Diagnosis and Management of Hepatic Artery Complications After Liver Transplantation

Hepatic artery stenosis following adult liver transplantation: evaluation of different endovascular treatment approaches

PURPOSE

To evaluate the efficacy and safety of hepatic artery interventions (HAI) versus extra-hepatic arterial interventions (EHAI) when managing clinically significant hepatic artery stenosis (HAS) after adult orthotopic liver transplantation.

MATERIALS AND METHODS

A single-center retrospective cohort analysis was conducted on liver transplant patients who underwent intervention for clinically significant HAS from September 2012 to September 2021. The HAI treatment arm included hepatic artery angioplasty and/or stent placement while the EHAI treatment arm comprised of non-hepatic visceral artery embolization. Primary outcomes included peri-procedural complications and 1-year liver-related deaths. Secondary outcomes included biliary ischemic events, longitudinal trends in liver enzymes and ultrasound parameters pre-and post-intervention.

RESULTS

The HAI arm included 21 procedures in 18 patients and the EHAI arm included 27 procedures in 22 patients. There were increased 1-year liver-related deaths (10% [2/21] vs 0% [0/27], p = 0.10) and complications (29% [6/21] vs 4% [1/27], p = 0.015) in the HAI group compared to the EHAI group. Both HAI and EHAI groups exhibited similar improvements in transaminitis including changes of ALT (-72 U/L vs -112.5 U/L, p = 0.60) and AST (-58 U/L vs -48 U/L, p = 0.56) at 1-month post-procedure. Both treatment arms demonstrated increases in post-procedural peak systolic velocity of the hepatic artery distal to the stenosis, while the HAI group also showed significant improvement in resistive indices following the intervention.

CONCLUSION

Direct hepatic artery interventions remain the definitive treatment for clinically significant hepatic artery stenosis; however, non-hepatic visceral artery embolization can be considered a safe alternative intervention in cases of unfavorable hepatic anatomy.

Successful Surgical Management of Ruptured Hepatic Artery Pseudoaneurysm Post-Liver Retransplant: A Case Report

INTRODUCTION

Hepatic Artery Pseudoaneurysm (HAP) is a rare and potentially fatal complication following liver transplantation, with unclear etiology. Various predisposing factors, including local infections, biliary-enteric anastomosis, particularly Roux-en-Y hepaticojejunostomy, vascular interventions, and iatrogenic injuries, have been identified.

PRESENTATION OF CASE

We report a case of HAP occurring after liver re-transplantation in a twenty-year-old male patient who had initially undergone liver transplantation for cirrhosis resulting from autoimmune hepatitis. Subsequently diagnosed with chronic ischemic liver disease accompanied by diffuse cholangiopathy and a liver abscess, the patient underwent a liver re-transplantation. Within the early days post-re-transplantation, the patient presented symptoms of gastrointestinal bleeding and sudden hypotension. A high clinical suspicion led to prompt laparotomy, ultimately successful preserving both the graft and the recipient's life.

DISCUSSION

HAP is an uncommon complication following liver transplantation. This condition may remain asymptomatic until the rupture of the HAP, which can result in gastrointestinal bleeding, hypotension, and, eventually, mortality. While there have been emerging non-surgical techniques proposed for HAP treatment, surgical intervention remains the definitive solution for preserving the graft and ensuring the recipient's survival.

CONCLUSION

HAP, while uncommon, represents a life-threatening complication post-transplantation. In the event of rupture, immediate intervention is imperative for the patient's survival. Hence, it is critical for surgeons to be cautious about this complication, recognize its symptoms, and be aware of associated risk factors.

Successful endovascular embolization of the common hepatic artery for pseudoaneurysm associated with pancreatic fistula after liver transplantation: a case report

BACKGROUND

After orthotopic liver transplantation (OLT), complications such as hepatic artery stenosis, thrombosis, and bleeding are possible. Hepatic artery pseudoaneurysms (HAP) are prone to rupture, rupture hemorrhage, and increased mortality risk. Endovascular treatment of HAP may result in recurrence, even after successful embolization with thrombin. Formation of a HAP in the common hepatic artery (CHA) is challenging because the CHA is the only artery in the liver graft after OLT. Therefore, CHA embolization in HAP is not an initial option. We report a case of HAP at the CHA after OLT that was treated with endovascular therapy, resulting in the occlusion of the CHA with coil embolization, achieving a radical cure.

