Primary stent placement for hepatic artery stenosis after liver transplantation

Safety and Effectiveness of Early Primary Stent Placement for Hepatic Artery Stenosis in Liver Transplant Recipients

PURPOSE

To evaluate the outcomes of early primary stent placement (within 30 days of liver transplantation) for hepatic artery stenosis (HAS).

MATERIALS AND METHODS

Patients who underwent liver transplantation between February 2001 and February 2024 were evaluated for HAS. Patients who underwent primary stent placement were selected and stratified based on the time from anastomosis to intervention. Early intervention was defined as primary stent placement within 30 days of surgical anastomosis. Kaplan-Meier analysis was performed for primary patency.

RESULTS

HAS occurred in 83 of 779 (11%) patients (median age, 55 years; interquartile range, 48-63 years; 27 [48%] women), with 56 patients meeting inclusion criteria. Stent placement was performed within 0-6 days of the anastomosis in 11 (20%), 7-14 days in 11 (20%), 15-30 days in 7 (12%), 31-70 days in 9 (16%), and >70 days in 18 (32%) patients. Technical success was 100%. Primary patency rates were 89%, 87%, and 87% at 1, 3, and 5 years, respectively. Primary assisted patency rates were 100% at 1, 3, and 5 years. Early interventions at 0-6 days, 7-14 days, and 15-30 days showed primary patency rates of 100%, 90%, and 86%, respectively, at 1 year (P = .58). There was no difference in primary patency between the early (<30 days) and late (>30 days) cohorts (P = .88). There was 1 Grade 4 adverse event. There were no cases of anastomotic rupture, hepatic artery dissection, or graft failure.

CONCLUSIONS

Hepatic artery stent placement within 30 days of liver transplantation is safe and technically successful with excellent long-term primary patency.

Thrombotic complications post liver transplantation: Etiology and management

Liver transplantation (LT) is the life saving therapeutic option for patients with acute and chronic end stage liver disease. This is a routine procedure with excellent outcomes in terms of patient survival and quality of life post LT. Orthotopic LT (OLT) patients require a critical care as they are prone to variety of post-operative vascular, cardiovascular, biliary, pulmonary and abdominal complications. Thrombotic complications (both arterial and venous) are not uncommon post liver transplant surgery. Such vascular problems lead to increased morbidity and mortality in both donor and graft recipient. Although thromboprophylaxis is recommended in general surgery patients, no such standards exist for liver transplant patients. Drastic advancements of surgical and anesthetic procedures have improvised survival rates of patients post OLT. Despite these, haemostatic imbalance leading to thrombotic events post OLT cause significant graft loss and morbidity and even lead to patient's death. Thus it is extremely important to understand pathophysiology of thrombosis in LT patients and shorten the timing of its diagnosis to avoid morbidity and mortality in both donor and graft recipient. Present review summarizes the current knowledge of vascular complications associated with LT to highlight their impact on short and long-term morbidity and mortality post LT. Also, present report discusses the lacunae existing in the literature regarding the risk factors leading to arterial and venous thrombosis in LT patients.

Hepatic Artery Thrombectomy after Orthotopic Liver Transplantation: A Stent Retriever and/or Aspiration-Guided Catheter Approach

Retransplantation has been the primary treatment for hepatic artery thrombosis (HAT) in patients with orthotopic liver transplant (OLT); however, because of scarcity of grafts, endovascular revascularization via mechanical thrombectomy offers an alternative to retransplantation should it provide similar long-term benefits. Data regarding a series of 8 patients with hepatic artery thrombectomies across 10 procedures (1 early HAT and 9 late HAT) utilizing stent retriever and/or suction catheter were collected. All had technically successful restoration of flow with stent placement of the anastomotic stenosis in 8 cases. Two patients required reintervention for HAT at 18 and 701 days after primary intervention, with the first dying from liver failure but with a patent hepatic artery on explant. One case had a procedure-related adverse event, hepatic artery dissection, Society of Interventional Radiology (SIR) adverse event classification of 2. Technical success was achieved in all procedures, demonstrating promise in effectively treating HAT in patients with OLT.

