A single highly sensitive cardiac troponin I measurement using the 20% CV LOQ cutpoint achieved 99.1% sensitivity for ruling out AMI, allowing immediate rule-out in 39% of patients.
Cohort (n=1,520)
Blinded adjudicators and measurement
Does a single hscTnI measurement safely rule out AMI compared to serial measurements in ED patients with suspected acute coronary syndrome?
A single highly sensitive cardiac troponin I measurement using a <20% CV LOQ cutpoint can safely and efficiently rule out AMI in nearly 40% of ED patients with suspected ACS.
Effect estimate: C-statistic 0.93 (95% CI 0.91-0.96)
Absolute Event Rate: 0.93% vs 0.95%
BACKGROUND: Serial Highly Sensitive Cardiac Troponin I (hscTnI) measures are commonly performed in patients presenting to the ED to exclude suspected Acute Myocardial Infarction (AMI). The previously published FAST-TRAC study prospectively enrolled patients presenting to the ED within 6 h of onset of symptoms consistent with suspected AMI. Our purpose was to evaluate the performance of a single hscTnI measurement, termed "one-and-done" using this cohort. METHODS: In emergency department suspected acute coronary syndrome patients, serial blood samples were prospectively obtained for blinded hscTnI measurement (Access TnI, Beckman Coulter, Brea, CA) at 1, 2, 3-4, and 6-12 h after presentation. Patients were followed for 30-day Major Adverse Cardiac Events (MACE) determined by adjudicators blinded to hsTnI results. RESULTS: Of 1520 patients enrolled, 113 (7.4%) were adjudicated as AMI, with 59% male, median (IQR: Interquartile Rank) age of 57 years (48-67), 66% White, 28% African American, and 3% Asian American. The overall median (IQR) time to first hscTnI draw after symptom onset was 3.67 (2.50-5.09) hours. Serial hscTnI and one-and-done strategies had comparable C-statistics for AMI; 0.95 (0.93-0.98) vs 0.93 (0.91-0.96), respectively. In no circumstance did the 99th percentile cutpoint meet an adequate rule-out AMI sensitivity of 99%. Serial measures using either the 10% or 20% Coefficient of Variation (CV) Level of Quantification (LOQ) cutpoint had the same sensitivity of 99.1%, but the 10% CV LOQ had higher specificity, 61.7%, (95% CI = 59.1-64.2). For a "one-and-done" strategy, only the 20% CV LOQ, with a sensitivity of 99.1 (95.2-99.8), met the 99% sensitivity goal. Using the 20% CV LOQ, a "one-and-done" strategy would have immediately ruled out 39% (n = 550) of patients for AMI, with only 61% (n = 857) requiring additional serial hscTnI testing. CONCLUSIONS: A "one-and-done" strategy using a hscTnI <20% CV LOQ provides the most efficient AMI rule-out performance. REGISTRATION: NCT00880802.
Peacock et al. (Fri,) conducted a cohort in Suspected acute coronary syndrome (n=1,520). Single hscTnI measurement ('one-and-done' strategy) vs. Serial hscTnI measurement was evaluated on C-statistic for AMI (C-statistic 0.93, 95% CI 0.91-0.96). A single highly sensitive cardiac troponin I measurement using the 20% CV LOQ cutpoint achieved 99.1% sensitivity for ruling out AMI, allowing immediate rule-out in 39% of patients.