CASE PRESENTATION

A 59-year-old man with decompensated hepatitis C virus cirrhosis underwent deceased donor whole-liver transplantation after graft failure of a living donor liver transplantation. After the second transplantation, the patient developed infectious narrow-necked HAP at the CHA associated with postoperative pancreatic fistula. Repeated transcatheter arterial embolization with thrombin and n-butyl-2-cyanoacrylate was unsuccessful, as confirmed by postprocedure angiography, which revealed recanalization and regrowth of the HAP. Eight months after the first transcatheter arterial embolization, the patient presented with a chief complaint of abdominal pain due to an enlarged HAP. Angiography of the superior mesenteric artery (SMA) revealed a collateral bypass around the bile duct from the SMA to the liver graft. Coil embolization of the HAP in the CHA completely occluded the HAP without complications. More than 2 years after coil embolization, the liver graft function test results remained within normal limits without HAP recurrence.

CONCLUSIONS

HAP at the CHA after liver transplantation can be fatal if ruptured. Because the liver is a highly angiogenic organ, even if initial treatment is not successful, radical treatment to occlude the CHA with HAP is possible if sufficient collateral vessels are developed.

CAQ Corner: Surgical evaluation for liver transplantation

The evaluation of a liver transplantation candidate is a complex and detailed process that in many cases must be done in an expedited manner because of the critically ill status of some patients with end-stage liver disease. It involves great effort from and the collaboration of multiple disciplines, and during the evaluation several studies and interventions are performed to assess and potentially prepare a patient for liver transplant. Here we review the liver transplantation evaluation from a surgical perspective.

Superb Microvascular Imaging (SMI) Compared with Color Doppler Ultrasound for the Assessment of Hepatic Artery in Pediatric Liver Transplants: A Feasibility Study

(1) Background: Despite progression in surgical techniques and immunological treatments, hepatic artery (HA) thrombosis and stenosis still develop as an early or late liver transplant (LT) complication. We aimed to compare superb microvascular imaging (SMI) with conventional Doppler imaging (CDI) in the assessment of HA in a cohort of pediatric patients undergoing follow-up ultrasound (US) for LT. (2) Methods: This prospective, observational study included 73 pediatric LT recipients (median age, 7 years; IQR, 5.8 years; 35 females) who underwent US during LT follow-up from March to December 2019. For each examination, CDI and SMI were separately assessed in terms of HA visibility and spectral waveform morphology (SWM). The former was scored based on HA discrimination from the blooming signal of the surrounding vessels, as follows: 0, not visible; 1, majority course hardly distinguishable; and 2, majority course clearly distinguishable. The latter was scored on a two-point scale: 0, combined venous and arterial SWM, and 1, pure arterial SWM. The patient’s overall score was finally calculated by adding the two individual scores. (3) Results: Both the absolute scores and frequency of overall scores equal to 3 (maximum global score) were higher using SMI compared with CDI. The median overall score was 3 for SMI and 2 for CDI (p = 0.011; IQR = 1). An overall score equal to 3 was obtained in 74% and 49.3% of the study population using SMI and CDI, respectively (p = 0.002). This was attributable to a better score in HA visibility (p = 0.007). (4) Conclusions: SMI has shown promise for assessing HA in pediatric LT recipients, possibly serving as a complementary non-invasive tool of CDI in everyday practice.

Multimodality Imaging after Liver Transplant: Top 10 Important Complications

Patients who have undergone liver transplant are now regularly seen in day-to-day radiology practice. All surgical techniques for liver transplant require arterial, portal venous, hepatic venous and caval, and biliary anastomoses. This review is focused on the 10 "not to be missed" complications of liver transplant that affect the health and life of the graft and graft recipient. Arterial complications are the most common and devastating. Early hepatic artery thrombosis may be catastrophic because the biliary tree is solely dependent on the hepatic artery after transplant and collateral vessels have not yet formed. In contrast, delayed hepatic artery thrombosis may be more insidious as collateral arteries develop. US findings of delayed hepatic artery thrombosis may be similar to those of hepatic artery stenosis and celiac artery stenosis. Splenic artery steal syndrome is an increasingly recognized cause of graft ischemia. Venous complications are much less common. Hepatic venous and caval complications are notable for their increased incidence in living-donor and pediatric transplants. Biliary complications often result from arterial ischemia. Biliary cast syndrome is a notable example in which ischemic biliary mucosa sloughs into and obstructs the duct lumens. Neoplasms also may occur within the hepatic graft and may be due to recurrent malignancy, posttransplant lymphoproliferative disorder, or metastases. US is the initial imaging modality of choice, particularly in the acute postoperative setting. Further evaluation with contrast-enhanced US, CT, or MRI; catheter angiography; endoscopic retrograde cholangiopancreatography; and/or nuclear medicine studies is performed as needed. An invited commentary by Bhargava is available online. Online supplemental material is available for this article. ^©RSNA, 2022.