Intraoperative indocyanine green fluorescence imaging to predict early hepatic arterial complications after liver transplantation

The purpose of this study was to propose an innovative intraoperative criterion in a liver transplantation setting that would judge arterial flow abnormality that may lead to early hepatic arterial occlusion, that is, thrombosis or stenosis, when left untreated and to carry out reanastomosis. After liver graft implantation, and after ensuring that there is no abnormality on the Doppler ultrasound (qualitative and quantitative assessment), we intraoperatively injected indocyanine green dye (0.01 mg/Kg), and we quantified the fluorescence signal at the graft pedicle using ImageJ software. From the obtained images of 89 adult patients transplanted in our center between September 2017 and April 2019, we constructed fluorescence intensity curves of the hepatic arterial signal and examined their relationship with the occurrence of early hepatic arterial occlusion (thrombosis or stenosis). Early hepatic arterial occlusion occurred in 7 patients (7.8%), including 3 thrombosis and 4 stenosis. Among various parameters of the flow intensity curve analyzed, the ratio of peak to plateau fluorescence intensity and the jagged wave pattern at the plateau phase were closely associated with this dreaded event. By combining the ratio of peak to plateau at 0.275 and a jagged wave, we best predicted the occurrence of early hepatic arterial occlusion and thrombosis, with sensitivity/specificity of 0.86/0.98 and 1.00/0.94, respectively. Through a simple composite parameter, the indocyanine green fluorescence imaging system is an additional and promising intraoperative modality for identifying recipients of transplant at high risk of developing early hepatic arterial occlusion. This tool could assist the surgeon in the decision to redo the anastomosis despite normal Doppler ultrasonography.

Incidence, management and outcomes in hepatic artery complications after paediatric liver transplantation: protocol of the retrospective, international, multicentre HEPATIC Registry

INTRODUCTION

Hepatic artery complications (HACs), such as a thrombosis or stenosis, are serious causes of morbidity and mortality after paediatric liver transplantation (LT). This study will investigate the incidence, current management practices and outcomes in paediatric patients with HAC after LT, including early and late complications.

METHODS AND ANALYSIS

The HEPatic Artery stenosis and Thrombosis after liver transplantation In Children (HEPATIC) Registry is an international, retrospective, multicentre, observational study. Any paediatric patient diagnosed with HAC and treated for HAC (at age <18 years) after paediatric LT within a 20-year time period will be included. The primary outcomes are graft and patient survivals. The secondary outcomes are technical success of the intervention, primary and secondary patency after HAC intervention, intraprocedural and postprocedural complications, description of current management practices, and incidence of HAC.

ETHICS AND DISSEMINATION

All participating sites will obtain local ethical approval and (waiver of) informed consent following the regulations on the conduct of observational clinical studies. The results will be disseminated through scientific presentations at conferences and through publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

The HEPATIC registry is registered at the ClinicalTrials.gov website; Registry Identifier: NCT05818644.

Treatment strategies for hepatic artery complications after pediatric liver transplantation: A systematic review

This study aimed to evaluate the effectiveness of different treatments for hepatic artery thrombosis (HAT) and hepatic artery stenosis (HAS) after pediatric liver transplantation. We systematically reviewed studies published since 2000 that investigated the management of HAT and/or HAS after pediatric liver transplantation. Studies with a minimum of 5 patients in one of the treatment methods were included. The primary outcomes were technical success rate and graft and patient survival. The secondary outcomes were hepatic artery patency, complications, and incidence of HAT and HAS. Of 3570 studies, we included 19 studies with 328 patients. The incidence was 6.2% for HAT and 4.1% for HAS. Patients with an early HAT treated with surgical revascularization had a median graft survival of 45.7% (interquartile range, 30.7%-60%) and a patient survival of 61.3% (interquartile range, 58.7%-66.9%) compared with the other treatments (conservative, endovascular revascularization, or retransplantation). As for HAS, endovascular and surgical revascularization groups had a patient survival of 85.7% and 100% (interquartile range, 85%-100%), respectively. Despite various treatment methods, HAT after pediatric liver transplantation remains a significant issue that has profound effects on the patient and graft survival. Current evidence is insufficient to determine the most effective treatment for preventing graft failure.

Role of interventional radiology in management of post-liver transplant anastomotic complications

Background

Liver transplantation is considered to be the treatment of choice in cases of end-stage liver disease; however, as a major procedure, the operation is fraught with complications. The etiology, symptoms, and diagnostic methods for arterial, portal, and biliary issues are thoroughly discussed. Interventional procedures such as balloon angioplasty and stent placement in the arterial and portal systems, as well as biliary interventional procedures, are described.

