Simpler Test May Be Best for Diagnosing Blood Clots in Leg

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By Serena Gordon
HealthDay Reporter

TUESDAY, Oct. 7 (HealthDay News) -- An older, simpler test to look for blood clots in the leg -- called deep vein thrombosis, or DVT -- is as effective as a newer, more expensive test, new research says.

European researchers found that 2-point ultrasonography of the leg -- sometimes called compression or duplex ultrasound -- was as good at detecting DVT as the newer, whole-leg, color-coded doppler ultrasound test.

"In general, the 2-point approach is safe, reproducible, easy, fast and convenient; [the test] may be performed with any ultrasound machine by any physician with minimal training," said the study's lead author, Dr. Enrico Bernardi, head of the emergency department at Conegliano Hospital in Italy.

Bernardi and his colleagues reported their findings in the Oct. 8 issue of the Journal of the American Medical Association.

The whole-leg scan, on the other hand, requires a specially trained physician and a special machine. Because of these requirements, the test isn't as widely available, according to Dr. C. Seth Landefeld, of the San Francisco Veterans Affairs Medical Center, who wrote an accompanying editorial in the journal.

DVT is a type of blood clot that forms in veins located deep within the body. Commonly, these clots occur in the legs. Certain factors increase your risk of DVT, including: traveling long distances, especially on an airplane; having a blood-clotting disorder; being pregnant; being overweight or obese; having a history of DVT; undergoing cancer treatment; and being older than 60, according to the U.S. National Heart, Lung, and Blood Institute.

The new study included 2,465 people being assessed for a possible DVT at 14 Italian hospitals.

The patients were randomly selected to receive either 2-point sonography or whole-leg sonography as part of their initial assessment. Those in the 2-point group with abnormal findings had a blood test called D-dimer that further assessed the risk of a blood clot, and were reassessed by 2-point ultrasound again in a week. If the findings were normal on the repeat test, they were not treated with blood-thinning medications. Abnormal findings on the repeat 2-point test warranted treatment, as did initial abnormal findings on the whole-leg test. Study volunteers from both groups were revaluated at three months.

During the three-month follow-up, blood clots were found in 0.9 percent of the 2-point group and in 1.2 percent of the whole-leg ultrasound group, according to the study.

"This study is an example of where the test with more bells and whistles doesn't have any advantage. One of the challenges of modern medicine is that as things get more complex, we have to make sure they're compared to what's tried and true. Here, they've identified that the simpler strategy works every bit as well," said Landefeld, who's a professor of medicine and chief of the division of geriatrics at the University of California, San Francisco.

Dr. Mark Adelman is chief of the division of vascular and endovascular surgery at New York University Langone Medical Center in New York City. He said that, while the study's findings were somewhat unexpected, he was pleased to see that the 2-point ultrasound along with the D-dimer test appeared to be just as effective in diagnosing most DVTs.

"In most hospitals, it's very difficult to do the total leg ultrasound. It requires skilled personnel, and it's very time-consuming," he said.

Adelman cautioned that anyone who has calf pain, swelling, redness or warmth that only occurs in one leg should be evaluated for DVT.

A good way to prevent DVT when flying, he said, is to make sure you stay hydrated with water -- coffee or alcohol can dehydrate you further. He also recommended getting up to walk at least every two hours during a flight, and to do calf exercises -- like you're stepping on a gas pedal -- periodically during your flight.

More information

To learn more about deep vein thrombosis, visit the U.S. National Heart, Lung, and Blood Institute.

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