BACKGROUND: Cardiac troponin I (cTnI) is known as a sensitive and specific marker for myocardial ischemia. The purposes of this study are to establish cut-off values of cTnI for acute myocardial infarction (AMI) and to analyze clinical significance of minor elevation of cTnI. METHODS: Two hundred and four patients from whom cTnI was measured at Ewha Womans University Dongdaemun hospital from January to March, 2006 were enrolled in the study. cTnI was measured using Dimension RxL (Dade Behring, USA). The lower limit of detection (LLD), 10% CV value, 99th percentile of healthy individuals, and cut-off value for AMI by ROC curve analysis were determined. RESULTS: LLD, 10% CV value, and 99th percentile of cTnI were 0.00 ng/mL, 0.10 ng/mL, and 0.07 ng/mL, respectively. The cut-off value of peak cTnI for AMI by ROC curve analysis was 0.13 ng/mL with the sensitivity, specificity, and AUC of 90.9%, 87.7%, and 0.921, respectively. The peak value of cTnI of patients with ischemic heart disease (IHD) was higher than that of the patients without IHD (P<0.05). According to the above reference and cut-off values of the initial cTnI, patients were categorized into four groups; < or =0.05 ng/mL (group 1), 0.06-0.09 ng/mL (group 2), 0.10-0.59 ng/mL (group 3), > or =0.60 ng/mL (group 4), and compared frequencies of AMI, IHD, cardio vascular disease (CVD) and death after 1 month among groups. Frequencies of AMI, IHD, CVD, and death after 1 month were significantly increased as the cTnI concentrations were increased (P<0.05). CONCLUSIONS: Minor elevation of cTnI value, even in group 3 was significantly associated with high incidence of AMI, IHD, CVD, and death rate after 1 month.
Acute Disease ; Aged ; Aged, 80 and over ; Biological Markers/blood ; Cardiovascular Diseases/*diagnosis/etiology/mortality ; Data Interpretation, Statistical ; Female ; Humans ; Male ; Middle Aged ; Myocardial Infarction/*diagnosis/etiology/mortality ; Myocardial Ischemia/diagnosis/etiology/mortality ; Predictive Value of Tests ; ROC Curve ; Sensitivity and Specificity ; Survival Analysis ; Troponin I/*blood

INTRODUCTIONThe relationship between electrocardiograph (ECG) changes and troponin levels after the emergency orthopaedic surgery are not well characterised. The aim of this study was to determine the correlation between ECG changes (ischaemia or arrhythmia), troponin elevations perioperatively and cardiac complications.

MATERIALS AND METHODSOne hundred and eighty-seven orthopaedic patients over 60 years of age were prospectively tested for troponin I and ECGs were performed on the fi rst 3 postoperative mornings or until discharge.

RESULTSThe incidences of pre- and postoperative troponin elevation were 15.5% and 37.4% respectively, the majority were asymptomatically detected. Most of the patients who sustained a troponin rise did not have any concomitant ECG changes (51/70 or 72.9%). Postoperative ECG changes were noted in 18.4% (34/185) and of those with ECG changes, slightly more than half (55.9%) had a troponin elevation. Most ECG changes occurred on postoperative day 1 and were non-ST elevation in type. ECG changes occurred more frequently with higher troponin levels. Postoperative troponin elevation (P = 0.018) and not preoperative troponin level (P = 0.060) was associated with ECG changes on univariate analysis. Two premorbid factors were predictors of postoperative ECG changes using multivariate logistical regression; age [odds ratio (OR), 1.05; 95% CI, 1.005 to 1.100, P = 0.029) and sex OR, 2.4; 95% CI, 1.069 to 5.446, P = 0.034). Twenty patients sustained postoperative cardiac complications; 9 (45%) were associated with ECG changes and 16 (80%) with postoperative troponin elevation. Pre- or postoperative troponin elevation better predicted cardiac complications compared with preoperative ECG changes.

CONCLUSIONElectrocardiograph changes do not necessarily accompany troponin elevations after the emergency orthopaedic surgery but are more likely to have higher troponin levels. The best predictor of postoperative cardiac complications is troponin elevation.

Aged ; Aged, 80 and over ; Arrhythmias, Cardiac ; blood ; diagnosis ; etiology ; mortality ; Biomarkers ; blood ; Electrocardiography ; Female ; Humans ; Logistic Models ; Male ; Middle Aged ; Multivariate Analysis ; Myocardial Ischemia ; blood ; diagnosis ; etiology ; mortality ; Orthopedic Procedures ; Postoperative Complications ; blood ; diagnosis ; etiology ; mortality ; Postoperative Period ; Preoperative Period ; Prospective Studies ; ROC Curve ; Risk Factors ; Single-Blind Method ; Troponin I ; blood