Results

In our study, we reviewed 25 cases of post-living donor transplanted liver, with anastomotic complications including biliary stenosis 40%, hepatic vein stenosis 20%, portal vein stenosis 16%, biliary leakage 16%, and hepatic artery stenosis or pseudo-aneurysm 16%. We had 10 cases of biliary stenosis, 7 of which were successfully treated with the insertion of an internal/external drain, and one case failed. Two patients died. We had four cases of hepatic venous obstruction with successfully implanted stents and a perfect outcome, efficacy, and patency rate of 100%. We also had two cases of hepatic artery stenosis that were perfectly managed by stent placement, with a patency rate of 100%. We came across two cases of hepatic artery pseudo-aneurysm. One case failed due to large sac size, while the other was successful. Finally, in our study, we had a 100% success rate in 5 cases of portal vein stenosis in the early postoperative period.

Conclusions

Percutaneous IR was effective treatment for hepatic vein occlusion, portal vein stenosis, hepatic artery stenosis, and anastomotic biliary stricture after living donor liver transplantation. The interventional radiology team is now an integral part of the multi-disciplinary care of transplant patients. As new interventional instruments are developed and experience is gained, the outcomes of interventional treatments will continue to improve.

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

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

Neuroform EZ Stents for Hepatic Artery Stenosis After Liver Transplantation: A Single-Center Preliminary Report

PURPOSE

This preliminary study evaluated the safety and effectiveness for off-label use of Neuroform EZ (NEZ) stents in the revascularization of hepatic artery stenosis (HAS) after orthotopic liver transplantation (OLT).

MATERIALS AND METHODS

Nine of 489 (5%) OLTs with HAS were managed with NEZ stents between September 2016 and July 2021. Stenting outcomes were evaluated based on the technical success rate, procedure-related complications, and primary patency.

RESULTS

A total of 10 NEZ stents (4.5 mm × 3 cm, n = 6; 4 mm × 3 cm, n = 4) were successfully deployed in 9 torturous hepatic arteries and in 1 relatively straight artery without any procedure-related complications. Combined thrombolysis (n = 3) and balloon angioplasty (n = 6) was performed. The median duration of follow-up was 438 days (range, 120-1126 days). Asymptomatic re-stenoses were detected in 2 stents on days 60 and 433 after stenting. A Kaplan-Meier curve predicted cumulative primary stent patencies at 1, 2, and 3 years of 90%, 75%, and 75%, respectively.

CONCLUSION

NEZ stents can be safely used to treat HAS after OLT with high technical success and favorable primary patency.

How to Handle Arterial Conduits in Liver Transplantation? Evidence From the First Multicenter Risk Analysis

OBJECTIVE

The aims of the present study were to identify independent risk factors for conduit occlusion, compare outcomes of different AC placement sites, and investigate whether postoperative platelet antiaggregation is protective.

BACKGROUND

Arterial conduits (AC) in liver transplantation (LT) offer an effective rescue option when regular arterial graft revascularization is not feasible. However, the role of the conduit placement site and postoperative antiaggregation is insufficiently answered in the literature.

STUDY DESIGN

This is an international, multicenter cohort study of adult deceased donor LT requiring AC. The study included 14 LT centers and covered the period from January 2007 to December 2016. Primary endpoint was arterial occlusion/patency. Secondary endpoints included intra- and perioperative outcomes and graft and patient survival.

RESULTS

The cohort was composed of 565 LT. Infrarenal aortic placement was performed in 77% of ACs whereas supraceliac placement in 20%. Early occlusion (≤30 days) occurred in 8% of cases. Primary patency was equivalent for supraceliac, infrarenal, and iliac conduits. Multivariate analysis identified donor age >40 years, coronary artery bypass, and no aspirin after LT as independent risk factors for early occlusion. Postoperative antiaggregation regimen differed among centers and was given in 49% of cases. Graft survival was significantly superior for patients receiving aggregation inhibitors after LT.

CONCLUSION

When AC is required for rescue graft revascularization, the conduit placement site seems to be negligible and should follow the surgeon's preference. In this high-risk group, the study supports the concept of postoperative antiaggregation in LT requiring AC.

The Application of Interventional Radiology in Living-Donor Liver Transplantation

Owing to improvements in surgical techniques and medical care, living-donor liver transplantation has become an established treatment modality in patients with end-stage liver disease. However, various vascular or non-vascular complications may occur during or after transplantation. Herein, we review how interventional radiologic techniques can be used to treat these complications.

