Postoperative Electrocardiograph Changes and its Relation to Troponin Elevation and Cardiac Complications After Lower Limb Surgery

Abstract

Currently, there are no standard single diagnostic criteria for perioperative MI in patients undergoing non-cardiac surgery. Optimal diagnostic criteria must consider the unique features of perioperative MIs, in particular that a large proportion are clinically silent. The first of our criteria requires a typical rise in troponin I level detected after surgery in a patient without a documented alternative explanation for an elevated troponin level (e.g., pulmonary embolism). We encourage to use troponin measurement, because perioperative CK-MB measurements are prone to false-positive and false-negative values. Surgical trauma after orthopedic surgery can result in the release of CK-MB from skeletal muscle and a false-positive CK-MB value for MI. Despite major advances in perioperative management techniques, PMI remain the most common cause of postoperative morbidity and mortality in patient undergoing non- cardiac surgery. Patients experiencing MI in the perioperative period have a hospital mortality of 15%-25%. The high mortality rate could be due to difficulty in detecting PMI because typical ECG changes and classical clinical symptoms are often absent. As a growing number of elderly patients at risk of cardiac diseases are undergoing surgery, management of such complication will remain a significant clinical and economical challenge. In our study we performed a prospective observational study in Ain-Shams University hospitals, on 300 patients aged 60 years old or more, in the first 3 postoperative days after orthopeadic lower limb surgeries to determine the presence of myocardial injury in susceptible patients, by correlating the relationship between elevated troponin I level and new ECG changes, their relation to myocardial injury and cardiac events and to evaluate if troponin I is a specific tool for diagnosis and prediction of outcome in those patients. In our study we found that troponin I elevations that occurred after orthopaedic surgery are not always associated with ECG changes. Our results showed that postoperative ECG changes during the ICU admission, 76/300 (25.3%). Of those with an ECG change, 41/76 (55.9%) had a troponin elevation whereas 35/76 (44.1%) did not have a troponin elevation. The majority of patients who sustained a troponin rise did not have any ECG changes, 80/111 (72.9%).