Preventing blood clots from coming back

March 1, 2019

Dr. Marc CarrierDr. Marc Carrier

Hundreds of thousands of people in Canada and the U.S. take blood thinners every day to prevent dangerous blood clots from coming back after an initial clot (called a venous thromboembolism). But multiple blood thinners are available and very few studies have compared them head-to-head. So Dr. Marc Carrier and his colleagues pooled data from more than 22,000 patients from 16 clinical trials around the world to come up with the best evidence possible. Their systematic review and network meta-analysis shows that warfarin and newer anti-clotting pills known as NOACs are both more effective than aspirin, but more data is needed to compare warfarin with NOACs. This research will guide doctors and patients around the world while they wait for results of a massive clinical trial (co-led by Dr. Lana Castellucci) that is comparing warfarin and anti-clotting pills head-to-head.  See Heart for details.

Authors: Wang KL, van Es N, Cameron C, Castellucci LA, Büller HR, Carrier M

Funding: No specific funding was provided. Research at The Ottawa Hospital is possible because of generous donations to The Ottawa Hospital Foundation.

The Ottawa Hospital: Inspired by research. Driven by compassion 

The Ottawa Hospital is one of Canada’s largest learning and research hospitals with over 1,100 beds, approximately 12,000 staff and an annual budget of over $1.2 billion. Our focus on research and learning helps us develop new and innovative ways to treat patients and improve care. As a multi-campus hospital, affiliated with the University of Ottawa, we deliver specialized care to the Eastern Ontario region, but our techniques and research discoveries are adopted around the world. We engage the community at all levels to support our vision for better patient care. See for more information about research at The Ottawa Hospital.

University of Ottawa: —A crossroads of cultures and ideas

The University of Ottawa is home to over 50,000 students, faculty and staff, who live, work and study in both French and English. Our campus is a crossroads of cultures and ideas, where bold minds come together to inspire game-changing ideas. We are one of Canada’s top 10 research universities—our professors and researchers explore new approaches to today’s challenges. One of a handful of Canadian universities ranked among the top 200 in the world, we attract exceptional thinkers and welcome diverse perspectives from across the globe.

Media Contact

Jennifer Ganton
Director, Communications and Public Relations
Ottawa Hospital Research Institute
Office: 613-798-5555 x 73325
Cell: 613-614-5253


Scientific Program tags: Inflammation and Chronic Disease Program