Cardiac troponin I levels >36 microg/L at 24 hours postoperatively diagnosed perioperative myocardial infarction with 100% sensitivity and 93% specificity.
Observational (n=260)
No
Does cardiac troponin I measurement improve the diagnosis of perioperative myocardial infarction and complications in patients undergoing cardiac surgery compared to CK-MB?
Cardiac troponin I is a highly sensitive and specific biomarker for diagnosing perioperative myocardial infarction and other cardiac complications following cardiac surgery, outperforming CK-MB.
OBJECTIVE: To study the value of assaying cardiac troponin I (cTnI) for the early diagnosis of perioperative myocardial infarction (PMI) and various complications of cardiac surgery. DESIGN: A prospective observational clinical study. SETTING: Biochemical laboratory, anesthesia, and cardiac surgery department of Hôpital Broussais. PATIENTS: Two hundred and sixty consecutive patients undergoing cardiac surgery. INTERVENTIONS: All patients underwent coronary artery bypass grafting and/or valvular surgery under extracorporeal circulation. Per-operative and postoperative follow-up consisted of electrocardiogram, echocardiography (mainly by the transesophageal approach), and serial determinations of biochemical markers such as creatinine kinase-MB isoenzyme (CK-MB) and cTnI. PMI, new ST segment changes, and ventricular arrhythmias were considered postoperative adverse cardiac outcome. MEASUREMENTS AND MAIN RESULTS: CTnI was measured before cardiopulmonary bypass (T0) and 12 and 24 hrs after (T12, T24). CK-MB was measured on arrival in the intensive care unit and on the first postoperative day (D1). Patients were divided into three groups according to the type of surgery: coronary artery bypass graft (CABG), valvular surgery (VS), or both procedures. The plasma CK-MB and cTnI concentrations were high in all patients after extracorporeal circulation because of aortic clamping or cardioplegia. The CK-MB and cTnI values were higher in the VS group than in the CABG group. Values peaked at T12 and fell by T24, except when PMI occurred. Eight patients developed a PMI. Patients with PMI had significantly higher cTnI levels at T12 and T24, and higher CK-MB values at D1 than patients without PMI. Cutoff values of cTnI for diagnosing PMI were >19 microg/L at T12 with 100% sensitivity and 73% specificity, and >36 microg/L at T24, with 100% sensitivity and 93% specificity. Lower cTnI values were highly suggestive of the absence of PMI after CABG and/or VS. Other complications such as ST segment changes, ventricular arrhythmias and cardiac failure were indicated by high cTnI levels at T12 and T24. Myocardial protective measures were associated with a nonsignificant increase in cTnI values. CONCLUSIONS: CTnI is more sensitive and specific than CK-MB for diagnosing PMI and other forms of heart failure after cardiac surgery.
Benoit et al. (2001) conducted an observational in Cardiac surgery (n=260). Cardiac troponin I (cTnI) measurement vs. Creatinine kinase-MB isoenzyme (CK-MB) measurement was evaluated on Early diagnosis of perioperative myocardial infarction (PMI). Cardiac troponin I levels >36 microg/L at 24 hours postoperatively diagnosed perioperative myocardial infarction with 100% sensitivity and 93% specificity.