By: Shelagh McNally for Veins1
When it comes to diagnosing deep vein thrombosis (DVT), a simpler method is proving to be just as effective as a more complex test.
DVT is often difficult to diagnose initially. The symptoms of a painful and swollen calf can be connected to other diseases as well. It’s usually confirmed with a combination of ultrasonography and a D-dimers blood test. D-dimers are fibrin protein fragments found in blood clots. An increase in d-dimer levels can mean a blood clot is present that is not being dissolved.
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Deep vein thrombosis commonly affects the legs, pelvis or lungs. Veins of the arm are not usually affected.
DVT can occur without symptoms in some cases. Usual symptoms are for the affected area to become painful, swollen, red and warm to the touch. Superficial veins may become engorged.
DVT is also known as Economy Class Syndrome. In the late 1980s, there was an epidemic of DVT with people traveling long distance in economy class on airplanes. The combination of cramped space and dehydration made people more susceptible to thrombosis.
DVT can also be brought on by physical trauma, infections or inflammatory diseases. Surgery, hospitalization, obesity, smoking, and certain drugs such as estrogen can also bring about thrombosis.
There are two types of non-invasive ultrasonography images used. Whole-leg Doppler ultrasonography bounces sound waves off red blood cells to evaluate the changes in frequency. This one-day test is quick and extremely thorough. Unfortunately it requires expensive ultrasound equipment and experienced operators. The test is usually not available after hours or during weekends. As a result, patients are usually prescribed anticoagulant medication as a preventive measure.
The other simpler (and older) test used is the 2-point ultrasonography test where compression is applied to only two veins. This test can be performed with virtually any ultrasound scanner and doesn’t need as skilled a technician. Its major limitation is that the test has to be performed again within one week in patients with normal findings.
The medical profession has favored the whole-leg approach with the rationale being that it could better detect isolated calf clots. But a new study recently published in the Journal of the American Medical Association has shown that the 2-point has equal if not better results.
Enrico Bernardi, M.D., Ph.D., and his research team at the Civic Hospital in Conegliano, Italy set out to evaluate the two diagnostic strategies following 2,098 outpatients with a first episode of suspected DVT. One group with 1,045 patients underwent the 2-point test while the other group of 1,053 underwent whole leg ultrasonography.
During the three-month follow-up period, Bernardi found that patients in the 2-point strategy group had a 0.9 percent (7 of 801 patients) confirmation of symptomatic VTE while patients in the whole-leg ultrasonography group had a 1.2 percent (9 of 763 patients) incidence. VTE is venous thromboembolism (blood clots in the deep veins of the legs or lungs).
Bernardi concluded that “Either strategy may be chosen based on the clinical context, on the patients' needs, and on the available resources. Two-point ultrasonography plus D-dimer is simple, convenient, and widely available but requires repeat testing in one-fourth of the patients. Whole-leg ultrasonography offers a 1-day answer, desirable for patients with severe calf complaints, for travelers, and for those living far from the diagnostic service, but is cumbersome, possibly more expensive, and may expose patients to the risk of (unnecessary) anticoagulation.”
C. Seth Landefeld, M.D., of the University of California, San Francisco, San Francisco Veterans Affairs Medical Center, and Stanford University, agreed with the finding, stating that “The results of the trial by Bernardi et al show that whole-leg ultrasonography has little advantage, unless a course of anticoagulant therapy for isolated calf DVT is preferable to repeating 2-point ultrasonography a week later."