Multidetector computed tomography for preoperative assessment of hepatic vasculature and prediction of splenic artery steal syndrome in patients with liver cirrhosis before transplantation

Splenic artery steal syndrome after liver transplantation: A case series and review of literature

Splenic steal syndrome (SASS) represents a challenge to interventional radiologists after orthotopic liver transplantation. In this case series, we present three cases of patients who developed SASS after their liver transplants.

Transplant Hepatic Artery Complications

Hepatic artery complications can be divided into 2 different categories, nonocclusive and steno-occlusive disease. Steno-occlusive disease is a collective term that encompasses hepatic artery thrombosis, hepatic artery stenosis, and hepatic arterial kinks, while nonocclusive arterial disease encompasses less than 5% of complications and is a collective term used to describe arteriovenous fistulae, pseudoaneurysms, arterial rupture and nonocclusive hepatic artery hypoperfusion syndrome. This article details the angiographic techniques and definitions needed to accurately diagnose arterial transplant complications and describes the technical aspects and results of endoluminal management of these arterial complications. In addition, this article discusses the presentation, etiology and indications for treatment, including surgical management of these various complications.

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

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

Splenic artery steal syndrome after liver transplantation - prophylaxis or treatment?: A case report and literature review

Splenic artery steal syndrome (SASS) is a cause of graft hypoperfusion leading to the development of biliary tract complications, graft failure, and in some cases to retransplantation. Its management is still controversial since there is no universal consensus about its prophylaxis and consequently treatment. We present a case of SASS that occurred 48 hours after orthotopic liver transplantation (OLTx) in a 56-year-old male patient with alcoholic cirrhosis and severe portal hypertension, and who was successfully treated by splenic artery embolization. A literature search was performed using the PubMed database, and a total of 22 studies including 4,789 patients who underwent OLTx were relevant to this review. A prophylactic treatment was performed in 260 cases (6.2%) through splenic artery ligation in 98 patients (37.7%) and splenic artery banding in 102 (39.2%). In the patients who did not receive prophylaxis, SASS occurred after OLTx in 266 (5.5%) and was mainly treated by splenic artery embolization (78.9%). Splenic artery ligation and splenectomies were performed, respectively, in 6 and 20 patients (2.3% and 7.5%). The higher rate of complications registered was represented by biliary tract complications (9.7% in patients who received prophylaxis and 11.6% in patients who developed SASS), portal vein thrombosis (respectively, 7.3% and 6.9%), splenectomy (4.8% and 20.9%), and death from sepsis (4.8% and 30.2%). Whenever possible, prevention is the best way to approach SASS, considering all the potential damage arising from an arterial graft hypoperfusion. Where clinical conditions do not permit prophylaxis, an accurate risk assessment and postoperative monitoring are mandatory.

Diagnostic Value of Color Doppler Ultrasound and Contrast-Enhanced Ultrasound in the Artery Steal Syndrome After Orthotopic Liver Transplantation

Purpose

This study aimed to investigate the application of color Doppler ultrasound (CDU) and contrast-enhanced ultrasound (CEU) in the early diagnosis of arterial steal syndrome (ASS) after orthotopic liver transplantation (OLT).

Patients and Methods

A total of 1827 patients received OLT in our department between January 2007 and December 2021, and CDU and CEU were performed after surgery. Ultrasonographic data were collected and further analyzed. ASS was confirmed by digital subtraction angiography (DSA), and the use of splenic artery embolization was dependent on the DSA findings and clinical conditions. The ultrasonographic data were collected before and after embolization.

Results

ASS was found in 23 patients (23/1827; 1.26%). CDU: the portal vein velocity was higher than normal in 17 patients (52.83±21.74 cm/s); the hepatic artery flow signals disappeared in 7 patients; the hepatic artery velocity was 13.57±5.85 cm/s in 16 patients. In 23 patients, the spleen artery velocity was 170.12±32.04 cm/s. CEU: the hepatic artery was observed in 7 patients without hepatic artery flow signals on CDU; in 23 patients, the contrast agent reached the portal vein at the presence of contrast in the hepatic artery or earlier (difference: 2.21±1.09 s). Splenic artery embolization was done in 17 of 23 patients with ASS. The hepatic artery flow velocity, hepatic artery resistance index, splenic artery velocity and time to the presence of contrast were significantly improved after embolization (P<0.05).

