Selective revascularization of hepatic artery thromboses after liver transplantation improves patient and graft survival

Vascular complications after liver transplantation: contemporary approaches to detection and treatment. A literature review

Vascular complications (VCs) after liver transplantation (LT) are rare but are one of the most dreaded conditions that can potentially lead to graft loss and recipient death. This paper has analyzed the international experience in the early diagnosis of various VCs that can develop following LT, as well as the optimal timing and methods of treatment of these complications.

Low hepatic artery resistive index on Doppler ultrasound performed on the first post-liver transplant day is associated both with hepatic artery thrombosis and decreased graft survival

PURPOSE

Although liver transplantation (LT) outcomes have improved significantly over the last decades, early vascular complications are still associated with elevated risks of graft failure. Doppler ultrasound (DUS) enables detection of vascular complications, provides hepatic artery Resistive Index (RI). The aim of our study was to evaluate the association of the RI parameters of DUS performed in the first post-transplant week with post-transplant outcomes.

METHODS

All consecutive patients undergoing a first LT between 2001 and 2019 at a single center were included. Patients were divided into two groups: RI < 0.55 and RI ≥ 0.55. Patients were also divided according to the presence or absence of hepatic artery thrombosis (HAT). Graft survival was compared between groups.

RESULTS

Overall, 338 patients were included. HAT occurred in 23 patients (6.8%), of which 7 were partial and 16, complete. Biliary complications were more common in patients with HAT (10 [43.5%]) vs. 38 [12.1%] [p < 0.001]). Graft survival was lower for patients with HAT (p = 0.047). Also, RI < 0.55 was associated with increased incidence of HAT (p < 0.001). Additionally, patients with RI < 0.55 on post-operative day 1 had decreased graft survival as compared to patients with RI > 0.55 (p = 0.041). RI on post-operative day 3 and 5 was not predictive of inferior graft outcomes.

CONCLUSIONS

Intensive use of DUS in the early post-LT period offers the possibility of early diagnosis of vascular complications, guiding medical and surgical management of HAT. Additionally, according to our data, low RI (< 0.55) on the first postoperative day also is a predictor of HAT and decreased graft-survival.

Intensive care management of liver transplant recipients

PURPOSE OF REVIEW

Liver transplantation remains the only definitive treatment for advanced liver disease and liver failure. Current allocation schemes utilized for liver transplantation mandate a 'sickest first' approach, thus most liver transplants occur in patients with severe systemic illness. For intensive care providers who care for liver transplant recipients, a foundation of knowledge of technical considerations of orthotopic liver transplantation, basic management considerations, and common complications is essential. This review highlights the authors' approach to intensive care management of the postoperative liver transplant recipient with a review of common issues, which arise in this patient population.

RECENT FINDINGS

The number of centers offering liver transplantation continues to increase globally and the number of patients receiving liver transplantation also continues to increase. The number of patients with advanced liver disease far outpaces organ availability and, therefore, patients undergoing liver transplant are sicker at the time of transplant. Outcomes for liver transplant patients continue to improve owing to advancements in surgical technique, immunosuppression management, and intensive care management of liver disease both pretransplant and posttransplant.

SUMMARY

Given a global increase in liver transplantation, an increasing number of intensive care professionals are likely to care for this patient population. For these providers, a foundational knowledge of the common complications and key management considerations is essential.

Patency rates of hepatic arterial resection and revascularization in locally advanced pancreatic cancer

BACKGROUND

Arterial resection (AR) for pancreatic adenocarcinoma is increasingly considered at specialized centers. We aimed to examine the incidence, risk factors, and outcomes of hepatic artery (HA) occlusion after revascularization.

METHODS

We included patients undergoing HA resection with interposition graft (IG) or primary end-to-end anastomoses (EE). Complete arterial occlusion (CAO) was defined as "early" (EO) or "late" (LO) before/after 90 days respectively. Kaplan-Meier and change-point analysis for CAO was performed.

RESULTS

HA resection was performed in 108 patients, IG in 61% (66/108) and EE in 39% (42/108). An equal proportion (50%) underwent HA resection alone or in combination with celiac and/or superior mesenteric artery. CAO was identified in 18% of patients (19/108) with arterial IG least likely to occlude (p=0.019). Hepatic complications occurred in 42% (45/108) and correlated with CAO, symptomatic patients, venous resection, and postoperative portal venous patency. CAO-related operative mortality was 4.6% and significantly higher in EO vs LO (p = 0.046). Median CAO occlusion was 126 days. With change-point analysis, CAO was minimal beyond postoperative day 158.

