Fatal VTE Not Common in Leg Fractures

ATLANTA -- Thromboprophylaxis is used routinely in patients with isolated leg fractures, but findings from a large prospective cohort study suggest this practice is unwarranted, Dr. Rita Selby reported at the annual meeting of the American Society of Hematology.

Of nearly 1,200 patients with isolated leg fractures who received no prophylaxis against venous thromboembolism (VTE), none experienced fatal pulmonary embolism, said Dr. Selby of the University of Toronto.

"We also found, surprisingly, that the risk of symptomatic clots was quite low," she said at a press briefing, noting that although 82% of patients were immobilized in a cast for 6 weeks, and 7% were treated surgically, only 0.6% developed symptomatic VTE. These included five patients with deep vein thrombosis (DVT) and two with pulmonary embolism (PE).

The low incidence of symptomatic VTE suggests it is also unlikely that subgroups could be identified for targeted prophylaxis, Dr. Selby said.

Patients were enrolled in the 3-year, multicenter study if they experienced fractures of the patella, fibula, or foot (treated operatively or conservatively) or of the tibia (treated nonoperatively). Those with major trauma, active cancer, and previous VTE were excluded.

Participants were educated about symptoms of DVT and PE and were interviewed via telephone at 14 days, 6 weeks, and 3 months following the injury. Suspected VTE events were investigated in a standardized manner.

The findings highlight the discrepancy in the incidence of VTE with clinical end points vs. venography, Dr. Selby said.

The standard practice of providing thromboprophylaxis in patients with isolated leg fractures emerged in response to findings from screening venography studies showing a DVT incidence as high as 40%. However, most venographically detected DVTs are asymptomatic distal thrombi with unclear clinical relevance, she explained.

The findings underscore the need to reevaluate the use of screening venography in clinical trials on VTE prevention, and to move toward using clinical end points, she said