Angiography of liver transplantation patients

Management of early hepatic artery thrombosis following living-donor liver transplantation: feasibility, efficacy and potential risks of endovascular therapy in the first 48 hours post-transplant-a retrospective cohort study

This retrospective cohort study aims to review our 18-year experience with early hepatic artery thrombosis (e-HAT) following living-donor liver transplantation (LDLT), as well as to assess the feasibility, efficacy and potential risks of endovascular management of e-HAT in the first 48 hours (hrs) post-LDLT. Medical records of 730 patients who underwent LDLT were retrospectively reviewed. In all cases who had developed e-HAT, treatment modalities employed and their outcomes were evaluated. Thirty-one patients developed e-HAT(4.2%). Definite technical success and 1-year survival rates of surgical revascularization[11/31 cases(35.5%)] were 72.7% & 72.7%, whereas those of endovascular therapy[27/31 cases(87.1%)] were 70.4% & 59.3%, respectively. Endovascular therapy was carried out in the first 48hrs post-transplant in 9/31 cases(29%) [definite technical success:88.9%, 1-year survival:55.6%]. Four procedure-related complications were reported in 3 of those 9 cases(33.3%). In conclusion, post-LDLT e-HAT can be treated by surgical revascularization or endovascular therapy, with comparable results. Endovascular management of e-HAT in the first 48hrs post-LDLT appears to be feasible and effective, but is associated with a relatively higher risk of procedure-related complications, compared to surgical revascularization. Hence, it can be reserved as a second-line therapeutic option in certain situations where surgical revascularization is considered futile, potentially too complex, or potentially more risky.

Case Report of Multiple Bilobar Hepatic Arterio-Portal Fistulas Post-Liver Transplantation Managed Conservatively

Multiple intrahepatic arterio-portal fistulas are rare. The majority are isolated and occur secondary to liver trauma including iatrogenic interventions such as liver biopsy. Post-liver transplantation 18 cases have been reported, all secondary to an interventional radiological procedure. We report multiple bi-lobar arterio-portal fistulas in a liver transplant recipient recognized 1 year after transplantation. The donor died due to intracerebral bleeding following blunt head and abdominal trauma. In the present case, the etiology is not very clear. The patient was managed conservatively and to date has not required intervention.

Perfusion CT and PET with 18F-FDG and 18F-FCh in the complex diagnosis of hepatocellular carcinoma

Background

The purpose of the study to evaluate possibilities of CT-perfusion and PET methods with 18F-FDG and 18F-fluorocholine in the complex diagnosis of hepatocellular carcinoma. The study included the results of PET/CT with 18F-FDG, 18F-FCh and CT-perfusion of the liver in 18 patients with histologically confirmed diagnosis of hepatocellular carcinoma (HCC). Depending on the degree of tumor differentiation, all patients were divided into 3 groups - patients with highly differentiated (6 patients), moderately differentiated (4 patients), and low-differentiated HCC (8 patients).

Results

Average values of maxSUV in the group of patients with highly differentiated HCC in PET/CT with 18F-FDG and 18F- fluorocholine in a solid component of tumor reached 3.51 and 18.24, respectively; in patients with moderately differentiated HCC - 3.91 and 12.32, respectively; in patients with low-differentiated HCC - 9.58 and 9.70, respectively. Average values of CT perfusion imaging in a solid component of the tumor in the group of patients with highly differentiated HCC were the following: BF - 55,33 ml/100 ml/min, BV - 13,71 ml/100 ml, ALP - 52,41 ml/100 ml/min, PVP - 10.81 ml/100 ml/min (p ≤ 0,05), in the group of patients with moderately differentiated HCC: BF - 52,78 ml/100 m /min, BV - 12,23 ml/100 ml, ALP - 47,26 ml/100 ml/min, PVP - 9,10 ml/100 ml/min (p ≤ 0.05), in the solid component of low-differentiated HCC: BF - 46,96 ml/100 ml/min, BV - 9,49 ml/100 ml, ALP - 40.54 ml/100 ml/min, PVP - 7,66 ml/100 ml/min (p ≤ 0,05).

Conclusions

The diagnostic capabilities of the complex of PET/CT techniques with 18F-FDG and 18F-FCh and CT perfusion in a single-scan mode for hepatocellular carcinoma were evaluated for the first time. The obtained data allow to assume that the integrated use of PET with 18F-FDG and 18F-FCh and CT perfusion in a single scan improves the differential diagnostic possibilities of PET/CT diagnostics, which can find application in planning and prognosis of the disease. Due to the small number of patients further study of the problem is required.