Conclusion

CDU and CEU are the preferred, effective tools in the diagnosis of ASS. Reduced peak hepatic artery velocity, increased spleen artery velocity and reduced time difference in the contrast reaching the portal vein and hepatic artery are indicative of ASS.

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.

Refractory Ascites with Intrahepatic Portal Thrombosis after Living Donor Liver Transplantation Successfully Treated by Splenic Artery Embolization and Apixaban (Case Report)

Refractory ascites is a rare complication after liver transplantation, and its incidence ranges from 5% to 7%. A 56-yearold man diagnosed with HBV-LC with massive ascites underwent living donor liver transplantation. After transplantation, more than 1000 ml/day of ascites was steadily drained until two weeks after LT. CT showed intrahepatic Rt. portal vein thrombosis and many remnant collaterals with splenomegaly. We decided to embolize the proximal splenic artery and use apixaban to reduce portal flow and resolve the intrahepatic portal thrombosis. One day after splenic artery embolization, the patient's ascites dramatically decreased. Three days later, he was discharged from the hospital. Three months later, a follow-up liver CT showed resolution of thrombosis and no ascites. Splenic artery embolization was an effective and safe procedure for portal flow modulation in portal hyertension. Apixaban was effective for partial portal vein thrombosis in a liver transplant recipient.

Pre-operative CT scan helps predict outcome after liver transplantation for acute-on-chronic grade 3 liver failure

OBJECTIVES

The aim of this study was to identify the prognostic value of pre-operative imaging to predict post-transplantation survival in critically ill cirrhotic patients with severe acute-on-chronic liver failure (ACLF).

METHODS

Patients with grade 3 ACLF who underwent liver transplantation between January 2010 and January 2020 and with available contrast-enhanced abdominal computed tomography (CT) performed less than 3 months before LT were retrospectively included (n = 82). Primary endpoint was 1-year mortality. Imaging parameters (sarcopenia, liver morphology and volumetry, and signs of portal hypertension) were screened and tested to build a prognostic score.

RESULTS

In the multivariate analysis, three independent CT-derived prognostic factors were found: splenomegaly (p = 0.021; HR = 5.6 (1.29-24.1)), liver atrophy (p = 0.05; HR = 2.93 (1.01-10.64)), and vena cava diameter ratio (p < 0.0001; HR = 12.7 (3.4-92)). A simple prognostic score was proposed, based on the presence of splenomegaly (5 points), liver atrophy (5 points), and vena cava diameter ratio < 0.2 (12 points). A cutoff at 10 points distinguished a high-risk group (score > 10) from a low-risk group (score ≤ 10) with 1-year survival of 27% vs. 67% respectively (p < 0.001). It was found to be an independent predictive factor in association with the Transplantation for ACLF3 Model (TAM) score.

CONCLUSION

Pre-transplantation contrast-enhanced abdominal CT has a significant impact on selection of patients in ACLF3 in order to predict 1-year survival after LT.

KEY POINTS

• Splenomegaly, liver atrophy, and vena cava diameter ratio are independent CT-derived prognostic factors after transplantation for severe acute-on-chronic liver failure. • A simple CT-based prognostic score is an independent predictive factor, complementary to clinical and biological parameters. • The use of the CT-derived score allows stratification based on 1-year mortality for patients with otherwise uncertain prognosis with clinical and biological parameters alone.

Portosystemic shunt surgery in the era of TIPS: imaging-based planning of the surgical approach

PURPOSE

With the spread of transjugular intrahepatic portosystemic shunts (TIPS), portosystemic shunt surgery (PSSS) has decreased and leaves more complex patients with great demands for accurate preoperative planning. The aim was to evaluate the role of imaging for predicting the most suitable PSSS approach.

MATERIAL AND METHODS

Forty-four patients who underwent PSSS (2002 to 2013) were examined by contrast-enhanced CT (n = 33) and/or MRI (n = 15) prior to surgery. Imaging was analyzed independently by two observers (O1 and O2) with different levels of experience (O1 > O2). They recommended two shunting techniques (vessels and anastomotic variant) for each patient and ranked them according to their appropriateness and complexity. Findings were compared with the actually performed shunt procedure and its outcome.