Treatment of Hepatic Artery Stenosis in Liver Transplant Patients Using Drug-Eluting versus Bare-Metal Stents

Hepatic artery stenosis after liver transplant is often treated with endovascular stent placement. Our institution has adopted use of drug-eluting stents, particularly in small-caliber arteries. We aimed to compare patency rates of drug-eluting stents vs. traditional bare-metal stents. This was a single-institution, retrospective study of liver transplant hepatic artery stenosis treated with stents. Primary patency was defined as time from stent placement to resistive index on Doppler ultrasonography (<0.5), hepatic artery thrombosis, or any intervention including surgery. Fifty-two patients were treated with stents (31 men; mean age, 57 years): 15, drug-eluting stents; 37, bare-metal stents. Mean arterial diameters were 4.1 mm and 5.1 mm, respectively. Technical success was 100% (52/52). At 6 months, 1, 2, and 3 years, primary patency for drug-eluting stents was 80%, 71%, 71%, and 71%; bare-metal stents: 76%, 65%, 53%, and 46% (p = 0.41). Primary patency for small-caliber arteries (3.5–4.5 mm) with drug-eluting stents was 93%, 75%, 75%, and 75%; bare-metal stents: 60%, 60%, 50%, and 38% (p = 0.19). Overall survival was 100%, 100%, 94%, and 91%. Graft survival was 100%, 98%, 96%, and 90%. Stenting for hepatic artery stenosis was safe and effective. While not statistically significant, patency improved with drug-eluting stents compared with bare-metal stents, especially in arteries < 4.5 mm in diameter. Drug-eluting stents can be considered for liver transplant hepatic artery stenosis, particularly in small-caliber arteries.

Biliary Strictures Are Associated With Both Early and Late Hepatic Artery Stenosis

Background.

Hepatic artery stenosis (HAS) following liver transplantation results in hypoperfusion and ischemic damage to the biliary tree. This study aimed to investigate how vascular intervention, liver function test derangement, and time point of HAS onset influence biliary complications.

Methods.

A single-center retrospective study of adult patients that underwent primary liver transplantation. Patients were grouped according to the presence or absence of HAS and then into early (≤90 d) or late (>90 d) subgroups. Biliary complications comprised anastomotic (AS) or non ASs (NASs).

Results.

Computed tomography angiography confirmed HAS was present in 39 of 1232 patients (3.2%). This occurred at ≤90 and >90 days in 20 (1.6%) and 19 (1.5%), respectively. The incidence of biliary strictures (BSs) in the group with HAS was higher than the group without (13/39; 33% versus 85/1193; 7.1%, P = 0.01). BS occurred in 8/20 (40.0%) and 5/19 (26.3%) of the early and late groups, respectively. The need for biliary intervention increased if any liver function test result was ≥3× upper limit of normal (P = 0.019).

Conclusions.

BS occurs at a significantly higher rate in the presence of HAS. Onset of HAS at ≤90 or ≥90 days can both be associated with morbidity. Significant liver function test derangement at HAS diagnosis indicates a higher likelihood of biliary intervention for strictures.

Diagnosis and management of hepatic artery in-stent restenosis after liver transplantation by optical coherence tomography: A case report

BACKGROUND

Percutaneous transluminal angioplasty and stenting represent an effective treatment for hepatic artery stenosis after liver transplantation. In the first year after stenting, approximately 22% of patients experience in-stent restenosis, increasing the risk of artery thrombosis and related complications, and 50% experience liver failure. Although angiography is an important tool for diagnosis and the planning of therapeutic interventions, it may raise doubts, especially in small-diameter arteries, and it provides low resolution rates compared with newer intravascular imaging methods, such as optical coherence tomography (OCT).

CASE SUMMARY

A 64-year-old male developed hepatic artery stenosis one year after orthotropic liver transplantation and was successfully treated with percutaneous transluminal angioplasty with stenting. Five months later, the Doppler ultrasound results indicated restenosis. Visceral arteriography confirmed hepatic artery tortuosity but was doubtful for significant in-stent restenosis (ISR) and intrahepatic flow reduction. To confirm ISR, identify the etiology and guide treatment, OCT was performed. OCT showed severe stenosis due to four mechanisms: Focal and partial stent fracture, late stent malapposition, in-stent neointimal hyperplasia, and neoatherosclerosis.

