Myocardial Ischemia on Exercise Stress Echocardiography Testing Is Not Associated with Changes in Troponin T
Alexander T Limkakeng1, Weiying Drake1, Yuliya Lokhnygina2
1Division of Emergency Medicine, Department of Surgery, Duke University School of Medicine, Durham, NC.
Insights
Exercise stress testing did not significantly change high-sensitivity cardiac troponin T (hs-cTnT) levels, even in patients with myocardial ischemia. This suggests hs-cTnT may not be sensitive to ischemia induced by exercise.
Area of Science:
- Cardiology
- Biomarkers
- Diagnostic Testing
Background:
- High-sensitivity cardiac troponin T (hs-cTnT) assays are increasingly used for myocardial ischemia detection.
- A hypothesis proposed that exercise-induced myocardial ischemia would elevate hs-cTnT levels.
Purpose of the Study:
- To investigate if exercise stress testing causes significant changes in hs-cTnT concentrations.
- To compare hs-cTnT changes in patients with and without exercise-induced myocardial ischemia.
Main Methods:
- Prospective recruitment of 317 adult patients with possible ischemic symptoms for exercise echocardiography.
- Collection of plasma hs-cTnT concentrations pre-stress and 2-h post-stress.
- Comparison of absolute and relative hs-cTnT changes between ischemic and non-ischemic groups.
Main Results:
- 8.1% of patients developed exercise-induced myocardial ischemia.
- Baseline and 2-h hs-cTnT levels were higher in patients with abnormal stress tests (P ≤0.05).
- No significant difference in absolute or relative hs-cTnT changes was observed between patients with and without ischemia.
Conclusions:
- Exercise stress testing did not induce a detectable change in hs-cTnT values.
- hs-cTnT levels did not change in response to exercise, irrespective of myocardial ischemia presence.
Background:
Some posit that any amount of myocardial ischemia can be detected by high-sensitivity cardiac troponin assays. We hypothesized that patients with myocardial ischemia induced by exercise stress would have significantly higher increases in high-sensitivity cardiac troponin T (hs-cTnT) concentrations than patients without ischemia.
Methods:
We prospectively recruited for a biorepository 317 adult patients who presented to an academic hospital emergency department for evaluation possible ischemic symptoms and who were scheduled for exercise echocardiography. Blood samples were obtained before stress testing and 2-h post-testing. For this study, plasma hs-cTnT (Roche Diagnostics) concentrations were determined in a core laboratory blinded to clinical status. Absolute and relative changes between baseline and 2-h post-stress measurements were compared between patients with and without ischemia induced by stress testing.
Results:
The median age was 51 (44.0, 60.0) years, 45.9% were male, and 37.8% were African American. In total, 26 patients (8.1%) had myocardial ischemia induced by exercise. Median baseline, 2-h post-stress, and absolute δ concentrations were, respectively, 6.0, 8.0, and 0.2 ng/L for patients with evidence of ischemia; 3.8, 4.6, and 0.0 ng/L for those without; and 3.9, 4.9, and 0.0 ng/L overall. Baseline and 2-h hs-cTnT concentrations were higher among patients with abnormal stress tests (all P ≤0.05), but absolute and relative changes in hs-cTnT concentrations were not significantly different between individuals with ischemia and individuals without.
Conclusions:
There was no evidence of change in hs-cTnT values in response to exercise stress testing, regardless of the presence of myocardial ischemia.
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