The Critical Importance of Hepatic Venous Blood Flow Doppler Assessment for Patients in Shock

Hepatic venous blood flow can be easily obtained using bedside ultrasound with either transthoracic or transesophageal echocardiography. Six critically ill patients with shock associated with absent or significantly reduced hepatic venous blood flow in the presence of normal or increased pulmonary venous flow are presented. In all these patients, the etiology of shock was secondary to increased resistance to venous return from either an intraabdominal process or through extrinsic or intrinsic occlusion of the proximal inferior vena cava or right atrium. These shock situations are secondary to increased resistance to venous return. Their treatment is highly specific and typically involves a surgical intervention.

Duplex Doppler Sonography and Angiography in the Evaluation for Liver Transplantation

Duplex Doppler sonography (DDS) and angiography were performed in a prospective study comprising 22 adult patients with hepatic failure. The ability of the 2 methods to visualize the different splanchnic vessels was compared, as well as any abnormality in the liver parenchyma and vessels. The purpose of the study was to decide if DDS could replace angiography in the pretransplantation work-up in these patients. The portal vein was correctly identified as open in 20 patients using DDS and in 21 patients at angiography. Portal vein thrombosis in one patient was correctly diagnosed by both methods. The identification of other vascular structures in the upper part of the abdomen, e.g., liver arteries and splenic vein, was demonstrated in 14 and 16 patients respectively at DDS. Hepatoma in one patient was correctly identified by both methods, as well as the presence of ascites. Splenic artery aneurysms were found in 4 patients at angiography, and in none of these was DDS able to show this abnormality. We conclude that abdominal angiography still seems superior to DDS in the evaluation of patients with hepatic failure prior to orthotopic liver transplantation, especially to demonstrate possible splenic artery aneurysms and detailed mapping of the hepatic arteries.

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.

Endoluminal Management of Arterioportal Fistulae in Liver Transplant Recipients: A Single-Center Experience

Transcatheter embolization of arterioportal fistulae in liver transplant recipients is restricted to symptomatic arterioportal fistulae. Angiograms of liver transplant recipients from a single university medical center were retrospectively reviewed. Hemodynamically significant arterioportal fistulae were defined as those exhibiting opacification of the main portal vein of the transplanted hepatic graft or its first order branch with or without portal venous changes by Doppler ultrasound imaging. Six arterioportal fistulae were found. Doppler ultrasound imaging detected 50% of all arterioportal fistulae and all 3 hemodynamically significant arterioportal fistulae. Three successful embolizations were performed. Follow-up (37 to 67 months) demonstrated patent hepatic arteries and no parenchymal ischemic changes with graft preservation. High-throughput arterioportal fistulae may require larger intrahepatic artery branch embolization. There is a window of opportunity for embolizing significant arterioportal fistulae before their progression to large symptomatic, high through-put arterioportal fistulae with their added risk of ischemic changes before and after embolization.

Arterioportal fistulas in liver transplant recipients

Arterioportal fistulas (APFs) are classified into intrahepatic (>75% of all reported) and extrahepatic (<25% of all reported ). Anecdotally, investigators are more likely to report more sensational cases (typically extrahepatic APFs), so the actual prevalence of intrahepatic APFs is probably much higher (likely >90% of APFs). All reported APFs in liver transplant recipients have been intrahepatic. Hemodynamically significant APFs in liver transplant recipients are rare, occurring in 0.2%; however, APFs (hemodynamically significant or not) are not uncommonly seen in hepatic angiograms of liver transplant recipients (up to 5.4% of hepatic arteriograms in transplants). Interestingly, hemodynamically significant APFs warranting endovascular treatment are reported more commonly in the literature in native compared with transplanted livers (n >280-300 versus n = 13, respectively). This article discusses APFs that are specific to liver transplant recipients; their incidence, etiology, pathogenesis, natural history, clinical presentation, and endovascular management are discussed in detail.

Prevalence, presentation, and endovascular management of hemodynamically or clinically significant arterio-portal fistulae in living and cadaveric donor liver transplant recipients

PURPOSE

To compare the prevalence (cadaveric vs. living donor transplants), clinical features, and the effectiveness of endovascular management of significant arterio-portal fistulae (APF) in liver transplant recipients.

METHODS

A retrospective audit of liver transplant recipients in two institutions was performed (1996-2009). Significant APF were included and were defined as symptomatic and/or hemodynamically significant (causing graft dysfunction and/or having abnormal Doppler findings in the portal vein). Patients with significant APF were evaluated for presenting symptoms, imaging features, size/branch order portal vein involvement, and effectiveness of the endovascular management (coil embolization).

