April 13, 2000 (Eugene, Ore.) -- Small doses of ordinary aspirin may help decrease complications in people who go through major hip or knee surgery, according to a large study just published in the April 15 issue of thejournal Lancet.
Two of the main complications of major surgery are deep-vein thrombosis or pulmonary embolism. A deep-vein thrombosis is a blood clot that forms in the blood vessels of the legs. If a clot breaks loose, it can travel upward, creating a blockage in the lung called a pulmonary embolism. An embolism is a serious condition that can lead to death. A thrombosis or embolism can occur weeks or even months after surgery.
Thrombosis and embolism are treated with certain medications that break up blood clots or prevent more clots from forming. These same medications can often be used to prevent them as well. Researchers examined whether aspirin could be used in patients undergoing hip and knee surgery to prevent these dangerous complications.
"In the past, there has been uncertainty whether aspirin would prevent this type of clot," says Anthony Rodgers, MD, lead author of the article. "The key advantage of aspirin is that it is easy to take, and its side effects are well known." Rodgers is with the University of Auckland in New Zealand.
Researchers looked at more than 17,000 people who were having surgery for hip fracture or hip or knee replacements. Half of them got low dose aspirin each day, starting before their operation and continuing for 35 days. The other half got placebo pills that looked just the same.
When they tallied up the results, the difference was striking. Among patients with hip fracture, aspirin reduced the risk of an embolism by 43% and the risk of thrombosis by 29%. The effects of aspirin on patients having hip or knee replacements were similar. Based on his results, Rodgers urges physicians to consider that aspirin may be of benefit in other types of major surgeries or illnesses that increase the risk for blood clots.
Stephan Moll, MD, says he finds the study provides valuable benefits of aspirin. However, he remarks that the study does not conclude that aspirin is as good or better than other medications currently used to treat thromboses and emboli. Moll is an assistant professor at the University of North Carolina Medical School in Chapel Hill and wasn't involved in the study.
Many of the current medications are expensive and require frequent injections and monitoring, however. In comparison, aspirin is easy to take and inexpensive. Moll agrees that the study shows that aspirin is beneficial in lowering the risk of thrombosis and embolism. Until future studies say otherwise, Moll says that if a patient is not on another medication then "the physician should at least recommend that the patient take low-dose aspirin for up to 35 days."