WEDNESDAY, Sept. 22 (HealthDay News) -- A blood-thinning drug could help some patients with superficial-vein thrombosis avoid more serious blood clots, a new study suggests. But experts question whether the benefit is worth the drug's high price.

Superficial-vein thrombosis, or superficial phlebitis, is characterized by blood clots in leg veins close to the skin. "This clot occurs in 90 percent of cases of varicose veins and is painful and visible for the patient," said the study's lead author, Dr. Herve Decousus, a researcher with University Hospital in Saint-Etienne, France.

Many factors -- long flights, pregnancy or recent surgery, among them -- can cause the condition. While serious complications of superficial-vein clots are rare, people with the condition can be at risk of developing deep-vein thrombosis, which is more serious and potentially fatal. Some doctors treat the superficial clots with blood-thinning medication or surgery; others don't treat them at all.

In the new study, researchers treated the superficial clots with Arixtra (fondaparinux), which is used to prevent and treat clots in the deep veins of the legs and in the lungs (pulmonary embolism), or a placebo. The pharmaceutical company GlaxoSmithKline, which makes Arixtra, funded the study.

Researchers randomly assigned 3,002 patients to receive either injections of 2.5 mg of Arixtra daily or a placebo for 45 days. They monitored the patients for another 32 days.

The study findings appear in the Sept. 23 issue of The New England Journal of Medicine.

The risk of developing deep-vein blood clots or clots in the lungs was lower in those who took the drug: 0.2 percent in those taking Arixtra vs. 1.3 percent in those getting the placebo.

The researchers also found that the risk of serious adverse events was less in the Arixtra group (0.7 percent) compared with the placebo group (1.1 percent). One patient in each group suffered major bleeding, they said.

"This treatment is effective, safe and relatively simple," Decousus said.

However, the risk of death -- one in 1,000 -- was the same in both groups. And overall, the researchers estimated that they'd have to treat 88 people with the drug to prevent one case of a deep-vein or lung blood clot.

Since the drug is safe, Decousus said, it's an acceptable treatment. "There are many diseases with a low risk of mortality which, nevertheless, require effective treatment to prevent disabling complications and the need for more aggressive therapies such as surgery."

But one American expert was more cautious. Dr. Julie Freischlag, director of the department of surgery at Johns Hopkins School of Medicine in Baltimore, said that it was rare that the clots would pose a serious threat. The findings "didn't convince me to use this in all patients. I've only seen a few clots go deeper," she said.

And in an accompanying commentary in the journal, two American doctors cautioned that the drug is expensive, costing $2,124 to $7,380 in New York City for a once-daily, 45-day supply. They recommended that government officials spend more time studying the drug and its cost-effectiveness. Until there's a consensus, they wrote, "it would be premature" to recommend the drug for this use.

More information

For more about superficial-vein thrombosis, visit the U.S. National Library of Medicine.