Long-term health outcomes associated with detectable troponin I concentrations
Peter A Kavsak1, Alice M Newman, Viliam Lustig
1Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. kavsakp@mcmaster.ca
Insights
Even slightly elevated cardiac troponin I (cTnI) levels in patients with chest discomfort indicate a higher risk of future cardiovascular events, including death and heart failure.
Area of Science:
- Cardiology
- Biomarkers
- Emergency Medicine
Background:
- Recent data indicate older men with detectable cardiac troponin I (cTnI) below the 99th percentile are at increased cardiovascular risk.
- This risk extends to women and requires further investigation in emergency department settings.
Purpose of the Study:
- To assess the predictive value of detectable cTnI concentrations, even below the 99th percentile, for adverse cardiovascular events in both men and women.
- To extend previous observations on cardiac troponin I risk stratification in patients presenting with chest discomfort.
Main Methods:
- Retrospective analysis of 448 patients presenting with acute coronary syndrome (ACS) in 1996.
- Measurement of peak cardiac troponin I (cTnI) concentrations in frozen plasma samples.
- Assessment of all-cause mortality and hospital readmissions for acute myocardial infarction (AMI) or congestive heart failure (CHF) up to 8 years post-presentation.
Main Results:
- Patients with detectable cTnI (≥0.02 µg/L), even below the 99th percentile (0.04 µg/L), faced higher risks of death and AMI/CHF readmissions at 2, 5, and 8 years.
- A statistically significant increase in adverse events was observed for cTnI levels between 0.02 and 0.03 µg/L compared to undetectable levels (<0.02 µg/L).
- Kaplan-Meier analyses confirmed worse outcomes for both men and women with cTnI ≥0.02 µg/L (P <0.001).
Conclusions:
- Detectable cardiac troponin I (cTnI) concentrations, even below the 99th percentile cutoff, signify an elevated risk for future adverse cardiovascular events in patients with possible ACS.
- This finding applies to both men and women presenting to the emergency department with chest discomfort.
- cTnI remains a crucial biomarker for risk stratification in acute coronary syndrome.
Background:
Recent data suggest that older men with detectable cardiac troponin I (cTnI) concentrations that remain below the 99th percentile concentration cutoff are at increased risk for subsequent cardiovascular events. We designed this study to extend this observation by examining risk prediction in both men and women presenting to an emergency department with chest discomfort.
Methods:
We obtained data for all-cause mortality and hospital discharges associated with either acute myocardial infarction (AMI) or congestive heart failure (CHF) for up to 8 years after the initial presentation in 448 patients who originally presented in 1996 with acute coronary syndrome (ACS). We performed retrospective analysis for cTnI (AccuTnI; Beckman Coulter) in frozen plasma samples based on the patients' reported time from onset of symptoms. Peak cTnI concentration was used for risk assessment.
Results:
Patients with cTnI concentrations > or =0.02 microg/L (i.e., limit of detection), including those whose peak values remained below the 99th percentile (0.04 microg/L), were at greater risk for death and AMI/CHF readmissions at 2, 5, and 8 years of follow-up compared with those with peak cTnI <0.02 microg/L. All results were statistically significant (P <0.05) except for death within 2 years among patients with normal but detectable cTnI (0.02 to 0.03 microg/L), relative to the group with values <0.02 microg/L. Kaplan-Meier analyses indicated that both men and women with cTnI > or =0.02 microg/L had worse outcomes (P <0.001).
Conclusion:
Both men and women who present with possible ACS with detectable cTnI concentrations that remain below the 99th percentile are at a greater risk for future adverse events.
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