RESULTS

Four significant APF were found in 1992 (0.2%) liver transplants. Two were symptomatic and two were asymptomatic but were hemodynamically significant with liver function test abnormalities. All four APF were found in cadaveric donor graft recipients (0.23%, N = 4/1753) and none in 239 living donor graft recipients. However, there was no statistical difference between cadaveric and living donor graft recipients (p = 1.0, odds ratio = 1.23). Coil embolization was technically and clinically successful in all 4 without complications and causing normalization of the abnormal Doppler findings.

CONCLUSION

Significant APF are a rare diagnosis (0.2% of transplants). Coil embolization is a safe and effective treatment option for APF in transplants.

Treatment of early hepatic artery complications after adult liver transplantation: A single center experience

Introduction

Hepatic artery complication represents recognized sequel of liver transplantation that carries significant morbidity and mortality. Besides retransplantation, hepatic artery recanalization is provided surgically, or by percutaneous angioplasty and stent placement. This study provides an analysis of a single center experience comparing surgical and interventional treatments in cases of early hepatic artery complications.

Methods

In this retrospective single center study, 25 of 365 liver transplant recipients were enrolled who developed early hepatic artery complication after transplantation. Percutaneous intervention was performed in 10 cases, while surgical therapy in 15 cases. Mean follow-up time was not different between the groups (505±377 vs. 706±940 days, respectively).

Results

6 patients in the Intervention Group and 10 patients in the Surgery Group are alive. The retransplantation rate (1 and 3) was lower after interventional procedures, while the development of biliary complications was higher. The mortality rate was higher after operative treatment (2 and 5).

Conclusion

Interventional therapy is a feasible and safe technique for treatment of early hepatic artery complication after transplantation. Being less invasive it is an invaluable alternative treatment having results comparable to surgical methods.

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.

Imaging of the transplant liver

As the number of patients with liver transplants continues to increase, radiologists need to be aware of the normal post-operative appearance of the different liver transplants currently performed along with the wide variety of complications encountered. The complications commonly affect the biliar and vascular systems and can include anastomotic bile leakage and biliary stenosis along with stenosis or obstruction of the hepatic artery, portal or hepatic veins and IVC. Other complications include parenchymal abnormalities such as hepatic infarction, organ rejection, localized collections and post transplant lymphoproliferative disorder. This article reviews and illustrates the role of imaging for pediatric transplantation including the role of interventional radiology.

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.

Management of nonocclusive hepatic artery complications after liver transplantation

Nonocclusive arterial disease represents less than 5% of posttransplant arterial complications. Nonocclusive arterial complications are classified into (1) nonocclusive diminished flow in the hepatic artery, (2) arteriovenous fistulae, (3) pseudoaneurysms, and (4) arterial rupture. Due to the rarity of these complications, particularly when considering them individually, many of the opinions and managements of these complications are anecdotal. Transcatheter embolization is the main mode of minimal invasive management of these uncommon complications. Other minimal invasive methods have been described such as stent placement or direct percutaneous embolization/thrombosis. The article discusses the presentation, etiology, types, treatment indications, and various modes of minimal invasive therapy used to manage these complications.

Hepatic artery pseudoaneurysms in adult living-donor liver transplantation: efficacy of CT and Doppler sonography

OBJECTIVE

The purpose of this study was to evaluate the efficacy of contrast-enhanced CT and Doppler sonography in the diagnosis of hepatic artery pseudoaneurysm after adult living-donor liver transplantation (LDLT).

CONCLUSION

Because patients with hepatic artery pseudoaneurysm after LDLT can have diverse clinical presentations, routine imaging follow-up is important for early detection. Although Doppler sonography is limited in showing the pseudoaneurysm, contrast-enhanced CT, especially MDCT with CT arteriography, is effective in showing it in most patients.

Total fibrous obliteration of main portal vein and portal foam cell venopathy in chronic hepatic allograft rejection

CONTEXT

Chronic hepatic allograft rejection is characterized by arteriopathy and bile duct loss. Pathology of the portal vein or its branches is not considered to play a major role in chronic rejection.

OBJECTIVE

A recent case of chronic rejection with total fibrous obliteration of the portal vein at the hilum and graft loss prompted us to retrospectively analyze cases of failed allografts for portal vein changes.

DESIGN

Six cases of failed hepatic allograft recorded in our files from 1994 to 1998 were selected for the study. For comparison, 4 cases of hepatitis C cirrhosis were included. Clinical features, including arteriograms or Doppler studies, were reviewed whenever available. Sections taken from the hilum and random parenchyma stained with routine hematoxylin-eosin, elastic van Gieson, and Masson trichrome were examined by 3 experienced liver pathologists in a randomized, blinded fashion.

