Older patients who have a hip or knee replaced face an increased risk of heart attack in the two weeks after the procedure, according to an international study.
Researchers, whose findings appeared in the Archives of Internal Medicine, said that people having joint surgery had up to 31 times the risk of a heart attack shortly afterward.
"The risk of acute myocardial infarction is substantially increased in the first two weeks after total hip replacement (25-fold) and total knee replacement surgery (31-fold) compared with controls," wrote Arief Lalmohamed from Utrecht University in the Netherlands, who led the study.
The link between joint surgeries and heart problems was especially high for patients age 80 or older, they found. Those under the age of 60 weren't at any higher risk.
Although it's not clear that the hip and knee procedures triggered the heart attacks, researchers said it's reasonable to think they would have some role.
"Surgery is a risk, because surgery and anesthesia ... increase stress levels for patients," said William Hozack, an orthopedic surgeon at the Rothman Institute in Philadelphia, who wasn't involved in the study.
The findings come from hospital records for 95,000 people who had a hip or knee replaced in Denmark between 1998 and 2007. The researchers compared each patient with three people, of the same age and gender, who didn't have a joint replaced.
Over the six weeks after their surgeries, one in 200 patients who had a hip replaced and one in 500 who underwent knee replacement had a heart attack.
The researchers couldn't account for everything about patients that might affect both their risk of needing a joint replaced and having a heart attack, such as being overweight or having high blood pressure.
