Determination of troponin I release after CABG surgery

J Card Surg. 2005 Mar-Apr;20(2):129-35. doi: 10.1111/j.0886-0440.2005.200387.x.

Abstract

Background: Troponin I is used to diagnose myocardial infarction (MI). Its use and pattern of elevation is not well defined in coronary artery bypass graft (CABG) surgery. This study assessed the timing of troponin I elevation in patients undergoing urgent CABG.

Method: Patients undergoing urgent isolated-CABG with cardiopulmonary bypass were studied prospectively. Blood samples were taken to measure CK, CK-MB, and troponin I: preoperatively, 7 hours postoperatively, 14 to 18 hours postoperatively, 30 to 48 hours postoperatively, and on postoperative day 4. Electrocardiograms and in-hospital course were recorded. Perioperative MI (PMI) was defined by either (i) ECG criteria of new Q-waves in the presence of CK-MB elevation >50 microg/L or (ii) CK-MB > 100 microg/L.

Results: Of the 50 patients studied, 6 met the criteria for PMI (12%); 2 by criteria (i) and 4 by criteria (ii). In patients not meeting the criteria for MI the troponin I level peaked at 7 hour post-op with a mean of 20.97 microg/L (95% CI, 17.11 to 24.83). At this time, patients who met the criteria for MI had a mean troponin I level of 46.85 microg/L (95% CI, 36.40 to 57.30). Of variables investigated for the 44 patients who did not meet MI criteria, only preoperative troponin I level impacted peak postoperative troponin I.

Conclusions: CABG elevates troponin I far beyond current diagnostic benchmarks without the clinical occurrence of a MI and appears to peak during the second postoperative day. An elevated preoperative troponin I may predict an elevated peak postoperative troponin I in patients who do not have a PMI.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Biomarkers / blood
  • Coronary Artery Bypass / adverse effects*
  • Creatine Kinase / blood
  • Electrocardiography
  • Female
  • Humans
  • Isoenzymes / blood
  • Male
  • Myocardial Infarction / blood*
  • Myocardial Infarction / enzymology
  • Myocardial Infarction / etiology
  • Postoperative Period
  • Prognosis
  • Prospective Studies
  • Time Factors
  • Troponin I / blood*

Substances

  • Biomarkers
  • Isoenzymes
  • Troponin I
  • Creatine Kinase