Total hip and knee replacement surgeries linked to increased heart attack risk

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A recent study published in JAMA finds that patients undergoing total hip replacement (THR) and total knee replacement (TKR) surgeries have an increased risk of heart attacks.

With an estimated 1.8 million surgeries performed each year around the world, THR and TKR are commonly used procedures to treat patients suffering from moderate to severe osteoarthritis (and much less commonly, rheumatoid arthritis). Unfortunately, the risk of acute myocardial infarction associated with the procedures, as with most major operations under general anesthesia, is not insignificant.

The study analyzed data from Danish national registries that included over 95,000 patients undergoing THR or TKR from 1998 to 2007. These patients were then matched with over 285,000 controls. Researchers from Utrecht University in the Netherlands found that, compared to the control group, the risk of a heart attack increased 25-fold in the first two weeks among those who underwent THR surgery. Worse still, during the same study period, the risk of a heart attack following TKR increased 31-fold. And while six weeks after TKR the initial spike in heart attack risk greatly decreased, for those patients undergoing THR, the risk remained elevated.

The risk was greatest in patients over the age of 80 and in patients who had experienced a heart attack in the six months leading up to the surgery. These factors, however, did not affect the significance of the results for the whole population.

These findings call for careful surveillance of THR and TKR patients, especially those at a higher risk for heart attacks, says ACSH s Dr. Elizabeth Whelan. ACSH's Dr. Gilbert Ross adds, While the risk of heart attack generally increases during the intra- and post-operative time frame, this study should alert physicians surgeons and internists alike to make sure their elderly patients and those with pre-existing cardiac histories are in a condition to withstand such surgery, and to closely monitor them for weeks thereafter.