According to a new study, people who undergo hip or knee replacement are at higher risk of heart attack. The study, published in the journal Arthritis & Rheumatology, also adds that these patients are also at higher risk of developing venous thromboembolism (VTE).
common form of arthritis in the US is osteoarthritis and it affects round 13.9% of adults aged 25 and older and 33.6% of those over 65.
Currently, there is no permanent cure for osteoarthritis. In the most of cases, osteoporosis can be treated with simple method, including medications, physical therapy and weight control. However, the more severe cases may need joint replacement surgery-called arthroplasty.
There are around 1.8 million arthroplasty procedures conducted worldwide annually, and most of them are total knee and hip replacements, according to the study authors, led by Yuqing Zhang, professor of medicine and epidemiology at Boston University School of Medicine, MA.
This method is certainly effective as it significantly reduces pain and improves quality of life. However, the influence of arthoplasty on cardiovascular system is still unclear, according to Prof. Zhang.
“Our study examines if joint replacement surgery reduces risk of serious cardiovascular events among osteoarthritis patients,” explains Prof. Zhang.
Heart attack risk highest in first month after knee arthroplasty
The study involved 13,849 individuals aged with knee osteoporosis who underwent total knee replacement surgery in the period between January 2000 and December 2000, and other 13,849 participants who did not undergo any surgery.
Furthermore, the study included 6,063 patients aged 50 and older with hip osteoporosis who underwent total hip replacement surgery, and other 6.063 who did not undergo this procedure.
“During the average follow-up period of 4.2 years, 306 patients with knee OA who underwent knee arthroplasty had a heart attack, compared with 286 control patients. The researchers found the risk of heart attack was significantly higher for knee arthroplasty patients in the first month after surgery, though this declined over time.”
Patients with hip OA who underwent hip arthroplasty, 128 had a heart attack, compared to 138 controls. The heart attack was more frequent in hip arthroplasty patients in the first 6 months of the procedure, while it was much rarer in patients who did not have the surgery.
Moreover, patients who underwent knee or hip arthroplasty were more likely to develop DVT and pulmonary embolism, years after the procedure, when compared to the control group.
DVT occurs when a blood clot forms in a deep vein, most commonly in the lower leg, thigh or pelvis. PE is a common complication of DVT, occurring when a blood clot breaks loose and goes to the lungs through the bloodstream. According to statistics, around 300,000-600,000 people in the US suffer from DVT or PE every year.
Prof. Zhang says:
“Our findings provide the first general population-based evidence that osteoarthritis patients who have total knee or total hip replacement surgery are at increased risk of heart attack in the immediate postoperative period.
The long-term risk of heart attack was insignificant, but risk of blood clots in the lung remained for years after surgery to replace a hip or knee damaged by osteoarthritis.”
Moreover, possible causes for increased risk of heart attack may also be the effects of anesthesia on the cardiovascular system.
The study authors also add that the change in medication for OA patients during the period of the surgery, including low-dose of aspirin or introducing anticoagulation prevention against VTE, can also lead to increased risk of heart attack.
“Regardless,our findings suggest that the immediate postoperative risk of myocardial infarction following total joint arthroplasty may have been previously underappreciated, and further measures to prevent this serious event may need to be considered.” explain the researchers.