MR imaging findings in two patients with hepatic veno-occlusive disease following bone marrow transplantation

Liver transplantation following late-onset hepatic sinusoidal obstruction syndrome occurred beyond 1-year postallogeneic hematopoietic stem cell transplantation

Late-onset HOVD should be taken into consideration when patients develop liver dysfunction and/or weight gain no matter how long post-HSCT. Solid organ transplantation offers a valuable therapeutic option for selected patients with single organ failure after HSCT without adverse impact on graft function or overall outcomes.

Imaging of the chemotherapy-induced hepatic damage: Yellow liver, blue liver, and pseudocirrhosis

The liver is the major drug-metabolizing and drug-detoxifying organ. Many drugs can cause liver damage through various mechanisms; however, the liver response to injury includes a relatively narrow spectrum of alterations that, regardless of the cause, are represented by phlogosis, oxidative stress and necrosis. The combination of these alterations mainly results in three radiological findings: vascular alterations, structural changes and metabolic function reduction. Chemotherapy has changed in recent decades in terms of the drugs, protocols and duration, allowing patients a longer life expectancy. As a consequence, we are currently observing an increase in chemotherapy-associated liver injury patterns once considered unusual. Recognizing this form of damage in an early stage is crucial for reconsidering the therapy regimen and thus avoiding severe complications. In this frontier article, we analyze the role of imaging in detecting some of these pathological patterns, such as pseudocirrhosis, “yellow liver” due to chemotherapy-associated steatosis-steatohepatitis, and “blue liver”, including sinusoidal obstruction syndrome, veno-occlusive disease and peliosis.

Clinical characteristics, CT signs, and pathological findings of Pyrrolizidine alkaloids-induced sinusoidal obstructive syndrome: a retrospective study

BACKGROUND

One major etiology of hepatic sinusoidal obstruction syndrome (HSOS) in China is the intake of pyrrolizidine alkaloids (PAs). Since PAs-induced HSOS is a rare disease that has not been clearly characterized until now, the aim of this study was to investigate clinical characteristics, CT features, and pathological findings of PA-induced HSOS.

METHODS

This retrospective cohort study included 116 patients with PAs-induced HSOS and 68 patients with Budd-Chiari syndrome from Jan 2006 to Sep 2016. We collected medical records of the patients, and reviewed image features of CT, and analyzed pathological findings.

RESULTS

Common clinical manifestations of PAs-induced HSOS were abdominal distention (98.26%), ascites (100%), jaundice (52.94%), abdominal pain (36.36%). Abnormal liver function was observed in most of PAs-induced HSOS. On CT scan, common findings included: ascites, hepatomegaly, the thickening of gallbladder wall, pleural effusion, patchy liver enhancement, and heterogeneous hypoattenuation. Most of the patients had a low ascitic total protein (< 25 g/L) and a high SAAG (≥ 11.0 g/L). In acute stage, pathologic features were massive sinusoidal dilatation, sinusoidal congestion, the extravasation of erythrocytes, hepatocellular necrosis, the accumulation of macrophages, the deposition of hemosiderin. In subacute stage, complete loss of pericentral hepatocytes, sinusoidal dilatation, the deposition of pigment granules were observed.

CONCLUSIONS

The PAs-induced HSOS patients displayed distinct clinical characteristics, imaging features, and pathological findings, which provided some evidences for the diagnosis of PAs-induced HSOS.

TRIAL REGISTRATION

ChiCTR-DRD-17010709.

Sinusoidal obstruction syndrome: A systematic review of etiologies, clinical symptoms, and magnetic resonance imaging features

BACKGROUND

Sinusoidal obstruction syndrome (SOS) is a kind of rare liver disease which is characterized by damage to small hepatic vessels, affecting particularly the sinusoidal endothelium. Due to the special etiology and high mortality, early diagnosis of SOS is significant for clinical survival and prognosis.

AIM

To generalize the common etiologies and clinical symptoms of SOS and summarize the characteristic magnetic resonance imaging (MRI) features so as to provide more valuable information for early diagnosis of SOS.

METHOD

We searched PubMed, Web of science, Wanfang Data, China Knowledge Resource Integrated, VIP, and Cochrane Library databases without a limiting period and the types of articles. The search process mainly revolved around the etiologies, common clinical symptoms, and MRI imaging features of SOS. Ultimately, 29 full articles were included in this review and 222 articles were excluded.

