January 1, 1997Academic Emergency Medicine
Evaluation of a New Assay for Cardiac Troponin I vs Creatine Kinase‐MB for the Diagnosis of Acute Myocardial Infarction
Why the study?
Does a cardiac troponin I assay improve the diagnosis of acute myocardial infarction compared to creatine kinase-MB in patients presenting with symptoms of cardiac ischemia?
Population
171 patients presenting with symptoms consistent with cardiac ischemia at a university teaching hospital
Comparison
Cardiac troponin I (cTn-I) assay vs Creatine kinase-MB (CK-MB) assay
Design
Cross-sectional
Authors
Discussion
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Member takes
Implication
cTn-I may aid late AMI diagnosis and early risk stratification; leaves open prospective validation before practice change.
Key Points
- To compare the diagnostic performance of a new cardiac troponin I assay with creatine kinase-MB for diagnosing acute myocardial infarction.
- Prospective cross-sectional study conducted at a university teaching hospital on patients presenting with symptoms of cardiac ischemia.
- Serial serum sampling for cardiac troponin I and creatine kinase-MB was performed at 0, 1, 3, 8, and 16 hours after presentation.
- A cohort of 35 consecutive patients with acute myocardial infarction was compared to 136 randomly selected non-infarction control patients using World Health Organization diagnostic criteria.
- Cardiac troponin I demonstrated equivalent sensitivity and specificity to creatine kinase-MB within 24 hours of symptom onset, but showed superior sensitivity in patients presenting at or after 24 hours.
- Elevations of either marker within 6 hours of symptom onset predicted an increased risk for cardiovascular complications or need for intervention (creatine kinase-MB: OR 5.8; cardiac troponin I: OR 6.3).
Structured PICO
Does a cardiac troponin I assay improve the diagnosis of acute myocardial infarction compared to creatine kinase-MB in patients presenting with symptoms of cardiac ischemia?
P
Population
171 patients presenting with symptoms consistent with cardiac ischemia at a university teaching hospital (35 with acute myocardial infarction, 136 without)
I
Intervention
Cardiac troponin I (cTn-I) assay
C
Comparator
Creatine kinase-MB (CK-MB) assay
O
Outcome
Sensitivity and specificity for the diagnosis of acute myocardial infarction (AMI) stratified by time from symptom onsetsurrogate
Cardiac troponin I is a highly sensitive and specific biomarker for diagnosing acute myocardial infarction, outperforming CK-MB in patients presenting more than 24 hours after symptom onset.
Cite This Study
Brogan et al. (1997) studied this question.