Different diagnostic value of risk factors for ACS in relation to initial troponin level and early dynamic change

Abstract

Abstract Introduction/background Early rule in/rule out algorithms using high sensitivity cardiac troponin T (hs-cTnT) have improved the evaluation for acute coronary syndrome (ACS) and facilitated the care of chest pain patients in the emergency department (ED). It is still unknown whether risk factors and comorbidities provide additional diagnostic information for ACS to one-hour hs-cTnT dynamics in the ED. Purpose To evaluate whether cardiovascular risk factors and comorbidities are associated with ACS in chest pain patients with elevated and normal initial hs-cTnT, and with and without early dynamic change. Methods 48,283 unique patients with chest pain and a measured hs-cTnT were identified at 4 university hospitals during 2013-2016 where a one-hour algorithm was implemented during the study period. Among these, 7903 patients had two hs-cTnT measurements obtained within 105 minutes. Clinical information was cross-linked to national registers to obtain previous diagnoses, outcomes and prescriptions. Early dynamics of hs-cTnT was defined as a change by 3ng/l or more if the first hs-cTnT was at or below 14 ng/l, or otherwise a change by more than 20% if the first hs-cTnT was above 14ng/l. Logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) for associations between risk factors and ACS in subgroups by different hs-cTnT levels and with or without dynamic change. Results 516 out of 39777 (1.3%) patients with normal and 1999 out of 8506 (23.5%) with elevated hs-cTnT levels were diagnosed with ACS. In patients with normal initial hs-cTnT 55 out of 5936 (0.9%) without and 44 out of 186 patients (23.7%) with dynamic change were diagnosed with ACS. In patients with elevated hs-cTnT 196 out of 1464 (13.4%) without and 202 out of 317 patients (63.7%) with dynamic change had ACS. In patients with normal hs-cTnT, hypertension (OR 3.24, 95% CI, 2.72-3.87), hyperlipidaemia (OR 3.21, 95% CI 2.67-3.85), diabetes (OR 3.46, 95% CI, 2.81-4.27) and atherosclerotic cardiovascular disease (ASCVD) (OR 2.92, 95% CI 3.24-4.70) were associated with increased risk for ACS (figure 1), whereas the opposite or no association for ACS was shown for these conditions when the initial hs-TnT was elevated. Among patients with normal initial hs-cTnT, hypertension (OR 2.52, 95% CI, 1.47-4.30) and hyperlipidaemia (OR 2.63. 95% CI, 1.51-4.57) were only associated with ACS in patients without early dynamic change (p-value for interaction <0.001 and p=0.02 respectively) whereas diabetes and ASCVD were associated with ACS irrespective of early dynamics (figure 2). Conclusion Cardiovascular risk factors and comorbidities have different diagnostic value for ACS depending on whether the initial hs-cTnT level is elevated and whether an early dynamic change in hs-cTnT is present. Further investigations of combined comorbidities, hs-cTnT levels and its correlation with ACS could refine risk stratifying algorithms among these patients.Figure 1troponin - ACSFigure 2troponin, dynamics - ACS