RESULTS

Significant hepatic artery occlusion with foam cell change and bile duct loss was seen in all cases of chronic rejection (3/3), but not in the other cases. Foam cell change in the portal vein at the hilum (3/3) and occasionally into the distal branches (2/3) with variable occlusion of the lumen was seen only in cases of chronic hepatic allograft rejection. Mild luminal narrowing was observed in all the cases of cirrhosis (4/4) as a result of phlebosclerosis, most likely representing a change secondary to portal hypertension. Total obliteration of the portal vein at the hilum was seen in the index case (case 1) only.

CONCLUSION

Portal venopathy can be a significant finding in chronic hepatic allograft rejection and may contribute to graft dysfunction or failure. Two-vessel disease must be considered in cases of chronic hepatic allograft rejection, and pathologists should thoroughly examine the hilum in explanted hepatic allografts.

Cigarette smoking is associated with an increased incidence of vascular complications after liver transplantation

Hepatic artery thrombosis (HAT) and other vascular complications are significant causes of morbidity after liver transplantation. Although cigarette smoking increases the risk of vascular complications after renal transplantation, its impact after liver transplantation remains unknown. Between May 1995 and April 2001, 288 liver transplantations were performed in 263 patients. Vascular complications developed in 39 patients (13.5%) (arterial complications, 28 patients [9.7%]; venous complications, 11 patients [3.8%]). Patient demographics, comorbid illnesses, and risk factors were analyzed using the Mann-Whitney U test, Chi-squared test, and Fisher's exact test. In patients with a history of cigarette smoking, incidence of vascular complications was higher than in those without history of cigarette smoking (17.8% v 8%, P =.02). Having quit cigarette smoking 2 years before liver transplantation reduced the incidence of vascular complications by 58.6% (24.4% v 11.8%, P =.04). The incidence of arterial complications was also higher in patients with a history of cigarette smoking compared with those without such history (13.5% v 4.8%, P =.015). Cigarette smoking cessation for 2 years also reduced the risk of arterial complications by 77.6% (21.8% v 5.9%, P =.005). However, the incidence of venous complications was not associated with cigarette smoking. Furthermore, there was no significant association between development of vascular complications and all other characteristics studied. Cigarette smoking is associated with a higher risk for developing vascular complications, especially arterial complications after liver transplantation. Cigarette smoking cessation at least 2 years before liver transplantation can significantly reduce the risk for vascular complications. Cigarette smoking cessation should be an essential requirement for liver transplantation candidates to decrease the morbidity arising from vascular complication after liver transplantation.

Superior diagnostic strength of combined contrast enhanced MR-angiography and MR-imaging compared to intra-arterial DSA in liver transplantation candidates

To evaluate the diagnostic value of combined contrast enhanced MRA (ce-MRA) and MRI compared to that of intra-arterial DSA (i.a.DSA) in liver transplantation, transjugular porto-systemic (TIPSS) and spleno-renal shunt candidates. 50 patients in the workup for liver transplantation underwent ce-MRA/MRI and i.a.DSA within a three days interval. Both examinations were assessed with respect to vessel anatomy and patency of the arterial, portal venous, porto-systemic collateral and systemic venous system. The results were compared with the intra-operative findings when available. Malignancy detection in ce-MRA/MRI and i.a.DSA were compared. There are no significant differences for the arterial part of the vascular supply to the liver that is important for transplantation. Although the differences for the portal system are not significant, the difference between the two techniques is of clinical importance because i.a.DSA failed to detect portal vein occlusion in 4 patients. Ce-MRA is significantly better for the detection of collaterals (p < 0.001) and the assessment of the inferior vena cava, the hepatic and the renal veins (p < 0.001). Although the detection of liver malignancy is poor in both techniques, ce-MRA/MRI is superior to i.a.DSA. This study shows that a one step diagnostic approach with a combination of ce-MRA and MRI is a valuable radiological tool with a superior diagnostic strength compared to i.a.DSA in the liver transplantation and shunt candidate. Therefore, ce-MRA/MRI should replace i.a.DSA in these patients groups.

Uni- and multi-variate analysis of risk factors for early and late hepatic artery thrombosis after liver transplantation

BACKGROUND

Hepatic artery thrombosis (HAT) is a significant cause of morbidity after liver transplantation. The aims of this study are to identify and compare risk factors that might contribute to HAT.

METHODS

A total of 424 liver transplants performed at the University of Virginia were reviewed. HAT was defined as complete disruption of arterial blood flow to the allograft and was identified in 29 cases (6.8%). HAT was classified as early (less than 1 month posttransplant, 9 cases: 2.1%) or late (more than 1 month posttransplant, 20 cases: 5.4%). Possible risk factors for HAT were analyzed using Pearson chi2 test for univariate analysis and logistic regression for multivariate analysis.

