Significance of and contributing factors for a high resistive index on Doppler sonography of the hepatic artery immediately after surgery: prognostic implications for liver transplant recipients

Hepatic artery vasospasm masquerading as early hepatic artery thrombosis in progressive familial intrahepatic cholestasis 3: a case report

Post-liver transplant (LT) hepatic artery vasospasm is a vascular complication that is not well recognized and its incidence is not known. As a possible sequela to vasospasm, hepatic artery thrombosis is the second major cause of allograft failure after primary nonfunction and its reported incidence is 2.9% in adults and 8.3% in pediatric LT. Lacuna in knowledge regarding early hepatic artery vasospasm post-LT makes it a difficult condition to diagnose and treat, as the initial ischemic insult on graft can have devastating consequences. We report a case of pediatric progressive familial intrahepatic cholestasis type 3-related chronic liver disease who underwent cadaveric orthotopic LT and postoperatively developed fever, worsening hypotension, and elevated liver enzymes with an absence of arterial flow in intrahepatic branches on Doppler ultrasound. Suspecting early hepatic artery thrombosis, the patient was re-explored and the graft hepatic artery was found to be in a state of vasospasm. Following the infusion of intra-arterial papaverine, urokinase, and intravenous nicorandil, there was an improvement in blood flow. The patient responded well and was discharged on postoperative day 23 with normal liver enzymes.

Hepatic artery and portal vein Doppler ultrasound reference values in children aged 0-17 years old

Introduction

Doppler ultrasound of the portal vein peak systolic velocity and hepatic artery peak systolic velocity and resistive index in children is often performed during abdominal ultrasound for the assessment of liver and other abdominal pathology. However, evidence-based reference values are not available. We aimed to determine these reference values and to investigate whether they are age-dependent.

Methods

Children who underwent abdominal ultrasound between 2020 and 2021 were retrospectively identified. Patients without hepatic or cardiac abnormalities at the time of ultrasound or during at least 3 months follow-up were eligible for the study. Ultrasound without hepatic hilum portal vein peak systolic velocity and/or hepatic artery peak systolic velocity and resistive index measurements were excluded. Age-dependent changes were analyzed using linear regression. Normal range reference values were described using percentiles for all ages, and for age subgroups.

Results

One-hundred ultrasound examinations performed in 100 healthy children aged 0-17.9 years (median 7.8 years, interquartile range 1.1-14.1 years) were included. Ninety-nine portal vein peak systolic velocity and 80 hepatic artery peak systolic velocity and resistive index measurements were obtained. There was no significant association between portal vein peak systolic velocity and age (β = -0.056, p = 0.68). There were significant associations between age and hepatic artery peak systolic velocity, and between age and hepatic artery resistive index (β = -0.873, p = 0.04 and β = -0.004, p < 0.001, respectively). Detailed reference values were provided for all ages, and for age subgroups.

Conclusion

Reference values for the hepatic hilum portal vein peak systolic velocity, hepatic artery peak systolic velocity, and hepatic artery resistive index in children were established. Portal vein peak systolic velocity is not age-dependent, whereas hepatic artery peak systolic velocity and hepatic artery resistive index decrease when children get older.

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.

Doppler evaluation of hepatic hemodynamics after living donor liver transplantation in infants

Objective: The aim of this study was to explore the hemodynamic changes of hepatic artery and portal vein detected by Doppler ultrasound (DU) in infants who underwent living donor liver transplantation (LDLT).

Methods: The data of 41 infant patients (22 Males, 19 Females, median age of 5 months) were collected in the Children’s Hospital affiliated to the Chongqing Medical University from May 2018 to December 2019. The patients underwent left lateral segment LDLT (LLS -LDLT) because of biliary atresia (BA). Hemodynamic parameters, including the peak systolic velocity (PSV), resistivity index (RI) of the hepatic artery (HA), portal vein velocity (PVV), and portal vein flow (PVF) were recorded from Doppler ultrasound on the day before the operation, and on the 1st, the 7th, the 14th and the 30th day after LDLT procedures. The changes of PSV_HA, RI_HA, PVV and PVF before and on the 1st day after transplantation were analyzed by paired t-test. The comparison of the data between different postoperative time points were assessed by ANOVA.