CONCLUSION

CAO can occur in up to 18% of patients and the first 5-month post-operative period is critical for surveillance. LO is associated with better outcomes compared to EO unless there is inadequate portal venous inflow.

Intensive Doppler Ultrasonography for Early Detection of Hepatic Artery Thrombosis After Adult Living Donor Liver Transplantation

Background

Early hepatic artery thrombosis (eHAT) is a severe arterial complication leading to biliary complications and graft failure in living donor liver transplantation (LDLT). This study sought to early identify the abnormal waveforms of eHAT by using intensive Doppler ultrasonography (DUS) after LDLT and to assess the clinical outcome in these eHAT patients.

Material/Methods

DUS for 419 adult LDLT recipients was performed twice after vascular anastomosis during liver transplantation and once a day at the bedside for at least 2 weeks.

Results

Nine adult LDLT recipients with eHAT were identified by using bedside DUS with subsequent computed tomography angiography (CTA). All eHAT cases were noted in the first 2 weeks. Five patients with CTA findings of partial thrombus with the small visualized intrahepatic hepatic artery (HA) were treated with intravenous thrombolysis (IVT) (medical group). Another 4 patients with CTA findings of extrahepatic HA occlusion and nonvisualization of intrahepatic HAs were treated by arterial re-anastomosis (surgical group). The prevalence of long-term non-anastomotic biliary strictures was 33.3% in the surgical group. Intensive post-LDLT DUS is a convenient and sensitive tool for eHAT detection.

Conclusions

Subsequent CTA gives valid information on occluded arteries and associated findings, which impact decision-making and are correlated with patient outcome. Our protocol of DUS has high sensitivity and diagnostic accuracy for use in in eHAT patients with partial occlusion, and it can be applied for IVT treatment, avoiding the need for reoperation and preventing long-term biliary complications.

Liver Transplantation

The field of liver transplantation has changed since the MELD scoring system became the most widely used donor allocation tool. Due to the MELD-based allocation system, sicker patients with higher MELD scores are being transplanted. Persistent organ donor shortages remain a challenging issue, and as a result, the wait-list mortality is a persistent problem for most of the regions. This chapter focuses on deceased donor and live donor liver transplantation in patients with complications of portal hypertension. Special attention will also be placed on donor-recipient matching, perioperative management of transplant patients, and the impact of hepatic hemodynamics on transplantation.

Catheter directed hepatic artery thrombolysis following liver transplantation. Case report and review of the literature

Hepatic artery thrombosis is the most frequent vascular complication following orthotopic liver transplantation, and often results in biliary complications, early graft loss and death. Surgical revascularization and retransplantation are considered the mainstay of treatment. However, intraarterial endovascular therapy is an alternative that has shown low morbidity and mortality, thereby avoiding the need for retransplantation. We describe a case of orthotopic liver transplantation complicated with hepatic artery thrombosis that was successfully treated with endovascular therapy.

Graft Dysfunction and Management in Liver Transplantation

Graft dysfunction of the liver allograft manifests across a spectrum in both timing posttransplantation and clinical presentation. This can range from mild transient abnormalities of liver tests to acute liver failure potentially leading to graft failure. The causes of graft dysfunction can be divided into those resulting in early and late graft dysfunction. Although nonspecific, liver biochemistry abnormalities are still the mainstay investigation used in monitoring for dysfunction. This article provides a summary of the main causes and management strategies for liver graft dysfunction in the early through late posttransplant stages.

Marked Decrease in Urgent Listing for Liver Transplantation Over Time: Evolution of Characteristics and Outcomes of Status-1 Liver Transplantation

BACKGROUND

Approximately 5% of liver transplants annually are performed urgently with "status-1" designation. This study aims to determine if the demand, characteristics, and outcome for status-1 liver transplantation has changed over time.

METHODS

We used the Scientific Registry of Transplant Patients (2003-2015) to characterize 2352 adult patients who underwent 2408 status-1 liver transplants and compared them between Era1 (2003-6/2009) and Era2 (7/2009-2015).