RESULTS

Multiple transplants, recipient/donor weight ratio >1.25, biopsy-proven rejection within 1 week of transplant, recipient negative cytomegalovirus (CMV) status, arterial anastomosis to an old conduit (defined as a previously constructed aorto-hepatic artery remnant using donor iliac artery), and CMV negative patients receiving allograft from CMV positive donors were found to be significant risk factors for developing early HAT. After logistic regression, factors independently predicting early HAT included arterial anastomosis to an old conduit [odds ratio (OR)=7.33], recipient/donor weight ratio >1.25 (OR=5.65), biopsy-proven rejection within 1 week posttransplant (OR=2.81), and donor positive and recipient negative CMV status (OR=2.66). Female donor, the combination of female donor and male recipient, recipient hepatitis C-related liver disease, donor negative CMV status, and the combination of recipient CMV negative and donor CMV negative were found to be significant risk factors for late HAT. Factors independently predicting late HAT by logistic regression included negative recipient and donor CMV status (OR=2.26) and the combination of a female donor and male recipient (OR=1.97).

CONCLUSION

Therefore, in nonemergency situations attention to these factors in donor allocation may minimize the possibility of HAT.

Arteriography and portal venography on routine follow-up after orthotopic liver transplantation

RATIONALE AND OBJECTIVES

To describe the findings of routinely performed angiographic examinations in patients at discharge 2 months after orthotopic liver transplantation (OLT) and at follow-up 1 year later.

METHODS

The findings of 315 angiographic examinations performed in 190 patients 2 months and 1 year after OLT were reviewed, and the changes at the anastomotic site of the hepatic artery and portal vein were analyzed.

RESULTS

Routine angiography 2 months and 1 year after OLT demonstrated a normal anastomosis or low-grade stenosis in 82% and 84% of the patients (hepatic artery) and in 88% and 84% (portal vein), respectively. High-grade stenosis occurred in 9% and 5% of the patients (hepatic artery) and in 3% and 5% (portal vein). Hepatic artery occlusion and portal vein occlusion were observed in two and seven patients and in one and three patients, respectively. In 76% of patients, the anastomotic site of the hepatic artery did not change significantly. In eight patients, a normal anastomosis or a low- or medium-grade stenosis developed into high-grade stenosis or occlusion. Conversely, in nine patients, medium- or high-grade stenosis developed into a normal anastomosis or a low-grade stenosis. In all eight patients who initially had a high-grade stenosis, the hepatic artery proved to be patent at 1 year. In 98% of patients, the anastomotic site of the portal vein did not change significantly. In one patient who initially had a normal anastomosis, occlusion was found at I year.

CONCLUSIONS

In most patients, routine angiography 2 months and 1 year after OLT demonstrated normal findings or a low-grade stenotic anastomosis of the hepatic artery and portal vein. Significant changes occurred mainly at the anastomotic site of the hepatic artery and could not be predicted by previous angiograms.

Color Doppler sonography in the diagnosis and monitoring of arterial complications after liver transplantation

PURPOSE

We assessed the usefulness of color Doppler imaging in the diagnosis and monitoring of arterial complications after liver transplantation.

METHODS

Subjects were 142 liver transplant recipients who underwent serial color Doppler sonographic evaluations of the hepatic arteries after surgery. Patients with abnormal sonographic findings underwent subsequent angiography.

RESULTS

Eighteen subjects experienced 20 hepatic arterial complications (13 thromboses and 7 stenoses). In 7 of the 13 thrombosis incidents, hepatic arterial obstruction occurred within a month of surgery and was evident from the absence of Doppler signals; angiography confirmed the absence of hepatic arterial perfusion in these cases. In the other 6 thrombosis cases, the thrombosis developed 3 or more months after surgery and became apparent from the absence of color Doppler signals at the level of the main arterial trunk and the presence of intraparenchymal "tardus parvus" waveforms. In these cases, angiography showed obstruction of the main arterial trunk and the development of compensatory collateral vessels. In 3 of the 7 cases of stenosis, high flow velocities were recorded at the site of the narrowing, and intrahepatic tardus parvus waveforms were present. In the other 4 stenosis cases, the site of stenosis could not be identified, but intraparenchymal tardus parvus waveforms were recorded.

CONCLUSION

The use of color Doppler sonography allows the early diagnosis of hepatic arterial complications after liver transplantation. Tardus parvus waveforms indicated severe impairment of hepatic arterial perfusion, from either thrombosis or severe stenosis. The presence of these waveforms enhanced the accuracy of color Doppler diagnosis (100% positive predictive value), and their detection should prompt angiography.