Persistent biliary hypoxia and lack of regeneration are key mechanisms in the pathogenesis of posttransplant nonanastomotic strictures

BACKGROUND AND AIMS

Nonanastomotic biliary strictures (NAS) are a major cause of morbidity after orthotopic liver transplantation (OLT). Although ischemic injury of peribiliary glands (PBGs) and peribiliary vascular plexus during OLT has been associated with the later development of NAS, the exact underlying mechanisms remain unclear. We hypothesized that bile ducts of patients with NAS suffer from ongoing biliary hypoxia and lack of regeneration from PBG stem/progenitor cells.

APPROACH AND RESULTS

Forty-two patients, requiring retransplantation for either NAS (n = 18), hepatic artery thrombosis (HAT; n = 13), or nonbiliary graft failure (controls; n = 11), were included in this study. Histomorphological analysis of perihilar bile ducts was performed to assess differences in markers of cell proliferation and differentiation in PBGs, microvascular density (MVD), and hypoxia. In addition, isolated human biliary tree stem cells (hBTSCs) were used to examine exo-metabolomics during in vitro differentiation toward mature cholangiocytes. Bile ducts of patients with NAS or HAT had significantly reduced indices of PBG mass, cellular proliferation and differentiation (mucus production, secretin receptor expression, and primary cilia), reduced MVD, and increased PBG apoptosis and hypoxia marker expression, compared to controls. Metabolomics of hBTSCs during in vitro differentiation toward cholangiocytes revealed a switch from a glycolytic to oxidative metabolism, indicating the need for oxygen.

CONCLUSIONS

NAS are characterized by a microscopic phenotype of chronic biliary hypoxia attributed to loss of microvasculature, resulting in reduced proliferation and differentiation of PBG stem/progenitor cells into mature cholangiocytes. These findings suggest that persistent biliary hypoxia is a key mechanism underlying the development of NAS after OLT.

Non-invasive diagnosis and follow-up in liver transplantation

The field of liver transplantation directly or indirectly embodies all liver diseases, in addition to specific ones related to organ rejection (cellular and humoral). The recommended non-invasive methods for determining the indication for liver transplantation are the Model for End-stage Liver Disease score, and the alpha-foetoprotein score in case of hepatocellular carcinoma. Radiological methods are the cornerstones for the diagnosis of vascular and biliary complications after liver transplantation. The possible diseases of the liver graft after transplantation are multiple and often intertwined. Non-invasive diagnostic methods have been poorly evaluated in this context, apart from the recurrence of hepatitis C. Liver biopsy remains the gold standard for evaluating graft lesions in the majority of cases, especially graft rejection.

Application of resuscitative endovascular balloon occlusion in post-transplant mycotic hepatic artery pseudoaneurysm rupture in the setting of Aspergillus Constellatus bacteremia

Hepatic artery pseudoaneurysm (HAP) is a rare, highly morbid and frequently fatal complication of liver transplantation. Most are a mycotic mediated weakness of the arterial wall, with associated bacterial or fungal infection of ascitic fluid. As it is usually asymptomatic prior to rupture, the majority present in acute hemorrhagic shock and dire extremis. Resuscitative endovascular balloon occlusion (REBOA) was initially developed for the management of noncompressible hemorrhagic shock in trauma; however, remains underutilized and understudied in the non-trauma setting. We present the case of a mycotic hepatic artery pseudoaneurysm rupture due to Streptococcus constellatus and Klebsiella pneumoniae post directed donor orthoptic liver transplant, in which REBOA was employed in the setting of impending exsanguination as a bridge to definitive surgical intervention. Although this patient passed away of multiorgan system failure prior to re-transplant, this case demonstrates the importance of a heightened suspicion of this devastating complication, especially in the setting of bilioenteric reconstruction and perihepatic fluid collection, as well as the benefit of utilizing resuscitative techniques such as REBOA prior to definitive surgical or endovascular therapy to mitigate the high morbidity and mortality of this condition.

Duplex Doppler evidence of high hepatic artery resistive index after liver transplantation: Role of portal hypertension and clinical impact

BACKGROUND

Early increase of hepatic artery resistive index (HARI) is frequently observed after liver transplant (LTx).

