Written by Alex Chen, MD
In patients admitted to the hospital with concern for ACS and discharged without a specific diagnosis, the higher the troponin elevation above the 99th percentile, the greater their risk for major adverse events (MAEs).
Why does this matter?
Chest pain is one of the most common complaints in the Emergency Department. A troponin is a common test that is ordered in the evaluation of chest pain. There are plenty of times that the troponin is elevated, but not enough to pique the interest of your cardiology colleagues. If I had a dollar for every time a troponin of 0.04 was waived off as “just demand”, I would be much less poor but probably still working because I’m in debt. This study looks at what happens to patients who have an elevated troponin but no clear cause for it.
“It’s not cardiac chest pain, why did you even send that troponin?” –Every cardiologist ever
This was a retrospective registry-based cohort study of patients enrolled in the SWEDEHEART registry, a national database in Sweden that tracks patients admitted for suspected ACS. Patients were included in this study if they were admitted during this study period without a specified diagnosis according to their registry. 94.8% of patients were admitted for acute chest pain. Primary outcomes were all-cause mortality, MI, cardiovascular mortality, non-CV mortality (all other causes of death), hospitalization for heart failure, ischemic stroke, and MAEs (which was a composite of all of the above).
They enrolled 48,872 patients and broke them down into tertiles based on how high their troponin was elevated beyond the 99th percentile. This value varied based on the assay. For example, a common TnI assay had a cut-off of 0.03ng/ml for the 99th percentile. Tertile 1 was 0.031-0.05ng/ml, Tertile 2 was 0.051-0.06ng/ml, Tertile 3 was ≥0.06ng/ml.
A total of 7,529 patients (15.4%) suffered a MAE. The incidence rates for MAEs increased in a stepwise fashion across tertiles. In Tertile 1, the hazard ratio was 1.25 (1.18-1.34), group 2 was 1.53 (1.40-1.67), group 3 was 2.59 (2.39-2.80). This was a similar trend for all-cause mortality, CV mortality, non-CV mortality, MI, and heart failure.
While this was a retrospective study, it suggests that patients with troponin elevation are at higher risk for adverse events, and they need to be taken seriously as such. The authors emphasize referral for echocardiography and coronary imaging in these patients.
Cardiac Troponin Elevation in Patients Without a Specific Diagnosis. J Am Coll Cardiol. 2019 Jan 8;73(1):1-9. doi: 10.1016/j.jacc.2018.09.082.
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