Results: Compared with the parameters measured before LDLT, PSV_HA, and RI_HA decreased, and PVV and PVF increased significantly (p < 0.001) on the 1st day after LLS-LDLT. As for PSV, there was no significant difference between the 7th day and the 1st day after transplantation (POD7 VS POD1, p = 0.167) while there was a substantial difference between the 14th, 30th and 1st day after LT (POD14 vs. POD1, p = 0.003) (POD30 vs. POD1, p ＜0.001). And there was a significant difference between the 14th, 30th, and 7th days after LT (POD14 vs. POD7, p = 0.014) (POD30 vs. POD7, p ＜0.001). There was no significant difference between 30th and 14th after transplantation (POD30 vs. POD14, p = 0.092). As for RI_HA and PVV, the decrease was slow within the first month after the operation, and there was no significant difference at different times.

Conclusion: We have identified major hepatic flow changes that occurred in 41 infants who underwent LLS -LDLT due to BA. The data could be used for future studies of LDLT in infants including hemodynamic modeling, liver regeneration and clinical management.

Intraoperative Doppler Ultrasound for Detection of Early Postoperative Vascular Complications in Orthotopic Liver Transplants

Liver transplantation is currently the only curative treatment for patients with end-stage liver disease. However, liver transplantation can be associated with catastrophic complications in the early postoperative setting, including hepatic artery thrombosis (HAT) and portal vein thrombosis (PVT). Postoperative complications are associated with hepatic artery resistive index (RI) < 6, systolic acceleration time (SAT) > 0.08 seconds and peak systolic velocity (PSV) > 200 cm/s on doppler ultrasound (DUS). DUS is also used in an intraoperative setting to assess patency and early complications prior to the end of the operative period, allowing for early correction. This literature review evaluates the prevalence of DUS use in intraoperative settings to identify transplant complications. A lack of consistency and minimal knowledge of intraoperative DUS warrants additional research into its usage and standardization.

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.

Splenic artery steal syndrome in patients with orthotopic liver transplant: Where to embolize the splenic artery?

Purpose

This study compared proximal and distal embolization of the splenic artery (SA) in patients with splenic artery steal syndrome (SAS) after orthotopic liver transplantation (OLT) regarding post interventional changes of liver function to identify an ideal location of embolization.

Methods and materials

85 patients with SAS after OLT treated with embolization of the SA between 2007 and 2017 were retrospectively reviewed. Periinterventional DSA was used to assess treatment success and to stratify patients according to the site of embolization. Liver function was assessed using following laboratory values: bilirubin, albumin, gamma-glutamyl transferase, glutamat-pyruvat-transaminase (GPT), glutamic-oxaloacetic transaminase (GOT), Alkaline Phosphatase (ALP), aPTT, prothrombin time and thrombocyte count. Descriptive statistics were used to summarize the data. Median laboratory values of pre, 1- and 3-days, as well as 1-week and 1-month post-embolization were compared between the respective embolization sites using linear mixed model regression analysis.

Results

All procedures were technically successful and showed an improved blood flow in the hepatic artery post-embolization. Ten Patients were excluded due to re -intervention or inconsistent image documentation. Pairwise comparison using linear mixed model regression analysis showed a significant difference between proximal and distal embolization for GPT (57.0 (IQR 107.5) vs. 118.0 (IQR 254.0) U/l, p = 0.002) and GOT (48.0 (IQR 48.0) vs. 81.0 (IQR 115.0) U/l, p = 0.008) 3-days after embolization as well as median thrombocyte counts 7-days after embolization (122 (IQR 108) vs. 83 (IQR 74) in thousands, p = 0.014). For all other laboratory values, no statistically significant difference could be shown with respect to the embolization site.

Conclusion

We conclude that long-term outcomes after embolization of the SA in the scenario of SAS after OLT are irrespective of the site of embolization of the SA, whereas a proximal embolization potentially facilitates earlier normalization of liver function. Choice of technique should therefore be informed by anatomical conditions, safety considerations and preferences of the interventionalist.