CT angiography of the visceral vasculature

CT angiography (CTA) is a minimally invasive technique that has proven to be clinically useful in evaluating the vasculature of the abdominal viscera. In many instances, the diagnostic information obtained from abdominal CTA is sufficient to avoid the expense and morbidity of conventional angiography. This article reviews the indications, technique, and pitfalls of abdominal CTA with specific emphasis on disorders of the hepatic, splenic, and superior mesenteric arteries and the portal venous system.

Imaging of hepatic transplantation

This article provides a clinical overview of liver transplantation. Preoperative radiologic imaging methods are discussed. Relevant surgical anatomy is illustrated, including vascular and biliary anastomoses. The radiologic features of vascular complications in liver transplantation are also reviewed.

Biphasic spiral computed tomography versus digital subtraction angiography for evaluation of arterial thrombosis after orthotopic liver transplantation

RATIONALE AND OBJECTIVES

The authors characterize the spiral computed tomographic (CT) findings in patients with hepatic arterial thrombosis after orthotopic liver transplantation (OLT).

METHODS

In nine with and 15 patients without hepatic artery thrombosis (HAT) after OLT, unenhanced and contrast-enhanced biphasic spiral CT was performed during arterial and venous phases, and evaluated by consensus of two blinded readers. Evaluation included signs of parenchymal and vascular changes in the liver. Findings subsequently were correlated with those of digital subtraction angiography (DSA).

RESULTS

Among all patients, eight had complete occlusion of the proximal hepatic artery and one patient had partial thrombosis, as revealed by conventional DSA. Characteristic CT findings of HAT included irregularly shaped confluent hypoattenuating liver areas (n = 8), seen both before and after administration of contrast material. Necrotic lesions and changes consistent with ischemic type of biliary lesion were documented in six patients. Biphasic CT allowed detection of HAT in eight patients. Because of inadequate contrast enhancement during the arterial phase, thrombosed intrahepatic arteries were not adequately diagnosed in one patient. Overall CT sensitivity to detect HAT was 89%, specificity was 100%.

CONCLUSIONS

Characteristic biphasic spiral CT findings in hepatic artery thrombosis contribute to early detection of arterial thrombosis after OLT and are helpful for planning more invasive diagnostic approaches.

Hepatic artery thrombosis and infarction: evolution of the ultrasound appearances in liver transplant recipients

Hepatic infarction is a serious complication of liver transplantation, causing significant morbidity and mortality and often requiring retransplantation. Real time ultrasonography with Doppler examination is often the first imaging modality employed to investigate post-operative complications. We report on the sonographic appearances of three patients in whom hepatic infarction followed transplantation but who did not require retransplantation, allowing us to study the evolution of sonographic features. Geographic areas of decreased echogenicity with preservation of the portal tracts are an early sign of hepatic ischaemia and may either resolve completely or progress to true infarction with the development of transient small hyperechoic lesions. Calcification may also occur quite rapidly. Biliary strictures, bilomas and abscess formation are later complications.

Hepatic artery angioplasty after liver transplantation: experience in 21 allografts

PURPOSE

To assess whether percutaneous transluminal angioplasty (PTA) can help prolong allograft survival and improve allograft function in patients with hepatic artery stenosis after liver transplantation.

PATIENTS AND METHODS

Hepatic artery PTA was attempted in 19 patients with 21 allografts over 12 years. The postangioplasty clinical course was retrospectively analyzed. Liver enzyme levels were measured before and after PTA to determine if changes in liver function occurred after successful PTA.

RESULTS

Technical success was achieved in 17 allografts (81%). Retransplantation was required for four of 17 allografts (24%) in which PTA was successful and four of four allografts in which PTA was unsuccessful; this difference was significant (P = .03). Two major procedure-related complications occurred: an arterial leak that required surgical repair and an extensive dissection that necessitated retransplantation 14 months after PTA. Hepatic failure necessitated repeat transplantation in seven cases from 2 weeks to 27 months (mean, 8.4 months) after PTA. Six patients died during follow-up, three of whom had undergone repeat transplantation. Markedly elevated liver enzyme levels at presentation were associated with an increased risk of retransplantation or death regardless of the outcome of PTA.

CONCLUSION

PTA of hepatic artery stenosis after liver transplantation is relatively safe and may help decrease allograft loss due to thrombosis. Marked allograft dysfunction at presentation is a poor prognostic sign; thus, timely intervention is important.

