Study: Aspirin as effective as warfarin for prevention of blood clots after TJR

Patients on aspirin showed lower rates of pulmonary embolism, bleeding, wound discharge and infections.

Issue: April 2013

Researchers from the Rothman Institute found that patients who took aspirin following total joint replacement had a significantly lower rate of pulmonary embolism than patients on warfarin.

“Aspirin is not only as effective as [warfarin] at preventing venous thromboembolic episodes, its use was associated with less bleeding, less wound discharge, fewer hospital readmissions, less reoperations and [less] incidence of infection,” lead study author Javad Parvizi, MD, FRCS, director of research at the Rothman Institute in Philadelphia, told Orthopedics Today.

According to a Thomas Jefferson University press release, the investigators assessed 1,824 patients who received aspirin (325 mg twice daily) and 24,567 patients who received warfarin after joint replacement surgery at their institution between 2000 and 2011. They reviewed the incidences of pulmonary embolism (PE), readmissions, reoperations, infections, bleeding or wound complications up to 90 days postoperatively. They matched the patients for comorbidities and demographic variables.

Javad Parvizi

The aspirin group had a significantly lower rate of PE than the warfarin group (0.2% vs. 1%). Hematoma and seroma formation, wound problems, acute infections and 90-day mortality rates were not statistically significant between the groups. Patients on aspirin showed fewer incidences of bleeding, wound discharge, hospital readmissions, reoperations and infections.

Aspirin may not be safe to use for all patients, because they do not all share the same risk profile, Parvizi said. Parvizi and colleagues recently completed a follow-up study to this one using individualized anticoagulant protocols for every patient. In the study, Parvizi and the researchers treated the high-risk group “a little more aggressively.” The results to that study will be published soon, he said.

“Use of aspirin is more convenient to patients,” Parvizi told Orthopedics Today. “They do not have to have blood tests. There does not need to be a nurse to monitor their [international normalized ratio] INR. Its use is associated with fewer problems like bleeding into brain and other parts of the body, which can happen with aggressive anticoagulation, and it is extremely cheap compared to other modalities that we use.”

Some physicians may worry that aspirin is not endorsed by the Surgical Care Improvement Project (SCIP) guidelines, Parvizi said. However, both the American Academy of Chest Physicians (AACP) and the American Academy of Orthopaedic Surgeons endorse aspirin for use as an anticoagulant.

“I can assure everybody that right now with the ACCP endorsing aspirin with the highest endorsement they have, and no other anticoagulant has received a 1A, it is the highest endorsement for aspirin under the ACCP guideline,” Parvizi said. “Finally, they should not worry about the SCIP guidelines, because SCIP has never endorsed a specific anticoagulant. They just want the patients to be anticoagulated or at least the thought needs to be there that the patient has been evaluated and appropriate form of anticoagulation has been administered to the patient.” – by Renee Blisard Buddle

Reference:

Parvizi J. Aspirin is an effective alternative for prevention of pulmonary embolism following joint arthroplasty. Presented at: American Association of Hip and Knee Surgeons; Nov. 2-4, 2012. Dallas.

For more information:

Javad Parvizi, MD, FRCS, can be reached at the Rothman Institute, 925 Chestnut Street, Philadelphia, PA 19107; email: parvj@aol.com.
Disclosure: Parvizi is a paid consultant for Zimmer, Smith&Nephew, 3M, Convatec and United Healthcare, and receives research support from Stryker, 3M, Convatec, and Zimmer.