Hepatic Artery Vasospasm Masquerading as Hepatic Artery Thrombosis in a Case of Deceased Donor Liver Transplant

Hepatic arterial vasospasm can be a potential vascular complication after liver transplantation and can manifest as hepatic artery thrombosis. Due to the scarcity of literature on this pathology, its incidence, mechanism, relevance, diagnosis, and prognosis remain to be investigated. Our index case, a 64-year-old man with decompensated alcohol-related cirrhosis, underwent a cadaveric orthotopic liver transplant and was having a normal postoperative course. On postoperative day 12, liver enzymes were elevated, and Doppler ultrasound performed showed hepatic arterial occlusion. In view of hepatic artery thrombosis digital subtraction angiography (DSA) was done, which showed a string bead appearance of graft hepatic artery, with no thrombosis or stenosis of hepatic artery anastomosis. It was managed by oral administration of vasodilator, as well as intra-arterial administration of vasodilators through DSA catheter tip placed in the hepatic artery. He responded well to the management and was discharged on postoperative day 24 with normal liver enzymes.

Transgastric Abdominal Ultrasonography in Anesthesia and Critical Care: Review and Proposed Approach

The use of transesophageal echocardiography (TEE) in the operating room and intensive care unit can provide invaluable information on cardiac as well as abdominal organ structures and function. This approach may be particularly useful when the transabdominal ultrasound examination is not possible during intraoperative procedures or for anatomical reasons. This review explores the role of transgastric abdominal ultrasonography (TGAUS) in perioperative medicine. We describe several reported applications using 10 views that can be used in the diagnosis of relevant abdominal conditions associated with organ dysfunction and hemodynamic instability in the operating room and the intensive care unit.

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.

Normal and transitory ultrasonography findings in the immediate postoperative period after liver transplantation

OBJECTIVE

Liver transplantation is one of the treatments for patients with advanced stage chronic liver disease and for selected patients with hepatic tumors. Ultrasonography is the first-choice imaging technique to evaluate liver transplants. This article reviews the surgical technique, anatomy, and normal findings on ultrasonography in the immediate postoperative period in patients who have undergone liver transplantation, which will be used as a reference in follow-up studies.

CONCLUSION

Early vascular (arterial and portal) complications can represent a threat for the graft or the patient. During the period after liver transplantation, the patient is recovering from surgery and the transplanted organ is adapting to its new environment. In this period, ultrasonography can show alterations in the parenchyma or Doppler findings that would be considered abnormal in other situations; these findings are usually transitory. Knowing how to interpret them is key to detecting or ruling out complications.

Role of imaging in the evaluation of vascular complications after liver transplantation

Clinical manifestations of liver transplantation complications can be subtle and non-specific. Medical imaging, mainly Doppler ultrasound, plays an important role to detect and grade these. Colour Doppler ultrasound exams are routinely performed at 24–48 h, on the 7th day, the first and third month after transplantation. MDCT and MR images are acquired based on the Doppler ultrasound (DUS) findings, even in the absence of abnormal liver function. As vascular complications appear early after surgery, DUS should be performed by experience personnel. Diagnostic angiography is seldom performed. This pictorial review illustrates the key imaging findings of vascular complications in patients with liver transplantation: hepatic artery complications (such as thrombosis, stenosis of the anastomosis and pseudoaneurysms), portal vein abnormalities (such as occlusion and stenosis) and hepatic veins and/or inferior vena cava flow changes (Budd-Chiari syndrome).

Impact on the hepatic flow velocity after pediatric combined liver-kidney transplantation compared to isolated pediatric liver transplantation-A matched-pair analysis

BACKGROUND

Combined liver-kidney transplantation (CLKT) in children is still a rarely performed procedure. Our aim was to analyze the effect of the simultaneous transplantation of the kidney in pediatric CLKT on the liver graft flow velocity, and vascular complications compared to singular liver transplantation (LTX) in children.

METHODS

All pediatric CLKT performed at our institution from 1998 to 2016 were matched with singular LTX and retrospectively analyzed.

