A recent study published in the Journal of American College of Cardiology found an association between elevated concentrations of high sensitivity troponin I (hsTnI) with increasing prevalence of coronary artery disease (CAD) in stable patients, who were suspected of coronary artery disease and underwent non-emergent coronary computed tomography angiography (CTA).
Since it is known that elevated concentrations of hsTnI correlate with CAD in patients with myocardial infarction, Dr. Jannuzzi and his colleagues investigated hsTnI concentrations in stable symptomatic outpatients. They conducted an ad hoc analysis of the PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) trial that randomized 10,003 patients who received CTA (4,500) and those that had no CTA performed (5,503). Out of the arm that underwent CTA, 1844 patients participated in the biorepository with samples available for hsTnI measurement.
In the study, the median hsTnI concentration was 1.5ng/l. Out of the study sample, 98.5% subjects had measurable hsTnI and 6.1% had concentrations ≥99th percentile concentration for this assay (>6ng/l). Elevated concentrations of hsTnI were associated with higher coronary artery calcium (CAC) scores as well as a diffuse CAD with greater frequency and proportion of vessels CAD50 ( ≥50% stenosis in any vessel) and CAD70 ( ≥70% stenosis or ≥50% left main). Independent predictors of hsTnI concentrations were age, male sex, and CAC scores.
“To this point, use of highly sensitive troponin might also help refine which patients benefit the most from treatment with more aggressive medical therapy approaches for atherothrombotic diseases, such as PCSK9 inhibitors or oral anticoagulants.”- Dr. James Januzzi, M.D.
When asked how these findings are going to impact clinical practice, Dr. Januzzi said, “The development of very highly sensitive troponin assays, such as the one we studied in PROMISE open up the door for examining how this marker may be of value in the evaluation of those with more stable symptoms, such as patients with stable chest pain.” However, he acknowledged that while highly sensitive troponin was significantly associated with the presence and severity of coronary artery disease in the patients studied, it was only modestly discriminatory. Dr. Januzzi added, “Troponin could be used as a gatekeeper, to decide who will be referred immediately for invasive angiography.”
Dr. Januzzi believes that the marker is particularly useful to stratify risk in patients found to have coronary disease using other methods, such as coronary computed tomography. However, he emphasizes that “Until such an algorithm for how to use troponin in this setting is developed, clinicians should not begin using highly sensitive troponin in the office in this manner.” Dr. Januzzi expresses his excitement about the future use of highly sensitive troponin by saying that “It is tempting to think highly sensitive troponin might be helpful to understand which patients at risk for these diagnoses- such as diabetes-might be more aggressively managed. To this point, use of highly sensitive troponin might also help refine which patients benefit the most from treatment with more aggressive medical therapy approaches for atherothrombotic diseases, such as PCSK9 inhibitors or oral anticoagulants.”