High-sensitivity cardiac troponin T in the emergency department : admissions, resource utilization and outcomes

Background Patients presenting with chest pain in the emergency department (ED) may have myocardial infarction (MI) requiring immediate treatment. High-sensitivity cardiac troponin T (hs-cTnT) was recently introduced as a biomarker that aids in determining whether the patient requires hospital admission or can be safely discharged home. The aim of this thesis was to evaluate the implementation of hs-cTnT in the ED, with respect to hospital admission, resource utilization and patient outcomes. Methods and Results Two separate datasets were created by combining administrative information from the ED at Karolinska University Hospital with laboratory data and linking several national health care registers through the National Board of Health and Welfare. The first dataset was used for Studies I and II, while the second dataset was used for Studies III and IV. Cox regression was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). Study I: In total, 14,636 patients with chest pain who presented to the EDs at Karolinska University Hospital, Solna and Huddinge, during 2011 and 2012 were included to evaluate whether a first undetectable (<5 ng/L) hs-cTnT level and an electrocardiogram (ECG) without signs of ischaemia could be used to safely rule out MI in the ED. We identified 15 patients with an undetectable hs-cTnT level and non-ischaemic ECG who were diagnosed with MI within 30 days. The negative predictive value for MI using this strategy was 99.8%, and for death 100%. Study II: We included 13,046 patients with chest pain who visited the ED at Karolinska University Hospital, Solna and Huddinge, during 2011 and 2012. We calculated HRs at different hs-cTnT levels for the risk of revisits to the ED, readmissions to hospital and resource utilization in terms of whether the patient was discharged or admitted. In patients with a hs-cTnT level of <5 ng/L who were admitted to the hospital compared with discharged home, we observed a 24% increased risk (adjusted HR 1.24, 95% CI 1.05–1.46) of revisiting the ED within 30 days and a three-fold increased risk of coronary angiography or revascularization during follow-up. Study III: We evaluated trends in admission rates among 15,472 patients with chest pain who presented to the ED at Karolinska University Hospital, Huddinge from 2011 to 2014. Proportions of admitted patients were calculated using each year of the study period (2012, 2013 and 2014) as exposure with year 2011 as reference. We found a 36% relative reduction in hospital admissions. All-cause mortality increased (adjusted HR 1.51, 95% CI 1.18–1.92), but for non-cardiovascular causes only. Coronary angiography significantly increased, but revascularizations remained stable. Study IV: Survival and resource utilization in 31,904 patients with chest pain were compared during the initial 3 years (2011 -2013) when the hs-cTnT assay was implemented to the preceding 2 years (2009-2010) when the conventional troponin (cTnT) assay was in use at Karolinska University Hospital, Solna and Huddinge. Patients who were tested with hs-cTnT had a 15% increase in all-cause mortality (adjusted HR 1.15, 95% CI 1.02–1.29), 13% increase in coronary angiography (adjusted HR 1.13, 95% CI 1.00–1.28) and 18% increase in revascularizations (adjusted HR 1.18, 95% CI 1.01 – 1.37). Conclusions [I] Patients presenting with chest pain, a first undetectable hs-cTnT level and a normal ECG may be safely discharged from the ED because the risk of MI or death is minimal. [II] When patients with chest pain and an undetectable hs-cTnT level are admitted to the hospital instead of discharged home, they have an increased risk of revisits to the ED, recurrent hospital stays, coronary angiography and revascularization. [III] Admissions for chest pain were reduced by 36% during the first 4 years of hscTnT use. All-cause mortality increased, but for non-cardiovascular causes only. [IV] After the introduction of hs-cTnT testing in the ED, an increase in mortality, coronary angiography and revascularizations was observed

Undetectable High-Sensitivity Cardiac Troponin T Level in the Emergency Department and Risk of Myocardial Infarction

ObjectivesThis study sought to evaluate if an undetectable (<5 ng/l) high-sensitivity cardiac troponin T (hs-cTnT) level and an electrocardiogram (ECG) without signs of ischemia can rule out myocardial infarction (MI) in the emergency department (ED).BackgroundChest pain is a common symptom often associated with benign conditions, but may be a sign of MI. Because there is no rapid way to rule out MI, many patients are admitted to the hospital.MethodsAll patients who sought medical attention for chest pain and had at least 1 hs-cTnT analyzed during 2 years at the Karolinska University Hospital, Stockholm, Sweden, were included. We calculated the negative predictive values of an undetectable hs-cTnT and ECG without ischemia for MI and death within 30 days.ResultsWe included 14,636 patients, of whom 8,907 (61%) had an initial hs-cTnT of <5 ng/l; 21% had 5 to 14 ng/l, and 18% had >14 ng/l. During 30-day follow-up, 39 (0.44%) patients with undetectable hs-cTnT had a MI, of whom 15 (0.17%) had no ischemic ECG changes. The negative predictive value for MI within 30 days in patients with undetectable hs-cTnT and no ischemic ECG changes was 99.8% (95% confidence interval [CI]: 99.7 to 99.9). The negative predictive value for death was 100% (95% CI: 99.9 to 100).ConclusionsAll patients with chest pain who have an initial hs-cTnT level of <5 ng/l and no signs of ischemia on an ECG have a minimal risk of MI or death within 30 days, and can be safely discharged directly from the ED

Outcomes in patients with chest pain in emergency departments using high-sensitivity versus conventional troponins

Objectives: There is a paucity of data regarding the association between the use of high-sensitivity troponin (hs-cTn) compared with conventional troponin (cTn) and outcomes in chest pain patients in emergency departments (EDs). This study examined the impact of hs-cTnT on prognosis in chest pain patients in EDs. Design: In an observational cohort study, we included chest pain patients visiting the EDs of 14 hospitals in Sweden from 2011 to 2016. The study population was retrieved from each hospital, and information on characteristics and outcomes was collected from nationwide registries. Cox regression was used to estimate adjusted hazard ratios with 95% confidence intervals (HR, 95% CI) for (1) 1-year all-cause mortality, (2) missed acute coronary syndromes (ACSs), (3) use of coronary angiography, and (4) revascularizations within 30 days. Results: We included 170461 patients with chest pain where 62669 patients were tested with cTn while 107792 patients were tested with hs-cTnT. We found 4149 (4.6%) deaths in the cTn group and 6087 (3.7%) deaths in the hs-cTnT group. Patients in the hs-cTnT group had 9% lower mortality (0.91, 0.87-0.94), and were 14% more likely to undergo coronary angiography (1.14, 1.10-1.17), and 12% more likely to be revascularized (1.12, 1.08-1.17) than patients in the cTn group. Conclusions: Patients with chest pain visiting EDs using hs-cTnT had lower mortality and a higher likelihood of undergoing coronary angiographies and revascularizations than those using cTn. There may be a survival benefit of being tested with hs-cTnT compared with cTn in patients seeking medical attention for chest pain