Risk Factors for Cardiovascular Complications Following Total Joint Replacement Surgery

Arthritis & Rheumatism. 2008;57(7):1915-1920. 

From blood clots to heart attack, cardiovascular complications are a prevalent, costly, and sometimes deadly outcome of non-cardiac surgery. The American College of Cardiology and the American Heart Association both recommend that physicians use clinical and surgical predictors to assess the cardiac risk for all patients prior to surgery. In general, orthopedic procedures are not high risk, as numerous studies attest. However, there is little specific data on cardiac events directly related to joint replacement surgery.

Total joint replacement (TJR) surgery is now a widely accepted treatment for advanced arthritis, with over 700,000 knee and hip replacements performed in U.S. hospitals each year. Recipients of the majority of TJR procedures are 65 years and older. Since the risk of heart disease increases with age, the number of TJR candidates at risk of suffering or dying from a heart-related problem is substantial. To help reduce this risk for arthritis patients, a group of researchers in Boston set out to determine the risk factors for cardiac complications following TJR surgery. Their efforts, featured in the July 2008 issue of Arthritis & Rheumatism (www.interscience.wiley.com/journal/arthritis), yielded a new key finding: patients who undergo revision or bilateral joint replacement surgery are at significantly higher increased risk for heart attack or failure than patients who undergo their first replacement of a single knee or hip.

Led by Dr. Jeffrey N. Katz, Director of the Orthopaedic and Arthritis Center for Outcomes Research at Brigham and Women's Hospital, the research team conducted a case-control study, drawing on the large pool of patients who had undergone total knee or hip replacement surgery at New England Baptist Hospital between November 1, 2001, and March 31, 2004. 209 patients were identified as cases if they experienced a cardiovascular event -- myocardial infarction, congestive heart failure, unstable angina, arrhythmia, symptomatic hypertension, or pulmonary embolism -- while in the hospital recovering. 209 controls (who did not have cardiac events) were selected from the pool and matched to the cases according to surgeon, age at the time of surgery, and year of surgery.

The mean age of the 418 patients was 71 years; 55 percent of them were female, and 96 percent were Caucasian. Of the total TJR surgeries performed, 80 percent were primary procedures and 20 percent were revisions; 11 percent were bilateral procedures; 51 percent were knee replacement surgeries and 49 percent were hip replacement surgeries.

Through a thorough review of medical records, research team members documented potential cardiac risk factors for both cases and controls. Then, they applied a variety of statistical analyses to identify independent predictors of cardiovascular complications. Differences in patients' sex, body mass index, and alcohol habits, having diabetes or hypertension, hip versus knee surgery, and the type of anesthesia used had no impact on the risk of cardiac complications. The factors strongly associated with increased cardiac risk were advanced age, a history of cardiac problems, revision surgery, and bilateral surgery. Age 75 and older was associated with a nearly 2-fold increased risk of cardiac complications following TJR surgery, even though controls were matched with cases for age in broad categories (under 50, ages 50 to 69, ages 70 to 79, and 80 years and older). A history of arrhythmia raised the risk nearly 3-fold. Most strikingly, revision surgery and bilateral surgery were both revealed as independent predictors of postoperative cardiac complications. Revision surgery was associated with a 2-fold increased cardiac risk; for bilateral surgery, the risk was increased 3.5-fold.

"Revision joint replacement and bilateral surgery are much more prolonged operations than primary unilateral joint replacement," Dr. Katz observes. "These findings suggest an increased risk with more prolonged surgery."

Along with confirming the traditional risk factors -- age and underlying heart disease -- that increase the risk of postsurgical cardiac events for TJR patients, this study calls attention to a new high-risk group: all patients requiring revision hip or knee replacement surgery and all patients seeking to have both hips or both knees replaced during one surgical procedure. "Clinicians can use this information to better estimate the risk of cardiovascular complications following TJR surgery," notes Dr. Katz, "and, ultimately, to prevent and better manage these complications."

Item is available via Wiley InterScience at http://www.interscience.wiley.com/journal/arthritis.


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