New guidelines for VTE focus on diagnostic risk assessment and aggressive management

Leawood, KS - The American College of Physicians and American Academy of Family Physicians announced clinical practice guidelines for the diagnosis and management of venous thromboembolism (VTE), which claims more than 200 000 deaths each year in the US.

 

The guidelines, which are the first ever to be developed by the two physician groups, were released on January 29, 2007 and will be published jointly in the February issues of the Annals of Internal Medicine and Annals of Family Medicine [1,2].

 

"The purpose of the guidelines is to present recommendations to clinicians that are based on the current evidence to aid in the diagnosis and management of lower-extremity deep vein thrombosis [DVT] and pulmonary embolism [PE]," according to lead author Dr Amir Qaseem (American College of Physicians, Philadelphia, PA).

 

The guidelines are also meant to bring attention to an expanding population at risk, Qaseem said in an interview with heartwire. "The annual incidence of VTE in the US is 600 000 cases, and it is increasing with the aging population. Undiagnosed and untreated PE can result in up to 25% mortality. Early diagnosis and treatment is very crucial to prevent the mortality and morbidity associated with it," stressed Qaseem. He said the new guidelines are meant to help clinicians understand the value and use of various diagnostic tools, such as D-dimer and ultrasound, and the significance of the clinical characteristics that are useful in identifying high-risk patients. "Strong evidence supports the use prediction rules," he said. "Use of high-sensitivity D-dimer assay in patients who have a low pretest probability of VTE has a high negative predictive value and is highest in younger patients with a low pretest probability and no associated comorbidities."

 

There is strong evidence supporting the use of ultrasonography for diagnosing proximal DVT in patients with intermediate to high risk of pretest probability; however, he noted that sensitivity is much lower in asymptomatic patients for detecting calf vein DVT.

Positive D-dimer test may indicate need for ultrasound

"The clinical prediction rules will help physicians determine risk categories. If patients are low to intermediate risk, they should get the D-dimer test. If the test is positive, ultrasound may be indicated," he said in an interview with heartwire.

 

For management, he said, low-molecular-weight heparin (LMWH) is indicated for DVT, as it is as effective as unfractionated heparin, especially for reducing morbidity and mortality during initial therapy. Outpatient therapy is safe and cost effective to treat DVT (but is good only for the highly selected population and if good support services are in place). The recommendations call for the use of compression stockings to prevent postphlebitic syndrome, and anticoagulation is important.

"Duration depends on risk factors: three to six months for VTE secondary to transient risk factors and more than 12 months for recurrent VTE," he said.

 

The diagnostic guideline recommends:

• Validated clinical prediction rules should be used to estimate pretest probability of VTE, both DVT and PE, and as the basis of interpretation of subsequent tests. Validated clinical prediction rules should be used to estimate probability of VTE, DVT, and PE on the basis of subsequent tests. The Wells Prediction Rule for DVT is the standard and is based on clinical characteristics (cancer, recently bedridden, swollen leg or calf, edema; for PE, they are previous embolism, elevated heart rates, and hemoptysis).

• In appropriately selected patients with low pretest probability of DVT or PE, obtaining a high-sensitivity D-dimer is a reasonable option and, if negative, indicates a low likelihood of venous thromboembolism.

• Ultrasound is recommended for patients with intermediate to high pretest probability of DVT in the lower extremities.

• Patients with intermediate or high pretest probability of PE require diagnostic imaging studies.

LMWH preferred over unfractionated heparin

The management guideline recommends:

• LMWH, rather than unfractionated heparin, should be used whenever possible for the initial inpatient treatment of DVT. Either unfractionated heparin or LMWH are appropriate for the initial treatment of PE.

• Outpatient treatment of DVT and possibly PE with LMWH is safe and cost effective for carefully selected patients and should be considered when required support services are in place.

• Compression stockings should be used routinely to prevent postthrombotic syndrome, beginning within a month of diagnosis of proximal DVT and continuing for at least one year after diagnosis.

• There is insufficient evidence to make specific recommendations for types of anticoagulation management of VTE in pregnant women.

• Anticoagulation should be for three to six months for VTE and for more than 12 months for recurrent VTE. While the appropriate duration of anticoagulation for idiopathic or recurrent VTE is not definitively known, there is evidence of benefit for extended-duration therapy.

• LMWH is safe and efficacious for the long-term treatment of VTE in selected patients (and may be preferable for patients with cancer).