Hip- and knee-implant patients older than 60 have a higher risk of heart attacks following surgery than those the same age who do not have joint surgery, a new study has found.
Researchers studied hospital records of 95,000 people from Denmark who had a hip or knee replaced and their counterparts who didn’t. The study, reported in the Archives of Internal Medicine on July 23, 2012, notes that implant patients were almost 26 times more likely to have a heart attack during the two weeks after surgery, according to the Chicago Tribune. The risk still was elevated fivefold in the third through sixth weeks of recovery after the operation.
Lead researcher Dr. Arief Lalmohamed, from Utrecht University in the Netherlands, attributed the increased risk of heart attacks to the effects of undergoing such a major surgery. He said side effects include the aftereffects of anesthesia, blood loss, irregular heartbeat and lack of oxygen, all of which are known to increase risk of heart attacks, according to the National Institutes of Health.
This new data is especially troubling, given that about 2 million hip- and knee-replacement surgeries are performed globally each year.
“Joint replacement surgery has all sorts of effects that last many days beyond the operation itself,” explains Dr. Thomas Lee, a professor of medicine at Harvard Medical School and editor in chief of the Harvard Heart Letter. “There is a lot of inflammation as the body tries to repair the damage, and the circulating proteins make blood clots more likely to form — both at the site of surgery, and in the arteries of the heart and elsewhere. That is why the heart attacks continue for so long afterwards.”
Heart attacks following knee- and hip-replacement surgeries are more likely for patients older than 80 and those who have previously suffered heart attacks. In fact, researchers said patients who had a heart attack in the previous year should not have the elective joint surgery.
Patients already are wary of such implants after DePuy Orthopaedics recalled 93,000 ASR metal hip implants in August 2010 because of early failure rates. The devices included in the recall are the ASR XL Acetabular System, a socket used in total hip replacement surgeries, and the ASR Hip Resurfacing System, a partial hip replacement used to preserve the bone. When the metal parts grind against each other, it causes the devices to fail, and the subsequent metal shavings are dangerous. Studies have found metal poisoning, metallosis, in patients’ blood and surrounding tissue from the shavings. British researchers even have linked the shavings to an increased risk of cancer of the kidneys and bladder.