RESULTS

Eleven case reports included 13 patients. The etiologies of these patients including chemotherapy (5/13), medicinal herbs containing pyrrolidine alkaloids (PAs, e.g. Tusanqi) (4/13), hematopoietic stem cell transplantation (HSCT) (2/13), drug toxicity (6-thioguanine) (1/13), and “poppers”, a recreational drug used during anal intercourse (1/13). Eighteen case series including 497 patients, and SOS in 465 (93.6%) patients was caused by PAs. Ascites, abdominal pain and swelling, jaundice were the most common clinical symptoms. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), total bilirubin (TBil), direct bilirubin (DBil), and prothrombin time (PT) had varying degrees of elevation. Heterogeneous signals on T1 weighted imaging/T2 weighted imaging (T1WI/T2WI), heterogeneous enhancement of liver parenchyma, ascites, hepatomegaly, narrowing and blurring of intrahepatic inferior vena cava and three main hepatic veins, edema around the portal vein, and gallbladder wall edema were the most common MRI imaging features of SOS.

CONCLUSION

In the West, SOS was mostly secondary to HSCT. Some SOS developed in the process of chemotherapy for hepatic metastatic tumor. A few SOS were caused by toxicity of certain drugs. In the East, Tusanqi was a major cause of SOS. Ascites, abdominal pain and swelling, jaundice were the common clinical symptoms. Elevations of ALT, AST, GGT, ALP, TBil, and DBil could be used as predictors of liver function damage. Numerous characteristic MRI imaging features could provide more valuable information for early diagnosis of SOS.

Role of imaging techniques in liver veno-occlusive disease diagnosis: recent advances and literature review

Veno-occlusive-disease (VOD), known also as sinusoidal-obstruction-syndrome (SOS), is one of the main complications of haematopoietic stem cell transplantation and is related to the treatment with pyrrolizidine alkaloids or other toxic agents (chemotherapy for liver-metastasis). Clinical diagnosis using the recent criteria from the European Society for Blood and Marrow Transplantation, is the reference for VOD/SOS diagnosis. However, increasing evidence suggests the emerging role of several imaging methods that could help the clinician in VOD/SOS assessment. Areas covered: This review evaluates the current literature on the various imaging techniques used in VOD/SOS diagnosis in several clinical scenarios. Literature searches were performed using several keywords on MEDLINE/Ovid/In-Process/Cochrane Library/EMBASE and PubMed up to July 2018. Expert commentary: Hepatic-gradient-measurement (HVPG) and contextual transjugular-liver-biopsy are invasive and should always be considered in unclear cases. The main studies revolve around ultrasound with Doppler evaluation, identifying numerous findings suggestive of VOD/SOS. However, their accuracy and validation are still suboptimal and controversial. CT-Scan and MRI have shown encouraging data in other contexts in which VOD/SOS can develop, but studies on the post-HSCT patient are lacking. Elastography techniques measuring liver stiffness (LSM) represent the most recent and promising approach for an accurate and early diagnosis of VOD/SOS. In our view, a multidisciplinary approach to the VOD/SOS diagnosis should be highly encouraged.

Gadoxetic Acid-Enhanced Hepatobiliary-Phase Magnetic Resonance Imaging for Pyrrolizidine Alkaloid-Induced Hepatic Sinusoidal Obstruction Syndrome and Association with Liver Function

Hepatic sinusoidal obstruction syndrome (HSOS) can be caused by pyrrolizidine alkaloids(PAs)-containing herbals. In this study, the aim of our study was to investigate the imaging features of PAs-induced HSOS on gadoxetic acid-enhanced magnetic resonance imaging (MRI), susceptibility-weighted imaging(SWI) and T2* weighted imaging (T2* WI). We analyzed medical records and MR images of 28 PAs-induced HSOS patients enrolled from Feb, 2013, to Apr, 2017. Abnormal liver function was observed in most of the PAs-induced HSOS patients. Heterogeneity of liver parenchyma in hepatobillary phase (HBP) of gadoxetic acid-enhanced MR scan was observed in 100% of the PAs-induced HSOS patients. Distributional patterns of heterogeneous hypointensity were multifocal distribution (mild) in 4 patients (14.29%), multifocal distribution (severe) in 15 cases (53.57%), and diffuse distribution in 9 patients (32.14%). Hypointense in SWI and T2*WI was observed in the patients of PAs-induced HSOS, and the distribution of hypointense in SWI and T2*WI was similar to that of portal-venous phase of MR scan. The severity of heterogeneous hypointensity scored by volume fraction in hepatobillary phase of gadoxetic acid-enhanced MRI was positively correlated with PT and INR, the severity of hypointensity in HBP was a risk factor of death events. In conclusion: Heterogenous hypointensity of liver parenchyma was an imaging sign of hepatobillary phase in gadoxetic acid-enhanced MRI; thus, it will provide evidences for the diagnosis of PA-induced HSOS.

