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Guideline Summary
Guideline Title
Vascular disorders of the liver.
Bibliographic Source(s)
DeLeve LD, Valla DC, Garcia-Tsao G, American Association for the Study Liver Diseases. Vascular disorders of the liver. Hepatology. 2009 May;49(5):1729-64. [368 references] PubMed External Web Site Policy
Guideline Status

This is the current release of the guideline.

FDA Warning/Regulatory Alert

Note from the National Guideline Clearinghouse: This guideline references a drug(s) for which important revised regulatory and/or warning information has been released.

  • November 6, 2013 – Low Molecular Weight Heparins External Web Site Policy: The U.S. Food and Drug Administration (FDA) is recommending that health care professionals carefully consider the timing of spinal catheter placement and removal in patients taking anticoagulant drugs, such as enoxaparin, and delay dosing of anticoagulant medications for some time interval after catheter removal to decrease the risk of spinal column bleeding and subsequent paralysis after spinal injections, including epidural procedures and lumbar punctures. These new timing recommendations, which can decrease the risk of epidural or spinal hematoma, will be added to the labels of anticoagulant drugs known as low molecular weight heparins, including Lovenox and generic enoxaparin products and similar products.

Scope

Disease/Condition(s)

Vascular disorders of the liver including:

  • Portal vein thrombosis (PVT)
  • Sinusoidal obstruction syndrome (SOS)
  • Budd-Chiari syndrome (BCS)
  • Congenital vascular malformations
Guideline Category
Diagnosis
Evaluation
Management
Risk Assessment
Treatment
Clinical Specialty
Family Practice
Gastroenterology
Hematology
Internal Medicine
Medical Genetics
Oncology
Pediatrics
Intended Users
Physicians
Guideline Objective(s)

To provide clinicians with approaches to diagnose and manage the disorders of the liver for which there are sufficient data to make recommendations

Target Population

Adults and children with vascular disorders of the liver

Interventions and Practices Considered

Diagnosis of Portal Vein Thrombosis (PVT)

  1. Medical history and clinical examination
  2. Assessment of risk factors
  3. Computed tomography (CT) scan, Doppler sonography, or magnetic resonance imaging (MRI) as needed
  4. Blood cultures as indicated
  5. Screening for gastroesophageal varices

Treatment of PVT

  1. Prophylaxis for variceal bleeding if indicated
  2. Anticoagulation therapy (low-molecular-weight heparin followed by oral anticoagulation)
  3. Antibiotics
  4. Children referral to expert surgical centers for consideration of a mesenteric-to-left portal vein bypass or using band ligation of large esophageal varices

Diagnosis of Sinusoidal Obstruction Syndrome (SOS)

  1. Clinical examination and assessment of symptoms (elevated bilirubin, hepatomegaly, and weight gain)
  2. Doppler ultrasound
  3. Transvenous liver biopsy if indicated

Management of SOS

  1. Diuretics, paracentesis, hemofiltration, and hemodialysis as needed
  2. Liver transplantation

Note: Transjugular intrahepatic portosystemic stent shunts (TIPS) or tissue plasminogen activator were considered but not recommended for the therapy of SOS. No recommendation was made for defibrotide due to lack of evidence.

Diagnosis of Budd-Chiari Syndrome (BCS)

  1. Investigating causes of primary BCS (ruling out space occupying lesions and malignant tumors, checking for risk factors for thrombosis, etc.)
  2. Assessment of symptoms (upper abdominal pain, ascites, or liver enlargement)
  3. Doppler sonography, CT, or MRI
  4. Liver biopsy, if indicated
  5. X-ray venography

Treatment of BCS

  1. Anticoagulation therapy (low-molecular-weight heparin followed by oral anticoagulation)
  2. Transjugular intrahepatic portosystemic stent shunts (TIPS) if no improvement on anticoagulation therapy
  3. Management of complications of portal hypertension
  4. Liver transplantation
  5. Monitoring patients for late development of hepatocellular carcinoma

Diagnosis of Congenital Vascular Malformations

  1. Screening for liver involvement in selected patients with hereditary hemorrhagic telangiectasia (HHT) (routine screening is not recommended)
  2. Doppler ultrasound, CT scan, or angiography
  3. Investigating congenital portosystemic shunting in selected patients (e.g., unexplained hyperammonemia, mental retardation)

