High-Sensitivity Cardiac Troponin T Identifies Myocardial Injury with COVID-19

Cardiac troponin (cTn) is the preferred biomarker for the detection of myocardial injury (MI), which is defined when there is at least one cTn concentration above the 99th percentile upper-reference limit (URL) of a healthy reference cohort.

While pulmonary complications are frequent with COVID-19, studies suggest that myocardial injury is common, in particular among those with chronic cardiovascular conditions and more severe COVID-19 presentations, and that its presence and magnitude is associated with worse outcomes.

Cardiologist and a large team of medical scientists at the Mayo Clinic (Rochester, MN, USA) conducted a multicenter, retrospective, observational, US-based study of COVID-19 patients undergoing high-sensitivity cardiac troponin T (hs-cTnT). The final study cohort included 367 COVID-19 patients in whom at least one hs-cTnT was obtained, amongst which 46% were identified to have myocardial injury based on hs-cTnT concentrations above the sex-specific 99th percentiles. The mean ± SD age of the cohort was 61 ±17 years and most patients presented through the Emergency Department (83%).

The hs-cTnT was measured with the Elecsys Troponin T Gen 5 STAT (Roche Diagnostics, Indianapolis, IN, USA). The lowest reportable clinical value is the <6 ng/L limit of quantification (LoQ). Sex-specific 99th percentiles URLs of 10 ng/L for women and 15 ng/L for men were used. Patients with suspected MI are evaluated using a 0/2 hour hs-cTnT protocol that uses sex-specific 99th percentile URLs to rule-in and rule-out myocardial injury and an absolute delta (serial change) of ≥10 ng/L to identify patients with acute injury. MI is diagnosed when there is objective evidence of myocardial ischemia.

The team reported that among 367 COVID-19 patients undergoing hs-cTnT, myocardial injury was identified in 46%. They had a higher risk for mortality (20% versus 12%), unadjusted hazard ratio (HR) of 4.44 and major adverse events (35% versus 11%). The hs-cTnT results were independent predictors of major adverse events. Most (95%) increases were due to myocardial injury, with 5% classified as type 1 or 2 myocardial infarction. A single hs-cTnT <6 ng/L identified 26% of patients without mortality, with a 94.9% (negative predictive value and 93.1% sensitivity for major adverse events in those presenting to the ED.

The authors concluded that myocardial injury is frequent and prognostic in COVID-19. While most hs-cTnT increases are modest and due to myocardial injury, they have important prognostic implications. A single hs-cTnT <6 ng/L at presentation may facilitate the identification of patients with a favorable prognosis. The study was published in the August 2021 issue of the journal Clinical Chemistry.

Related Links:
Mayo Clinic
Roche Diagnostics