Imaging manifestations of hepatic sinusoidal obstruction syndrome

Hepatic sinusoidal obstruction syndrome (HSOS), previously known as hepatic veno-occlusive disease, is a kind of vascular disorder of the liver. HSOS is caused by toxic destruction of hepatic sinusoidal endothelial cells. Major etiologies of HSOS include hematopoietic stem cell transplantation, oxaliplatin-containing chemotherapy, intake of pyrrolizidine alkaloid-containing herbal remedies, etc. There have been many studies on the imaging manifestations of HSOS in recent years. This paper summarizes the imaging manifestations of HSOS by reviewing the latest literature and our work.

Revised diagnosis and severity criteria for sinusoidal obstruction syndrome/veno-occlusive disease in adult patients: a new classification from the European Society for Blood and Marrow Transplantation

Sinusoidal obstruction syndrome, also known as veno-occlusive disease (SOS/VOD), is a potentially life threatening complication that can develop after hematopoietic cell transplantation. Although SOS/VOD progressively resolves within a few weeks in most patients, the most severe forms result in multi-organ dysfunction and are associated with a high mortality rate (>80%). Therefore, careful attention must be paid to allow an early detection of SOS/VOD, particularly as drugs have now proven to be effective and licensed for its treatment. Unfortunately, current criteria lack sensitivity and specificity, making early identification and severity assessment of SOS/VOD difficult. The aim of this work is to propose a new definition for diagnosis, and a severity-grading system for SOS/VOD in adult patients, on behalf of the European Society for Blood and Marrow Transplantation.

Hepatic sinusoidal obstruction syndrome caused by herbal medicine: CT and MRI features

Objective

To describe the CT and MRI features of hepatic sinusoidal obstruction syndrome (HSOS) caused by herbal medicine Gynura segetum.

Materials and Methods

The CT and MRI features of 16 consecutive Gynura segetum induced HSOS cases (12 men, 4 women) were analyzed. Eight patients had CT; three patients had MRI, and the remaining five patients had both CT and MRI examinations. Based on their clinical presentations and outcomes, the patients were classified into three categories: mild, moderate, and severe. The severity of the disease was also evaluated radiologically based on the abnormal hepatic patchy enhancement in post-contrast CT or MRI images.

Results

Ascites, patchy liver enhancement, and main right hepatic vein narrowing or occlusion were present in all 16 cases. Hepatomegaly and gallbladder wall thickening were present in 14 cases (87.5%, 14/16). Periportal high intensity on T2-weighted images was present in 6 cases (75%, 6/8). Normal liver parenchymal enhancement surrounding the main hepatic vein forming a clover-like sign was observed in 4 cases (25%, 4/16). The extent of patchy liver enhancement was statistically associated with clinical severity classification (kappa = 0.565).

Conclusion

Ascites, patchy liver enhancement, and the main hepatic veins narrowing were the most frequent signs of herbal medicine induced HSOS. The grade of abnormal patchy liver enhancement was associated with the clinical severity.

BCSH/BSBMT guideline: diagnosis and management of veno-occlusive disease (sinusoidal obstruction syndrome) following haematopoietic stem cell transplantation

DIAGNOSIS

It is recommended that the diagnosis of veno-occlusive disease (sinusoidal obstruction syndrome) [VOD (SOS)] be based primarily on established clinical criteria (modified Seattle or Baltimore criteria) (1A). Ultrasound imaging may be helpful in the exclusion of other disorders in patients with suspected VOD (SOS) (1C). It is recommended that liver biopsy be reserved for patients in whom the diagnosis of VOD (SOS) is unclear and there is a need to exclude other diagnoses (1C). It is recommended that liver biopsies are undertaken using the transjugular approach in order to reduce the risks associated with the procedure (1C). It is suggested that the role of plasminogen activator inhibitor 1 levels remains an area for further research but that these levels should not form part of the routine diagnostic work-up for VOD (SOS) at present (2C).