Duplex Doppler detection of hepatic artery thrombosis following liver transplantation

Hepatic artery thrombosis is a major cause of morbidity and mortality following liver transplantation. We assessed the value of prospective duplex Doppler ultrasound in detecting hepatic artery thrombosis. One hundred consecutive transplants in 90 patients were studied. Duplex Doppler detected all 10 proven cases of hepatic artery thrombosis. No case of hepatic artery thrombosis was found with a normal duplex study. All arteriograms performed following an abnormal ultrasound demonstrated hepatic arterial occlusion or anastomotic stenosis or a segment of irregular arterial narrowing. We conclude that duplex Doppler is a practical and sensitive method of selecting patients with a presumptive diagnosis of hepatic artery thrombosis for further investigation by angiography.

The spectrum of portal vein thrombosis in liver transplantation

Thrombosis of the portal vein with or without patency of its tributaries used to be a contraindication to orthotopic liver transplantation (OLTX) until quite recently. Rapid progress in the surgical technique of OLTX in the last few years has demonstrated that most patients with portal vein thrombosis can be safely and successfully transplanted. Presented here is a series of 34 patients with portal vein thrombosis transplanted at the University of Pittsburgh since 1984. The various techniques used to treat various forms of thrombosis are described. The survival rate for this series was 67.6% (23 of 34 patients). Survival was best for patients who underwent phlebothrombectomy or placement of a jump graft from the superior mesenteric vein. The survival rate also correlated with the amount of blood required for transfusion during surgery. Overall it is concluded that a vast majority of the patients with thrombosis of the portal system can be technically transplanted and that their survival rate is comparable to that of patients with patent portal vein.

Applications of duplex ultrasonography in the liver transplant patient

Duplex ultrasonography plays an important role in the preoperative and postoperative assessment of liver transplant patients. Before surgical intervention, the principal use of sonography is to assess the patency of the extrahepatic portal vein because a narrowed or thrombosed portal vein may preclude transplantation. Postoperatively, several potential complications can lead to allograft dysfunction (rejection, infection, vascular thromboses, and biliary tract complications). Because these complications often manifest with variable and nonspecific symptoms, diagnosing them can be difficult. Sonography is a valuable noninvasive means of evaluating postoperative complications in liver transplant patients. When vascular complications are suspected, duplex sonography is the optimal screening procedure for assessment of the vascular anastomoses. Focal parenchymal abnormalities (hematomas, infarcts, and bilomas) and localized collections of abdominal fluid are readily detected by ultrasonography and can be safely aspirated and, when infected, percutaneously drained under sonographic guidance. Sonography is less useful in the detection of biliary tract complications early after transplantation.

Increased galactose clearance after liver transplantation: a measure of increased blood flow through the denervated liver?

This study measured the liver blood flow-dependent index of galactose clearance in patients after liver transplantation, to test the hypothesis that liver blood flow is increased in the denervated liver. Eight normal subjects and 16 patients 1 to 8 months after liver transplant were studied. All patients were stable with no evidence of severe rejection at the time of study. Galactose clearance was measured at steady state during continuous infusion of 75 mg per min of 5% galactose. The results show a statistically significant (p less than 0.01) higher average galactose clearance in the transplant patients (1,187 +/- 316 ml per min per m2) compared to the control group (709 +/- 121 ml per min per m2). The major limiting factor in galactose clearance at low concentrations is liver blood flow, and we interpret these data as evidence for increased blood flow in the transplanted liver. Possible mechanisms for the increased galactose clearance are (i) loss of normal vasomotor tone in the denervated liver, or (ii) persistence of abnormal systemic hemodynamics after transplantation. Elucidation of these mechanisms awaits further study.

Pseudoaneurysms complicating organ transplantation: roles of CT, duplex sonography, and angiography

In a retrospective study of proved pseudoaneurysms (PAs) in 15 patients with transplanted organs (11 liver, three kidney, one pancreas), the results of computed tomography (CT), duplex sonography, and angiography were reviewed. Of the 15 cases of PA, eight occurred at the arterial anastomosis and seven were nonanastomotic. Three of the eight anastomotic PAs were caused by infection. Of the seven nonanastomotic PAs, four were caused by percutaneous biopsy, two were caused by infection, and one was of undetermined cause. In nine (60%) of the 15 patients the PAs were incidentally detected at imaging studies performed for other reasons. Diagnosis requires a high degree of suspicion. CT was performed in nine cases and duplex sonography in ten. The diagnosis of PA was made with CT in six (67%) patients and with duplex sonography in five (50%). CT and duplex sonography could not enable diagnosis when the PA was small, when the arterial anastomosis was not included in the field of study, or when enhancement with intravenously administered contract material was suboptimal. Angiography depicted the PAs in all 15 patients. In three liver transplant recipients with gastrointestinal tract bleeding, the causative PAs were detected only with angiography.