RESULTS

The first two choices taken together covered the performed PSSS regarding vessels in 88%/100% (CT/MRI, O1) and 76%/73% (O2); and vessels + anastomosis in 79%/73% (O1) and 67%/60% (O2). The prediction of complex surgical procedures (resection of interposing structures, additional thrombectomy, use of a collateral vessel, and use of a graft interposition) was confirmed in 87%, resulting in 80% sensitivity and 96% specificity. Larger shunt vessel distances were associated with therapy failure (p = 0.030) and a vessel distance of ≥ 20 mm was identified as optimal cutoff, in which a graft interposition was used. There was no significant difference between MRI and CT in predicting the intraoperative decisions (p = 0.294 to 1.000).

CONCLUSION

Preoperative imaging and an experienced radiologist can guide surgeons in PSSS. CT and MRI provide the information necessary to identify technically feasible variants and complicating factors.

Advantages of time-resolved contrast-enhanced 4D MR angiography in splenic arterial steal syndrome

Splenic artery steal syndrome (SASS) is a severe complication affecting up to 10% of orthotopic liver transplant (OLT) patients. In this case report, we present a 35-year-old male with OLT secondary to liver failure due to hemochromatosis, who developed SASS. We describe potential application of different imaging techniques for diagnosis of SASS with focus on the value of time-resolved contrast enhanced 4D magnetic resonance angiography (MRA).

Pediatric Liver Transplant: Techniques and Complications

Liver transplant is considered to be the last-resort treatment approach for pediatric patients with end-stage liver disease. Despite the remarkable advance in survival rates, liver transplant remains an intricate surgery with significant morbidity and mortality. Early diagnosis of complications is crucial for patient survival but is challenging given the lack of specificity in clinical presentation. Knowledge of the liver and vascular anatomy of the donor and the recipient or recipients before surgery is also important to avoid complications. In this framework, radiologists play a pivotal role on the multidisciplinary team in both pre- and postoperative scenarios by providing a road map to guide the surgery and by assisting in diagnosis of complications. The most common complications after liver transplant are (a) vascular, including the hepatic artery, portal vein, hepatic veins, and inferior vena cava; (b) biliary; (c) parenchymal; (d) perihepatic; and (e) neoplastic. The authors review surgical techniques, the role of each imaging modality, normal posttransplant imaging features, types of complications after liver transplant, and information required in the radiology report that is critical to patient care. They present an algorithm for an imaging approach for pediatric patients after liver transplant and describe key points that should be included in radiologic reports in the pre- and postoperative settings. Online supplemental material is available for this article. ^©RSNA, 2017.

Impact of Doppler Ultrasound on Diagnosis and Therapy Control of Lienalis Steal Syndrome After Liver Transplantation

Background

Lienalis steal syndrome is a rare complication after orthotopic liver transplantation leading to severe complications. Routine duplex sonography allows early and safe detection of lienalis steal syndrome and secondarily helps to monitor the outcome by evaluating the hemodynamics.

Material/Methods

This analysis included eight patients who after orthotopic liver transplantation needed splenic artery embolization due to lienalis steal syndrome. Lienalis steal syndrome was assumed in case of elevated transaminases, bilirubinemia or persistent ascites, and the absence of further pathologies. Diagnosis was supported by ultrasound, confirmed by digital subtraction angiography, and followed by splenic artery embolization for treatment. We analyzed blood levels and ultrasound findings before and after splenic artery embolization as well as during follow-up and evaluated for incidence of severe biliary complications and survival.

Results

Arterial resistive index (RI) significantly regularized after splenic artery embolization while the maximum arterial velocity increased. The portal venous flow volume and maximum velocity decrease. Laboratory parameters normalized. Two of eight patients developed ischemic-type biliary disease. Survival rate was 88% over a median follow-up of 33 months.

Conclusions

Beside unspecific clinical findings, bedside ultrasound examination enabled a quick verification of the diagnosis and allowed direct treatment to minimize further complications. Furthermore, ultrasound can immediately monitor the therapeutic effect of splenic artery embolization.

Current understanding and management of splenic steal syndrome after liver transplant: A systematic review

BACKGROUND

Splenic steal syndrome (SSS) is a condition that can occur after orthotopic liver transplant (OLT). However, limited information is available about this condition.

