A Danish, retrospective cohort study showed that the mortality risk was highest in individuals with suspected ACS who had persistently elevated hs-TnI concentrations and lowest in those with 2 normal concentrations.

This summary is based on the publication of Pareek M, Kristensen AMD, Vaduganathan M, et al. - Serial troponin-I and long-term outcomes in subjects with suspected acute coronary syndrome. Eur J Prev Cardiol. 2023 Dec 6:zwad373 [Online ahead of print]. doi: 10.1093/eurjpc/zwad373

Introduction and methods

Background

Among individuals with suspected ACS, those with persistently elevated hs-TnT levels had the highest mortality risk, as recently shown by a Danish, retrospective cohort study [1]. Moreover, the short-term, but not long-term, mortality risk in this subgroup was higher in those with a >20% relative rise in hs-TnT concentration between the first and second measurements compared with a smaller rise or a fall. However, it is unclear whether this conclusion can be extrapolated to levels of hs-TnI.

Aim of the study

The authors assessed the prognostic implications with regard to mortality of hs-TnI levels and their relative percentage change from the first to second measurement, irrespective of whether the level at presentation was normal or elevated, in subjects with suspected ACS.

Methods

This was a retrospective cohort study based on individual participant-level data from 4 Danish national health registries. The authors identified 20,609 individuals with a first-time hospitalization for MI, unstable angina, observation for suspected MI, or chest pain from 2012 through 2019. Subjects had 2 hs-TnI measurements, which were obtained ≥1 h and ≤7 h apart at any time during the same hospitalization.

Outcomes

The primary endpoint was all-cause mortality. Secondary endpoints were MI and coronary revascularization (PCI or CABG).

Main results

• From 0–30 days, the standardized absolute mortality risk was highest among persons with 2 elevated hs-TnI concentrations (n=4820; 8.00%; 95%CI: 7.25%–8.25%) and lowest among those with 2 normal hs-TnI concentrations (n=14,853; 0.46%; 95%CI: 0.35%–0.56%). The same pattern was seen for the standardized absolute mortality risk from 31–365 days (11.11%; 95%CI: 10.20%–12.02% and 2.65%; 95%CI: 2.39%–2.90%, respectively).
• In neither of these groups, the mortality rate was affected by the degree of relative hs-TnI concentration change between measurements.
• The standardized absolute mortality risk at 30 days was intermediate in individuals with a rising hs-TnI concentration (i.e., going from normal to elevated concentration; n=867; risk: 1.97%; 95%CI: 1.05%–2.88%) and those with a falling concentration (i.e., going from elevated to normal concentration; n=69; risk: 3.81%; 95%CI: 0%–8.12%). The same pattern applied to the standardized absolute mortality risks from 31–365 days (6.09%; 95%CI: 4.49%–7.70% and 3.99%; 95%CI: 0%–8.49%, respectively).
• Among individuals with a rising hs-TnI level, a >50% increase was associated with an increased standardized relative mortality risk at 30 days (9.65 × 10⁷; 95%CI: 1.17 × 10⁶–1.92 × 10⁸) and a decreased risk from 31–365 days (0.56; 95%CI: 0.17–0.95) compared with those with a 20% fall to 20% rise.

Conclusion

In this Danish, retrospective, registry-based cohort study among individuals with suspected ACS and 2 hs-TnI measurements drawn within 1–7 h, the risk of all-cause mortality was highest in those with persistently elevated hs-TnI concentrations and lowest in persons with 2 normal concentrations. The mortality risk was not affected by the degree of relative change from the first to second measurement in either of these groups. Subjects with a >50% relative rise between the 2 hs-TnI measurements had an increased mortality risk at 30 days and a decreased risk after 1 year compared with those with a less pronounced rise.

The authors believe that the combined findings of their earlier research on hs-TnT [1] and the present study “suggest that high-sensitivity troponin-I may potentially be better at discriminating mortality risk between those presenting with normal vs. rising patterns, while high-sensitivity troponin-T more accurately identifies individuals with myocardial infarction when values are persistently elevated.”

Find this article online at Eur J Prev Cardiol.

Reference

1. Pareek M, Kragholm KH, Kristensen AMD, Vaduganathan M, Pallisgaard JL, Byrne C, et al. Serial troponin-T and long-term outcomes in suspected acute coronary syndrome. Eur Heart J 2023;44:502–512.