Transluminal balloon angioplasty of infrahepatic caval anastomotic stenosis following liver transplantation: case report

Treatment of an infrahepatic caval anastomotic stenosis with percutaneous transluminal balloon angioplasty is described in a patient 5 weeks after liver transplantation. Pressure measurements confirmed the significance of the obstruction and the success of the dilatation procedure.

Interruption of inferior vena cava with anomalous continuations

A case of interruption of the inferior vena cava which has two continuational pathways is reported. One is the hemiazygos and azygos continuation and the other is an unusual intrathoracic continuation, phrenic and pericardial vein draining through the highest intercostal vein into the left brachiocephalic vein.

Orthotopic liver transplantation in children

Ten children, aged 3 to 16 years, were part of a group of 61 patients who received liver transplants at University Hospital in London, Canada between November 1982 and April 1986. All of the children received cyclosporine in combination with other agents for immunosuppression. Two children died of rejection, one child died from a lymphoma, and one child died from a hypoxic brain injury sustained during a respiratory arrest. Six children are currently alive from 4 months to 2 1/2 years following transplantation. All of the survivors have returned to a normal life style. With current surgical techniques and modern immunosuppression, hepatic transplantation has become the treatment of choice for patients with endstage irreversible liver disease. The extreme shortage of donor organs is now the major factor limiting the application of liver transplantation in children.

Complications of venous reconstruction in human orthotopic liver transplantation

In 313 consecutive recipients of 393 orthotopic liver grafts, there were 51 (16.3%) and nine (2.9%) patients who had pre-existing portal vein and inferior vena cava abnormalities, respectively. These abnormalities required adjustments in the transplant operation and were a source of morbidity and mortality. The incidence of thrombosis of the reconstructed portal vein was 1.8%. Only three (0.8%) vena caval thromboses were seen after 393 liver replacements. Venous stenoses or disruptions were rare. Six women with the Budd-Chiari syndrome had liver replacement. Although this disorder is a veno-occlusive disease, five of the recipients achieved prolonged survival, only one had recurrence of disease, and three are alive after 2-6 years.

Vascular complications after liver transplantation: a 5-year experience

During the past 5 years, 104 angiographic studies were performed in 87 patients (45 children and 42 adults) with 92 transplanted livers for evaluation of possible vascular complications. Seventy percent of the studies were abnormal. Hepatic artery thrombosis was the most common complication (seen in 42% of children studied, compared with only 12% of adults) and was a major complication that frequently resulted in graft failure, usually necessitating retransplantation. In six children, reconstitution of the intrahepatic arteries by collaterals was seen. Three survived without retransplant. Arterial stenosis at the anastomosis or in the donor hepatic artery was observed in 11% of patients. Portal vein thrombosis or stenosis occurred in 13% of patients. Two children and one adult with portal vein thrombosis demonstrated hepatopetal collaterals that reconstituted the intrahepatic portal vessels. Uncommon complications included anastomotic and donor hepatic artery pseudoaneurysms, a hepatic artery-dissecting aneurysm, pancreaticoduodenal mycotic aneurysms, hepatic artery-portal vein fistula, biliary-portal vein fistula, hepatic vein occlusion, and inferior vena cava thrombosis.

Hepatic artery thrombosis after liver transplantation: radiologic evaluation

Hepatic artery thrombosis after liver transplantation is a devastating event requiring emergency retransplantation in most patients. Early clinical signs are often nonspecific. Before duplex sonography (combined real-time and pulsed Doppler) capability was acquired in October 1984, 76% of all transplants in this institution referred for angiography with a clinical suspicion of hepatic artery thrombosis had patent arteries. In an effort to reduce the number of negative angiograms, CT, real-time sonography, and pulsed Doppler have been evaluated as screening examinations to determine which patients need angiography. Of 14 patients with focal inhomogeneity of the liver architecture detected by CT and/or real-time sonography, 12 (86%) had hepatic artery thrombosis, one had slow arterial flow with hepatic necrosis, and one had a biloma with a patent hepatic artery. In 29 patients undergoing duplex sonography of the hepatic artery, six (21%) had absence of a Doppler arterial pulse. All six had abnormal angiograms: Four had thrombosis, one had a significant stenosis, and one had slow flow with biopsy-proven ischemia. Of 23 patients with a Doppler pulse, two had hepatic artery thrombosis at surgery. However, real-time sonography demonstrated focal inhomogeneity in the liver in both cases. Our data demonstrate that pulsed Doppler of the hepatic artery combined with real-time sonography of the liver parenchyma currently is the optimal screening test for selecting patients who require hepatic angiography after liver transplantation. A diagnostic algorithm is provided.