CONCLUSION

Intravascular diagnostic methods can be useful in evaluating cases in which initial angiography results are not sufficient to provide a proper diagnosis of significant stenosis, especially with regard to ISR. A wide range of diagnoses are provided by OCT, resulting in different treatment options. Interventional radiologists should consider intravascular diagnostic methods as additional tools for evaluating patients when visceral angiography results are unclear.

Hepatic artery stenosis angioplasty and implantation of Wingspan neurovascular stent: A case report and discussion of stenting in tortuous vessels

BACKGROUND

Hepatic artery stenosis is a complication of orthotopic liver transplant occurring in 3.1%-7.4% of patients that can result in graft failure and need for re-transplantation. Endovascular therapy with angioplasty and stenting has been used with a high degree of technical success and good clinical outcomes, but tortuous hepatic arteries present a unique challenge for intervention. Suitable stents for this application should be maneuverable and conformable while also exerting adequate radial force to maintain a patent lumen.

CASE SUMMARY

Herein we report our experience with a neurovascular Wingspan stent system in a challenging case of recurrent hepatic artery stenosis and discuss the literature of stenting in tortuous transplant hepatic arteries.

CONCLUSION

Wingspan neurovascular stent is self-expanding, has good conformability, and adequate radial resistance and as such it could be added to the armamentarium of interventionalists in the setting of a tortuous and stenotic transplant hepatic artery.

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.

Primary Stent Placement for Hepatic Artery Stenosis After Liver Transplantation: Improving Primary Patency and Reintervention Rates

Recent studies have reported high rates of reintervention after primary stenting for hepatic artery stenosis (HAS) due to the loss of primary patency. The aims of this study were to evaluate the outcomes of primary stenting after HAS in a large cohort with longterm follow-up. After institutional review board approval, all patients undergoing liver transplantation between 2003 and 2017 at a single institution were evaluated for occurrence of hepatic artery complications. HAS occurred in 37/454 (8%) of patients. HAS was defined as >50% stenosis on computed tomography or digital subtraction angiography. Hepatic arterial patency and graft survival were evaluated at annual intervals. Primary patency was defined as the time from revascularization to imaging evidence of new HAS or reaching a censored event (retransplantation, death, loss to follow-up, or end of study period). Primary stenting was attempted in 30 patients (17 female, 57%; median age, 51 years; range, 24-68 years). Surgical repair of HAS prior to stenting was attempted in 5/30 (17%) patients. Endovascular treatment was performed within 1 week of the primary anastomosis in 5/30 (17%) of patients. Technical success was accomplished in 97% (29/30) of patients. Primary patency was 90% at 1 year and remained unchanged throughout the remaining follow-up period (median, 41 months; interquartile range [IQR], 25-86 months). Reintervention was required in 3 patients to maintain stent patency. The median time period between primary stenting and retreatment was 5.9 months (IQR, 4.4-11.1 months). There were no major complications, and no patient developed hepatic arterial thrombosis or required listing for retransplantation or retransplantation during the follow-up period. In conclusion, primary stenting for HAS has excellent longterm primary patency and low reintervention rates.

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.

Tardus parvus waveforms in Doppler ultrasonography for hepatic artery stenosis after liver transplantation: can a new cut-off value guide the next step?

PURPOSE

Considering the high false-positive diagnosis of the tardus parvus waveform (TPW) in Doppler ultrasonography (DUS) for hepatic artery stenosis (HAS) after liver transplantation (LT), this study aimed to determine clinical features and new cut-off values to help guide treatment.

MATERIALS AND METHODS

This retrospective study was approved by an Institutional Review Board. A total of 171 LT recipients were included and underwent DUS and either computed tomography angiography or digital subtraction angiography with an interval < 4 weeks at least 1 month post-LT. The DUS of 69 patients exhibited TPW [defined as resistive index (RI) < 0.5 and systolic acceleration time (SAT) > 0.08 s]. A multilevel likelihood ratio (LR) analysis was used to explore new cut-off values for DUS. In addition, abnormal liver function was considered additional evidence (defined as any liver enzyme > 3-fold of the upper limit of normal level or 2-fold increased). The results were stratified into three categories, category 1 (subjects with traditional TPW), category 2 (subjects with traditional TPW and abnormal liver function), and category 3 (subjects with traditional TPW and abnormal liver function, or with new cut-off values), and the diagnostic performance of each category was analyzed.