RISK FACTORS

It is recommended that patients are assessed for risk factors for VOD (SOS) and that these risk factors are addressed prior to haematopoietic stem cell transplantation (1A).

PROPHYLAXIS

Defibrotide is recommended at a dose of 6.25 mg/kg intravenously four times daily for the prevention of VOD (SOS) in children undergoing allogeneic stem cell transplantation with the following risk factors: pre-existing hepatic disease, second myeloablative transplant, allogeneic transplant for leukaemia beyond second relapse, conditioning with busulfan-containing regimens, prior treatment with gemtuzumab ozogamicin, diagnosis of primary haemophagocytic lymphohistiocytosis, adrenoleucodystrophy or osteopetrosis (1A). Defibrotide is suggested at a dose of 6.25 mg/kg intravenously four times daily for the prevention of VOD (SOS) in adults undergoing allogeneic stem cell transplantation with the following risk factors: pre-existing hepatic disease, second myeloablative transplant, allogeneic transplant for leukaemia beyond second relapse, conditioning with busulfan-containing regimens, prior treatment with gemtuzumab ozogamicin, diagnosis of primary haemophagocytic lymphohistiocytosis, adrenoleucodystrophy or osteopetrosis (2B). Prostaglandin E1 is not recommended in the prophylaxis of VOD (SOS) due to lack of efficacy and toxicity (1B). Pentoxifylline is not recommended in the prophylaxis of VOD (SOS) due to lack of efficacy (1A). Ursodeoxycholic acid is suggested for use in the prophylaxis of VOD (SOS) (2C). Heparin (unfractionated and low molecular weight) is not suggested for use in the prophylaxis of VOD (SOS) due to the risk of increased toxicity (2B). Antithrombin is not suggested for the prophylaxis of VOD (SOS) due to lack of efficacy (2B).

TREATMENT

Defibrotide is recommended in the treatment of VOD (SOS) in adults and children (1B). Tissue plasminogen activator is not recommended for use in the treatment of VOD (SOS) due to the associated risk of haemorrhage (1B). N-acetylcysteine is not routinely recommended for use in the treatment of veno-occlusive disease due to lack of efficacy (1A). Methylprednisolone may be considered for use in the treatment of veno-occlusive disease with the appropriate caveats of caution regarding infection (2C). Judicious clinical care, particularly in the management of fluid balance, is recommended in the management of VOD (SOS) (1C). Early discussion with critical care specialists and a specialist hepatology unit is recommended in the management of VOD (SOS) and other treatment options including transjugular intrahepatic portosystemic shunt or hepatic transplantation may be considered (1C).

SUMMARY

A joint working group established by the Haemato-oncology subgroup of the British Committee for Standards in Haematology (BCSH) and the British Society for Blood and Marrow Transplantation (BSBMT) has reviewed the available literature and made recommendations for the diagnosis and management of veno-occlusive disease of the liver following haematopoietic stem cell transplantation (HSCT). This guideline includes recommendations for both prophylaxis and treatment of the condition and includes recommendations for children and adults undergoing HSCT.

Hyperbilirubinemia in the early phase after allogeneic HSCT: prognostic significance of the alkaline phosphatase/total bilirubin ratio

Hyperbilirubinemia in the early phase after allogeneic hematopoietic SCT (HSCT) is due to various causes. One of the most important causes of hyperbilirubinemia is veno-occlusive disease/sinusoidal obstructive syndrome (VOD/SOS). However, the prognosis of patients who are clinically diagnosed as SOS varies. We retrospectively evaluated 82 patients who underwent their first allogeneic HSCT. GVHD prophylaxis was a combination of short-term MTX and CsA (n=77) or tacrolimus (n=5). Thirty-three patients developed hyperbilirubinemia, with a bilirubin level of at least 2 mg/dL, within 20 days after HSCT. Of these patients, 24 were diagnosed as VOD/SOS using the modified Seattle criteria. Twenty-six recovered to a bilirubin level of <2 mg/dL. We focused on the serum alkaline phosphatase/total bilirubin ratio (ALP/TB) at the onset of hyperbilirubinemia and found that it significantly predicted the recovery from hyperbilirubinemia. OS was significantly higher in patients with a lower ALP/TB ratio (P=0.00056). In addition, a lower ALP/TB ratio was associated with better survival even in patients who were clinically diagnosed as SOS (P<0.001). The ALP/TB ratio at the onset of hyperbilirubinemia may be a useful predictor for the prognosis of hyperbilirubinemia and SOS early after HSCT.