RESULTS

Overall, there were fewer liver transplants performed with the status-1 designation in Era2 than Era1 (1099 vs 1309). Although the number of urgent liver transplants was relatively constant with successive years, the proportion transplanted with status-1 designation decreased markedly over time. Era2 patients were older (43.2 years vs 41.7 years, P = 0.01) and less likely be ABO-incompatible (1.1% vs 2.4%, P = 0.01) or retransplant (77 vs 124, P = 0.03). In terms of disease etiology, the largest group was "acute liver failure (ALF), nonspecified" (43.4%). There was no difference in proportion with drug-induced liver injury (DILI), but the subset of herbal/dietary supplements increased in Era2 (1.3% vs 0.46%, P = 0.04). Survival was increased in Era2 in the overall cohort and for patients with autoimmune disease (P < 0.05), despite longer waiting times for this etiology (186 days vs 149 days). DILI or nonspecified ALF had shorter waiting times, and 90% were transplanted within 7 days.

CONCLUSIONS

Liver transplantation for the most urgent indications (status-1) is decreasing while survival remains excellent. Fewer incidences of ALF are classified as indeterminate, mostly as a result of increasing awareness of autoimmune hepatitis and DILI as causes of the syndrome.

Preoperative Thromboelastography as a Sensitive Tool Predicting Those at Risk of Developing Early Hepatic Artery Thrombosis After Adult Liver Transplantation

BACKGROUND

Whilst causes of hepatic artery thrombosis (HAT) after liver transplantation (LT) are multifactorial, early HAT (E-HAT) remains pertinent complication impacting on graft and patient survival. Currently there is no screening tool that would identify patients with increased risk of developing E-HAT.

METHODS

We analyzed the native procoagulant state of LT recipients, identified through pretransplant thromboelastographic (TEG) data among other known risk factors, to identify risk factors for E-HAT.

RESULTS

The outcomes of 828 adult patients undergoing LT between 2008 and 2013 were analyzed. Overall, 79 (9.5%) patients experienced HAT, E-HAT was diagnosed in 23, and in the remainder this was "late" HAT. The maximum amplitude (MA) on preoperative TEG was significantly higher in patients diagnosed with E-HAT compared with those who did not (71.2 mm vs 57.9 mm; P < 0.0001). Receiver operating characteristic analysis with the cutoff value for MA of 65 mm or greater returned area under the curve of 0.750 (P < 0.001) predicting E-HAT with a sensitivity of 70%. A total of 7% of patients with an MA of 65 mm or greater went on to develop E-HAT (hazard ratio, 5.28; 95% confidence interval, 2.10-12.29; P < 0.001), whereas only 1.2% patients with an MA less than 65 mm experienced E-HAT.

CONCLUSIONS

Preoperative TEG may reliably identify group of recipients at greater risk of developing E-HAT, and intense surveillance and anticoagulation prophylaxis may avoid this serious complication after LT.

Vascular complications in living donor liver transplantation at a high-volume center: Evolving protocols and trends observed over 10 years

Vascular complications continue to have a devastating effect on liver transplantation recipients, even though their nature, incidence, and outcome might have actually changed with increasing experience and proficiency in high-volume centers. The aim of this study was to analyze the trends observed in vascular complications with changing protocols in adult and pediatric living donor liver transplantation over 10 years in 2 time frames in terms of nature, incidence, and outcome. It is a retrospective analysis of 391 (group 1, January 2006 to December 2010) and 741 (group 2, January 2011 to October 2013) patients. With a minimum follow-up of 2 years, incidence of hepatic artery thrombosis (HAT) in adults has reduced significantly from 2.2% in group 1 to 0.5% in group 2 (P = 0.02). In group 2, nonsignificantly, more adult patients (75% with HAT) could be salvaged compared with only 25% patients in group 1 (P = 0.12). However, HAT in children had 100% mortality. Incidence of portal vein thrombosis (PVT) in complicated transplants in 2 eras remained the same (P = 0.2) and so has its mortality. The thrombosis rate of the neo-middle hepatic vein was significantly reduced in group 2 (P = 0.01). The incidence of HAT, particularly in adults, has decreased significantly though PVT has continued to puzzle surgeons in complicated transplants. In high-volume centers, increasing proficiency, technical modifications, early diagnosis, and multimodality of treatment is the key to decrease overall morbidity and mortality due to vascular complications. Liver Transplantation 23 457-464 2017 AASLD.

[Liver abscess]

Liver abscess is a rare and severe infection. Incidence increases because of aging of population, advances in liver and biliary surgery including liver transplantation, and immunodeficiency factors. Diagnosis depends mainly on imaging and needle aspiration for microbiological identification. Treatment is based on antibiotics, percutaneous or surgical drainage, and control of the primary source.