RESULTS

The LR analysis revealed new cut-off values of RI < 0.4 (LR = 10.58) or SAT > 0.12 s (LR = 16.46). The false-positive rates for categories 2 and 3 were significantly lower (7.6% vs. 18.1%, P = 0.038; 1.9% vs. 18.1%, P < 0.001, respectively) than those for category 1, while the sensitivity for category 2 was significantly lower (41.8% vs. 74.6%, P < 0.001; 41.8% vs. 61.2%, P = 0.038, respectively) than that for categories 1 and 3.

CONCLUSION

Using either (1) RI < 0.4 or SAT > 0.12 s, or (2) traditional TPW (RI < 0.5 and SAT > 0.08 s) in the presence of abnormal liver functions as the DUS criteria for HAS will significantly decrease the false-positive rate compared to traditional TPW without a significant increase in the false-negative rate.

Interventional radiology in the management of the liver transplant patient

Liver transplantation (LT) is commonly used to treat patients with end-stage liver disease. The evolution of surgical techniques, endovascular methods, and medical care has led to a progressive decrease in posttransplant morbidity and mortality. Despite these improvements, a multidisciplinary approach to each patient remains essential as the early diagnosis and treatment of the complications of transplantation influence graft and patient survival. The critical role of interventional radiology in the collaborative approach to the care of the LT patient will be reviewed. Liver Transplantation 23 1328-1341 2017 AASLD.

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.

Refractory anastomotic bile leaks after orthotopic liver transplantation are associated with hepatic artery disease

BACKGROUND AND AIMS

Anastomotic bile leaks are common after orthotopic liver transplant (OLT), and standard treatment consists of placement of a biliary endoprosthesis. The objectives of this study were to identify risk factors for refractory anastomotic bile leaks and to determine the morbidity associated with refractory bile leaks after OLT.

METHODS

Consecutive adult patients who underwent ERCP for treatment of post-OLT biliary adverse events between 2009 and 2014 at a high-volume transplant center were retrospectively identified. A refractory leak was defined as a bile leak that persisted after placement of a plastic biliary endoprosthesis and required repeat endoscopic or surgical intervention.

RESULTS

Forty-three subjects met study inclusion criteria. Median age was 57 years, and 36 (84%) subjects were men. Refractory bile leaks were diagnosed in 40% of subjects (17/43). Time-to-event analysis revealed an association between refractory bile leaks and the combined outcome of death, repeat transplant, or surgical biliary revision (hazard ratio, 3.78; 95% confidence interval, 1.25-11.45; P = .01). Hepatic artery disease was more common with refractory compared with treatment-responsive bile leaks (53% vs 8%, P = .001).

CONCLUSIONS

Refractory anastomotic bile leaks after liver transplantation are associated with decreased event-free survival. Hepatic artery disease is associated with refractory leaks. Large-scale prospective studies should be performed to define the optimal management of patients at risk for refractory bile leaks.

Percutaneous Retrograde Transhepatic Arterial Puncture to Regain Access in the True Lumen of the Dissected and Acutely Occluded Transplant Hepatic Artery

Iatrogenic hepatic artery dissection is a serious complication that can progress to complete hepatic artery occlusion and graft loss. Restoration of arterial flow to the graft is urgent, but the severity and extent of the dissection may interfere with endovascular techniques. The authors describe a technique of percutaneous retrograde transhepatic arterial puncture to regain access into the true lumen of the dissected hepatic artery to restore in-line flow to the liver graft.

Doppler Characteristics of Recurrent Hepatic Artery Stenosis

OBJECTIVES

We sought to assess midterm sonographic findings in patients after stenting for hepatic artery stenosis.

METHODS

Thirty-nine hepatic artery stent procedures were performed for hepatic artery stenosis after liver transplantation between September 2009 and December 2013. Thirty cases were technically successful and met the minimum follow-up time (76 days, defined by earliest diagnosed stenosis). Routine ultrasound surveillance was obtained on all patients, and statistical analysis of the findings in the patency and restenosis groups was performed.

RESULTS

Of the 30 cases, restenosis occurred 9 times in 6 patients. Mean follow-up was 677 days. Mean time to restenosis was 267 days. Five cases (56%) were identified within the first 6 months after stent placement. Four cases (44%) were recognized in the second year after stent placement. Prior to the sonographic diagnosis of restenosis, the mean resistive indices of the main (.64 versus .57, P < .0001), left (.63 versus .54, P < .0001), right anterior (.60 versus .52, P < .0001), and right posterior (.60 versus .53, P = .001) hepatic artery branches differed among patency and restenosis groups, respectively. The mean peak systolic velocity also differed significantly between the 2 groups: 254 cm/sec in patients with eventual restenosis versus 220 cm/sec in patients without restenosis (P = .02).