Treatment of Congenital Vascular Malformations

  1. No treatment for asymptomatic patients
  2. Treatment of heart failure and portal hypertension
  3. Ursodeoxycholic acid for biliary disease
  4. Analgesics for pain
  5. Consider hepatic artery embolization in nontransplant candidates with intractable heart failure and hepatic artery "steal" syndrome
  6. Liver transplantation
Major Outcomes Considered

  • Sensitivity and specificity of diagnostic tests
  • Risk factors for vascular disorders of the liver
  • Efficacy and safety of treatment
  • Mortality

Methodology

Methods Used to Collect/Select the Evidence
Hand-searches of Published Literature (Primary Sources)
Hand-searches of Published Literature (Secondary Sources)
Searches of Electronic Databases
Description of Methods Used to Collect/Select the Evidence

These recommentations are based on the following: (1) formal review and analysis of the recently published world literature on the topic (Medline search); (2) American College of Physicians Manual for Assessing Health Practices and Designing Practice Guidelines; (3) guideline policies, including the American Association for the Study of Liver Diseases (AASLD) Policy on the Development and Use of Practice Guidelines and the American Gastroenterological Association Policy Statement on Guidelines; and (4) the experience of the authors in the specified topic.

Number of Source Documents

Not stated

Methods Used to Assess the Quality and Strength of the Evidence
Weighting According to a Rating Scheme (Scheme Given)
Rating Scheme for the Strength of the Evidence

Levels of Evidence

Level A Data derived from multiple randomized clinical trials or meta-analyses

Level B Data derived from a single randomized trial, or nonrandomized studies

Level C Only consensus opinion of experts, case studies, or standard-of-care

*Adapted from the American College of Cardiology and the American Heart Association Practice Guidelines.

Methods Used to Analyze the Evidence
Review of Published Meta-Analyses
Systematic Review
Description of the Methods Used to Analyze the Evidence

Not stated

Methods Used to Formulate the Recommendations
Expert Consensus
Description of Methods Used to Formulate the Recommendations

Not stated

Rating Scheme for the Strength of the Recommendations

Grading System for Recommendations*

Class I Conditions for which there is evidence and/or general agreement that a given diagnostic evaluation, procedure or treatment is beneficial, useful, and effective

Class II Conditions for which there is conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of a diagnostic evaluation, procedure, or treatment

Class IIa Weight of evidence/opinion is in favor of usefulness/efficacy

Class IIb Usefulness/efficacy is less well established by evidence/opinion

Class III Conditions for which there is evidence and/or general agreement that a diagnostic evaluation/procedure/treatment is not useful/effective and in some cases may be harmful

*Adapted from the American College of Cardiology and the American Heart Association Practice Guidelines.

Cost Analysis

A formal cost analysis was not performed and published cost analyses were not reviewed.

Method of Guideline Validation
Peer Review
Description of Method of Guideline Validation

This guideline has been approved by the American Association for the Study of Liver Diseases (AASLD) and represents the position of the association. This guideline was produced in collaboration with the Practice Guidelines Committee of the AASLD which provided extensive peer review of the manuscript.

Recommendations

Major Recommendations

The grading system for the class of recommendations (I, II, IIa, IIb, III) and the levels of evidence (A–C) are defined at the end of the "Major Recommendations" field.

Causes of Portal Vein Thrombosis (PVT)

Recommendations for investigating causes of PVT:

  1. Check first for cirrhosis, cancer of the abdominal organs, and an inflammatory focus in the abdomen, based on initial computed tomography (CT) scan and sonography findings, followed by additional procedures, as appropriate (Class I, Level B).
  2. Check for multiple, concurrent risk factors for thrombosis, in all patients without advanced cirrhosis or cancer, as indicated in Table 5 of the original guideline document (Class I, Level B).
  3. Do not rule out a diagnosis of myeloproliferative disease solely on the basis of normal or low peripheral blood cell counts (Class I, Level B).
  4. When coagulation factor levels are decreased, consider low levels of protein C, protein S, or antithrombin as a possible consequence of liver dysfunction; consider inherited deficiency when screening of a first-degree relative is positive (Class I, Level C).