AIM

We aimed to investigate contributing factors and prognostic relevance of high HARI after LTx from deceased donor.

METHODS

We conducted a retrospective analysis of prospectively collected data from January 2017 and February 2019. According to the Duplex Doppler HARI values (3^d post-operative day), patients were grouped in normal (0.55-0.80) and high (>0.80-1) HARI groups.

RESULTS

Among 81 LTx, 36 had a high HARI and 45 a normal HARI. Patients developing high HARI were older, exhibited lower platelet, hemoglobin, platelet count/spleen diameter ratio, higher serum creatinine, and a more pronounced spleen enlargement (median values 170 versus 120 mm). At multivariate analysis, PLT/spleen diameter ratio (OR 0.994, p < 0.001) creatinine levels (OR 2.418, p = 0.029), and recipient age (OR 1.157, p = 0.004) significantly predicted the occurrence of high HARI. Patients with high or normal HARI had similar vascular complications, rejection rate and 90-day mortality. In most cases, HARI recovered to normal without any clinical effect.

CONCLUSIONS

HARI rises in presence of several surrogate markers of portal hypertension. The increase is mostly transitory, and it may result from the hepatic artery spasm due to the high portal blood flow.

Hepatic Artery Pseudoaneurysm in the Liver Transplant Recipient: A Case Series

Introduction

Hepatic artery pseudoaneurysm is a rare and potentially fatal complication of liver transplantation with a reported incidence of 0.3–2.6% and associated mortality approaching 75%. Clinical presentation typically includes sudden hypotension, gastrointestinal bleed or abnormal liver function tests within two months of transplantation. We report a series of four cases of hepatic artery pseudoaneurysm in adult liver transplant recipients with the goal of identifying factors that may aid in early diagnosis, prior to the development of life threatening complications.

Methods

A retrospective chart review at a high volume transplant center revealed 4 cases of hepatic artery pseudoaneurysm among 553 liver transplants (Incidence 0.72%) between March 2013 and March 2017.

Results

Two of the four patients died immediately after intervention, one patient survived an additional 151 days prior to death from an unrelated condition and one patient survived at two years follow up. All cases utilized multiple imaging modalities that failed to identify the pseudoaneurysm prior to diagnosis with computed tomography angiography (CTA). Two cases had culture proven preoperative intrabdominal infections, while the remaining two cases manifested a perioperative course highly suspicious for infection (retransplant for hepatic necrosis after hepatic artery thrombosis and infected appearing vessel at reoperation, respectively). Three of the four cases either had a delayed biliary anastomosis or development of a bile leak, leading to contamination of the abdomen with bile. Additionally, three of the four cases demonstrated at least one episode of hypotension with acute anemia at least 5 days prior to diagnosis of the hepatic artery pseudoaneurysm.

Conclusions

Recognition of several clinical features may increase the early identification of hepatic artery pseudoaneurysm in liver transplant recipients. These include culture proven intrabdominal infection or high clinical suspicion for infection, complicated surgical course resulting either in delayed performance of biliary anastomosis or a biliary leak, and an episode of hypotension with acute anemia. In combination, the presence of these characteristics can lead the clinician to investigate with appropriate imaging prior to the onset of life threatening complications requiring emergent intervention. This may lead to increased survival in patients with this life threatening complication.

Large Hepatic Artery Pseudoaneurysm Resection After Orthotopic Liver Transplantation

Patient: Female, 41

Final Diagnosis: Hepatiic artery aneurysm

Symptoms: None

Medication: —

Clinical Procedure: —

Specialty: Surgery

Dissection of the Hepatic Artery: A Rare Cause of Late Ischemia After Liver Transplant

Hepatic artery dissection is an infrequent vascular complication that can arise after orthotopic liver transplant. Most patients with this complication are diagnosed during the intraoperative period or the first days after liver transplant, with an association shown with living-donor liver transplant. In this study, we discuss a rare case of an extrahepatic artery dissection that was successfully managed through surgical excision and arterial revascularization that was diagnosed 4 years after orthotopic liver transplant. Furthermore, we hypothesize on the potential causes of its occurrence.