The effects of cancer chemotherapy on liver imaging

Chemotherapy changes the appearance of liver tumours and may also affect the liver parenchyma. Tumours respond with changes in size, outline, and internal architecture. The accuracy of liver CT for detecting metastases is reduced after chemotherapy. Histologic studies have shown that some metastases which become invisible on follow-up CT are completely sterile at later resection, but most 'disappearing' lesions still contain active tumour. Hepatic steatosis becomes much more common after chemotherapy. Diffuse fatty change may conceal metastases on US and CT, whilst focal steatosis may mimic tumour. Chemical-shift MRI will distinguish fat from tumour. Fatty change is usually reversible, unless the liver receives a 'second hit' of damage from other causes. Sinusoidal obstructive syndrome (SOS), nodular regenerative hyperplasia, veno-occlusive disease and peliosis are manifestations of microvascular injury which can result from chemotherapy. SOS, the most common of these, is undetectable on US and CT, but can be shown on SPIO-enhanced MRI. Although SOS causes no symptoms in most patients, it may cause increased bleeding from the friable liver at surgery, and greater risk of peri-operative adverse events. Rarer complications of chemotherapy include pseudo-cirrhosis and sclerosing cholangitis.

Sinusoidal obstructive syndrome diagnosed with superparamagnetic iron oxide-enhanced magnetic resonance imaging in patients with chemotherapy-treated colorectal liver metastases

PURPOSE

To assess the predictive value of superparamagnetic iron oxide (SPIO) -enhanced T2-weighted gradient echo (GRE) imaging to determine the presence and severity of sinusoidal obstructive syndrome (SOS).

PATIENTS AND METHODS

Sixty hepatic resection patients with colorectal metastases treated with chemotherapy underwent unenhanced magnetic resonance imaging (MRI) followed by T2-weighted GRE sequences obtained after SPIO. The images were reviewed in consensus by two experienced observers who determined the presence and severity of linear and reticular hyperintensities, indicating SOS-type liver injury, using a 4-point ordinal scale. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with 95% CIs for the detection of SOS were calculated.

RESULTS

Twenty-four of 60 patients had moderate to severe SOS on MRI. MRI achieved a sensitivity of 87% (95% CI, 66% to 97%), specificity of 89% (95% CI, 75% to 97%), PPV of 83% (95% CI, 63% to 95%), and NPV of 92% (95% CI, 77% to 98%). SOS was never found at surgery or histology in patients whose background liver parenchyma was normal on SPIO-enhanced MRI.

CONCLUSION

SOS is present in a significant proportion of patients with treated colorectal metastases and is effectively detected on SPIO-enhanced T2-weighted GRE images.

CT features of hepatic venoocclusive disease and hepatic graft-versus-host disease in patients after hematopoietic stem cell transplantation

OBJECTIVE

We conducted this study to evaluate whether CT scans could be used to differentiate hepatic venoocclusive disease from hepatic graft-versus-host disease in patients treated with hematopoietic stem cell transplantation.

SUBJECTS AND METHODS

We retrospectively evaluated 18 patients (eight women, 10 men; mean age, 42.4 years) after hematopoietic stem cell transplantation with biopsy-proven hepatic venoocclusive disease (n = 5), hepatic graft-versus-host disease (n = 6), or both (n = 7). Two radiologists reviewed abdominal and pelvic CT scans for hepatomegaly (> 18 cm), splenomegaly (> 13 cm), size of main portal and right hepatic veins, presence of periportal edema, gallbladder wall edema, hydropic gallbladder, ascites, and small-bowel wall thickening. CT and histopathology findings were correlated using analysis of variance and Fisher-Free-man-Holton tests.

RESULTS

Ascites and periportal edema were present in all five patients with venoocclusive disease, but of six patients with graft-versus-host disease, ascites was seen in two (p < 0.05) and periportal edema in only one (p < 0.05). Small-bowel wall thickening was encountered in five patients with graft-versus-host disease and in none with venoocclusive disease (p < 0.05). The right hepatic vein diameter in patients with venoocclusive disease (mean, 0.27 cm) was significantly smaller than the right hepatic vein diameter in patients with graft-versus-host disease (mean, 0.87 cm; p < 0.05).