Acute Portal Vein Thrombosis

Recommendations for diagnosis of acute PVT:

  1. Consider a diagnosis of acute PVT in any patient with abdominal pain of more than 24 hours duration, whether or not there is also fever or ileus (Class I, Level B).
  2. If acute PVT is suspected, CT scan, before and after injection of vascular contrast agent, should be obtained for early confirmation of diagnosis. If CT scan is not rapidly available, obtain Doppler sonography (Class I, Level B).
  3. In patients with acute PVT and high fever and chills, septic pyelophlebitis should be considered, whether or not an abdominal source of infection has been identified, and blood cultures should be routinely obtained (Class I, Level B).
  4. In acute PVT, the possibility of intestinal infarction should be considered from presentation until resolution of pain. The presence of ascites, thinning of the intestinal wall, lack of mucosal enhancement of the thickened intestinal wall, or the development of multiorgan failure indicate that intestinal infarction is likely and surgical exploration should be considered (Class I, Level B).

Recommendations for the treatment of acute PVT (see also Table 6 in the original guideline document):

  1. Give anticoagulation therapy for at least 3 months to all patients with acute PVT. Start with low molecular weight heparin in order to achieve rapid anticoagulation. Shift to oral anticoagulation as soon as the patient's condition has stabilized, when no invasive procedure is planned (Class I, Level B).
  2. Continue on long-term anticoagulation therapy in patients with acute PVT and permanent thrombotic risk factors that are not correctable otherwise (Class I, Level B).
  3. In the absence of contraindication, also consider long term anticoagulation for patients with acute PVT and thrombus extension distal into the mesenteric veins (Class IIa, Level C).
  4. Initiate antibiotics promptly in patients with acute PVT and any evidence of infection (Class I, Level C).

Chronic Portal Vein Thrombosis

Recommendations for diagnosis of chronic PVT:

  1. Consider a diagnosis of chronic PVT in any patient with newly diagnosed portal hypertension (Class I, Level B).
  2. Obtain Doppler sonography, then either CT scan or magnetic resonance imaging (MRI), before and after a vascular contrast agent, to make a diagnosis of chronic PVT.
  3. Base the diagnosis on the absence of a visible normal portal vein and its replacement with serpiginous veins (Class I, Level B).

Recommendations for treatment of chronic PVT (See also Table 6 in the original guideline document):

  1. Screen all patients with chronic PVT for gastroesophageal varices, and apply treatment for active variceal hemorrhage and for primary and secondary prophylaxis according to guidelines for patients with cirrhosis (Class I, Level B).
  2. Consider long-term anticoagulation therapy in patients with chronic PVT, without cirrhosis, and with a permanent risk factor for venous thrombosis that cannot be corrected otherwise, provided there is no major contraindication. In patients with gastroesophageal varices, do not initiate anticoagulation until after adequate prophylaxis for variceal bleeding has been instituted (Class IIa, Level C).

Extrahepatic Portal Vein Obstruction in Children

Recommendations for the management of chronic PVT in children:

  1. When possible, refer children with extrahepatic portal venous obstruction to an expert surgical center for consideration of a mesenteric-to-left portal vein bypass (Class I, Level B).
  2. If a mesenteric-to-left portal vein bypass is not possible in a child with chronic PVT, use band ligation of large esophageal varices for prophylaxis of gastrointestinal bleeding. If band ligation is not feasible, consider a central portosystemic shunt when either the superior mesenteric or splenic vein is patent (Class I, Level B)

Sinusoidal Obstruction Syndrome (SOS, Hepatic Veno-occlusive Disease)

  1. Consider the diagnosis of SOS in patients in the appropriate clinical scenario who present with tender hepatomegaly, fluid retention and weight gain, and elevated serum bilirubin (Class I, level B).
  2. Rule out other common causes of jaundice (such as biliary tract obstruction, hemolysis, sepsis, drug-induced liver injury and viral and fungal infections involving the liver) and weight gain (for example due to fluid overload, renal insufficiency or congestive heart failure) in this population (Class I, Level C).
  3. Image the liver with Doppler ultrasound or another modality to rule out other causes and to demonstrate features consistent with SOS (Class I, Level C).
  4. In complicated cases, perform a transvenous liver biopsy with hepatic venous pressure gradient to confirm the diagnosis. In hematopoietic cell transplantation patients, a hepatic venous pressure gradient of greater than 10 mm Hg is highly specific for SOS (Class I, Level C).

