Researchers from Brigham and Women's Hospital have created a porous material that reportedly maximizes blood absorption and activates clotting mechanisms — even in patients who are on anticoagulation or antiplatelet medication, such as heparin or aspirin, for treating conditions like heart attack and stroke.

While such medications put patients at risk of life-threatening bleeding sustained due to injury or surgery, the researchers report that the bleed-stopping material, or "hemostat," stopped bleeding in about five minutes on average in patients currently prescribed anticoagulants following cardiac catheterization. This, according to the researchers, was a significant reduction from the more than two hours that traditional compression methods tend to take.

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To develop a more effective hemostat, the researchers simulated blood flow through pores to gauge which microscopic design would enhance absorption. Further, the developers were inspired by the spherical "air sacs" in human lungs, called alveoli, which enable a high rate of interaction with blood in a short time.

Specifically, the team was inspired by the large surface area and porous structure of the alveoli, thereby leading to the development of a highly interconnected and spherical microporous structure in the engineered material that quickly absorbs blood and accumulates clotting components — such as platelets — which subsequently encourages blood clotting.

To create the alveoli-inspired structure, the researchers used chitosan derived from shellfish, which is already used in select hemostats thanks to its positively charged surface, which is known to attract negatively charged platelets and fibrinogen: the two major ingredients of a blood clot. The team also discovered that chitosan stimulates blood clotting. This is accomplished when the chitosan activates the TLR-2 clotting pathway, thereby making it possible to increase blood clotting — even in patients who are prescribed anticoagulants.

During trials, the chitosan pad was applied to roughly 70 patients who underwent cardiovascular catheterization procedures while prescribed the anticoagulant heparin and who subsequently experience bleeding. Bleeding stopped after a mean time of roughly five minutes for patients taking low doses of heparin and in less than nine minutes in patients prescribed heparin doses of up to 12,500 IU.

"This hemostat can save valuable time in emergency situations," explained the researchers. "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."

An article detailing the material, “An architecturally rational hemostat for rapid stopping of massive bleeding on anticoagulation therapy,” appears in the journal PNAS.