Using postoperative cardiac troponin-I (cTi) levels to detect myocardial ischaemia in patients undergoing vascular surgery

Background, Cardiac complications occur commonly in vascular surgery patien ts. Diagnosis of cardiac complications is difficult because of the inaccura cies associated with traditional cardiac enzyme measurements. CTi, a highly sensitive and specific marker of myocardial injury, may be able to detect cardiac complications with greater ease and accuracy. Methods. The study prospectively examined 100 consecutive patients who unde rwent major vascular surgery between 6/7/98 and 31/12/98 at the Royal Brisb ane Hospital. Daily measurements of cTi, creatine kinase (CK), creatine kin ase MB (CKMB), CKMB index, renal function and haemoglobin were taken for th ree postoperative days. One postoperative electrocardiograph (ECC) was take n. An extensive cardiac history was taken. Intraoperative and postoperative events were recorded. Findings. There were 100 patients, 18 patients (18%) had a cTi elevation. O n the basis of classical diagnostic criteria, 15 patients (15%) suffered on e or more cardiac complication (either myocardial infarction, congestive ca rdiac failure, unstable angina or atrial fibrillation), One patient (1%) wh o had a cTi elevation died. CTI elevation occurred in five patients (5%) wh o were not diagnosed with cardiac complications based on traditional criter ia. Despite not meeting specific diagnostic criteria for cardiac complicati ons, all patients showed signs and symptoms that could be attributed to myo cardial ischaemia, Every patient who developed congestive cardiac failure o r atrial fibrillation had a cTi elevation. A Chi-square analysis revealed a significant association between cTi elevation and postoperative cardiac co mplications. Four variables contributed small but significant amounts of un ique variance to the prediction of peak cTi on linear regression analysis. These were peak CKMB index, postoperative congestive cardiac failure, posto perative chest pain and postoperative cardiac complications. Conclusions. Routine cTi monitoring of postoperative vascular patients woul d be an effective and inexpensive way to detect patients with cardiac compl ications. The relationship between postoperative cTi elevation and signific ant coronary artery disease remains to be shown, (C) 2001 The international Society for Cardiovascular Surgery. Published by Elsevier Science Ltd. All rights reserved.