Doctors have always known that there is some risk of heart complications associated with major surgery, especially for those who are older or who have preexisting heart problems. There was a study done in the summer of 2008 that looked at the risk factors for cardiovascular problems after total joint replacement (TJR) surgery on the knees and the hips. Two new heart risk factors in TJR surgery were identified: having bilateral joint replacement, replacing joints on both sites of the body during one surgery, and having revision surgery to replace an earlier joint implant.
Researchers looked into the heart risk of TJR by studying the medical records of those who received new or revision total hip or knee replacements over the time of 29 months at a large hospital in New England. From these, the researchers identified the records of patients who, during their hospitalization, had experienced an irregular heartbeat (arrhythmia), heart attack, unstable angina, congestive heart failure, or blockage of an artery in the lung. Records were then matched with those of another group of those who had joint replacement surgery but no documented heart problems. These groups were matched as closely as possible according to surgeon, approximate age of the patient, and year when they had their total joint replacement. Eliminating incomplete records, the researchers had a total of 418 patient records for the study with an average age of 71.4 years; 55% were women; and 51% had knee surgery, 49% were hip surgeries; 20% of the operations were revisions; the rest were initial joint replacements; 11% were bilateral procedures, replacing both knees or both hips in one operation.
The researchers obtained information about any preexisting heart risk factors fro the medical record reviews and fro physical exams, electrocardiograms (EKG), and patient intake questionnaires. Included in these are the well known risks like high blood pressure, diabetes, lung disease, and smoking just for example. Researchers also sifted through data to pick out the factors associated with cardiac problems during the patients’ hospital stays. In 70% of the patients who had some post-surgical heart problems irregular heartbeat was present; 24% had a drop in blood pressure; 8% had unstable angina; 2% had a heart attack; 11% had congestive heart failure and in 1% there was death.
There were many factors had no effect on the risk of heart complications, including gender, being overweight, type of anesthesia, use of NSAIDs, knee versus hip surgery, or having diabetes or high blood pressure are just a few examples of these factors. Some of the traditional factors known to raise heart risk in other types of surgery also hold risk for those who are getting a TJR; age over 75 years; some preexisting heart problems like coronary artery disease, heart attack, congestive heart failure, or diseased heart valves; and irregular heartbeat were confirmed by this study.
A new finding from this study is that patients getting a bilateral joint replacement or revision surgery have 2 to 3.5 times the risk of heart complications during a total joint replacement compared to those getting a single, first time joint replacement.
There were two drawbacks to this study, and they were that it included the data from only one hospital and the results were not typical for other populations where there were TJR’s or hospitals.
Researchers hope that their findings will help doctors to do a better job of weighing the risk and reducing the heart complications that come up in total joint replacement patients. And giving that more than 700,000 total hip or knee replacements were done in the U. S. in 2004, it is essential that there are targeted measures to reduce cardiovascular risks and potentially save many lives.