METHODS

A systematic literature search of studies performed through May 2016 was conducted to identify reports of angiographically confirmed SSS and its variants. All of the factors relevant to this disorder were collected and analyzed.

RESULTS

A total of 219 cases of SSS and its variants were identified. The condition occurred in 4.7% of patients after OLT, and 93.7% of cases were diagnosed within the first 2 months after OLT. Conventional arteriography demonstrated nonocclusive hepatic artery hypoperfusion in all affected patients. Abnormal liver function was the most common clinical presentation, reported in 71.9% of cases. Less common presentations included thrombocytopenia, acute graft failure, and persistent ascites. On Doppler ultrasound, a high resistance index of the hepatic artery was present in 84.1% of patients. Increased spleen volume (≥829 mL) before OLT was suggestive of a potential risk for SSS. Splenic artery embolization (SAE) was performed in 94.7% of cases; this procedure immediately reversed flow abnormalities on Doppler ultrasound and improved liver function tests in 96.3% of cases.

CONCLUSIONS

The risk factors and potential etiologies of SSS remain largely unknown. Future studies should investigate the possible role of pre-OLT portal hypertension and portal hyperperfusion after OLT in the development of this syndrome. Collecting intraoperative hemodynamic data and performing Doppler ultrasound screening after OLT could potentially help clinicians to identify patients at high risk of arterial hypoperfusion and prevent potential complications from hepatic artery hypoperfusion.

Clinical application of modern ultrasound techniques after liver transplantation

Liver transplantation has been established as a first-line therapy for a number of indications. Conventional ultrasound and contrast-enhanced ultrasound (CEUS) are methods of choice during the postoperative period as a safe and fast tool to detect potential complications and to enable early intervention if necessary. CEUS increases diagnostic quality and is an appropriate procedure for the examination of vessels and possibly bile ducts. This article presents the state of the art of ultrasound application during the early period after liver transplantation. It addresses common vascular complications and describes the identification of postoperative abnormal findings using ultrasound and CEUS.

Role of Doppler Sonography in Early Detection of Splenic Steal Syndrome

OBJECTIVES

To retrospectively investigate the role of Doppler sonography in the early detection of splenic steal syndrome.

METHODS

Fifty cases of splenic steal syndrome after orthotopic liver transplantation were identified. A control group was matched to the splenic steal syndrome group. Information was collected about the clinical presentation, liver enzyme levels, Doppler sonographic results, and follow-up after patients underwent splenic artery embolization.

RESULTS

A persistent hepatic arterial diastolic reversal waveform was observed in 25 patients with splenic steal syndrome versus 0 control patients. The mean hepatic arterial resistive index (RI) values ± SD were 0.95 ± 0.09 in patients with splenic steal syndrome and 0.80 ± 0.10 in control patients (P < .0001). One week after orthotopic liver transplantation, the area under the receiver operating characteristic curve for the RI was 0.884 (95% confidence interval, 0.793-0.975; P = .001) for splenic steal syndrome diagnosis. After splenic artery embolization, there was normalization of the reversal waveform, with an average RI of 0.77 ± 0.11 (P < .0001).

CONCLUSIONS

Dynamic changes in the hepatic arterial waveform and RI are keys to detecting splenic steal syndrome with Doppler sonography.

Feasibility of MDCT angiography for determination of tumor-feeding vessels in chemoembolization of hepatocellular carcinoma

OBJECTIVE

To investigate the feasibility and accuracy of multidetector computed tomography (MDCT) angiography for assessment of subsegmental tumor-feeding vessels in transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

A total of 23 patients with 36 HCCs who underwent TACE during a 14-month period were enrolled. All patients underwent 3-phase dynamic MDCT within a month before TACE. Arterial phase MDCT images were retrospectively reformatted and analyzed for determination of single subsegmental tumor-feeding vessel using maximum intensity projection (MIP) and volume-rendering technique (VRT). Two radiologists independently assessed and scored the MIP and VRT images using 4-grade visual scores (grade 1, no depiction of tumor-feeding vessel; grade 2, indeterminate tumor-feeding vessel; grade 3, probable tumor-feeding vessel; and grade 4, good depiction of tumor-feeding vessel). The weighted kappa test was used to determine interobserver variability, and Wilcoxon signed rank test was used to differentiate visual scores of each technique. Results of digital subtraction angiography were defined as the criterion standard; therefore, assessment of subsegmental tumor-feeding vessel using MIP or VRT was compared with digital subtraction angiography, and the accuracy of each technique was calculated.