Prophylactic Medical Therapy

  1. Consider regimens that are less likely to cause toxic liver injury in patients with extensive hepatic fibrosis, viral hepatitis, myelofibrosis with extramedullary hematopoiesis, recent treatment with gemtuzumab ozogamicin or a previous history of SOS. Regimens that are less liver toxic include reduced intensity regimens, regimens without cyclophosphamide, and regimens with lower doses of total body irradiation (Class I, Level B).
  2. Although widely used, no recommendation can be made for or against the use of prophylactic pharmacological strategies because none examined to date have consistently shown a reduction in the overall risk of SOS or the risk of fatal SOS in randomized controlled trials (Class IIb, Level A).

Management of Established Disease

  1. Fluid overload in SOS should be managed with diuretics, paracentesis, hemofiltration, and hemodialysis as needed (Class I, Level C).
  2. With the absence of randomized controlled trials, no recommendation can be made for or against defibrotide for the treatment of established SOS (Class IIb, Level B).
  3. Patients who undergo hematopoietic cell transplantation for a condition with a favorable prognosis may be considered for liver transplantation (Class I, Level C).
  4. Transjugular intrahepatic portosystemic stent shunts (TIPS) or tissue plasminogen activator are not recommended for the therapy of SOS (Class III, Level B).

Budd-Chiari Syndrome (BCS)

Recommendations for investigating causes of primary BCS:

  1. Rule out space occupying lesions, or malignant tumors, compressing or invading the hepatic venous outflow tract with sonography, CT scan or MRI (Class I, Level B).
  2. Seek clinical evidence for ulcerative colitis, celiac disease, and for systemic diseases (Class I, Level B).
  3. Routinely check for multiple, concurrent risk factors for thrombosis, as indicated in Table 5 in the original guideline document (Class I, Level B).
    • Do not rule out a diagnosis of myeloproliferative disease solely on the basis of normal or low peripheral blood cell counts (Class I, Level B).
    • When coagulation factor levels are below the normal range, do not regard decreased levels of protein C, protein S or antithrombin as a primary, possibly inherited, deficiency in the absence of a positive family history or screening (Class I, Level C).
    • Do not regard relatively weak thrombotic risk factors (factor V Leiden mutation, prothrombin gene mutation, hyperhomocysteinemia, or oral contraceptive use) as the only risk factor for BCS until other causes have been ruled out (Class I, Level B).

Recommendations for diagnosis of BCS:

  1. Consider a diagnosis of BCS in the following settings:
    • An acute or chronic illness occurs with upper abdominal pain, ascites, or liver enlargement
    • A liver disease occurs in a patient with known risk factors for thrombosis
    • A liver disease occurs in a patient with an extensive network of subcutaneous veins of the trunk suggesting inferior vena cava obstruction
    • A liver disease remains unexplained after other common or uncommon causes have been excluded (Class I, Level C).
  2. Consider only direct visualization of obstruction, and/or collaterals, of a hepatic vein or inferior vena cava, as definite evidence for the diagnosis (Class I, Level C).
  3. Consider Doppler sonography by an experienced examiner, aware of the diagnostic suspicion, as a most effective and reliable diagnostic means. Consider MRI or CT scan as a confirmatory study or, if an experienced Doppler-sonography examiner is not available, as an alternative (Class I, Level C).
  4. Consider performing a liver biopsy only when an obstructed hepatic venous outflow tract has not been demonstrated with noninvasive imaging (Class I, Level C).
  5. Consider X-ray venography as a diagnostic procedure in patients where the diagnosis remains uncertain (Class I, Level B).
  6. When making a decision regarding whether or not to perform an invasive diagnostic procedure, consider the potential renal toxicity of iodinated contrast agents and a possible need for rapid anticoagulation and/or pharmacological thrombolysis following the invasive procedure (Class I, Level C).
  7. Do not regard liver nodules enhancing at the arterial phase of contrast injection as hepatocellular carcinoma without additional support for this diagnosis (Class I, Level C).

