient portosystemic shunt ligation, and 7 patients had both procedures simultaneously. Portal venous patency has been maintained for 0-56 months (mean 16 months) in 42 (95%) of the 44 stent placements. In conclusion, intraoperative portal vein stent placement is an effective and long lasting treatment modality for treat portal venous stenosis, especially in patients with portal vein occlusion or small sized portal vein.

Sonographic evaluation of venous obstruction in liver transplants

OBJECTIVE

The purpose of our study was to identify specific Doppler criteria for portal vein and outflow vein (hepatic veins and inferior vena cava) obstruction in liver transplants.

MATERIALS AND METHODS

A retrospective review was performed of Doppler sonographic studies and angiograms in 94 liver transplant cases (72 whole liver, 22 lobar) with suspected vascular obstruction. The angiograms were classified as normal, occluded, or stenosed on the basis of appearance and elevated pressure gradient. Sonography was correlated with angiography. The following Doppler parameters were evaluated: for the portal vein, peak anastomotic velocity and anastomotic-to-preanastomotic velocity ratio; and for the outflow veins, venous pulsatility index. Receiver operating characteristic curves were constructed and optimum thresholds for stenosis were defined.

RESULTS

There were 16 cases of portal vein obstruction (11 stenosis, five occlusion) and 35 cases of outflow vein obstruction (34 stenoses, one occlusion). Mean peak anastomotic velocity in normal portal veins was 58 cm/s, whereas mean peak anastomotic velocity in stenosed veins was 155 cm/s (p = 0.0007). Peak anastomotic velocity threshold of > 125 cm/s was 73% sensitive and 95% specific for stenosis. Mean anastomotic-to-preanastomotic velocity ratio in normal portal veins was 1.5, and mean anastomotic-to-preanastomotic velocity ratio in stenosed veins was 4.69 (p = 0.001). A 3:1 ratio was 73% sensitive and 100% specific for stenosis. Mean venous pulsatility index for normal outflow veins was 0.75, and mean venous pulsatility index in stenosed veins was 0.39. A venous pulsatility index of < 0.45 was 95.7% specific for stenosis. The areas under the receiver operating characteristic curve were 0.83 for peak anastomotic velocity, 0.86 for anastomotic-to-preanastomotic velocity ratio, and 0.84 for venous pulsatility index, indicating good correlation.

CONCLUSION

Peak anastomotic velocity, anastomotic-to-preanastomotic velocity ratio, and venous pulsatility index are useful parameters for diagnosing venous stenosis in liver transplants.

Percutaneous treatment of venous outflow obstruction in pediatric liver transplants

PURPOSE

To evaluate the efficacy and safety of percutaneous dilation in the treatment of impaired venous outflow in pediatric patients with liver transplants.

MATERIALS AND METHODS

Review was undertaken of the records of 35 procedures to dilate impaired venous outflow in 16 consecutive children (aged 11 days to 17.8 years; mean, 7.2 +/- 5.8 y) after liver transplantation over a period of 8 years. Patients presented clinically with signs or symptoms of obstruction of the hepatic venous or inferior vena cava anastomosis and/or abnormal noninvasive imaging findings and were referred primarily to the interventional radiology department for treatment. None were excluded. Technical and clinical success rates were calculated. After venoplasty, patients with incomplete venographic resolution or pressure gradients exceeding 5 mm Hg were treated with stents. Seven died or required repeat transplantation during the study period for reasons unrelated to venous outflow obstruction. Patency rates were calculated for all other patients with sufficient follow-up in the pediatric hepatology clinic.

RESULTS

The combined technical success rate for venoplasty (12 of 16) and stent placement (three of 16) was 94% (15 of 16), and the clinical success rate was 81% (13 of 16). One minor complication occurred: a transient hypoxic episode. Primary patency rates were 72.7% (eight of 11) at 3 months, 60% (six of 10) at 6 months, 55.6% (five of nine) at 12 months, 50% (four of eight) at 18 months, and 50% (three of six) at 36 months. Primary assisted and secondary patency rates were 90.9% (10 of 11) at 3 months, 90% (nine of 10) at 6 months, 88.9% (eight of nine) at 12 months, 87.5% (seven of eight) at 18 months, and 83.3% (five of six) at 36 months.

CONCLUSIONS

Excellent technical and clinical success rates can be achieved with percutaneous dilation of impaired venous outflow after pediatric liver transplantation. Long-term patency may require repeated interventions.

Surgical experience in children with biliary atresia treated with portoenterostomy

OBJECTIVE

Biliary atresia is the result of a fibrosing destructive inflammatory process affecting intrahepatic and extrahepatic bile ducts, which lead to cirrhosis and portal hypertension. Without surgical intervention, mortality reaches 100%. The 5-year survival rate after portoenterostomy ranges from 13% to 60%, with approximately 60% of patients requiring liver transplantation at a later stage because of insufficient bile flow.

METHODS

This retrospective analysis includes 30 consecutive patients undergoing portoenterostomy for biliary atresia at our hospital.

RESULTS

The 5-year actuarial survival of the 30 patients was 68%. Thirteen patients (43.3%) died 3 days to 7 years after portoenterostomy. Four patients (13.3%) underwent liver transplantation 3 to 24 months after the Kasai procedure with a 100% survival. In 65% of patients without presence of cirrhosis, the portoenterostomy was successful, compared with 35% of cases with liver cirrhosis (p = 0.0148). Liver cirrhosis with extrahepatic biliary atresia alone was present in 5 of 17 patients (29%) as compared with 8 of 12 patients (66%) with intrahepatic biliary hypoplasia in addition to extrahepatic biliary atresia and cirrhosis.

CONCLUSIONS

Portoenterostomy remains the treatment of choice for patients with extrahepatic biliary atresia. However, the presence of cirrhosis portends a poorer prognosis and may be an indication for early transplantation. Cirrhosis is more commonly present in the setting of intrahepatic biliary hypoplasia and may account for the lower success rates of portoenterostomy in this group of patients. Five-year survival of the female patients was 88% as compared with 55% of the male patients.

Severe hypogammaglobulinemia associated with hepatic vein stenosis causes cytomegalovirus infection after living-related liver transplantation

Hepatic vein stenosis is a vascular complication that can lead to graft loss after liver transplantation. Although ascites frequently occurs as a symptom of hepatic vein stenosis, the development of severe hypogammaglobulinemia associated with hepatic vein stenosis has not been reported in the literature. An 8-year-old boy underwent living-related liver transplantation (LRLT) because of Wilson disease with chronic hepatic failure. Because de novo autoimmune hepatitis was diagnosed 1 year after LRLT, azathioprine, and prednisolone were added to the baseline immunosuppression of tacrolimus. The patient developed ascites with severe hypogammaglobulinemia (immunoglobulin G [IgG], 288 mg/dL) 2 years after LRLT. Ultrasonography and angiography disclosed stenosis of the hepatic vein. The ascites completely resolved after percutaneous balloon angioplasty. Despite serum IgG trough levels of >500 mg/dL maintained by the addition of immunoglobulin, cytomegalovirus reactivation and sepsis occurred. Serum IgG levels should be monitored to prevent opportunistic infections when hepatic vein stenosis is diagnosed after LRLT.