One and Done? Performance of a single, low high-sensitivity troponin in a multisite United States cohort
Allen B, Christenson R, Cohen SA, Nowak RM, Wilkerson RG, Mumma BE, Madsen T, McCord J, T'Veld MH, Massoomi M, Stopyra JP, Montero C, Weaver M, Yang K, and Mahler SA. One and Done? Performance of a single, low high-sensitivity troponin in a multisite United States cohort. Academic Emergency Medicine 2020; 27:S8.
Academic emergency medicine
Background and Objectives: European data suggest a single high-sensitivity troponin (hs-cTn) result below the limit of detection excludes major adverse cardiac events (MACE) in patients with symptoms concerning for acute coronary syndrome. However, the FDA limits hs-cTnT reporting to the limit of quantification (LOQ: 6 ng/L) and little US data exists evaluating this cut-point. The objective of this study is to test the diagnostic performance of an initial hs-cTnT measure below the LOQ in a multisite US cohort.
Methods: A prospective observational cohort study was conducted at 8 US sites. Adult ED patients with symptoms suggestive of acute coronary syndrome and without ST-segment elevation on ECG were enrolled. Blood samples were collected from participants and hs-cTnT concentrations were measured using the Roche (Basel, Switzerland) hs-cTnT assay. Patients with research blood collection >1 hour after their first clinical blood draw or insufficient sample volume were excluded from analysis. Treating providers were blinded to hs-cTnT results. Adjudicated outcomes included MACE (composite of cardiac death, myocardial infarction [MI], and coronary revascularization) at 30-days and cardiac death or MI at 30-days. The proportion of patients with an initial hs-cTnT measure below the LOQ was determined, and sensitivity and negative predictive value (NPV) for safety outcomes were calculated with exact 95% confidence intervals. Results: Among 1,460 with initial hs-cTnT measures, 46.3% (676/1,460) were women and 37.1% (542/1,460) were African American with a mean age of 57.6 (SD±12.8) years. MACE at 30-days occurred in 14.4% (210/1,460). The initial hs-cTnT measure was below the LOQ in 32.9% (479/1,460) of patients. Among these patients, 1.7% (8/479) had 30-day MACE, yielding a NPV of 98.3% (95%CI: 96.8-99.2%) and 1.0% (5/479) had 30-day cardiac death or MI with a NPV of 99.0% (95%CI: 97.6-99.6%). Sensitivity of the initial hs-cTnT measure below the LOQ was 96.2% (95%CI: 92.6-98.3%) and 97.4% (95%CI: 94.0-99.1%) for 30-day MACE and cardiac death or MI, respectively.
Conclusion: In a multisite prospective US cohort, a single hs-cTnT measure below the LOQ occurred in nearly a third of patients. However, the sensitivity and NPV of a single hs-cTnT measure may not be sufficient to rule-out 30-day MACE or 30-day cardiac death or MI.