CONCLUSION

In patients treated with hematopoietic stem cell transplantation, CT findings of periportal edema, ascites, and a narrow right hepatic vein suggest venoocclusive disease rather than graft-versus-host disease. Small-bowel wall thickening suggests graft-versus-host disease.

Review article: updates in the pathogenesis and therapy of hepatic sinusoidal obstruction syndrome

Hepatic sinusoidal obstruction syndrome is frequently linked to high-dose chemotherapy/total-body irradiation in recipients of haematopoietic stem cell transplantation, long-term use of azathioprine after organ transplantation and other chemotherapeutic agents. The incidence of hepatic sinusoidal obstruction syndrome varies from 0% to 70%, and is decreasing. Disease risk is higher in patients with malignancies, hepatitis C virus infection, those who present late, when norethisterone is used to prevent menstruation, and when broad-spectrum antibiotics and antifungals are used during and after the conditioning therapy. Hepatic sinusoidal obstruction syndrome presents with tender hepatomegaly, hyperbilirubinaemia and ascites, and diagnosis is mainly clinical (Seattle and Baltimore Criteria). Imaging excludes biliary obstruction and malignancy, but cannot establish accurate diagnosis. Hepatic sinusoidal obstruction syndrome may be prevented by avoiding the highest risk regimens, using non-myelo-ablative regimens, and reducing total-body irradiation dose. Treatment is largely symptomatic and supportive, because 70-80% of patients recover spontaneously. Tissue plasminogen activator plus heparin improves outcome in <30% of cases. Defibrotide, a polydeoxyribonucleotide, is showing encouraging results. Transjugular intrahepatic porto-systemic shunt relieves ascites, but does not improve outcome. Liver transplantation may be an option in the absence of malignancy. Prognosis is variable and depends on disease severity, aetiology and associated conditions. Death is most commonly caused by renal or cardiopulmonary failure.

Demonstration of reversed flow in segmental branches of the portal vein with hand-held color Doppler ultrasonography after hematopoietic stem cell transplantation

Hepatic veno-occlusive disease (VOD) is a severe complication of hematopoietic stem cell transplantation (SCT). When monitored with hand-held color Doppler ultrasonography during day -7 to +35 around SCT, reversed blood flow in the segmental branches of the portal vein was detected in nine of 56 patients who had undergone SCT. Three of nine patients had clinical evidence of VOD, but six patients did not fulfill the criteria for diagnosis of VOD initially. Two patients progressed to clinical VOD at a later date and the reversed portal flow disappeared with or without treatment for VOD in the other four patients. Monitoring for reversed portal flow with color Doppler ultrasonography may be a useful tool for the early diagnosis of VOD, and may improve prognosis by allowing early initiation of treatment.

Non-infectious manifestations of stem cell transplantation

Stem cell transplantation (SCT) is now commonplace within medical practice. With growth in transplant activities, outcomes are likely to continue to improve. Increasing numbers of the population now face life after transplantation. The aetiology of post transplant complications is multifactorial. Background knowledge of SCT and common, radiographically detectable, non-infective complications are important in everyday clinical practice. A review of these complications using a variety of imaging modalities is presented and the process of SCT briefly described. Tumour recurrence is outside the remit of this review.

Hepatic veno-occlusive disease: pathogenesis, diagnosis and treatment

Hepatic veno-occlusive disease (VOD) is one of the most serious complications following hematopoietic stem cell transplantation (SCT) and is associated with a very high mortality in its severe form. This review outlines the pathogenesis and clinical features of VOD, with an emphasis on endothelial cell injury and risk factors. The current status and future directions of research for both prophylaxis and treatment are also discussed.