Catheter Thrombolysis of Thrombosed Hepatic Arteries in Liver Transplant Recipients: Predictors of Success and Role of Thrombolysis

Hepatic artery thrombosis is an uncommon complication of liver transplantation. However, it is a major indication for re-transplantation. The use of transcatheter thrombolysis and subsequent surgical revascularization as a graft salvage procedure is discussed. Four of 5 cases (80%) were successful in re-establishing flow and uncovering underlying arterial anatomic defects. None were treated definitively by endoluminal measures due to an inability to resolve the underlying anatomic defects. However, 2 of 5 cases (40%) went on to a successful surgical revascularization and represent successful long-term outcome of transcatheter thrombolysis followed by definitive surgical revascularization. We conclude that, definitive endoluminal success cannot be achieved without resolving associated, and possibly instigating, underlying arterial anatomical defects. However, reestablishing flow to the graft can unmask underlying lesions as well as asses surrounding vasculature thus providing anatomical information for a more elective, better planned and definitive surgical revision.

Sonographic Evaluation of Post-transplantation Portal Vein Stenosis in Pediatric Living-donor Liver Transplant Recipients With Left-liver Grafts

INTRODUCTION

Portal vein (PV) stenosis is not uncommon in post-transplantation pediatric living-donor liver transplant (PLDLT) recipients. The purpose of this study was to identify specific ultrasound criteria that may be used to detect PV stenosis in PLDLT with left-liver grafts.

PATIENTS AND METHODS

From January 2010 to October 2014, 87 pediatric recipients underwent PLDLT with left lobes or left lateral segments at our hospital. All patients underwent routine liver Doppler ultrasound (DUS) as follow-up protocol. The morphologic narrowing and mean time averaged velocity (TAV) at the PV anastomotic site, change in anastomotic/pre-anastomotic TAV (ΔTAV), and the umbilical portal width were evaluated and analyzed. Ultrasound findings were correlated with computed tomography angiography where PV stenosis was suspected.

RESULTS

In the liver graft follow-up study, 80.4% (70 of 87 patients) of PV anastomosis was well visualized and measured by Doppler ultrasound. The optimal threshold values for TAV and ΔTAV were 49.6 cm/s and 30 cm/s, respectively, for significant PV anastomosis stenosis. In the other 19.5% (17/87), the PV anastomosis could not be identified properly. The PV anastomosis was not always visible with ultrasound; however, the optimal dilated umbilical portion of the PV indicating possible PV anastomosis narrowing threshold was umbilical portal width >1.5 cm.

CONCLUSIONS

Increased anastomotic TAV and ΔTAV are useful features for diagnosing PV stenosis. The identification of a dilated umbilical portion of the left PV helps in detection of PV stenosis in PLDLT recipients especially when the anastomotic narrowed region cannot be visualized.

Hepatic abscess: Diagnosis and management

Microbial contamination of the liver parenchyma leading to hepatic abscess (HA) can occur via the bile ducts or vessels (arterial or portal) or directly, by contiguity. Infection is usually bacterial, sometimes parasitic, or very rarely fungal. In the Western world, bacterial (pyogenic) HA is most prevalent; the mortality is high approaching 15%, due mostly to patient debilitation and persistence of the underlying cause. In South-East Asia and Africa, amebic infection is the most frequent cause. The etiologies of HA are multiple including lithiasic biliary disease (cholecystitis, cholangitis), intra-abdominal collections (appendicitis, sigmoid diverticulitis, Crohn's disease), and bile duct ischemia secondary to pancreatoduodenectomy, liver transplantation, interventional techniques (radio-frequency ablation, intra-arterial chemo-embolization), and/or liver trauma. More rarely, HA occurs in the wake of septicemia either on healthy or preexisting liver diseases (biliary cysts, hydatid cyst, cystic or necrotic metastases). The incidence of HA secondary to Klebsiella pneumoniae is increasing and can give rise to other distant septic metastases. The diagnosis of HA depends mainly on imaging (sonography and/or CT scan), with confirmation by needle aspiration for bacteriology studies. The therapeutic strategy consists of bactericidal antibiotics, adapted to the germs, sometimes in combination with percutaneous or surgical drainage, and control of the primary source. The presence of bile in the aspirate or drainage fluid attests to communication with the biliary tree and calls for biliary MRI looking for obstruction. When faced with HA, the attending physician should seek advice from a multi-specialty team including an interventional radiologist, a hepatobiliary surgeon and an infectious disease specialist. This should help to determine the origin and mechanisms responsible for the abscess, and to then propose the best appropriate treatment. The presence of chronic enteric biliary contamination (i.e., sphincterotomy, bilio-enterostomy) should be determined before performing radio-frequency ablation and/or chemo-embolization; substantial stenosis of the celiac trunk should be detected before performing pancreatoduodenectomy to help avoid iatrogenic HA.