Recommendations for therapy of Budd-Chiari syndrome (see also Table 6 in the original guideline document):

  1. Correct without delay the underlying risk factors for venous thrombosis, whenever possible (Class I, Level C).
  2. Initiate anticoagulation therapy immediately. Use low molecular weight heparin, targeting anti-Xa activity to 0.5-0.8 IU/mL. Change to an oral anticoagulation agent when clinically appropriate, targeting the international normalized ratio (INR) to between 2-3 (Class I, Level B).
  3. Maintain permanent anticoagulation therapy, unless a major contraindication is present or a complication of anticoagulation therapy occurs (Class I, Level C).
  4. Treat complications of portal hypertension as recommended for other types of liver disease until more data are available (Class I, Level C).
  5. Check for a venous obstruction amenable to percutaneous angioplasty/stenting in all symptomatic patients. Treat accordingly (Class I, Level C).
  6. In patients without ongoing improvement on anticoagulation therapy (with or without angioplasty), consider TIPS insertion (Class I, Level C).
  7. Consider liver transplantation:
    • If TIPS insertion fails or does not improve the patient's condition.
    • In patients with fulminant hepatic failure (Class I, Level C).
  8. Consider initial management for recently diagnosed BCS in close connection with a transplant center (Class III, Level C).
  9. Monitor patients with long-standing, well controlled BCS for late development of hepatocellular carcinoma and transformation of underlying myeloproliferative disease (Class I, Level C).

Congenital Vascular Malformations

Liver Involvement by Hereditary Hemorrhagic Telangiectasia (HHT)

Diagnosis

  1. Screening for liver involvement in patients with HHT is not recommended except in patients in whom the presence of liver vascular malformations would be key in establishing a definite diagnosis of HHT (Class III, Level C).
  2. The diagnosis of liver involvement in HHT should be made radiographically: by Doppler ultrasound, CT scan or angiography (Class I, Level C). The diagnosis is based on finding heterogeneous enhancement or hypervascularization of the liver and common hepatic artery enlargement (Class I, Level B). Liver biopsy should be avoided, as it is not useful in the diagnosis of liver involvement by HHT and could be complicated by bleeding (Class III, Level B).
  3. Isolated liver masses in patients with HHT should not be regarded as hepatocellular carcinoma without additional support for the diagnosis (Class I, Level B).

Treatment

  1. Treatment is not indicated in patients with HHT who have asymptomatic liver involvement (Class III, Level C).
  2. In patients with HHT who have symptomatic liver involvement, treatment depends on presentation:
    • Heart failure and portal hypertension are treated according to standards of care (Class I, Level A).
    • Biliary disease is treated with ursodeoxycholic acid and with analgesics for right upper quadrant pain (Class I, Level C).
  3. Hepatic artery embolization should be avoided in patients with liver involvement by HHT, as it is a palliative measure associated with significant morbidity. It is also contraindicated in patients with portosystemic shunting and in those with biliary presentation (Class III, Level B). It can be considered in nontransplant candidates with intractable heart failure and hepatic artery "steal" syndrome (Class IIa, Level C).
  4. Liver transplantation is the only curative treatment and should be considered for acute biliary necrosis syndrome and intractable heart failure or portal hypertension (Class I, Level C).

Isolated Congenital Liver Shunts

  1. Congenital portosystemic shunting should be investigated in patients with unexplained hyperammonemia, mental retardation and/or clinical picture compatible with hepatic encephalopathy in the absence of cirrhosis (Class I, Level C).

Definitions:

Levels of Evidence*

Level A Data derived from multiple randomized clinical trials or meta-analyses

Level B Data derived from a single randomized trial, or nonrandomized studies

Level C Only consensus opinion of experts, case studies, or standard-of-care

Grading System for Recommendations*

Class I Conditions for which there is evidence and/or general agreement that a given diagnostic evaluation, procedure or treatment is beneficial, useful, and effective

Class II Conditions for which there is conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of a diagnostic evaluation, procedure, or treatment

Class IIa Weight of evidence/opinion is in favor of usefulness/efficacy

Class IIb Usefulness/efficacy is less well established by evidence/opinion

Class III Conditions for which there is evidence and/or general agreement that a diagnostic evaluation, procedure/treatment is not useful/effective and in some cases may be harmful

*Adapted from the American College of Cardiology and the American Heart Association Practice Guidelines.

Clinical Algorithm(s)

None provided

Evidence Supporting the Recommendations

Type of Evidence Supporting the Recommendations

The guidelines are based on review of the published literature and the personal experience of the authors. The type of evidence is specifically stated for each recommendation (see the "Major Recommendations" field).

