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Serial hsTnT and Subsequent CV Events in Patients Stabilized After ACS
Quick Takes
- This is a secondary analysis of the IMPROVE-IT trial examining the association between changes in high-sensitivity troponin T (hsTnT) levels and cardiovascular outcomes in post–acute coronary syndrome (ACS) patients.
- HsTnT levels were measured at 1 and 4 months post-ACS.
- An increase in hsTnT level was associated with a higher risk of cardiovascular outcomes, while a decrease in levels was associated with a lower risk, relative to stable levels.
Study Questions:
Is a change in high-sensitivity troponin T (hsTnT) levels associated with cardiovascular (CV) outcomes in patients post–acute coronary syndrome (ACS)?
Methods:
In this secondary analysis from the IMPROVE-IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial) trial, the authors measured hsTnT levels in 6,035 participants at 1 and 4 months post-ACS and examined the association between absolute and relative change (%) in levels and outcomes. The outcomes of interest were the composite of CV death, myocardial infarction (MI), stroke, or hospitalization for heart failure (HHF). Associations of absolute and relative changes in hsTnT between month 1 and month 4 as a function of the starting month 1 hsTnT and the composite outcome were examined using landmark analyses. Absolute change was categorized at <3 ng/L, 12 ng/L, and 7 ng/L. Relative change was categorized at thresholds of 20% and 50%.
Results:
A total of 6,035 patients were included in this analysis (median [interquartile range] age, 64 [57-71] years, 1,486 [24.6%] women, 4,959 [82.2%] White, ~30% with diabetes mellitus). Most patients (4,114 [68.2%]) had stable hsTnT values (change <3 ng/L), with 1,158 (19.2%) and 763 (12.6%) having changes of 3 to <7 ng/L and ≥7 ng/L, respectively. An absolute increase in hsTnT of ≥7 ng/L was associated with a 3.33-fold (95% confidence interval [CI], 1.99-5.57) increase in the risk of the composite outcome, whereas decreases of ≥7 ng/L showed a near-statistically significant association with a lower risk of the event (hazard ratio, 0.51; 95% CI, 0.26-1.03) compared with stable values. A similar association was observed when analyzed on the basis of relative percent and continuous change, and the association did not vary based on sex, history of HF, and type of ACS.
Conclusions:
Among stable patients post-ACS, changes in hsTnT were associated with a gradient of risk of subsequent CV events across the range of starting hsTnT values.
Perspective:
This study reiterates in a post-ACS cohort what has previously been described in several population-based cohorts; higher increases in hsTnT levels are associated with an increased risk of CV outcomes. Notable findings include the observation that two thirds of patients had a stable hsTnT 4 months post-ACS, and <15% had an increase in hsTnT levels. On a glance, the defining characteristics of the group with increases in hsTnT levels appear to be the higher prevalence of diabetes mellitus and history of prior MI, but a more in-depth examination may yield important insights on the progression of disease in this subgroup. As with most biomarker studies, how the additional information provided by the serial hsTnT measurements impacts treatment decisions is unclear, since all patients post-ACS should be on guideline-directed optimal medical therapy. Characterizing patients as higher risk may help overcome clinical inertia and encourage physicians to be more aggressive in risk factor modification; however, the effectiveness of such a strategy remains to be proven.
Clinical Topics: Acute Coronary Syndromes, Cardiovascular Care Team, Dyslipidemia, Heart Failure and Cardiomyopathies, Prevention, ACS and Cardiac Biomarkers, Nonstatins, Statins, Acute Heart Failure, Heart Failure and Cardiac Biomarkers
Keywords: Acute Coronary Syndrome, Biomarkers, Diabetes Mellitus, Ezetimibe, Simvastatin Drug Combination, Heart Failure, Myocardial Infarction, Myocardial Ischemia, Primary Prevention, Risk Factors, Stroke
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