CONCLUSIONS

The sonographic evaluation of hepatic artery stenosis remains critical during the first 2 years after stent placement. While the vast majority of patients do not restenose, resistive index and peak systolic velocity differed significantly between the 2 groups and may be prognostic surveillance markers for the development of restenosis.

Organ transplantation and drug eluting stents: Perioperative challenges

Patients listed for organ transplant frequently have severe coronary artery disease (CAD), which may be treated with drug eluting stents (DES). Everolimus and zotarolimus eluting stents are commonly used. Newer generation biolimus and novolimus eluting biodegradable stents are becoming increasingly popular. Patients undergoing transplant surgery soon after the placement of DES are at increased risk of stent thrombosis (ST) in the perioperative period. Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor such as clopidogrel, prasugrel and ticagrelor is instated post stenting to decrease the incident of ST. Cangrelor has recently been approved by Food and Drug Administration and can be used as a bridging antiplatelet drug. The risk of ischemia vs bleeding must be considered when discontinuing or continuing DAPT for surgery. Though living donor transplant surgery is an elective procedure and can be optimally timed, cadaveric organ availability is unpredictable, therefore, discontinuation of antiplatelet medication cannot be optimally timed. The type of stent and timing of transplant surgery can be of utmost importance. Many platelet function point of care tests such as Light Transmittance Aggregrometry, Thromboelastography Platelet Mapping, VerifyNow, Multiple Electrode Aggregrometry are used to assess bleeding risk and guide perioperative platelet transfusion. Response to allogenic platelet transfusion to control severe intraoperative bleeding may differ with the antiplatelet drug. In stent thrombosis is an emergency where management with either a drug eluting balloon or a DES has shown superior outcomes. Post-transplant complications often involved stenosis of an important vessel that may need revascularization. DES are now used for endovascular interventions for transplant orthotropic heart CAD, hepatic artery stenosis post liver transplantation, transplant renal artery stenosis following kidney transplantation, etc. Several antiproliferative drugs used in the DES are inhibitors of mammalian target of rapamycin. Thus they are used for post-transplant immunosuppression to prevent acute rejection in recipients with heart, liver, lung and kidney transplantation. This article describes in detail the various perioperative challenges encountered in organ transplantation surgery and patients with drug eluting stents.

Intention-to-treat analysis of percutaneous endovascular treatment of hepatic artery stenosis after orthotopic liver transplantation

Hepatic artery stenosis (HAS) is a rare complication of orthotopic liver transplantation (LT). HAS could evolve into complete thrombosis and lead to graft loss, incurring significant morbidity and mortality. Even though endovascular management by percutaneous transluminal angioplasty ± stenting (PTA) is the primary treatment of HAS, its longterm impact on hepatic artery (HA) patency and graft survival remains unclear. This study aimed to evaluate longterm outcomes of PTA and to define the risk factors of treatment failure. From 2006 to 2012, 30 patients with critical HAS (>50% stenosis of HA) and treated by PTA were identified from 870 adult patients undergoing LT. Seventeen patients were diagnosed by post-LT screening, and 13 patients were symptomatic due to HAS. PTA was completed successfully in 27 (90%) patients with angioplasty plus stenting in 23 and angioplasty alone in 4. The immediate technical success rate was 90%. A major complication that was observed was arterial dissection (1 patient) which eventually necessitated retransplantation. Restenosis was observed in 10 (33%) patients. One-year, 3-year, and 5-year HA patency rates were 68%, 62.8%, and 62.8%, respectively. Overall patient survival was 93.3% at 3 years and 85.3% at 5 years. The 3-year and 5-year liver graft survival rates were 84.7% and 64.5%, respectively. No significant difference was observed in patient and graft survivals between asymptomatic and symptomatic patients after PTA. Similarly, no difference was observed between angioplasty alone and angioplasty plus stenting. In conclusion, endovascular therapy ensures a good 5-year graft survival (64.5%) and patient survival (85.3%) in patients with critical HAS by maintaining HA patency with a low risk of serious morbidity (3.3%). Liver Transplantation 22 923-933 2016 AASLD.