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.

Impact of contrast-enhanced ultrasound in the study of hepatic artery hypoperfusion shortly after liver transplantation: contribution to the diagnosis of artery steal syndrome

OBJECTIVE

To assess the value of contrast-enhanced ultrasound (CEUS) in the absence of hepatic artery signal on Doppler ultrasound (DUS) in the immediate postoperative period after liver transplant.

METHODS

This prospective study included 675 consecutive liver transplants. Patients without hepatic artery signal by DUS within 8 days post-transplant were studied with CEUS. If it remained undetectable, a thrombosis was suspected. In patent hepatic artery, a DUS was performed immediately after CEUS; if low resistance flow was detected, an arteriography was indicated. Patients with high resistance waveform underwent DUS+/CEUS follow-up. Arteriography was indicated when abnormal flow persisted for more than 5 days or liver dysfunction appeared.

RESULTS

Thirty-four patients were studied with CEUS. In 11 patients CEUS correctly diagnosed hepatic artery thrombosis. In two out of 23 non-occluded arteries, a low resistance flow lead to a diagnosis of stenosis/proximal thrombosis. Twenty-one patients had absence of diastolic flow, which normalized in the follow-up in 13 patients. In the remaining eight patients, splenic artery steal syndrome (ASS) was diagnosed.

CONCLUSIONS

CEUS allows us to avoid invasive tests in the diagnostic work-up shortly after liver transplant. It identifies the hepatic artery thrombosis and points to a diagnosis of ASS.

KEY POINTS

• CEUS is useful in the diagnostic work-up shortly after liver transplant • CEUS identifies the hepatic artery thrombosis with reliability • There is little information about DUS and CEUS findings in the ASS • DUS and CEUS offer functional information useful in the diagnosis of ASS.

Hepatic artery reconstruction in living donor liver transplantation: risk factor analysis of complication and a role of MDCT scan for detecting anastomotic stricture

BACKGROUND

In partial liver transplantation, reconstruction of the hepatic artery is technically highly demanding and the incidence of arterial complications is high. We attempted to identify the risk factors for anastomotic complications after hepatic artery reconstruction and examined the role of multidetector-row computed tomography (MDCT) in the evaluation of the reconstructed hepatic artery in liver transplant recipients.

METHODS

A total of 109 adult-to-adult living donor liver transplantations (LDLT) were performed at our institute between 1999 and July 2011. Hepatic artery reconstruction was performed under a surgical microscope (MS group, n = 84), until we began to adopt surgical loupes (4.5×) for arterial reconstructions in all cases after January 2009 (SL group, n = 25). A dynamic MDCT study was prospectively carried out on postoperative days 7, 14, and 28, and at postoperative month 3, 6, and 12 after April 2005 (n = 60).

RESULTS

There were no cases of hepatic artery thrombosis and six cases (5.5 %) of interventional radiology-confirmed hepatic artery stenosis (HAS). Risk factor analysis for HAS showed that ABO-incompatible LDLT was associated with HAS. Use of surgical loupes provided superior results as compared to anastomosis under a surgical microscope, and it also provided the advantage of reduced operative time. The MDCT procedure was useful for detecting HAS; however, the false positive rate was relatively high until 3 months after the LDLT (100 % sensitivity and 72.8 % specificity at 3 months).

CONCLUSIONS

Hepatic arterial anastomosis using surgical loupes tended to be time-saving and to yield similar or better results than traditional microscope-anastomosis. The use of MDCT aided the diagnosis of HAS, although the substantial false positive rate should be borne in mind in clinical practice.

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.

A comparison of open surgery and endovascular intervention for hepatic artery complications after pediatric liver transplantation

There are currently 2 major therapeutic options for the treatment of hepatic artery complications: endovascular intervention and open surgery. We herein report a retrospective analysis of 14 pediatric patients with hepatic artery complications after pediatric living donor liver transplantation (LDLT) at our institution. We divided them into an open surgery group and an endovascular intervention group based on their primary treatment, and compared the results and outcomes. We then evaluated which procedure is more effective and less invasive. In the open surgery group, recurrent stenosis or spasm of the hepatic artery occurred in 3 of the 8 patients (37.5%). In the endovascular intervention group, 5 of the 6 patients were technically successfully treated by only endovascular treatment. Of the 5 successfully treated patients, 3 developed recurrent stenosis (60%). There were significant differences in the mean length of the operation for the first treatment of hepatic artery complications (open surgery, 428 minutes vs endovascular intervention, 160 minutes; P = .01) and in the mean value of the posttreatment aspartate aminotransferase (AST)/alanine aminotransferase (ALT) (open surgery > endovascular intervention; P = .04/.05). Although endovascular intervention needs to be examined in further studies to reduce the rate of relapse, it is a less invasive method for the patient and graft than open surgery.

