High-Sensitivity Troponins and Outcomes After Myocardial Infarction.

BACKGROUND: It remains unknown how the introduction of high-sensitivity cardiac troponin T (hs-cTnT) has affected the incidence, prognosis, and use of coronary angiographies and revascularizations in patients with myocardial infarction (MI).

OBJECTIVES: The aim of this study was to investigate how the incidence of MI and prognosis after a first MI was affected by the introduction of hs-cTnT.

METHODS: In a cohort study, the authors included all patients with a first MI from the Swedish National Patient Registry from 2009 to 2013. Cox regression was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for risk of all-cause mortality, reinfarction, coronary angiographies, and revascularizations in patients with MI diagnosed using hs-cTnT compared with those diagnosed using conventional troponins (cTn).

RESULTS: During the study period, 47,133 MIs were diagnosed using cTn and 40,746 using hs-cTnT. The rate of MI increased by 5% (95% CI: 0% to 10%) after the introduction of hs-cTnT. During 3.9 ± 2.8 years of follow-up, there were 33,492 deaths, with no difference in the risk of all-cause mortality (adjusted HR: 1.00; 95% CI: 0.97 to 1.02). There were, in total, 15,766 reinfarctions during 3.1 ± 2.3 years of follow-up, with the risk of reinfarction reduced by 11% in patients diagnosed using hs-cTnT (adjusted HR: 0.89; 95% CI: 0.86 to 0.91). The use of coronary angiographies (adjusted HR: 1.16; 95% CI: 1.14 to 1.18) and revascularizations (adjusted HR: 1.13; 95% CI: 1.11 to 1.15) increased in the hs-cTnT group.

CONCLUSIONS: In a nationwide cohort study including 87,879 patients with a first MI, the introduction of hs-cTnT was associated with an increased incidence of MI, although with no impact on survival. We also found a reduced risk of reinfarction alongside increased use of coronary angiographies and revascularizations.