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High-Sensitivity Cardiac Troponin for Risk Assessment in Chronic CAD
Quick Takes
- 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.
Study Questions:
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?
Methods:
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.
Results:
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).
Conclusions:
In patients with CAD, hs-cTnI levels are associated with risk of MI or CV death independent of severity of CAD or risk factors.
Perspective:
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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