Experiences of microsurgical reconstruction for variant hepatic artery in living donor liver transplantation

There is an emergent need for improving the microsurgical technique of variant arterial anastomosis to reduce the often seen surgery-related complications. We describe in this article our experience in improving this technique, in 73 living donor liver grafts (64 right lobes, 9 left lobes) in patients with end-stage liver disease during living donor liver transplantation. The hepatic arteries were evaluated preoperatively with computed tomography and magnetic resonance angiography. In this series, 13 grafts (17.80 %) with variant hepatic artery were conducted arterioplasty on a back-table under a loupe or a high-power microscope, which included one recipient in situ interposition vessel graft of recipient proper hepatic artery for artery reconstruction. The back-table reconstruction time was 16 ± 5.6 min. No arterial thrombosis was found in these cases during the 6-month postoperative follow-up. On the basis of our experience, we suggest that back-table microsurgical plasty for graft with arterial variation should be applied to minimize operative difficulties and to avoid arterial complications in living donor liver transplantation.

Membrane cut-off does not influence results regarding the measurement of small molecules - a comparative study between 20- and 100-kDa catheters in hepatic microdialysis

BACKGROUND

Microdialysis is a method used to monitor hepatic tissue metabolism. Membranes with a molecular cut-off of 20 kilodalton (kDa) are currently used to measure the small metabolites glucose, glycerol, lactate and pyruvate. Using membranes with higher cut-off such as 100 kDa allows the possibility of measuring larger molecules but may affect results regarding small molecules. The aim was to compare microdialysis catheters with a cut-off of 20 and 100 kDa in the measurement of small molecules in a pig liver model.

METHODS

Four microdialysis catheters were inserted into the liver of each pig used in the experiment (n = 6). Two catheters with cut-off of 20 kDa were perfused with Ringer acetate, and two catheters with cut-off of 100 kDa: one perfused with Ringer acetate and one with hydroxyethyl starch (Voluven) at a flow rate of 0·3 μl min(-1). Dialysate samples were collected at 40-min intervals and analysed for glucose, glycerol, lactate and pyruvate.

RESULTS

Compared to the other catheters, the 100-kDa catheters perfused with Ringer acetate tended to measure higher dialysate concentrations of the small molecules, the difference reaching statistical significance in the case of pyruvate. Concentrations measured by the 100-kDa catheters perfused with Voluven were, however, comparable to the 20-kDa catheters.

CONCLUSIONS

Microdialysis catheters with membrane cut-off of 20 and 100 kDa can be used equally in hepatic microdialysis for the monitoring of glucose, glycerol, lactate and pyruvate, and lactate/pyruvate ratio if a high osmotic solution (Voluven) is used to perfuse the 100-kDa catheters.

Interventional radiology for hepatic artery complications soon after living donor liver transplantation in a neonate

Early hepatic artery complications after liver transplantation in children, having undergone LDLT, can directly affect graft and recipient outcomes, making early diagnosis and treatment essential. In the past, laparotomy (thrombectomy or reanastomosis) was generally employed to treat early hepatic artery complications. Recently, favorable outcomes of IR have been reported. In children, however, the number of such reports is small. To the best of our knowledge, there is no published report on IR applied to neonates with early hepatic artery complications. We recently succeeded in safely using IR for a neonate with early hepatic artery complications after LDLT and obtained a favorable outcome. This case is presented herein.

Vascular complications following liver transplantation

Vascular complications (stenosis or thrombosis of the hepatic artery, portal vein or hepatic vein) are a relatively common occurrence following liver transplantation. Routine screening with ultrasound is critical to early detection of these complications. Careful application of standard interventional techniques (diagnostic catheter angiography, balloon angioplasty with selective stenting) may be used to confirm the ultrasound findings, treat the underlying lesions, and contribute to long-term graft survival.

Early arterial revascularization after hepatic artery thrombosis may avoid graft loss and improve outcomes in adult liver transplantation

BACKGROUND

Hepatic artery thrombosis (HAT) represents a devastating complication after liver transplantation (LT), occurring in 1.6%-9.2% of adult recipients. Treatments of HAT include thrombectomy and thrombolysis (with or without redo of the arterial anastomosis), percutaneous thrombolysis through an angiogram, liver retransplantation, and clinical observation.