RESULTS

Interobserver agreement (weighted kappa, 0.746 on VRT and 0.806 on MIP) was substantial to almost perfect. The visual scores for MIP (mean, 3.64 for reviewer 1 and 3.5 for reviewer 2) were higher than those for VRT (mean, 2.11 for reviewer 1 and 2.22 for reviewer 2; P = 0.000). The accuracy for assessing subsegmental tumor-feeding vessel was 22.2% for VRT and 77.8% for MIP.

CONCLUSION

Multidetector CT angiography using MIP showed good imaging quality and high accuracy for determination of subsegmental tumor-feeding vessels.

New strategies for prevention and treatment of splenic artery steal syndrome after liver transplantation

AIM: To explore a prophylactic procedure to prevent splenic artery steal syndrome (SASS), as well as a therapeutic intervention to correct it.

METHODS: Forty-three liver transplant patients were enrolled in a non-randomized controlled trial, with the eligible criterion that the diameter of the splenic artery is more than 5 mm and/or 1.5 times of the diameter of the hepatic artery. The procedure of splenic artery banding was performed in 28 of the 43 patients, with the other 15 patients studied as a control group. SASS and other complications were compared between these two groups. A new therapeutic intervention, temporary incomplete blockade of the splenic artery with a balloon, was performed to treat SASS in this study.

RESULTS: The incidence of SASS was decreased by banding the splenic artery (0/28 vs 5/15, P = 0.006), and the same result was observed in total complications associated with prophylactic procedures (2/28 vs 6/15, P = 0.014). Five patients in the control group developed SASS within 5 d after OLT, 2 of whom were treated by coil embolization of the splenic artery, whereas the other 3 by temporary blockade of the splenic artery. Reappeared or better hepatic arteries with improved systolic amplitude and increased diastolic flow were detected by Doppler ultrasonography in all the 5 patients. Local splenic ischemic necrosis and nonanastomotic biliary stricture were diagnosed respectively in one patient treated by coil embolization, and no collateral complication was detected in patients treated by temporary blockade of the splenic artery.

CONCLUSION: SASS should be avoided during the operation by banding the splenic artery. Temporary blockade of the splenic artery is a new safe and effective intervention for SASS.

Splenic Artery Syndrome after orthotopic liver transplantation: a review

Splenic Artery Syndrome (SAS) has emerged as a controversial cause for graft ischemia in orthotopic liver transplant (OLTx) recipients. A complex combination of factors including hepatic artery hypoperfusion and portal hyperperfusion can result in SAS. Clinical and laboratory findings suggest graft ischemia but are generally non-specific. Conventional angiography findings of hepatic artery hypoperfusion with early and rapid filling of the splenic artery are suggestive of the diagnosis in the appropriate clinical setting. Treatment involves proximal splenic artery embolization, surgical splenic artery ligation, or in extreme cases, splenectomy. Most patients with SAS improve clinically following treatment. However, no randomized control trials are available to compare treatment options. Identification of at risk patients with pre-operative CT scans and intra-operative ultrasound has been proposed by some and may allow for prophylactic treatment of SAS.

Contrast-enhanced ultrasound diagnosis of splenic artery steal syndrome after orthotopic liver transplantation

The aim of this study was to investigate the use of contrast-enhanced ultrasound (CEUS) for the detection of splenic artery steal syndrome (SASS) after orthotopic liver transplantation (OLT). Two hundred forty-seven patients underwent OLT. Blood tests and color Doppler flow imaging (CDFI) were performed at various time points after the operation. CEUS and celiac angiography were used for patients suspected of having SASS. If the diagnosis of SASS was confirmed, splenic artery embolization was performed to enhance hepatic artery flow. CEUS and angiography were performed for the assessment of postinterventional clinical outcomes. Three of the 247 patients died postoperatively, and 8 patients were suspected of having SASS because of elevated liver enzyme levels and slim or undetectable hepatic artery blood signals by CDFI at various points after the operation. In these 8 patients, CEUS showed a delayed and weak contrast-enhanced blood signal in the hepatic artery associated with a rapid and intense enhancement of the portal vein blood. No narrowing of the hyperintense signal was observed in the hepatic artery by CEUS. The 8 diagnoses of SASS were proven by celiac angiography, which showed delayed perfusion of the hepatic artery and rapid filling of the splenic artery. Immediately after the interventional procedure, CEUS demonstrated a significantly enlarged hyperintense blood signal in the hepatic artery. In conclusion, approximately 3.27% of SASS cases occur after OLT. SASS can be identified as a sluggish and weak hyperintense blood signal in the hepatic artery without the narrowing and interruption of the hypointense signal in CEUS imaging. CEUS is an effective imaging modality for the detection of SASS after OLT.

