Most Treatments for Blood Clots Appear Safe, Effective

Almost all the various treatment options for blood clots that form in veins are equally safe and effective, new research shows.

In exploring the safety and effectiveness of treatments for such blood clots as deep vein thrombosis or pulmonary embolism (blood clot in a lung), Canadian researchers analyzed outcomes associated with eight blood-thinning options, including unfractionated heparin, low-molecular-weight heparin (LMWH) and fondaparinux in combination with vitamin K antagonists.

The investigators also examined LMWH with dabigatran (Pradaxa), edoxaban, rivaroxaban (Xarelto), apixaban (Eliquis), as well as LMWH alone.

After examining nearly 50 randomized studies, the researchers found that unfractionated heparin combined with vitamin K antagonist was associated with a higher percentage of recurrent blood clots over the course of three months than the LMWH-vitamin K antagonist combination.

Meanwhile, bleeding risk was lowest with Xarelto and Eliquis compared with LMWH and vitamin K antagonist. The study showed that during three months of treatment, 0.49 percent of patients taking Xarelto had a major bleeding event. The same was true for 0.28 percent of those taking Eliquis. In contrast, 0.89 percent of those taking the LMWH-vitamin K antagonist combination experienced a major bleeding event.

All other treatment options had bleeding risks similar to LMWH with vitamin K antagonist, the study authors reported.

The research, led by Dr. Lana Castellucci of the Ottawa Hospital Research Institute at the University of Ottawa, was published in the Sept. 17 issue of the Journal of the American Medical Association.

"To our knowledge, this network meta-analysis is the largest review, including nearly 45,000 patients, assessing the clinical outcomes and safety associated with different anticoagulation strategies for the treatment of acute venous thromboembolism," the study authors wrote.

Venous thromboembolism includes two related conditions: deep vein thrombosis and pulmonary embolism. In deep vein thrombosis, a blood clot forms in the deep veins of the leg, causing swelling, redness, warmth and pain. If the blood clot breaks free, it can travel and lodge near the brain, heart or another vital organ, causing severe damage. If a clot blocks a blood vessel in the lungs, it's a life-threatening emergency called pulmonary embolism.

"We provide estimates on symptomatic recurrent venous thromboembolism and major bleeding outcomes (both patient-important outcomes), which are clinically relevant and are what clinical practice guideline recommendations are based on," the authors explained.

"All management options, with the exception of the unfractionated heparin-vitamin K antagonist combination, were associated with similar clinical outcomes compared with a management strategy using the LMWH-vitamin K antagonist combination," the study authors said.

"Treatment using the unfractionated heparin-vitamin K antagonist combination was associated with a higher risk of recurrent venous thromboembolism during the follow-up period," Castellucci's team concluded.

Venous thromboembolism is a common medical condition and the third leading cause of cardiovascular death, the authors noted in a journal news release.

More information

The American Society of Hematology has more on blood clots.