METHODS

We retrospectively analyzed data from 739 adult LTs between January 1992 and September 2009. HAT was classified as early (E-HAT), when occurring within the first 30 days after LT, or late HAT (L-HAT), when diagnosed from the 2nd month onward. HAT suspected clinically was confirmed by Doppler ultrasound and angiography in all cases. Attempted revascularization was defined as early (ER) if performed within the first 2 weeks after LT and late (LR) if performed between 15 and 30 days.

RESULTS

After a median follow-up (FU) of 62 months (range, 1-227 months), HAT occurred in 31/739 grafts (4.3%). E-HAT was recorded in 25/31 cases (3.4%) and L-HAT in 11/31 cases (0.8%). ER was performed in 20/31 patients (65%) leading to 62% graft salvage; it was 81% when the revascularization was performed within the first week after LT (P = ns). LR was unsuccessful in all cases (P = .08). The overall incidence of BC among rescued grafts was 54% without graft loss during FU. Graft survival was 79% versus 71%; and 50% versus 50% at 1 and 3 years for E-HAT and L-HAT, respectively (P = ns).

CONCLUSIONS

Urgent revascularization in cases of early HAT may decrease graft loss, especially when performed within the first week after LT, with improved overall outcomes.

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.

Microsurgical reconstruction of hepatic artery in A-A LDLT: 124 consecutive cases without HAT

AIM

To retrospectively investigate microsurgical hepatic artery (HA) reconstruction and management of hepatic thrombosis in adult-to-adult living donor liver transplantation (A-A LDLT).

METHODS

From January 2001 to September 2009, 182 recipients with end-stage liver disease underwent A-A LDLT. Ten of these patients received dual grafts. The 157 men and 25 women had an age range of 18 to 68 years (mean age, 42 years). Microsurgical techniques and running sutures with back-wall first techniques were performed in all arterial reconstructions under surgical loupes (3.5 x) by a group of vascular surgeons. Intimal dissections were resolved by interposition of the great saphenous vein (GSV) between the donor right hepatic artery (RHA) and recipient common HA (3 cases) or abdominal aorta (AA) (2 cases), by interposition of cryopreserved iliac vessels between the donor RHA and recipient AA (2 cases).

RESULTS

In the 58 incipient patients in this series, hepatic arterial thrombosis (HAT) was encountered in 4 patients, and was not observed in 124 consecutive cases (total 192 grafts, major incidence, 2.08%). All cases of HAT were suspected by routine color Doppler ultrasonographic examination and confirmed by contrast-enhanced ultrasound and hepatic angiography. Of these cases of HAT, two occurred on the 1st and 7th d, respectively, following A-A LDLT, and were immediately revascularized with GSV between the graft and recipient AA. HAT in one patient occurred on the 46th postoperative day with no symptoms, and the remaining case of HAT occurred on the 3rd d following A-A LDLT, and was cured by thrombolytic therapy combined with an anticoagulant but died of multiorgan failure on the 36th d after A-A LDLT. No deaths were related to HAT.

CONCLUSION

Applying microsurgical techniques and selecting an appropriate anastomotic artery for HA reconstruction are crucial in reducing the high risk of HAT during A-A LDLT.

Endovascular treatment of hepatic artery thrombosis following liver transplantation

Hepatic artery thrombosis (HAT) is the most frequent vascular complication following orthotopic liver transplantation. Urgent retransplantation has been considered as the mainstay therapy. Surgical revascularization is an effective alternative in asymptomatic patients. Endovascular therapies including intra-arterial thrombolysis, percutaneous transluminal angioplasty (PTA), and stent placement have shown encouraging results in recent years; however, their use remains controversial because of potential risk of hemorrhage. Until June 2009, 69 cases were published in 16 reports describing therapeutic potential of endovascular modalities. Interventions were performed as early as within 4 h to as late as 120 days in patients ranging from 4 months to 64 years of age. Majority of published reports suggested the use of urokinase. Thrombolysis was successful in 47 out of 69 (68%) patients. Bleeding was the most common complication including fatal intra-abdominal hemorrhage in three patients. Twenty-nine out of 47 (62%) patients underwent further intervention in the form of PTA, stenting, or both. The follow-up patency ranged from 1 month to 26 months. In conclusion, whenever possible, efforts should be made to rescue the liver grafts through urgent revascularization (surgical and/or endovascular) depending on patient's condition and interventional expertise at the transplant center; reserving the option of retransplantation for failure, complications, and cases with severe clinical symptoms or allograft dysfunction.