Quantifying increased hepatic arterial flow with test balloon occlusion of the splenic artery in liver transplant recipients with suspected splenic steal syndrome: quantitative digitally subtracted angiography correlation with arterial Doppler parameters

PURPOSE

The purpose of this study is to quantify hepatic arterial flow (HAF) in liver transplants with splenic steal syndrome (SSS) pre- and post-test balloon occlusion of the splenic artery utilizing Doppler ultrasound (DUS) and quantitative digitally subtracted angiography (Q-DSA).

METHODS

A total of 193 liver transplants were evaluated retrospectively. Hepatic arterial velocity (HAV) and HAF were calculated utilizing DUS and Q-DSA (i-flow prototype, Siemens) pre- and post-splenic artery balloon occlusion. The rate of HAF increase, total HAF, and peak contrast density (PKD) by Q-DSA were compared with HAF by DUS.

RESULTS

Of all, 4 suspected SSS cases underwent test-balloon occlusion with DUS and Q-DSA. Using DUS, HAV and HAF increased by 1.6- to 1.8-fold and 1.7- to 2.6-fold, respectively. Using Q-DSA, the HAF rate, total HAF, and PKD increased by 1.1 to 12.8, 1.5 to 7.6, and 1.3 to 5.3, respectively.

CONCLUSION

Occlusion of the splenic artery in liver transplants with SSS doubles the HAF (+1.7- to 2.6-fold). The Q-DSA parameters correlate qualitatively but overestimate the resultant increased HAF.

Nonocclusive hepatic artery hypoperfusion syndrome (splenic steal syndrome) in liver transplant recipients

There are numerous causes of reduced arterial inline flow to the liver transplant despite a patent hepatic artery. These include causes of increased peripheral resistance in the hepatic arterial bed, siphoning of the hepatic arterial flow by a dominant splenic artery (splenic steal syndrome), functional reduction of hepatic arterial flow in response to hyperdynamic portal inline flow, and small hepatic graft relative to normal portal inline flow (relative increase of portal flow). These causes are incompletely understood, and perhaps the most controversial of all is the splenic steal syndrome, which is possibly an underrecognized cause of graft ischemia in the United States. Splenic steal syndrome presents nonspecifically as graft dysfunction; if overlooked, it may lead to graft failure. Its incidence is reported to be 0.6 to 10.1% in liver transplant recipients, with some institutions performing prophylactic and/or posttransplant treatment procedures in up to a quarter of their transplant recipients. This wide disparity in the incidence of the diagnosis is probably because there are no objective diagnostic imaging criteria. This article presents a review of the literature that addresses the differential diagnostic considerations of hepatic artery hypoperfusion (splenic steal syndrome included) in the absence of an anatomical defect (hepatic artery stenosis, thrombosis, and/or kinks).

Effect of splenic artery embolization for splenic artery steal syndrome in liver transplant recipients: estimation at computed tomography based on changes in caliber of related arteries

PURPOSE

To estimate the effect of splenic artery embolization (SAE) on blood flow in orthotopic liver transplantation (OLT) recipients with splenic artery steal syndrome (SASS) based on changes in caliber of related arteries upon serial computed tomography (CT) scans.

METHODS

Between 2004 and 2007, nine OLT recipients with SASS underwent SAE. They had CT scans before and after SAE: short-, mid-, and long-term, ie, approximately 1 week, 1 month, and 1 year, respectively. The diameters of the celiac axis (CA), common hepatic artery (CHA), and splenic artery (SA) were measured with arterial phase of each CT scan and the ratios of SA to CHA diameter (SA/CHA) calculated to analyze their changes during the follow-up period.