RESULTS

Overall 30 CLKT were performed in 28 children (median age 8 years, range 1-16) and matched with 30 children undergoing singular LTX (median age 7.9 years, range 1-16). No significant differences were found concerning the systolic peak flow velocity of the hepatic artery (HA) or the resistance index (RI). Vascular complications of the hepatic vessels occurred in 16.7% (CLKT) and 6.7% (LTX). The 1-/5- and 10-year patient survival was 93.3%/93.3% and 93.3% (CLKT) and 100%/100% and 92.9% (LTX). 1-/5-and 10-year liver graft survival was 76.7%/73.2% and 73.2% (CLKT) and 84.4%/75.9% and 69.6% (LTX).

CONCLUSION

The simultaneous transplantation of the kidney in CLKT had no negative impact on hepatic flow velocity or vascular complications. Frequent Doppler ultrasound examinations, accurate volume management, and avoidance of abdominal pressure might be an explanation for the results and an excellent graft- and patient survival.

Updates on liver transplantation: vascular and biliary complications

This article uses a practical approach to explain the imaging findings for vascular and biliary complications after total liver transplantation in adults, comparing them to the normal imaging findings after transplantation. It emphasizes the radiologic management of patients who have undergone transplantations and explains the treatment of the different complications by interventional radiology. The information provided comes from the authors' experience and a thorough, up-to-date review of the indexed literature.

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.

A Case Report of Severe Hepatic Artery Vasospasm Induced by Hepatic Arterial Buffer Response After Liver Transplantation

The management of severe hepatic artery vasospasm soon after liver transplantation (LT) is challenging because it can lead to hepatic artery thrombosis and subsequent graft failure. A 61-year-old man with hepatitis C cirrhosis and portal vein thrombosis received a deceased donor LT. On postoperative day 1, Doppler ultrasonography revealed a high-resistance waveform in the hepatic artery. Angiography showed severe vasospasm of the donor hepatic artery on postoperative day 3. Strong hepatic arterial buffer response (HABR) was considered for this etiology due to high portal vein velocity. Therefore, vasodilators, including nitroglycerin and prostaglandin E₁, were initiated. The waveform of the hepatic artery vasospasm gradually improved as portal vein velocity decreased by Doppler ultrasonography within 7 days after LT. In conclusion, hepatic arterial buffer response can induce hepatic artery vasospasm immediately after LT. This vasospasm type may be managed conservatively with a positive outcome.

Role of Doppler Ultrasonography in Defining Normal and Abnormal Graft Hemodynamics After Living-Donor Liver Transplant

OBJECTIVES

Our aim was to investigate the early changes that occur after graft perfusion in living-donor liver transplant by Doppler ultrasonography.

MATERIALS AND METHODS

We prospectively evaluated liver grafts of 30 patients who underwent living-donor liver transplant during an 18-month period and who were followed for 1 year postoperatively. The hepatic artery peak systolic velocity, resistivity index, portal vein velocity, portal vein anastomotic velocity ratio, and hepatic vein pattern were compared after excluding patients who developed vascular complications and acute rejection episodes.

RESULTS

We observed intraoperative increases in the mean hepatic artery peak systolic velocity (96.3 ± 65 cm/s), the resistivity index (0.78 ± 0.091), and the portal vein velocity (99.6 ± 48 cm/s), which started to normalize after 2 weeks. In comparing the mean portal vein velocity, portal vein anastomotic velocity ratio, hepatic artery peak systolic velocity, and resistivity index after excluding 5 patients who developed vascular complications, we observed overall significance levels of P < .001, P = .039, P < .001, and P = .040. After we excluded 9 patients who developed acute rejection, our comparison of the portal vein velocity, hepatic artery peak systolic velocity, and resistivity index showed overall significance (P < .001, P < .001, and P = .043).

CONCLUSIONS

Early and transient increases in portal vein velocity, anastomotic velocity ratio, hepatic artery peak systolic velocity, and resistivity index are common after living-donor liver transplant, with significant declines in the first 2 weeks posttransplant.

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.