Outcome of foreign residents undergoing deceased donor liver transplantation in China: a single-center experience in Taiwan

Foreign residents seeking liver transplantation in China are not uncommon. The outcomes of these people have not been well reported, and the results remain unclear. A total of 64 adults [26 with end-stage liver disease (ESLD) and 38 with hepatocellular carcinoma (HCC)] who underwent donation after cardiac death (DCD) liver transplantation in China during a 5-year period were reviewed. The median follow-up period was 15.6 months. The estimated 3-month mortality rate was 4.7%. The overall survival (OS) rate of the entire patient group at 1 and 3 years was 80.3% and 63.6%, respectively. The 1- and 3-year graft survival rates were 78.5% and 64.4%, respectively. For ESLD, the 1- and 3-year OS rates were 82.5% and 82.5%, respectively. For HCC, the 1- and 3-year survival rates were 78.3% and 50.8%, respectively. The 1- and 3-year OS rates for the HCC patients who were beyond the Milan criteria (MC; n = 24) versus those who met the MC (n = 14) were 69.8% and 28.2% versus 92.9% and 92.9% (P = 0.0032). The 1- and 3-year disease-free survival rates for those beyond the MC versus those who met the MC were 56.8% and 39.0% versus 92.3% and 92.3% (P = 0.0089). The incidence of complications was 59.4%. Biliary complications (n = 24, 37.5%), vascular complications (n = 24, 37.5%), and infection (n = 16, 25%) were the 3 most frequent transplant-related complications. There were 10 patients with unsolved biliary complications, and a total of 5 patients died of posttransplant infections. In conclusion, patients with ESLD or HCC within the MC seeking DCD liver transplants in China obtained survival results comparable to those of other major cohorts from Western countries. However, a considerably high incidence of biliary complications, vascular complications, and infection substantially threatening the lives of patients is notable. Furthermore, the associated cost impact on medical resource utilization should not be overlooked.

Doppler ultrasound findings in the hepatic artery shortly after liver transplantation

OBJECTIVE

The purpose of this article is to describe the Doppler waveform findings in the hepatic artery in the early posttransplantation period, both in the absence and presence of arterial complications.

CONCLUSION

The presence of transient high-resistance Doppler waveforms in normal hepatic arteries is a common finding after grafting. Hepatic artery thrombosis and stenosis, and arterial steal syndromes can be diagnosed by Doppler in the early liver transplantation period.

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.

The impact of meticulous management for hepatic artery thrombosis on long-term outcome after pediatric living donor liver transplantation

To analyze the risk factors in the development of hepatic artery thrombosis (HAT) and assess the impact of our perioperative management for HAT on the long-term outcome after pediatric living donor liver transplantation (LDLT), we reviewed 382 patients under 12 yr of age who underwent 403 LDLT from January 1996 to December 2005. One- and 10-yr patient survival rates were 78% and 78% in the patients with HAT (27 patients; 6.7%), and 84% and 76% in the patients without HAT, respectively (p = n.s.). Univariate analysis showed gender (female), body weight (lower), and graft-to-recipient weight ratio (higher) were significant risk factors in the patients with HAT (p < 0.05). Patients with Doppler ultrasound signal loss of the hepatic artery (HA) accompanied by an increase of liver enzymes underwent thrombectomy and reanastomosis (S-group, n = 13), and patients with a weak HA signal underwent anticoagulant therapy (M-group, n = 13). One patient underwent re-LDLT. One- and five-yr patient survival rates were 83% and 83% in the S-group, and 77% and 77% in the M-group (p = n.s.). The incidence of biliary complications in the S-group (58%) was significantly higher than that of the M-group (15%). For a successful long-term outcome, the early detection of HAT and prompt medical and surgical intervention are crucial to minimize the insult of HAT.

Review of nonimmunological causes for deteriorated graft function and graft loss after transplantation

Various factors determine the graft- and patient survival after transplantation. HLA-matching and immunological factors are of importance for the short- and long-term survival. Apart from these obvious determinants, nonimmunological factors play an important role in defining the baseline organ quality as well as the recipients' status. The influence of these parameters on graft- and patient survival is still underestimated and is a topic of debate. On account of the increasing acceptance of marginal-donor organs these events are of increasing importance for graft survival and long-term function. We review nonimmunological causes for deteriorated graft function and graft loss after solid organ transplantation.