P3595Risk factors, comorbidities and early dynamic change in high-sensitive cardiac troponin T -The importance of initial troponin level at presentation
Authors: Mysdotter V , Frick M , Jernberg T , Eggers K , Svensson P 
Published: October 2019

Abstract

Background
The one-hour troponin-algorithm is recommended together with a clinical evaluation for rule-in and rule-out of acute coronary syndrome (ACS) in the emergency department (ED). Since risk factors and many comorbidities are associated with small elevations of high-sensitive cardiac troponin T (hs-cTnT), their additive value for discrimination of ACS have been questioned. However, the importance of the initial troponin level for how risk factors and/or comorbidities associate with early dynamic change in hs-cTnT is poorly studied.

Purpose
To investigate the association between risk factors and early dynamic change of hs-cTnT among those with an elevated compared to non-elevated initial hs-cTnT.

Methods
This was a retrospective study among patients admitted to four urban emergency departments (ED) between 2014–2016 with the chief complaint of chest pain and with two clinical routine hs-cTnT measurements at presentation and at >30–104 minutes later. Clinical data from the ED visit were cross-referenced to national registers retrieving information on diagnoses and treatments to identify: cardiovascular disease (CVD, defined as previous myocardial infarction, stroke or peripheral vascular disease), hypertension (HT), hyperlipidemia (HL), diabetes mellitus (DM), chronic kidney disease (CKD), Heart failure (CHF) and atrial fibrillation (AF). The association between risk factors and early dynamic change was studied separately for those with an elevated (>14ng/L, dynamic change set as >20%) and a non-elevated (≤14ng/L, dynamic change set as >2ng/L) initial hs-cTnT.

Results
9278 patients were identified. All risk factors and comorbidities were more common among those with an elevated hs-cTnT. Dynamic change was present in 236 (3.4%) of 7024 patients with an initial hs-cTnT ≤14ng/L and 307 (13.6%) of 2254 with an initial hs-cTnT >14ng/L respectively. Among those with non-elevated initial hs-cTnT those with dynamic change were more likely to be older: age >70 (odds ratio (OR); 95% CI: 1.5; 1.1–2.0), have CVD (1.7: 1.2–2.5), HT (1.4; 1.1–1.8), eGFR<60 (1.8; 1.3–2.5) or AF (1.5; 1.0–2.4). Conversely, in patients with initial elevated hs-cTnT most conditions were negatively associated with early dynamic change: age >70 (0.5; 0.4–0.6), CVD (0.5; 0.4–0.7), HT (0.6; 0.46–0.8), eGFR<60 (0.4; 0.3–0.6), CHF (0.4; 0.3–0.5), AF (0.4; 0.3–0.6) and no risk factors were positively associated with dynamic change. Different cut-offs for dynamic change for instance >4ng/L (at initial hs-cTnT <14ng/L) and >50% (initial >14ng/L) were tested but did not affect the overall results.
Fig 1. Forest plot dynamic hs-cTnT

Conclusions
Many risk factors and comorbidities show opposite associations with early dynamic change of hs-cTnT depending on the baseline concentration. The findings stress the importance of initial troponin level when assessing patients with risk factors presenting with ACS symptoms in the ED, however further investigations are needed to establish the definite dependency.