Systematic computer tomographic scans 7 days after liver transplantation surgery can lower rates of repeat-transplantation due to arterial complications

Arterial complications are a major cause of graft lost after liver transplantation (LT). The aim of our study was to assess the clinical impact of systematic early postoperative injected computed tomographic (CT) scans after LT rather than its performance on demand in the event of abnormalities. Two series of consecutive transplantation patients in different periods (1997-1999, 231 patients versus 2008-2010, 250 patients) were analyzed. During the first period, an injected CT scan was only performed in the event of clinical, biological, or ultrasound abnormalities revealed by tests performed daily during the first week after surgery. During the second period, in addition to standard follow-up examination, an injected CT scan was performed systematically at approximately postoperative day 7. During the first (versus the more recent) period, both recipients (whose ages were 46 ± 13 years versus 50 ± 12 years; P = .004) and donors (whose ages were 42 ± 17 versus 52 ± 17 years; P = .0001) were younger and end-stage liver disease was more common (34% versus 12%; P = .0001), but hepatocellular carcinoma (7% vs 26%; P = .0001) and retransplantation (2% versus 7%; P = .01) were less frequent. Postoperative mortality was higher during the first period (14% versus 4%; P = .0003). The incidence of early arterial thrombosis (<1 month) was similar (1.3% versus 1.6%; P = .78), but that of arterial stenosis was higher with a systematic CT scan (1.7 versus 4.4; P = .07). As a consequence of the early detection and treatment of arterial abnormalities, the repeat LT rate due to late arterial thrombosis was nil in the second period and 2.1% (5/231) in the first period. In conclusion, a systematic CT angiogram at the end of the first postoperative week reduced retransplantation rates due to late hepatic artery thrombosis by detecting patients at risk who required specific treatment.

The haemodynamic effects of the perioperative terlipressin infusion in living donor liver transplantation: A randomised controlled study

Background and Aims:

Liver disease is usually accompanied with a decline in systemic vascular resistance (SVR). We decided to assess effects of the peri-operative terlipressin infusion on liver donor liver transplantation recipients with respect to haemodynamics and renal parameters.

Methods:

After Ethical Committee approval for this prospective randomised controlled study, 50 recipients were enrolled and allotted to control (n = 25) or terlipressin group (n = 25) with simple randomisation method. Terlipressin was infused at 1.0 μg/kg/h and later titrated 1.0–4.0 μg/kg/h to maintain mean arterial pressure (MAP) >65 mmHg and SVR index <2600 dyne.s/cm5^/ m2 till day 4. Nor-epinephrine was used as appropriate. Haemodynamic and transoesophageal Doppler parameters (intraoperative), renal function, peak portal vein blood flow velocity (PPV), hepatic artery resistive index (HARI), urine output (UOP), liver enzymes, catecholamine support were compared intra-operatively and 4 days post-operatively. Desflurane administration was guided with entropy.

Results:

Terlipressin maintained better MAP and SVR (P < 0.01) during reperfusion versus controls (66.5 ± 16.08 vs. 47.7 ± 4.7 mmHg and 687.7 ± 189.7 vs. 425.0 ± 26.0 dyn.s/cm⁵), respectively. Nor epinephrine was used in 5 out of 25 versus 20 in controls. Urea, creatinine and UOP were significantly better with terlipressin. PPV was reduced with terlipressin post-reperfusion versus controls (44.8 ± 5.2 vs. 53.8 ± 3.9 ml/s, respectively, P < 0.01) without affecting HARI (0.63 ± 0.06 vs. 0.64 ± 0.05, respectively, P > 0.05) and was sustained post-operatively.

Conclusion:

Terlipressin improved SVR and MAP with less need for catecholamines particularly post-reperfusion. Terlipressin reduced PPV without hepatic artery vasoconstriction and improved post-operative UOP.

