Anticoagulation and antiplatelet medications like heparin or aspirin, commonly taken by millions worldwide to treat heart attack and stroke, also elevate the risk of potentially fatal bleeding during injuries or surgeries. Globally, over five million people die annually from trauma, with more than a third of these deaths due to uncontrolled bleeding. Now, researchers have created a porous material that significantly absorbs blood and effectively initiates clotting, even in patients on these medications. Remarkably, this new hemostat managed to stop bleeding in an average of about five minutes in cardiac catheterization patients on anticoagulants, marking a substantial improvement from the lengthy traditional compression methods that can take more than two hours.

The research team, led by investigators from Brigham and Women’s Hospital (Boston, MA, USA), developed a more effective hemostat by employing a “rational engineering” approach. They simulated blood flow through various pore structures, drawing inspiration from the lung’s alveoli – spherical air sacs with a large surface area and a complex porous structure that enable efficient blood interaction. This guided them to design their material with a similar intricate, spherical microporous structure, optimizing blood absorption and the accumulation of vital clotting components like platelets.

Chitosan, a substance extracted from shellfish, forms the base of this alveoli-like structure. Already utilized in some hemostats, chitosan’s positive charge effectively attracts negatively charged platelets and fibrinogen, key blood clot components. The researchers discovered an additional benefit: chitosan activates the TLR-2 clotting pathway, directly stimulating clotting even in patients on anticoagulants. When tested on 70 patients undergoing cardiovascular catheterization and on heparin, the material reduced bleeding to an average stoppage time of about five minutes for low-dose heparin patients, and under nine minutes for those on up to 12,500 IU heparin doses.

The chitosan pad simplifies application and removal compared to traditional gauze, which often requires long, strong compression and can be painful and risky to remove. The chitosan hemostat, being more absorptive, can be removed more cleanly and comfortably from wounds. The research team is now exploring further advancements, including studying the wound healing process post-application of the chitosan hemostat and developing next-generation wound dressings capable of drug delivery or enhancing wound cleanliness, potentially reducing the frequency of dressing changes.

“This is a next-generation hemostat that effectively stops bleeding, even in patients who take anticoagulation or antiplatelet medications,” said corresponding author Hae Lin Jang, Ph.D., of the Center for Engineered Therapeutics. “We used an exciting, interdisciplinary approach that combines engineering principles, materials science, and understandings of molecular biology to overcome the limitations of existing therapies and address a real clinical need.”

“This hemostat can save valuable time in emergency situations,” added first author Vivian K. Lee, PhD, of the Center for Engineered Therapeutics. “In emergencies, it can be extremely challenging to screen the prescription information of a patient to provide appropriate anticoagulation reversal therapy to patients on anticoagulants. If a hemostat can bypass a medication’s anticoagulating mechanisms, it can be used in a wide range of patients, saving time, and potentially saving lives.”

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