Aspirin Alone Good Enough for Preventing Blood Clots After Knee Surgery.

When it comes to preventing blood clots after a knee replacement, good old aspirin may be just as effective as newer, more expensive drugs, according to a study published in JAMA Surgery.

The swap could help reduce the cost of caring for the nearly 1 million Americans who have a knee fixed each year, said Brian R. Hallstrom, MD, University of Michigan, Ann Arbor, Michigan.

“Aspirin alone may provide similar protection compared to anticoagulation treatments,” he said.

During the 2-year study period (2013-2015), aspirin use increased from 10% to 50% among the patients cared for by orthopaedic surgeons in the Michigan Arthroplasty Registry Collaborative Quality Initiative, a statewide effort to give patients the best possible recovery and outcomes after hip and knee replacements.

The study involved 41,537 patients undergoing knee replacement surgery at any of the 29 Michigan hospitals in the surgical quality group. One-third of the patients took aspirin alone, 54% took only an anticoagulant, and 13% took an aspirin/anticoagulant combination.

Over 3 months, just 1.16% of patients who took aspirin alone developed a serious blood clot, compared with 1.42% of patients on anticoagulants.

“This study is truly a real-world experience of what happened in Michigan when the majority of surgeons switched to aspirin,” said Dr. Hallstrom. “The incidence of blood clots, pulmonary embolism, and death did not increase despite this dramatic change in practice.”

Over the past decade, surgeons have turned away from powerful anticoagulants and toward aspirin used in addition to nondrug improvements such as compression devices for thwarting clots.

These days, most patients have a generally low risk of blood clots after knee replacement for a number of reasons. Those reasons include shorter surgical times, less invasive procedures, and use of regional anaesthesia that allows early mobilisation after surgery, explained Dr. Hallstrom.

The American College of Chest Physicians favour heparin to reduce the risk of blood clots, while the American Academy of Orthopaedic Surgeons guidelines state that no one drug is better than another for preventing clots, and while this is true, but aspirin has some obvious advantages.

“Aspirin is easy to take and much less expensive,” said Dr. Hallstrom. “Patients can get it over the counter for pennies, while the other anticoagulants require monitoring, injections, frequent dose adjustments, and are extremely expensive.”

Reference: https://jamanetwork.com/journals/jamasurgery/article-abstract/2708020