RESULTS

The diameters of celiac axis, CHA, and SA and SA/CHA changed most rapidly during the short-term period. The CHA diameter significantly increased short-term post-SAE by CT and slightly decreased thereafter. However, the mid-term and long-term post-SAE CT values were still significantly greater than those on the pre-SAE CT. The SA diameter steadily decreased throughout the follow-up. The SA/CHA decreased until the mid-term. The SA diameter and SA/CHA were significantly smaller upon mid-term and long-term post-SAE CT compared with those at pre-SAE CT.

CONCLUSIONS

The effect of SAE to improve hepatic arterial flow in OLT recipients with SASS might be expected for at least approximately one year. The effect maximally occurred during the short-term after SAE on the basis of changes in the caliber of related arteries upon CT.

Assessment of the cerebellar arteries with multidetector computed tomography angiography benefits from submillimeter slice thickness

PURPOSE

To evaluate the accuracy of 64-row-multidetector computed tomography (MDCT) with different slice thickness (0.625 vs. 1.25 mm) in assessing the cerebellar arteries.

MATERIALS AND METHODS

A total of 21 consecutive patients who underwent computed tomography angiography (CTA) of the cervicocranial arteries (64-row MDCT; slice thickness, 0.625 mm) because of suspicion of cerebral ischemia were enrolled retrospectively. The MDCT data set was secondarily reconstructed to a slice thickness of 1.25 mm. The examinations were reviewed by three independent blinded observers. Recorded parameters for reconstructed slice thicknesses of 0.625 compared to 1.25 mm were visualization and edge enhancement (based on a developed phantom reference model) of the cerebellar arteries including anterior and posterior inferior cerebellar arteries and the superior cerebellar artery.

RESULTS

With 0.625-mm slices, significantly more vessel segments were visualized and edge enhancement was superior compared to 1.25-mm slices by the three readers, and a significant difference for the interaction between vessel segments and the slice thickness was found (P<.001). Furthermore, for a slice thickness of 1.25 mm, there was a significant difference in visualization (P=.0042) and edge enhancement (P=.0015) of vessel segments between the three readers, whereas for thinner slices (0.625 mm), no significant differences were found (P=.412, P=.465).

CONCLUSIONS

MDCT with slice thickness of 0.625 mm is superior to 1.25 mm reconstructed slice thickness regarding the visualization of cerebellar arteries, representative for smallest assessable arteries in CTA. This is paralleled by a sharper edge enhancement of the vessel contours resulting from a reduced partial volume effect. Conclusively, cranial CTA protocols should be routinely optimized to generate submillimeter slices for diagnostic purposes and digital storage as additional diagnostic value can be expected.

Splenic artery syndrome after orthotopic liver transplantation: treatment with the Amplatzer vascular plug

PURPOSE

To evaluate the safety and efficacy of the Amplatzer vascular plug (AVP) for embolization of the splenic artery in patients with hepatic hypoperfusion after orthotopic liver transplantation (OLT).

MATERIALS AND METHODS

Thirteen patients (9 men and 4 women) with a mean age of 56 years (range 22-70) who developed splenic artery syndrome after OLT with decreased liver perfusion and clinically relevant impairment of liver function (increased transaminase or serum bilirubin levels, thrombocytopenia, and/or therapy-refractory ascites) were treated by embolization of the proximal third of the splenic artery using the AVP. The plugs ranged in diameter from 6 to 16 mm, and they were introduced through femoral (n = 9), axillary (n = 3), or brachial (n = 1) access using a 5F or 8F guiding catheter.

RESULTS

The plugs were successfully placed, and complete occlusion of the splenic artery was achieved in all patients. Placement of two plugs was necessary for complete occlusion in 3 of the 13 patients. Occlusion took on average 10 min (range 4-35). There was no nontarget embolization or plug migration into more distal segments of the splenic artery. All patients showed improved arterial perfusion, including the liver periphery, on postinterventional angiogram. After embolization, liver function parameters (transaminase and bilirubin levels) improved with normalization of concomitant thrombocytopenia and a decrease in ascites volume.

CONCLUSION

Our initial experience in a small patient population with SAS suggests that the AVP enables precise embolization of the proximal splenic artery, thus providing safe and effective treatment for poor liver perfusion after OLT due to SAS.

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.