A new study suggests that the standard therapy doctors use to prevent complications after a common type of blood clot may not actually be effective.

The blood clot, called Deep Vein Thrombosis, often results in a complication called Post Thrombotic Syndrome. Patients with PTS often suffer from leg swelling and painful ulcers.

Some estimates suggest that upwards of 50,000 Canadians are diagnosed with a Deep Vein Thrombosis every year, and half experience PTS.

Current guidelines for doctors recommend that patients who experience a Deep Vein Thrombosis wear elastic compression stockings for two years to prevent PTS. The theory is simple: the pressure the stockings exert on the veins will help prevent swelling..

But Dr. Susan Kahn, who works out of the Lady David Institute at the Jewish General Hospital in Montreal, says her recent study shows that patients who used elastic compression stockings after a blood clot were no less likely to experience painful complications than patients who were given placebo stockings.

“We have to look towards other interventions that could be delivered soon after DVT is diagnosed to prevent this chronic condition from occurring,” Kahn told CTV.

The study was the largest of its kind, following more than 800 patients for two years.

According to a summary of the study, stockings can be costly – upwards of $100 per pair – and need to be replaced as frequently as twice a year due to elasticity loss.

The hospital says stockings are also cumbersome and can be uncomfortable to wear.

Manufacturer disputes findings

Sigvaris, one of Canada’s largest manufacturers of compression garments, disputes the findings in Kahn`s study, adding that it contradicts findings in earlier studies.

Scott Dube, the company’s North American CEO, suggested one problem with Kahn’s study is that it looked at people who were wearing stockings three days a week or more.

“I’m pretty sure more physicians would say you have to wear compressions seven days a week,” Dube said.

Olga Novolodskaia, a Quebec woman who lived with DVT, told CTV that the elastic compression stockings do help her.

“With time of course, my legs get better and better. My legs are normal,” she said.

While Kahn’s study doesn’t entirely rule out the effectiveness of the stockings, she says the results should have an immediate impact on the way doctors prescribe stockings.

She says the study has disproved the theory that every patient with a Deep Vein Thrombosis needs to purchase and wear stockings for two years.

With a report from CTV News' Vanessa Lee