Variability in High-Sensitivity Cardiac Troponin T Testing in Stable Patients With and Without Coronary Artery
James M Brophy1, Gilles R Dagenais2, Luce Boyer2
1McGill University Health Center, Montréal, Québec, Canada.
Insights
High-sensitivity cardiac troponin T (hs-cTnT) levels are stable in patients with and without coronary artery disease over time. However, diabetes, renal function, and C-reactive protein influence hs-cTnT values, requiring careful interpretation.
Area of Science:
- Cardiology
- Biomarkers
- Clinical Chemistry
Background:
- High-sensitivity cardiac troponin T (hs-cTnT) is crucial for diagnosing acute myocardial infarction.
- Interpretation often relies on the 99th percentile threshold (14 ng/L) of normal populations.
- The variability of hs-cTnT in stable patients with or without coronary artery disease (CAD) remains largely unknown.
Purpose of the Study:
- To investigate the short- and long-term variability of hs-cTnT.
- To assess hs-cTnT levels in stable patients with CAD and controls without CAD.
- To identify predictors of elevated hs-cTnT values.
Main Methods:
- A prospective cohort study involving 75 stable patients with CAD and 25 controls without CAD.
- Each participant provided 15 hs-cTnT measurements over a one-year period.
- Patients with CAD were categorized into stable angina, remote myocardial infarction, or repetitive acute coronary syndrome groups.
Main Results:
- Individual hs-cTnT measurements showed no significant variation across different time windows (within-day to yearly).
- The repetitive acute coronary syndrome group exhibited the highest median hs-cTnT (6.3 ng/L) and variability (IQR 6.9 ng/L).
- Diabetes, impaired renal function, and elevated C-reactive protein independently predicted higher hs-cTnT values, with the 99th percentile reaching 39 ng/L in CAD patients.
Conclusions:
- Individual hs-cTnT readings are stable over extended periods in both CAD and non-CAD patients.
- Diabetes, renal dysfunction, and elevated C-reactive protein are key predictors of higher hs-cTnT, potentially exceeding conventional diagnostic thresholds.
- Clinical context is essential for accurate hs-cTnT interpretation due to influencing factors.
Background:
High-sensitivity cardiac troponin T (hs-cTnT) is used to diagnosis acute myocardial infarction, often based on values exceeding the 99th percentile threshold (14 ng/L) of normal populations. The short- and long-term variability of hs-cTnT in stable patients with or without coronary artery disease (CAD) is unknown.
Methods:
Prospective cohort study of 75 stable patients with CAD and 3 differing clinical profiles (stable angina [SA]; remote myocardial infarction [MI]; repetitive acute coronary syndrome [ACS]) and 25 controls without angiographic CAD, each with 15 hs-cTnT measurements over 1 year.
Results:
Individual results (1491 measurements) did not vary over within-day, daily, weekly, monthly, seasonal, or yearly time windows. The overall median was 2.8 ng/L (interquartile range [IQR] 5.2 ng/L) with the highest median (6.3 ng/L) and variability (IQR 6. 9 ng/L) in the repetitive ACS group. Diabetes, impaired renal function, and raised C-reactive protein were independent predictors of higher hs-cTnT values (average increase by 8.5 ng/L [95% CI, 5.0-11.9], 5.0 ng/L [95% CI, 2.0-8.1] and 4.0 ng/L (95% CI, 1.0-7.0), respectively). The 99th percentile value of all hs-cTnT measurements in the combined stable patients with CAD was 39 ng/L compared with 14 ng/L in the non-CAD patients.
Conclusions:
Individual hs-cTnT readings in both patients with and without CAD were stable over hours, days, weeks, and months. Diabetes, poor renal function, and elevated C-reactive protein were independent predictors of higher median and IQR hs-cTnT values, often exceeding conventional thresholds. These findings highlight the need for caution and clinical contextualization in the interpretation of hs-cTnT results.
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