Wagner, Barrett

Abstract Objectives Understanding whether the novel long-T ITC complex might assist in interpreting clinical prognostic utility compared to established cardiac biomarkers is needed. We determined long term major adverse cardiac events (MACE) and all-cause mortality (ACM) predicated on novel long-T ITC complex and high sensitivity cardiac troponin I (hs-cTnI) and T (hs-cTnT) assays in the emergency department (ED). Methods cTn assays were measured on the Mindray CL-1200i platform at presentation in consecutive patients enrolled in ‘Mindray hs-cTnI Assay Analytical and Clinical Evaluation for the Diagnosis and RIsk Assessment of Myocardial InfarctIon’ (MERITnI) (NCT05853042) trial with suspected ischemia. Sex specific 99th percentiles upper reference limits (URLs) were: hs-cTnI female 14 ng/L, male 15 ng/L; hs-cTnT female 10 ng/L, male 19 ng/L; long-T ITC complex 0.9 ng/L, same for female and male. Results Of 1,070 patients, 59.4 % were male, 43.4 % White, 45.5 % Black, and 39.5 % ≥65 years. Independent of biomarkers, a continuum of risk over 1 year showed MACE increased to 16.1 % and ACM to 16.5 %. Long-T ITC complex did not show a continuum change, increasing only 0.1 % (HR: 1.001 (1.0–1.001) per ng/L. However, hs-cTnI increased 1.8 % (HR: 1.018 [1.009–1.027] for each ng/L (p<0.0001) and hs-cTnT increased 0.3 % per ng/L (HR: 1.003 [1.001–1.006]) (p=0.0028). Between subjects ≤URLs and >URLs, MACE and ACM all biomarkers showed significant (p<0.0001) differences over 1 year. For MACE in those >URL long-T ITC complex increased 11.2–25.2 %, hs-cTnI 18.0–35.0 % and hs-cTnT 8.9–24.2 %. For ACM in those >URL long-T ITC complex increased 4.5–23.3 %, hs-cTnI 5.0–26.2 %, and hs-cTnT 3.6–24.1 %. Conclusions Novel long-T ITC complex did not provide new prognostic value to either hs-cTnI or hs-cTnT. Patients with increased hs-cTnI and hs-cTnT concentrations had marked increases in MACE and ACM risk at 1-year.

Abstract Background We determined whether circulating cardiac troponin I–cardiac troponin T–troponin C (ITC) complex containing long-form cardiac troponin T (long-T ITC) complex and ratios of high-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity cardiac troponin T (hs-cTnT) could differentiate myocardial infarction (MI) from chronic and acute non-MI myocardial injuries in patients with suspected acute coronary syndrome. Methods We measured long-T ITC complex, hs-cTnI, and hs-cTnT (Mindray) at 0- and 2-h in consecutive patients enrolled in the Mindray hs-cTnI Assay Analytical and Clinical Evaluation for the Diagnosis and RIsk Assessment of Myocardial InfarctIon (MERITnI) trial. Results Among the 882 subjects studied (median 3.0 h presentation), 47 had acute MI (5.3%), 116 had acute non-MI myocardial injury, and 90 had chronic myocardial injury. At 0 and 2 h, areas under the curve (AUC) significantly differentiated acute MI from chronic myocardial injury for long-T ITC complex (0.72 and 0.81, respectively; P = 0.0082) but not acute non-MI myocardial injury (AUC, 0.65 and 0.69, respectively; P = 0.23). 0 and 2 h AUCs for long-T ITC complex/hs-cTnT and hs-cTnI/hs-cTnT ratios also significantly differentiated acute MI from chronic myocardial injury (AUC, 0.79 and 0.86, respectively) and acute non-MI myocardial injury (AUC, 0.68 and 0.71, respectively). There was no biomarker concentration or ratio value discrimination between type 1 and type 2 MIs. Conclusions Long-T ITC concentrations and long-T ITC complex/hs-cTnT and hs-cTnI/hs-cTnT ratios may clinically assist in differentiating acute MI from non-MI myocardial injuries when evaluating patients with suspected acute coronary syndrome. ClinicalTrials.gov Registration Number: NCT05853042.