Hepatic veno-occlusive disease (sinusoidal obstruction syndrome) after hematopoietic stem cell transplantation

Hepatic veno-occlusive disease (VOD), increasingly referred to as sinusoidal obstruction syndrome, is a well-recognized complication of hematopoietic stem cell transplantation and contributes to considerable morbidity and mortality. In the Western Hemisphere, VOD, classified as a conditioning-related toxicity, is most commonly caused by stem cell transplantation. VOD has been described after all types of stem cell transplantation, irrespective of the stem cell source, type of conditioning therapy, or underlying disease. Recognition of this disease in the posttransplantation setting remains a challenge in the absence of specific diagnostic features because many other more common conditions can mimic it. Limited therapeutic or preventive strategies are currently available for the management of VOD. In this review, we provide a comprehensive account of the pathophysiology of this disease as we understand it today, risk factors for its development, and the current state of knowledge regarding preventive and therapeutic options.

Recent progress in the diagnosis and therapy for veno-occlusive disease of the liver

Veno-occlusive disease (VOD) is one of the severe complications of the liver, which may occur after hematopoietic stem cell transplantation (HSCT). Although an early diagnosis is important to initiate antithrombotic therapy before serious organ failure, the widely used clinical criteria only become clinically fulfilled at an advanced stage of disease. Liver biopsy provides useful findings for the diagnosis of VOD, however, in the later or less severe stages of VOD liver biopsy may provide false-negative sampling error because the biopsy sample may be too small to evaluate the whole liver. In addition it may be difficult to follow the clinical course with repeat biopsy in individual cases. Imaging diagnosis of VOD including gray-scale US, Doppler US, and MRI have been reported as convenient and useful. Color-Doppler US is superior because of its specificity and sensitivity. Blood sampling tests including factor VII, protein C, N-terminal propeptide for type III procollagen (P-III-P) and hyarulonic acid have predictive value, and their measurement may simply be another way to evaluate early hepatic impairment. Since no optimal treatment for VOD has been established as yet, the prophylaxis of VOD or early initiation of treatment is important. These new diagnostic approaches for VOD may provide a direction to resolve the clinical problems of VOD such as the time of initiation of therapy, the therapeutic regimen of choice, and the cessation of therapy.

Magnetic resonance imaging for disorders of liver vasculature

Magnetic resonance imaging (MRI) provides a noninvasive technique to evaluate the hepatic vasculature. Angiographic and flow-based techniques include intrinsic properties of MRI as well as those that use contrast media. Clinical and technical perspectives of a wide range of vascular disorders affecting the liver, particularly cirrhosis and portal hypertension, portal vein obstruction, as well as imaging of the vasculature prior to and postliver transplantation are presented in this article.

Mylotarg (gemtuzumab ozogamicin) therapy is associated with hepatic venoocclusive disease in patients who have not received stem cell transplantation

BACKGROUND

Mylotarg (Wyeth-Ayerst Laboratories, St. Davids, PA) is the brand name for a calicheamicin-conjugated humanized anti-CD33 monoclonal antibody (gemtuzumab ozogamicin, CMA-676) and has been approved recently for the treatment of a subset of elderly patients who have relapsed acute myeloid leukemia (AML). Mylotarg is associated with an incidence of approximately 20% Grade 3 or 4 hyperbilirubinemia and liver transaminitis in this patient population. Hepatic venoocclusive disease (VOD) has been reported in patients who have undergone stem cell transplantation (SCT) after Mylotarg therapy. Outside of the SCT setting, VOD has been associated very rarely with cytotoxic therapy.

METHODS

The authors assessed the incidence of VOD in 119 patients who were receiving Mylotarg-containing non-SCT regimens. VOD was diagnosed through the use of standard Seattle and Baltimore criteria.

RESULTS

A cohort of 119 (61 previously untreated, 58 with relapsed disease) patients with AML (92 patients), advanced myelodysplastic syndrome (25 patients), or chronic myeloid leukemia in blast phase (2 patients), received Mylotarg-based regimens. Fourteen (12%) developed VOD. The diagnosis of VOD was supported by histology in 2 patients and radiologic studies in a further 10 patients. Five (36%) of 14 patients with VOD had received no prior antileukemic cytotoxic therapy, including 2 patients who received single-agent Mylotarg therapy.

CONCLUSIONS

Mylotarg was shown to be associated with the development of potentially fatal VOD in patients with leukemia who had not received SCT. VOD occurred when Mylotarg was used either as a single agent or when it was given with other cytotoxic agents. VOD occurred in Mylotarg-treated patients who had received no prior cytotoxic therapy. The current study concluded that risk factors for VOD should be assessed when considering Mylotarg therapy, and that attempts to avoid and treat VOD are warranted in patients who receive Mylotarg therapy.