Postoperative doppler evaluation of liver transplants

Doppler ultrasound plays an important role in the postoperative management of hepatic transplantation, by enabling early detection and treatment of various vascular complications. This article describes the normal Doppler findings following liver transplantation and reviews the imaging appearances of various vascular complications associated with it. The article also discusses transient waveform abnormalities, often seen on a post-transplant Doppler examination, and the importance of differentiating them from findings suggestive of ominous vascular complications.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

KEY POINTS

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

Hepatic transplantation: postoperative complications

Advances in surgical techniques and immunosuppression have made orthotopic liver transplantation a first-line treatment for many patients with end-stage liver disease. The early detection and treatment of postoperative complications has contributed significantly to improved graft and patient survival with imaging playing a critical role in detection. Complications that can lead to graft failure or patient mortality include vascular abnormalities, biliary abnormalities, allograft rejection, and recurrent or post-transplant malignancy. Vascular abnormalities include stenosis and thrombosis of the hepatic artery, portal vein, and inferior vena cava, as well as hepatic artery pseudoaneurysm, arteriovenous fistula, and celiac stenosis. Biliary abnormalities include strictures, bile leak, obstruction, recurrent disease, and infection. While imaging is not used to diagnose allograft rejection, it plays an important role in identifying complications that can mimic rejection. Ultrasound is routinely performed as the initial imaging modality for the detection and follow-up of both early and delayed complications. Cholangiography and magnetic resonance cholangiopancreatography are used to characterize biliary complications and computed tomography is used to confirm abnormal findings on ultrasound or for the evaluation of postoperative collections. The purpose of this article is to describe and illustrate the imaging appearances and management of complications associated with liver transplantation.

Post-operative imaging in liver transplantation: State-of-the-art and future perspectives

Orthotopic liver transplantation (OLT) represents a major treatment for end-stage chronic liver disease, as well as selected cases of hepatocellular carcinoma and acute liver failure. The ever-increasing development of imaging modalities significantly contributed, over the last decades, to the management of recipients both in the pre-operative and post-operative period, thus impacting on graft and patients survival. When properly used, imaging modalities such as ultrasound, multidetector computed tomography, magnetic resonance imaging (MRI) and procedures of direct cholangiography are capable to provide rapid and reliable recognition and treatment of vascular and biliary complications occurring after OLT. Less defined is the role for imaging in assessing primary graft dysfunction (including rejection) or chronic allograft disease after OLT, e.g., hepatitis C virus (HCV) recurrence. This paper: (1) describes specific characteristic of the above imaging modalities and the rationale for their use in clinical practice; (2) illustrates main imaging findings related to post-OLT complications in adult patients; and (3) reviews future perspectives emerging in the surveillance of recipients with HCV recurrence, with special emphasis on MRI.

Postoperative haemodynamic changes in transplanted liver: Long-term follow-up with ultrasonography

OBJECTIVE

To investigate haemodynamic changes in the transplanted liver without postoperative complications.

METHODS

Colour Doppler ultrasound was used to monitor recipients of liver transplants who had no postoperative complications. The haemodynamic data for the hepatic vasculature were compared at different time-points during the first 4 years after liver transplantation.

RESULTS

A total of 144 liver transplant patients were enrolled in the study. Portal vein flow velocity decreased significantly from 72.1 ± 30.3 cm/s at 1 day to 44.2 ± 20.1 cm/s at 1 month after liver transplantation. Hepatic artery flow velocity was 61.4 ± 33.2 cm/s at day 1; it then decreased slowly but significantly to 48.3 ± 20.4 cm/s at 3 years after transplantation. There were 81 (56.3%) patients with high hepatic artery resistance index (HARI) (>0.80) and 19 (13.2%) with low HARI (<0.50) measured at least once during the 4-year follow-up examination.

CONCLUSIONS

Decreased portal vein flow velocity was the typical change observed during the first month after liver transplantation. Abnormal haemodynamic Doppler results should be interpreted with caution because they may not be clinically significant and may improve spontaneously.

Effect of perioperative terlipressin infusion on systemic, hepatic, and renal hemodynamics during living donor liver transplantation

BACKGROUND

End-stage liver disease is associated with marked hemodynamic disturbances that are further aggravated during liver transplantation. Terlipressin has been shown to be effective in the management of sepsis-induced hypotension and hepatorenal syndrome and recently has been tried as infusion during liver transplantation. This study assessed the effect of intraoperative and postoperative terlipressin infusion on systemic, hepatic, and renal hemodynamics during adult living donor liver transplantation.