Percutaneous Transarterial Stent Placement in a Transplant Liver Hepatic Artery Complicated by Angioplasty Balloon Rupture and Fragmentation

The incidence of posttransplant hepatic arterial stenosis (HAS) has been reported in 5 to 10% of orthotopic liver transplants and, left untreated, can lead to hepatic arterial thrombosis. Most vascular complications develop less than 3 months after initial transplant, with thrombosis representing over half of all complications. There has been a trend toward minimally invasive, endovascular techniques for treating HAS with angioplasty and stenting. In one review of endovascular therapies for HAS, primary technical success was achieved in 95% of the interventions. Complication rates following endovascular repair of HAS have been reported to be between 0 and 23% in the literature. The main risk factors for complications include tortuosity of the hepatic artery and history of a second liver transplant. Other associated risk factors include female gender, age greater than 60 years, prior history of transarterial chemoembolization, and multiple arterial graft anastomoses. The case presented here is representative of a complication of balloon rupture and fragmentation in a patient undergoing hepatic arterial stent placement post-liver transplant.

Use of a mechanical thrombectomy device to treat early hepatic artery thrombosis after orthotopic liver transplant

Hepatic artery thrombosis (HAT) is a major cause of morbidity and mortality after orthotopic liver transplantation, occurring in 5% of cases (Piardi et al, 2016). HAT is the second main cause of graft loss after primary nonfunction, the leading cause of graft failure in the immediate postoperative period (<1 month), and is associated with a mortality rate of up to 60% without intervention (Piardi et al, 2016; Pareja et al., 2010; Crossin et al., 2003). Although retransplantation is the preferred therapy, the limited availability of donor organs can necessitate urgent, alternative treatment. These patients present physicians with an often-severe clinical picture, which requires consideration of endovascular approaches as opposed to the more traditional, invasive surgical interventions. The following case study presents a novel mechanical therapy that uses an endovascular approach for revascularization—a stent retriever device.

Pretransplant Intra-arterial Liver-Directed Therapy Does Not Increase the Risk of Hepatic Arterial Complications in Liver Transplantation: A Single-Center 10-Year Experience

PURPOSE

To investigate the association between pretransplant intra-arterial liver-directed therapy (IAT) for hepatocellular carcinoma (HCC) and hepatic arterial complications (HAC) in orthotopic liver transplantation (OLT) [namely hepatic artery thrombosis (HAT) and/or the need for hepatic arterial conduit].

METHODS

A total of 175 HCC patients (mean age: 60 years) underwent IAT with either transarterial chemoembolization or yttrium-90 (90Y) transarterial radioembolization prior to OLT between 2003 and 2013. A matched control cohort of 159 HCC patients who underwent OLT without prior IAT was selected. Incidence of HAC in both cohorts was investigated. The categorical differences between both cohorts were calculated by chi-square test.

RESULTS

Among the 175 patients (chemoembolization, n = 82; radioembolization, n = 93), 8 (5%) required conduits due to HA disease (chemoembolization, n = 6; radioembolization, n = 2), 3 (2%) developed HAT (chemoembolization, n = 2; radioembolization, n = 1). Eleven of 175 patients (6.7%) had HAC. Of the 159 control patients, 6 (4%) needed conduits for HA disease and 3 (2%) developed HAT. Nine of 159 patients (5.7%) had HAC. Chi-square analysis between the IAT cohort and the control group yielded a p value of 0.810. When comparing chemoembolization to radioembolization, p = 0.076 (not significant at p < 0.05).

CONCLUSION

Although aggressive pretransplant radioembolization and chemoembolization are both utilized in most liver transplant centers, neither appears to increase the risk of peri-transplant hepatic arterial complications in HCC patients.

Complications after endovascular treatment of hepatic artery stenosis after liver transplantation

BACKGROUND

Hepatic artery stenosis (HAS) after liver transplantation can progress to hepatic artery thrombosis (HAT) and a subsequent 30% to 50% risk of graft loss. Although endovascular treatment of severe HAS after liver transplantation has emerged as the dominant method of treatment, the potential risks of these interventions are poorly described.

METHODS

A retrospective review of all endovascular interventions for HAS after liver transplantation between August 2009 and March 2016 was performed at a single institution, which has the largest volume of liver transplants in the United States. Severe HAS was identified by routine surveillance duplex ultrasound imaging (peak systolic velocity >400 cm/s, resistive index <0.5, and presence of tardus parvus waveforms).

