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Prognostic value of cardiac troponin I release kinetics in unstable angina
R Teles1, J Ferreira, C Aguiar
1Serviço de Cardiologia do Hospital de Santa Cruz, Portugal.
Insights
Cardiac troponin T (cTnT) kinetics and nadir levels predict outcomes in unstable angina (UA). Even with initially negative cTnT, specific kinetic patterns indicate higher risk, aiding risk stratification.
Area of Science:
- Cardiology
- Biomarkers
- Clinical Diagnostics
Background:
- Cardiac troponins (cTn) are crucial for diagnosing unstable angina (UA).
- Observed patterns in cTn elevation suggest varying prognostic implications in UA patients.
- Understanding cTn kinetics can refine risk assessment in UA.
Purpose of the Study:
- To investigate cardiac troponin (cTn) kinetics and nadir levels in unstable angina (UA) patients.
- To define UA as angina at rest within 24 hours of admission with ischemic ECG changes and no myocardial infarction (MI) enzymatic criteria.
- To correlate cTn kinetics with 30-day adverse outcomes.
Main Methods:
- Collected blood samples from 156 UA patients for cardiac enzymes and cTnI at admission and 6, 12, 18, 24 hours.
- Utilized chemiluminescence method (Access/Sanofi Pasteur) for cTnI analysis.
- Primary endpoint: composite of death, MI, and recurrent ischemia at 30 days.
Main Results:
- 114 patients (group N) had all cTnI < 0.10 ng/ml; 42 (group P) had at least one value ≥ 0.10 ng/ml.
- Primary endpoint occurred in 45.2% of group P vs. 24.6% of group N (p=0.02).
- Identified a subgroup with increasing cTnI within 12 hours and a total differential value ≥ 0.03 ng/ml, showing increased risk (50.0% vs. 21.4%, p=0.02).
Conclusions:
- cTnI elevation is prognostic in UA.
- cTnI kinetics analysis identifies a subgroup with adverse prognosis despite initially negative cTnI.
- Kinetic analysis of cTnI provides additional prognostic information beyond simple elevation thresholds.
Background:
Cardiac Troponins (cTn) are useful in unstable angina (UA). Moreover the different elevation patterns that can be observed in this condition seem to have different prognostic implications.
Aim:
To study cTn kinetics and cTn nadir in patients with UA, defined as angina at rest within the last 24 hours before admission accompanied by ischemic ECG changes and no myocardial infarction (MI) enzymatic criteria.
Population And Methods:
Samples were collected from 156 patients for cardiac enzymes and cTnI at admission and at 6, 12, 18 and 24 hours. The chemilluminescence method (Access/Sanofi Pasteur) was used for cTnI. The primary end-point at 30 days was the combined occurrence of death, MI and recurrent ischemia.
Results:
All determinations were below 0.10 ng/ml (group N) in 114 patients and the other 42 pts (group P) had at least one value equal to or above 0.10 ng/ml. The primary endpoint was observed in 24.6% of group N pts compared with 45.2% of group P pts (p = 0.02). Three different patterns of cTnI kinetics were observed. This enabled the identification of a subgroup--group N pts with increasing cTnI values within the first 12 hours and a total differential value > or = 0.03 ng/ml--with an increased risk (50.0% versus 21.4%--p = 0.02--Kaplan-Meier test).
Conclusion:
Besides the prognostic value conferred by cTnI elevation, cTnI kinetics analysis established another sub-group of patients with an adverse prognosis at 30 days follow-up, despite having a negative cTnI.