METHODS

Eighty recipients were randomly allocated into control (C group; n=40) and terlipressin (TP group; n=40), in which, terlipressin infusion was started at the beginning of surgery at a dose of 3 μg kg(-1) h(-1) to be reduced to 1.5 μg kg(-1) h(-1) after reperfusion and continued for 3 postoperative days; vasoactive agents were used as appropriate in all patients. Systemic hemodynamics, hepatic and renal arterial resistive indices (HARI, RARI), and portal venous blood flow (PBF) were compared between both groups intraoperatively and for 5 postoperative days.

RESULTS

With terlipressin infusion, there were significant increases in both mean arterial pressure and systemic vascular resistance (P<.001), whereas heart rate and cardiac output decreased significantly (P<.001) throughout the study period compared with the C group. Vasoconstrictor drugs required during reperfusion were significantly lower in the TP group. There was a significant decrease in HARI, RARI, and portal venous blood flow in the TP group compared with the C group throughout the study period. There was no significant difference between both groups regarding liver function tests and serum lactate, whereas renal function tests were significantly better in the TP group.

CONCLUSION

Terlipressin infusion significantly decreased HARI, RARI, and portal vein flow and improved low systemic vascular resistance and mean arterial pressure. It helped to reduce intraoperative vasoactive support and might improve postoperative renal function.

Orthotopic liver transplantation: reversible Doppler US findings in the immediate postoperative period

Orthotopic liver transplantation (OLT) is the only definitive treatment for irreversible acute liver failure and chronic liver disease. In the immediate postoperative period after OLT, patients are closely monitored with Doppler ultrasonography (US) to detect treatable vascular complications and ensure graft survival. The first postoperative Doppler US examination is performed fairly early on the first postoperative day, before surgical wound closure has been performed. The immediate postoperative images, obtained when the effects of surgery are very recent, often reveal an array of findings that may appear alarming but that tend to normalize within a few days and are compatible with changes related to the surgery itself. These findings include a starry-sky appearance of reperfusion hepatic edema, transient foci of increased echogenicity, pneumobilia, small fluid collections, perihepatic hematomas, pleural effusion, temporary elevation of hepatic arterial velocity, transient elevation of resistive index (RI), decreased RI with tardus parvus waveform, increased portal venous flow and mono- or biphasic waveforms of the hepatic veins. Most of these changes revert to normal in the first postoperative week; deterioration atypical of transient changes requires further evaluation.

Prediction of early hepatic artery thrombosis by intraoperative color Doppler ultrasound in pediatric segmental liver transplantation

Early hepatic artery thrombosis (eHAT) after transplantation is associated with a high incidence of graft failure and mortality in pediatric segmental liver transplantation (LT). The evaluation of intraoperative color Doppler ultrasound (CD-US) parameters and their sensitivity and specificity for the prediction of eHAT were important. Pediatric segmental LTs were performed in 49 consecutive patients from October 2006 to December 2010 in our hospital. A total of seven patients (14.3%) experienced eHAT (within one month) after LT. The intraoperative hepatic artery (HA) diameter (p = 0.026), hepatic arterial peak systolic velocity (HAPSV) (p = 0.006), and hepatic artery resistance index (HARI) (p = 0.000) had significant difference between eHAT group and non-eHAT group. Taking a HA diameter <2 mm, a HAPSV of <40 cm/s and a HARI of <0.6 as threshold to predict eHAT, the sensitivity and specificity were 85.7%, 85.7%, 85.7%, and 61.9%, 76.2%, 88.1%, respectively. A HARI of <0.6 was shown to be the most sensitive and specific single parameter for predicting eHAT.

Multimodality imaging of normal hepatic transplant vasculature and graft vascular complications

Orthotopic liver transplantation is an important treatment option for patients with end-stage liver disease. Advances in surgical technique, along with improvements in organ preservation and immunosuppression have improved patient outcomes. Post-operative complications, however, can limit this success. Ultrasound is the primary imaging modality for evaluation of hepatic transplants, providing real-time information about vascular flow in the graft. Graft vascular complications are not uncommon, and their prompt recognition is crucial to allow for timely graft salvage. A multimodality approach including CT angiography, MRI, or conventional angiography may be necessary in cases of complex transplant vascular anatomy or when sonography and Doppler are inconclusive to diagnose the etiologies of these complications. The purpose of this article is to familiarize radiologists with the normal post-transplant vascular anatomy and the imaging appearances of the major vascular complications that may occur within the hepatic artery, portal vein, and venous outflow tract, with an emphasis on ultrasound.