Benefits/Harms of Implementing the Guideline Recommendations

Potential Benefits

Improved diagnosis and treatment of vascular disorders of the liver

Potential Harms

  • Complications of anticoagulation (e.g., bleeding)
  • Complications of surgical procedures

Contraindications

Contraindications

  • Hepatic artery embolization should be avoided in patients with liver involvement by hereditary hemorrhagic telangiectasia (HHT), as it is a palliative measure associated with significant morbidity. It is also contraindicated in patients with portosystemic shunting and in those with biliary presentation.
  • For the diagnosis of sinusoidal obstruction syndrome (SOS), percutaneous liver biopsy is often contraindicated in moderately or severely ill patients because of thrombocytopenia, coagulopathy, or ascites.
  • Oral contraceptives are generally contraindicated in patients with Budd-Chiari syndrome (BCS).

Qualifying Statements

Qualifying Statements

These recommendations suggest preferred approaches to the diagnostic, therapeutic, and preventive aspects of care. They are intended to be flexible, in contrast to standards of care, which are inflexible policies to be followed in every case.

Implementation of the Guideline

Description of Implementation Strategy

An implementation strategy was not provided.

Implementation Tools
Mobile Device Resources
For information about availability, see the Availability of Companion Documents and Patient Resources fields below.

Institute of Medicine (IOM) National Healthcare Quality Report Categories

IOM Care Need
Getting Better
Living with Illness
IOM Domain
Effectiveness

Identifying Information and Availability

Bibliographic Source(s)
DeLeve LD, Valla DC, Garcia-Tsao G, American Association for the Study Liver Diseases. Vascular disorders of the liver. Hepatology. 2009 May;49(5):1729-64. [368 references] PubMed External Web Site Policy
Adaptation

Not applicable: The guideline was not adapted from another source.

Date Released
2009 May
Guideline Developer(s)
American Association for the Study of Liver Diseases - Nonprofit Research Organization
Source(s) of Funding

American Association for the Study of Liver Diseases

Guideline Committee

American Association for the Study of Liver Diseases (AASLD) Practice Guidelines Committee

Composition of Group That Authored the Guideline

Primary Authors: Laurie D. DeLeve; Dominique-Charles Valla; Guadalupe Garcia-Tsao

Committee Members: Margaret C. Shuhart, MD, MS, (Committee Chair); Gary L. Davis, MD (Board Liaison); Kiran Bambha, MD; Andres Cardenas, MD; MMSc.; Timothy J. Davern, MD; José Franco, MD; Steven-Huy B. Han, MD; Stephen A. Harrison, MD; Charles D. Howell, MD; Simon C. Ling, MBChB, MRCP; Lawrence U. Liu, MD; Paul Martin, MD; Robert S. O'Shea, MD; Nancy Reau, MD; Bruce A. Runyon, MD; Jayant A. Talwalkar, MD, MPH; John B. Wong, MD; Colina Yim, RN, MN

Financial Disclosures/Conflicts of Interest

Potential conflict of interest: Nothing to report.

Guideline Status

This is the current release of the guideline.

Guideline Availability

Electronic copies: Available in Portable Document Format (PDF) from the American Association for the Study of Liver Diseases Web site External Web Site Policy.

Print copies: Available from the American Association for the Study of Liver Diseases, 1729 King Street, Suite 200; Alexandria, VA 22314; Phone: 703-299-9766; Web site: www.aasld.org External Web Site Policy; e-mail: aasld@aasld.org.

Availability of Companion Documents

This guideline is available as a Personal Digital Assistant (PDA) download via the APPRISOR™ Document Viewer from www.apprisor.com External Web Site Policy.

Patient Resources

None available

NGC Status

This summary was completed by ECRI Institute on December 30, 2009. The information was verified by the developer on January 20, 2010. This summary was updated by ECRI Institute on March 7, 2014 following the U.S. Food and Drug Administration advisory on Low Molecular Weight Heparins.

Copyright Statement

This NGC summary is based on the original guideline, which is subject to the American Association for the Study of Liver Diseases' copyright restrictions.

Disclaimer

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The National Guideline Clearinghouse™ (NGC) does not develop, produce, approve, or endorse the guidelines represented on this site.

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