• Posted January 19, 2023

Aspirin OK After Fracture to Help Avoid Blood Clots

When people undergo surgery for broken arms or legs, they are often injected with prescription blood thinners to reduce their risk of developing potentially life-threatening blood clots in their lungs and legs.

But a large, new study suggests it may be time to rethink this practice. It found that aspirin may be as effective as injections of low-molecular-weight heparin when it comes to staving off blood clots and their related complications.

"Patients all over North America who come in for surgery for fractures are at risk for blood clots in their legs and lungs, and the standard treatment is injections of low-molecular-weight heparin in the hospital and for weeks after discharge," said study author Dr. Robert O'Toole, chief of orthopaedics at the University of Maryland Medical Center's R Adams Cowley Shock Trauma Center in Baltimore.

"It's a shot given twice a day, and patients hate it," he said. These heparin shots also have a much heftier price tag than aspirin.

The study included more than 12,000 patients with arm or leg fractures that required surgery or pelvic fractures regardless of treatment. They were treated at 21 trauma centers.

Of these, half received injections of low-molecular-weight heparin twice a day, and half received low-dose baby aspirin twice daily. All participants were followed for 90 days to see how they fared.

Outcomes were similar for both groups. There were no differences in terms of death, blood clots in the lungs, bleeding complications, infection, or wound healing problems, the study showed.

Folks in the aspirin group were more likely to develop blood clots below their knee. O'Toole noted these are not considered as serious as other types of blood clots.

"A lot of patients with no financial means or insurance are put on aspirin due to cost of low-molecular-weight heparin," he said. "This study is reassuring for those patients."

Now, ongoing research seeks to determine whether these findings also apply to people who are at higher risk for developing blood clots after surgery, O'Toole said.

The findings were published Jan. 19 in the New England Journal of Medicine.

Matthew Costa, a professor of orthopaedic trauma at the University of Oxford in England, wrote an editorial accompanying the new study.

"These research findings are good news for patients and good news for health care funding," he said.

"The findings of this new trial will/should influence the guidelines on [blood clot prevention] for every health care system in the world," Costa said. "Specifically, patients with broken bones who are considered at high risk may now be offered a tablet [aspirin] rather than having to have injections [heparin]."

Dr. Michael Ast has been recommending aspirin to some patients after fracture surgery for a while. He is an orthopedic surgeon at the Hospital for Special Surgery in New York City.

"It is an overlooked method for reducing blood clots," said Ast, who reviewed the new study.

The standard of care following elective joint replacement surgery for people who are not at high risk for blood clots is aspirin, and fracture repair will soon follow suit, he said.

As it stands, people who have surgery to repair fractures are often given compression boots and injectable blood thinners to lower the risk of blood clots, Ast said.

These folks may be at risk of developing blood clots because they are bedridden during recovery.

"There is also a true chemical reaction set off by the fracture and trauma to the bone, which can also increase this risk," Ast added.

The choice of medication to reduce blood clots after surgery should be part of a discussion with your surgeon. Some people who are at high risk for clots may not be appropriate candidates for aspirin and may need the injections, Ast said.

Risks for post-surgery blood clots include a personal history of clots, an underlying clotting disorder, or current cancer treatment, he said.

Not everyone can take aspirin either, Ast added. That includes patients with a history of gastrointestinal bleeding or ulcers.

More information

The American Academy of Orthopaedic Surgeons has more on blood clot prevention after surgery.

SOURCES: Robert O'Toole, MD, professor, orthopaedic trauma, University of Maryland School of Medicine, chief, orthopaedics, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore; Matthew Costa, PhD, professor, orthopaedic trauma, University of Oxford, U.K.; Michael Ast, MD, orthopedic surgeon, Hospital for Special Surgery, New York City; New England Journal of Medicine, Jan, 19, 2023