Researchers Work to Minimize Cardiac Complications of Joint Replacement Surgery

Newswise — New potential risk factors for cardiac complications following total joint replacement have been identified, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in Boston, Mass.

Modern joint replacement surgery involves removal of the worn cartilage from both sides of the joint, followed by resurfacing of the joint with materials that function much like a normal joint. Most joint replacement surgeries involve the hip or knee.

Nearly one million total joint replacements are performed in the U.S. each year. Of these, approximately 30,000 are complicated by postoperative cardiac events such as heart attacks and irregular heart rhythms.

Researchers identified 209 patients who received an initial or a second TJR of the knee or hip at one institution over a three year period and had cardiac complications during their admission—including heart attack, congestive heart failure, unstable angina, irregular heartbeat, or pulmonary embolism. These patients with complications were compared with patients who did not have complications following their TJR.

After reviewing medical records, researchers documented two newly identified risk factors for cardiac complications: bilateral surgery (having both joints replaced during the same procedure) and revision surgery (removing prosthesis, or replaced joint, and replacing it with a new one, often due to a break, infection or loosening of the original prosthesis). In addition, older age and a history of cardiac problems were associated with cardiac problems following surgery, two risks that were previously known.

"Orthopedic procedures such as total joint replacement are generally safe, with few complications," said Jeffrey N. Katz, MD; MSc; director, Orthopedics and Arthritis Center for Outcomes Research; Brigham and Women's Hospital associate professor of orthopedics and physician researcher; Harvard Medical School. "Physicians caring for total joint replacement patients should be aware that those who have bilateral or revision surgery and those with cardiac histories, along with the elderly, are at higher risk and merit closer observation for cardiac complications."

The ACR is an organization of and for physicians, health professionals, and scientists that advances rheumatology through programs of education, research, advocacy and practice support that foster excellence in the care of people with or at risk for arthritis and rheumatic and musculoskeletal diseases. For more information on the ACR's annual meeting, see http://www.rheumatology.org/annual.

Editor's Notes: Jeffrey N. Katz, MD, will present this research during the ACR Annual Scientific Meeting at the Boston Convention and Exhibition Center from 2:30 " 4:00 pm ET on Thursday, November 8, 2007, in Room 156. Dr. Elena Losina will be available for media questions and briefing at 1:30 pm ET on Saturday, November 10 in the on-site press conference room, Room 251. Presentation Number: 687

Risk Factors for Cardiovascular Complications following Total Joint Replacement Surgery

Jeffrey N. Katz1, Frederick Basilico2, Gerald Sweeney2, James Gaydos2, Debra Skoniecki2, Elizabeth A. Wright1, Elena Losina1. 1Department of Orthopaedic Surgery and Division of Rheumatology, Brigham and Women's Hospital, Boston, MA; 2Departments of Medicine and Physical Therapy, New England Baptist Hospital, Boston, MA

Background: Nearly one million total joint replacements (TJRs) are performed annually in the US. Approximately 30,000 of these procedures are complicated by postoperative cardiac events. Few studies have examined predictors of cardiac complications following TJR. The purpose of this study is to identify predictors of cardiac complications following total joint replacement.

Methods: We performed a case control study. Cases included patients receiving primary or revision total knee or hip replacement at one institution over a 3-year period, who sustained a cardiac complication during the admission. These complications included myocardial infarction, congestive heart failure, unstable angina, arrhythmia, or pulmonary embolus. Controls included patients receiving the same types of procedures in the same center over the same period who did not sustain a cardiac complication. We established case and control status with ICD-9 codes from hospital discharge data, which we confirmed with medical record review. We matched controls (one to one) with respect to age, year and surgeon. Medical record reviews identified potential risk factors for cardiac complications. We used conditional logistic regression to identify independent predictors of cardiac complications.

Results: The sample included 209 cases with cardiac complications following TJR and 209 controls. In conditional logistic regression analyses, factors associated with a higher risk of cardiac complications included history of arrhythmia (OR 2.6, 95% CI 1.5 to 4.3), history of CAD, MI, CHF, or valvular heart disease (OR 1.5, 95% CI 0.9 to 2.6), revision surgery (OR 2.2, 95% CI 1.2 to 3.9), and bilateral surgery (OR 3.5, 95% CI 1.5 to 8.0).

Conclusions: This study identified two new risk factors for cardiac complications following TJR - bilateral and revision surgery. We also confirmed previously documented risk factors including older age and a history of arrhythmia and other cardiac problems. These findings should help clinicians anticipate and potentially prevent cardiac complications following TJR.

Disclosure Block: J.N. Katz, None; F. Basilico, None; G. Sweeney, None; J. Gaydos, None; D. Skoniecki, None; E.A. Wright, None; E. Losina, None.