Evolving experience with prevention and treatment of splenic artery syndrome after orthotopic liver transplantation

Impaired hepatic arterial perfusion after orthotopic liver transplantation (OLT) may lead to ischemic biliary tract lesions and graft-loss. Hampered hepatic arterial blood flow is observed in patients with hypersplenism, often described as arterial steal syndrome (ASS). However, arterial and portal perfusions are directly linked via the hepatic arterial buffer response (HABR). Recently, the term 'splenic artery syndrome' (SAS) was coined to describe the effect of portal hyperperfusion leading to diminished hepatic arterial blood flow. We retrospectively analyzed 650 transplantations in 585 patients. According to preoperative imaging, 78 patients underwent prophylactic intraoperative ligation of the splenic artery. In case of postoperative SAS, coil-embolization of the splenic artery was performed. After exclusion of 14 2nd and 3rd retransplantations and 83 procedures with arterial interposition grafts, SAS was diagnosed in 28 of 553 transplantations (5.1%). Twenty-six patients were treated with coil-embolization, leading to improved liver function, but requiring postinterventional splenectomy in two patients. Additionally, two patients with SAS underwent splenectomy or retransplantation without preceding embolization. Prophylactic ligation could not prevent SAS entirely (n = 2), but resulted in a significantly lower rate of complications than postoperative coil-embolization. We recommend prophylactic ligation of the splenic artery for patients at risk of developing SAS. Post-transplant coil-embolization of the splenic artery corrected hemodynamic changes of SAS, but was associated with a significant morbidity.

Doppler ultrasound findings in the hepatic artery shortly after liver transplantation

OBJECTIVE

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

CONCLUSION

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

Role of imaging in the management of splenic artery steal syndrome

OBJECTIVE

The purpose of this study is to discuss the etiology and role of imaging in the management of splenic artery steal syndrome (SASS) following orthotropic liver transplantation (OLT).

METHODS

Hepatic arterial thrombosis and stenosis have been the most commonly recognized arterial complications following OLT. Splenic artery steal syndrome is a recently described entity in the transplant literature and thought to be an under-recognized cause of graft ischemia. It is characterized by hepatic arterial hypoperfusion accompanied by splenic arterial and portal venous hyperperfusion and leads to various vascular and biliary graft complications. Because the clinical manifestations of SASS are so non-specific, imaging plays a key role in the diagnosis of this condition.

RESULTS

This article discusses the role of imaging in the management of this potentially reversible cause of graft ischemia.

CONCLUSIONS

Awareness of the imaging features and having a high index of suspicion are essential for the early diagnosis and prompt management of this condition.

Spectrum of normal or near-normal sonographic findings after orthotopic liver transplantation

The initial imaging immediately after orthotopic liver transplantation is generally performed with ultrasound. Although significant posttransplant complications do occur, many abnormal findings including minor vascular waveform abnormalities, anastomotic mismatches, and fluid collections can be seen in asymptomatic patients. It is important to differentiate these benign findings from more serious complications to avoid unnecessary intervention.

Complications of liver transplantation: multimodality imaging approach

Liver transplantation is currently an accepted first-line treatment for patients with end-stage acute or chronic liver disease, but postoperative complications may limit the long-term success of transplantation. The most common and most clinically significant complications are arterial and venous thrombosis and stenosis, biliary disorders, fluid collections, neoplasms, and graft rejection. Early diagnosis is crucial to the successful management of all these complications, and imaging plays an important role in the diagnosis of all but graft rejection. A multimodality approach including ultrasonography and cross-sectional imaging studies often is most effective for diagnosis. Each imaging modality has specific strengths and weaknesses, and the diagnostic usefulness of a modality depends mainly on the patient's characteristics, the clinical purpose of the imaging evaluation, and the expertise of imaging professionals.