Rising and Falling High‐Sensitivity Cardiac Troponin in Diagnostic Algorithms for Patients With Suspected Myocardial Infarction

BACKGROUND: High‐sensitivity cardiac troponin (hs‐cTn)‐based diagnostic algorithms are recommended for the management of patients with suspected myocardial infarction (MI) without ST elevation. Although mirroring different phases of myocardial injury, falling and rising troponin patterns (FPs and RPs, respectively) are equally considered by most algorithms. We aimed to compare the performance of diagnostic protocols for RPs and FPs, separately. METHODS AND RESULTS: We pooled 2 prospective cohorts of patients with suspected MI and stratified patients to stable, FP, and RP during serial sampling separately for hs‐cTnI and hs‐cTnT and applied the European Society of Cardiology 0/1‐ and 0/3‐hour algorithms comparing the positive predictive values to rule in MI. Overall, 3523 patients were included in the hs‐cTnI study population. The positive predictive value for patients with an FP was significantly reduced compared with patients with an RP (0/1‐hour: FP, 53.3% [95% CI, 45.0–61.4] versus RP, 76.9 [95% CI, 71.6–81.7]; 0/3‐hour: FP, 56.9% [95% CI, 42.2–70.7] versus RP, 78.1% [95% CI, 74.0–81.8]). The proportion of patients in the observe zone was larger in the FP using 0/1‐hour (31.3% versus 55.8%) and 0/3‐hour (14.6% versus 38.6%) algorithms. Alternative cutoffs did not improve algorithm performances. Compared with stable hs‐cTn, the risk for death or MI was highest in those with an FP (adjusted hazard ratio [HR], hs‐cTnI 2.3 [95% CI, 1.7–3.2]; RP adjusted HR, hs‐cTnI 1.8 [95% CI, 1.4–2.4]). Findings were similar for hs‐cTnT tested in 3647 patients overall. CONCLUSIONS: The positive predictive value to rule in MI by the European Society of Cardiology 0/1‐ and 0/3‐hour algorithms is significantly lower in patients with FP than RP. These are at highest risk for incident death or MI. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT02355457, NCT03227159.