Serial High-Sensitivity Troponin T in Post-Primary Angioplasty Exercise Test

Abstract

BackgroundThe kinetics of high-sensitivity troponin T (hscTnT) release should be studied in different situations, including functional tests with transient ischemic abnormalities.ObjectiveTo evaluate the release of hscTnT by serial measurements after exercise testing (ET), and to correlate hscTnT elevations with abnormalities suggestive of ischemia.MethodsPatients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary angioplasty were referred for ET 3 months after infarction. Blood samples were collected to measure basal hscTnT immediately before (TnT0h), 2 (TnT2h), 5 (TnT5h), and 8 hours (TnT8h) after ET. The outcomes were peak hscTnT, TnT5h/TnT0h ratio, and the area under the blood concentration-time curve (AUC) for hscTnT levels. Log-transformation was performed on hscTnT values, and comparisons were assessed with the geometric mean ratio, along with their 95% confidence intervals. Statistical significance was assessed by analysis of covariance with no adjustment, and then, adjusted for TnT0h, age and sex, followed by additional variables (metabolic equivalents, maximum heart rate achieved, anterior wall STEMI, and creatinine clearance).ResultsThis study included 95 patients. The highest geometric means were observed at 5 hours (TnT5h). After adjustments, peak hscTnT, TnT5h/TnT0h and AUC were 59% (p = 0.002), 59% (p = 0.003) and 45% (p = 0.003) higher, respectively, in patients with an abnormal ET as compared to those with normal tests.ConclusionHigher elevations of hscTnT may occur after an abnormal ET as compared to a normal ET in patients with STEMI.

Challenges in high-sensitive troponin assay interpretation for intensive therapy

“…( 16 ) Lower values found in the initial evaluation of patients for acute coronary syndrome may not be related to type 1 AMI (ischemia due to atherosclerotic plaque rupture, thrombus formation, spontaneous fissuring, or dissection), and transient elevations can be detected without clinical evidence of AMI in some situations. ( 17 ) Substantial increases followed by falls should be considered for diagnosis (starting at five times the upper limit of normality) and have obtained the best positive predictive value (90%). ( 9 ) This situation is observed in clinical practice and was detailed in the study by Apple et al, which demonstrated that patients with ACS had lower cTn levels and an earlier decline in the presence of unstable angina or the absence of persistent ST-segment elevation.…”

“…( 73 ) In fact, these assays may be elevated during short periods of exercise in both cardiopathic and noncardiopathic patients. ( 17,74 ) Several studies have demonstrated that transient elevations do not indicate myocardial damage, since the levels normalize within 24 to 48 hours. ( 19 ) These data also reinforce the theory of cTn release in the cytosol and not from the structural content of the myocytes.…”