Serial changes in high-sensitivity troponin I levels indicate poorer prognosis in patients with suspected acute coronary syndrome who fail to reach a level greater than the 99th percentile

According to the fourth universal definition of myocardial infarction (MI) consensus paper, patients with changing troponins who do not reach a concentration greater than the 99th percentile may still be at high risk and should be followed closely.To determine long-term prognostic implications of high-sensitivity troponin I (hs-TnI) levels and their relative change (Δ) from baseline in subjects with suspected acute coronary syndrome (ACS).We conducted a retrospective cohort study through individual participant-level linkage between Danish national registries. Subjects with a final discharge diagnosis of acute MI, unstable angina, suspected MI, or chest pain from October 2013 through December 2016 who had a record of at least two serial hs-TnI (Dimension Vista®, Siemens Healthineers, Erlangen, Germany; 99th percentile: 45 ng/l) measurements during hospitalization comprised the study population. Kaplan-Meier analysis and multivariable Cox regression, incorporating the competing risk of death, were used to examine the prognostic implications of serial hs-TnI. Subjects were categorized according to whether their first and second hs-TnI were normal/elevated as well as Δhs-TnI and its direction, the latter using cut-offs for Δhs-TnI rises and/or falls of 20\0\ extrapolated from the recommendations for troponin T. The primary outcome was a composite of death from cardiovascular causes, recurrent MI, or repeat revascularization (i.e. not including the index event unless the patient died) at 12 months.A total of 14,514 individuals (mean age 62.2 years, 46.6\ were included of whom 3407 (23.5\ had a final diagnosis of MI, 667 (4.6\ of unstable angina, and 10,440 (71.9\ of either suspected MI or chest pain. Median baseline hs-TnI was 15 ng/l (25.3\, second hs-TnI 15 ng/l (29.4\, Δhs-TnI 0\ and time between samples 6.2 hours. At 12 months, 909 (6.3\ first primary events had occurred. Baseline hs-TnI and Δhs-TnI both displayed a significant, non-linear association with the primary outcome (P\lt;0.001). The Figure shows the prognostic implications of serial hs-TnI. Overall, subjects with two consecutively elevated hs-TnI had the highest 12-month event risk (15.7\, followed by those who went from a normal to an elevated hs-TnI (9.9\, those who went from an elevated to a normal hs-TnI (4.2\, and those with two normal hs-TnI (2.7\. Most either had no significant Δhs-TnI (−20\0\ 74.9\ or a large positive Δhs-TnI (\gt;50\ 17.5\. Individuals with any Δhs-TnI (\gt;20\ had a worse prognosis than those without. This was also true for the group of individuals with two normal hs-TnI (event risk 7.8\TnI \gt;20\.3\ P\lt;0.001).Δhs-TnI was an important determinant of poorer prognosis in subjects with suspected ACS, even among individuals who did not reach a concentration greater than the 99th percentile.Figure 1Type of funding source: None