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Arthritis Today

New Warning for Joint Replacement Patients With Atrial Fibrillation

A-fib may trigger complications during or after surgery and lengthen hospital stays.

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A brand new hip or knee may be just what you need – but if you’re considering joint replacement and you have atrial fibrillation (A-fib), you could be looking at a rougher-than-average ride, according to a study published recently in The Journal of Bone & Joint Surgery.

“The study found that A-fib patients had a longer length of stay [in the hospital], an increased cost of medical care and higher complication rates,” says senior study author Alvin C. Ong, MD, assistant professor of orthopaedic surgery at the Rothman Institute at Thomas Jefferson University Hospital in Philadelphia. In fact, the complication rates  were around 27 percent higher in patients who had A-fib compared with those who didn’t. The complications included infections around the new joint, the need for blood transfusions and later readmission to the hospital.

In A-fib, faulty electrical signals cause the upper chambers of the heart (the atria) to “fibrillate,” or contract irregularly and, usually, too fast. As a result, blood isn’t pumped effectively to the heart’s lower chambers and out through the body. Blood thinners (also called anti-coagulants) such as warfarin (Coumadin) are used to prevent blood clots that can result from the pooling of blood in the heart – and it’s these blood thinners that make joint replacement surgery more risky.

People with rheumatoid arthritis (RA) are up to 60 percent more likely than people without RA to develop A-fib, either due to the disease itself or the medications (such as corticosteroids) used to treat it. Additionally, the chances of anyone developing A-fib increase greatly with age.

Lead study author Vinay K. Aggarwal, MD, an orthopaedic surgery resident at the Rothman Institute, notes, “Given that elderly patients very frequently have chronic A-fib and also very frequently undergo total joint arthroplasty [repair or replacement], it made sense to examine the two distinct variables together.”

The study set out to learn more about the monetary costs of joint replacement in patients with A-fib. It involved 161 patients with A-fib, who were compared with 161 similar patients (called “matched controls”) who did not have A-fib. A total of 112 hips and 210 knees underwent 239 first time joint surgeries and 83 revisions (do-over surgery to repair problems with a previous replacement).

The patients with A-fib had a longer pre-operative hospital stay (1.7 days versus 0.2 days), a longer postoperative stay (4.6 days vs. 3.2 days) and were significantly more likely to develop a joint infection and need a blood transfusion. They were also four times more likely to be unexpectedly readmitted to the hospital after their release.

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.”

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