High-Sensitivity Cardiac Troponin for Risk Assessment in Chronic CAD
- The purpose of this study was to evaluate whether high-sensitivity cardiac troponin I (hs-cTnI) in patients with undergoing angiography for suspected CAD is associated with MI or CV death.
- Patients with hs-cTnI levels above the 99% URL were four times more likely to experience MI or CV death compared to those with troponin concentrations below 5 ng/L, and improved risk discrimination.
- Whether the additional information conferred by the measurement of hs-cTnI can impact clinical care remains to be shown.
In patients undergoing coronary angiography for suspected coronary artery disease (CAD), do high-sensitivity cardiac troponin I (hs-cTnI) levels improve risk stratification for the primary outcome of myocardial infarction (MI) or cardiovascular (CV) death at follow-up?
The MICA (Myocardial Injury in Patients Referred for Coronary Angiography) study is a prospective cohort study which enrolled consecutive patients referred for outpatient coronary angiography due to suspected stable angina symptoms. Hs-cTnI levels were measured using the ARCHITECT STAT High-Sensitivity Troponin-I assay in blood samples collected pre-angiogram. The primary study outcome was a composite of MI or CV death, while secondary outcomes included MI, CV death, non-CV death, all-cause death, and index coronary revascularization.
A total of 4,240 patients were included in the study and followed for a median period of 2.4 years. The median age of participants was 66 years, with 33% being female. About two-thirds of patients had obstructive CAD. Hs-cTnI levels were higher in patients with CAD (3.4 ng/L) compared to those without (1.9 ng/L), and in the majority of CAD patients, these concentrations were above the detection limit. During the follow-up, a total of 255 (6.0%) patients experienced a primary outcome event (MI or CV death), which was more common in patients with CAD (6.4%) than those without (1.7%). Hs-cTnI levels were two-fold higher in patients with CAD who had an event compared to those without (6.7 [3.2-14.2] vs. 3.3 [1.7-6.6] ng/L). Hs-cTnI levels were associated with the primary outcome after adjusting for CV risk factors and CAD severity (adjusted hazard ratio, 2.3; 95% confidence interval, 1.7-3.0, log10 troponin). An hs-cTnI level >10 ng/L identified patients with a 50% increase in the risk of MI or CV death. The addition of hs-cTnI levels improved discrimination for the primary outcome compared to the Duke Prognostic Index alone (area under the curve, 0.70 vs. 0.63; p < 0.001).
In patients with CAD, hs-cTnI levels are associated with risk of MI or CV death independent of severity of CAD or risk factors.
This study contributes to the extensive body of literature demonstrating the robust correlation between hs-cTnI measurements and CV outcomes across diverse patient populations, specifically when these measurements are taken outside the context of acute coronary syndrome. The risk discrimination power of hs-cTnI levels surpassing the upper reference limit of normal (URL) is compelling, suggesting a possible role in directing treatment strategies for stable patients following diagnosis. Notably, current guidelines are progressively advocating for stringent control of low-density lipoprotein cholesterol (<50 mg/dL) and blood pressure (<120/80 mm Hg), independent of hs-cTnI levels, leaving the potential impact of these biomarker-based strategies somewhat unclear. Hs-cTnI could also serve as a tool for identifying higher-risk patients eligible for clinical trials aimed at evaluating innovative therapeutic approaches. We are keenly anticipating further clarification regarding the strategies that could be guided by hs-cTnI levels to facilitate the effective integration of this biomarker in the management of stable patients.
Clinical Topics: Acute Coronary Syndromes, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Stable Ischemic Heart Disease, Atherosclerotic Disease (CAD/PAD), ACS and Cardiac Biomarkers, Cardiac Surgery and Arrhythmias, Cardiac Surgery and SIHD, Interventions and ACS, Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Nuclear Imaging, Chronic Angina
Keywords: Acute Coronary Syndrome, Angina, Stable, Biomarkers, Coronary Angiography, Coronary Artery Disease, Myocardial Infarction, Myocardial Ischemia, Myocardial Revascularization, Outpatients, Primary Prevention, Risk Factors, Troponin I
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