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Medical Policy

Policy Num:      06.001.037
Policy Name:    Scintigraphy of Acute Deep Venous Thrombus
Policy ID:          [06.001.037]  [Ar / B / M+ / P]  [6.01.22]

Last Review:     September 05, 2019
Next Review:     Policy Archived
Issue:                  9:2019

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Related Policies BCBS: None

Related Policies TSSS: None

Scintigraphy of Acute Deep Venous Thrombus

Summary

Deep vein thrombosis (DVT) is a common occurrence. It is estimated that in the United States approximately 5 million patients experience one or more episodes of DVT each year, resulting in over 500,000 cases of pulmonary embolism and 100,000 deaths. Prompt treatment of acute thrombus is considered essential to initiate anticoagulation or thrombolytic therapy to prevent the serious consequences of pulmonary embolus. Radiographic evaluation of deep venous thrombus is performed both in symptomatic patients and in asymptomatic patients at high risk of venous thrombus, i.e., after orthopedic surgery. Contrast venography is considered the gold standard of diagnosis, but this invasive procedure is not routinely used. Duplex ultrasonography is probably the most common noninvasive technique used, followed by impedance plethysmography. Ultrasonography is thought to have excellent sensitivity and specificity in the thigh, but poor diagnostic accuracy below the knee. Both of the above techniques provide indirect evidence of thrombus by imaging an alteration in blood flow and thus cannot distinguish between acute and chronic thrombus.

Direct detection of acute venous thrombus has been investigated using intravenously injected radiolabeled synthetic peptides that bind with high affinity to receptors expressed on activated platelets. In 1999, the FDA approved the radiopharmaceutical peptide apcitide (AcuTect™) for use in the scintigraphic imaging of acute venous thrombosis in the lower extremities in patients who have signs and symptoms of acute thrombophlebitis. Apcitide binds to glycoprotein IIb/IIIa fibrinogen receptors, which are expressed on the surface of activated platelets, thus making the radiopharmaceutical specific for acute, not chronic thrombus.

Objective

The objective of this evidence review is to evaluate the use and efficacy of Scintigraphy in the diagnosis of  Acute Deep Venous Thrombus

Policy Statements

Scintigraphic imaging of acute venous thrombus in the lower extremities may be considered medically necessary in patients with signs and symptoms of acute thrombus.

Scintigraphic imaging of acute venous thrombus in the lower extremities is considered investigational in asymptomatic patients at risk of acute venous thrombus.

Policy Guidelines

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Benefit Application

BlueCard/National Account Issues

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Background

Text

Regulatory Status

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Rationale

The following data are based on the package insert of AcuTect. (1)

Two multicenter clinical studies included 243 patients with signs and symptoms of acute thrombus who underwent evaluation with scintigraphic imaging compared with contrast venography, considered the gold standard. The primary outcome of the studies was agreement between the interpretations of the blindly read scintigraphic and contrast venography studies. The criterion for efficacy end point was pre-set at 75% agreement, with the lower limit of the 95% confidence interval being 60%. This agreement rate took into account the blind read variability of venography due to the adverse impact of the reader being blinded to the clinical information on the patient. The agreement rate between the results of scintigraphy vs. venography met this criterion.

It should be noted that the FDA-labeled indications are limited to symptomatic patients, and the data presented to the FDA focused on symptomatic patients. There are no data regarding the use of scintigraphic imaging in asymptomatic patients. Asymptomatic patients may represent a large percentage of patients undergoing imaging for DVT as a “rule out” test. For example, prior to hospital discharge after orthopedic procedures such as arthroplasties, many asymptomatic patients may undergo Doppler ultrasonography to rule out the presence of a thrombus. Data regarding this application of the scintigraphic imaging have not been published. The FDA labeling also states “How negative AcuTect images should be used in the diagnostic evaluation or therapeutic management of patients with suspected acute venous thrombosis has not been studied.”

In addition, no data are available regarding the diagnostic performance of scintigraphic imaging compared with Duplex ultrasonography, a more commonly used diagnostic technique than contrast venography. Therefore, it is not known whether the evaluation of DVT is improved by routinely performing both ultrasonography and scintigraphic imaging. Some imaging protocols suggest the use of scintigraphic imaging in the setting of indeterminate or nondiagnostic ultrasonography in symptomatic patients. (2)

Population Reference No. 1 

Individuals: With signs and symptoms of acute thrombus. Interventions of interest are: Scintigraphic imaging.  Comparators of interest are:  Standard of care.  Relevant outcomes are: Test validity,  Functional outcomes, Quality of life.

Supplemental Information

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Practice Guidelines and Position Statements

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Medicare National Coverage

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References

1. AcuTect package insert. Diatide, Inc. Londonderry, New Hampshire.

 2. Carretta RF, Vande Streek P, Weiland FL. Nuclear exam rivals venography for clots. Diagn Imaging 1998; 20(6):83-6.

Codes

Appplicable Modifiers

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Policy History