RESULTS

In 1129 liver transplant recipients during the study period, 106 angiograms were performed in 79 patients (6.9%) for severe de novo or recurrent HAS. Interventions were performed in 99 of 106 cases (93.4%) with percutaneous transluminal angioplasty alone (34 of 99) or with stent placement (65 of 99). Immediate technical success was 91%. Major complications occurred in eight of 106 cases (7.5%), consisting of target vessel dissection (5 of 8) and rupture (3 of 8). Successful endovascular treatment was possible in six of the eight patients (75%). Ruptures were treated with the use of a covered coronary balloon-expandable stent graft or balloon tamponade. Dissections were treated with placement of bare-metal or drug-eluting stents. No open surgical intervention was required to manage any of these complications. With a median of follow-up of 22 months, four of eight patients (50%) with a major complication progressed to HAT compared with one of 71 patients (1.4%) undergoing a hepatic intervention without a major complication (P < .001). One patient required retransplantation. Severe vessel tortuosity was present in 75% (6 of 8) of interventions with a major complication compared with 34.6% (34 of 98) in those without (P = .05). In the complication cohort, 37.5% (3 of 8) of the patients had received a second liver transplant before intervention compared with 12.6% (9 of 71) of the patients in the noncomplication cohort (P = .097).

CONCLUSIONS

Although endovascular treatment of HAS is safe and effective in most patients, target vessel injury is possible. Severe tortuosity of the hepatic artery and prior retransplantation were associated with a twofold to threefold increased risk of a major complication. Acute vessel injury can be managed successfully using endovascular techniques, but these patients have a significant risk of subsequent HAT and need close surveillance.

Postoperative Elevated Resistive Indices Do Not Predict Hepatic Artery Thrombosis in Extended Criteria Donor Livers

Postoperative transplant liver ultrasounds were analyzed in standard criteria donor (SCD), extended criteria donor (ECD), and donation after cardiac death (DCD) liver allografts to determine if elevated resistive indices (RIs) are consistently present and if they are pathological. Postoperative transplant liver ultrasounds were reviewed from 115 consecutive patients. Hepatic arterial RIs were stratified based on the type of donor: DCD, macrosteatosis (>30%), or standard criteria. In all patients with elevated RI, subsequent ultrasounds were reviewed to demonstrate RI normalization. The mean RI for all 115 patients was 0.64, DCD was 0.67, macrosteatosis was 0.81, and SCD was 0.61 ( p  = 0.033). The RI on subsequent liver ultrasounds for DCD and macrosteatosis normalized without any intervention. There were no incidences of early hepatic artery thrombosis (HAT) observed in the cohort. Hepatic arterial RI in ECDs and DCDs are elevated in the immediate postoperative period but are not predictive of HAT. It represents interparenchymal graft stiffness and overall graft edema rather than an impending technical complication. The results of our study do not support the routine use of anticoagulation or routine investigation with computed tomography angiography for elevated RIs as these findings are self-limiting and normalize over a short period of time. We hope that this information helps guide the clinical management of liver transplant patients from expanded criteria donors.

Common ultrasound and contrast-enhanced ultrasonography in the diagnosis of hepatic artery pseudoaneurysm after liver transplantation

The diagnostic value of common ultrasound and contrast-enhanced ultrasonography (CEUS) in hepatic artery pseudoaneurysm (HAP) after liver transplantation was investigated. From January 2005 to November 2015, information was collected on 2,085 cases of orthotopic liver transplantation. The cases included 1,617 men and 468 women. Common ultrasound and CEUS were used to monitor arterial blood flow following surgery, and the complications were assessed. Instruments used included Acuson Sequoia 512 and Mylab Twice, and the contrast agent was SonoVue. The standard of common ultrasound in the diagnosis of HAP was follicular structure, which had arterial blood flow signal present beside the hepatic artery. The diagnostic criteria of HAP using CEUS were abnormal and round contrast enhancement zone and perfusion of the contrast agent in the zone near the hepatic artery. The diagnostic standard of HAP was computed tomographic angiography (CTA) and emergency operation. Eight cases of HAP were diagnosed in 2,085 patients after liver transplantation (0.38%). Three cases of HAP were diagnosed successfully by common ultrasound while 5 cases were missed. Sensitivity, specificity and diagnostic accuracy for common ultrasound was 37.5, 100 and 99.76%, respectively. Six cases of HAP were diagnosed by CEUS and 2 cases were missed. Sensitivity, specificity and diagnostic accuracy for CEUS was 75, 100 and 99.9%, respectively. Collectively, CEUS is a convenient and effective diagnostic method for HAP following liver transplantation, the diagnostic sensitivity was obviously higher than that of the common ultrasound, and it was more convenient than CTA. Nevertheless, the diagnosis of pseudoaneurysm with deep location, and unsatisfactory grayscale images were easily missed.