It’s not news that people taking blood thinners for A-fib have an increased risk for complications such as bleeding problems, slow wound healing and infection when they undergo surgery. “But this has never been studied for joint replacement patients,” says Dr. Ong. “It is interesting because legislation has been put forth to decrease hospitalization cost and hasten recovery of patients undergoing joint replacement. Unfortunately, we are dealing with an aging population who are likely to have A-fib.”

The study results were not quite what Tad M. Mabry, MD, assistant professor of orthopaedics at Mayo Clinic in Rochester, Minn., who specializes in primary and revision hip and knee replacement, would have expected. “I was a little bit surprised at some of the difference between the two groups in terms of the risk for infection and hospital readmission and blood transfusion rate.”

Dr. Mabry notes several limitations of the study as it was presented. One problem may be how well the A-fib patients were matched with the controls. Patients in the study were matched in terms of factors such as age, gender, body weight and which side of the body was being operated on.

“I’m not sure the A-fib group and the control group were actually the same group of people – that the only thing that was different was A-fib,” says Dr. Mabry. “There are some other things that may be different between the groups that they did not talk about. For example, we don’t know if there was a difference in the two groups in terms of patients who had a history of heart attack or coronary artery disease, or a difference in patients that have diabetes or rheumatoid arthritis.”

He says if the group that had A-fib also had a higher rate of coronary artery disease, for example, that would increase the risk of them needing a blood transfusion and having postoperative readmission. “If a study like this were to be done elsewhere, I think it would be very important to try to look (at) some of the other medical conditions that may be driving some of these issues more than what the A-fib alone is actually doing,” he says.

Another question Dr. Mabry has with the study is, why were A-fib patients getting transfusions at a much higher rate even though hemoglobin levels – an indicator of anemia, which reflects increased bleeding – were not significantly different between the two groups. “Usually one of the main features that tells you that you’re going to give somebody a blood transfusion is how low their hemoglobin gets,” he says. “Despite the fact that the two groups’ hemoglobin levels were relatively similar, they were transfusing patients that had A-fib at a much higher rate. They don’t talk about why they were giving those patients blood.”

So what should an A-fib patient about to undergo joint replacement surgery do? “Before a patient who’s taking a blood thinner has elective surgery, they should always consult with a medical expert regarding their risk of clotting,” Dr. Mabry says. “A plan can be put together before surgery that finds the best balance of not exposing them to an undue risk of clotting, and at the same time avoiding an unnecessarily high bleeding risk.”