A Canadian clinical trial of over 8,000 major surgeries has found that a simple, inexpensive drug can dramatically reduce the need for blood transfusions without increasing the risk of dangerous clots—a discovery that could transform surgical safety for millions of patients worldwide. The landmark study, published in the New England Journal of Medicine and coordinated by the University of Manitoba with co-leadership from The Ottawa Hospital, tested tranexamic acid, a medication that prevents excessive bleeding and stabilizes blood clots.
The findings matter because major surgery—procedures involving the head, chest, abdomen, or pelvis—carries real risks. More than one in 20 patients undergoing major surgery require a blood transfusion. Tranexamic acid has been safely used in cardiac and orthopedic surgeries for over 30 years, but doctors have long questioned whether it could be safely used across the full spectrum of major surgeries, particularly cancer operations where patients already face elevated clotting risks.
Between February 2022 and March 2024, researchers at 10 Canadian hospitals randomly assigned patients to receive either tranexamic acid or placebo, switching treatments every four weeks in what's called a cluster-crossover trial design. The results were striking: 7.4% of patients who received tranexamic acid needed transfusions, compared to 9.8% in the placebo group. For every 100 patients treated with the drug, 10 units of blood could be saved. The researchers found no increase in venous blood clots 90 days after surgery—the clotting rate held steady at 2.1% in both groups.
What makes this trial uniquely valuable is that approximately 60% of the 8,273 participants—around 5,000 patients—were undergoing surgery to remove cancer. People with cancer are often excluded from these kinds of studies despite being a substantial part of the surgical population. The trial demonstrated that tranexamic acid was both safe and effective even for cancer patients, who typically face higher clotting risks due to their disease.
Dr. Ryan Zarychanski, the trial chair and a hematologist at the University of Manitoba, emphasized the economic dimension of these findings. "One transfusion in Canada costs more than $700 CAD, compared to under $10 for tranexamic acid," he noted. The researchers estimate that routine adoption of the drug in major non-cardiac surgeries could save 50,000 units of blood annually in Canada alone, with millions more units saved globally—translating to profound savings for health-care systems.
The potential impact extends far beyond economics. Dr. Daniel McIsaac, co-first author and an anesthesiologist at The Ottawa Hospital, stated that universal adoption across major surgeries could reduce the number of patients needing transfusions by 25% annually in Canada and decrease blood units required by 10%. Dr. Brett Houston, a hematologist at the University of Manitoba, called the findings "transformative to patient care," with the global potential to save millions of units of red blood cells each year.
The trial employed a rigorous design, with The Ottawa Hospital's Ottawa Methods Center playing a key role in efficiently structuring the research question. Data came directly from clinical and administrative health sources in Manitoba and through ICES, ensuring real-world applicability. These results suggest that tranexamic acid should become standard practice across the vast majority of major surgeries—a simple intervention that could reshape surgical safety worldwide.