He says aspirin is also cheaper and easier for patients to take. “Aspirin is pennies compared to the higher cost for anticoagulation medicines. Patients can take it on a daily basis with no need for monitoring,” Dr. Parvizi explains.

Dr. Parvizi says the key with aspirin is that it be used as part of a multi-faceted approach to prevent blood clots that includes the use of lower extremity compression devices during hospitalization. Similar to a blood pressure cuff, these compression devices, when inflated, gently squeeze the leg and increase blood flow from the lower extremity back to the heart.

Another important component, Dr. Parvizi says, is regional anesthesia or spinal anesthesia during the procedure, because it’s been shown to reduce the accumulation of blood in the leg veins and is associated with a lower incidence of DVT. Dr. Parvizi says intravenous heparin, a blood thinner, should also be used during surgery to reduce the risk of clots, and patients should be promptly “ambulated” –  that is, gotten out of bed within as little as two hours of the procedure.

The Rothman Institute at Jefferson has begun replacing warfarin with aspirin in the vast majority of joint replacement cases according to Dr. Parvizi and he expects other institutions will do the same since, he points out, new guidelines from the American College of Chest Physicians say aspirin can be used as an anticoagulation option to prevent against PEs in some joint-replacement patients. The American Academy of Orthopaedic Surgeons now considers this accepted practice as well, in certain low-risk patients..

“Patients who have had previous VTE [venous thromboembolism], are morbidly obese and are sedentary are at higher risk of subsequent VTE and may require a more aggressive form of prophylaxis [prevention]. Anyone else can be prophylaxed with aspirin,” Dr. Parvizi explains.

Geoffrey Westrich, MD, associate professor of clinical orthopedic surgery at Weill Cornell Medical College and co-director of joint replacement research at Hospital for Special Surgery (HSS) in New York, says he agrees aspirin is effective for low-risk patients – and HSS uses it in those cases. But he has questions about the methods of this study, including the vastly uneven number of participants in the two groups, because more than 26,000 received warfarin, compared to only 2,800 participants who got aspirin. He also says it’s tough to get an accurate assessment of pulmonary embolism rates from a retrospective chart review.

“The reality is, [after surgery] in our hospital, many patients [with] complications go to a local ER or another hospital, so it’s very hard to keep track of every single pulmonary embolism,” Dr. Westrich explains.

He also stresses that if patients are considered at high risk for complications, he still believes warfarin is better for them than aspirin.

“If a patient is older, morbidly obese and you can tell they will be slower to recover, that patient probably is not a good choice for aspirin,” Dr. Westrich explains.

Dr. Parvizi says the bottom line is, if you or a loved one has a joint replacement planned, find out what drugs the doctors plan to use.

“Patients should be aware, and if they are receiving anything other than aspirin, they should ask why they are receiving the aggressive agents. They need to be engaged in the process,” Dr. Parvizi says.

Dr. Westrich agrees that this should be something patients bring up with their surgeons. “They should be asking what they are using after surgery,” says Dr. Westrich. “I will talk with patients about this, and if they are at standard risk I will tell them we use aspirin routinely.”