Patients with low high-sensitivity troponin i values have similar outcomes whether discharged or hospitalized
Nowak RM, Peacock F, Christenson R, Limkakeng A, Jacobsen G, McCord J, Apple FS, Singer AJ, and DeFilippi C. Patients with low high-sensitivity troponin i values have similar outcomes whether discharged or hospitalized. Academic Emergency Medicine 2020; 27:S89.
Academic emergency medicine
Background and Objectives: The multicenter High Sensitivity Cardiac Troponin I (hs-cTnI) (HIGH-US) study reported a serial 1 hour ED hs-cTnI algorithm with an acute myocardial infarction (AMI) rule-out rate of 50.4% (negative predictive value 99.7%, sensitivity 98.7%). In the ruled out patients the 30 day myocardial infarction/all cause death rate was 0.2%. Our purpose was to describe the clinical characteristics and ECG findings in ED discharged patients compared to those placed in observation or inpatient status in this ruled out population.
Methods: 2113 consenting adults with suspected acute coronary syndromes were enrolled from 2015-2016 in 29 US medical centers. Baseline and 1-hour plasma samples were analyzed using the Siemens Atellica hs-cTnI assay (URL 99th % = 45.0 ng/L). AMI diagnosis was independently adjudicated by cardiologists and ED physicians using local contemporary troponin assays and all 30-day clinical information. Clinical variables used to aid in disposition decision making were compared in the ruled out patients.
Results: 1020 (48.3%) individuals were ruled out for AMI in 1 hour. Of these, 584 (57.3%) were discharged home and 436 (42.7%) were placed in observation/inpatient beds. The hospitalized group were significantly (p <0.05) older (55.0 v 52.0 years) with more comorbidities of hypertension (71.8 v 50.4%), diabetes (30.0 v 19.1%), dyslipidemia (45.3 v 27.9%) smoking (32.3 v 22.9%), heart failure (11.4 v 7.0), renal insufficiency (9.7 v 5.7%), personal or family history of coronary artery disease (41.0 v 16.1 and 52.8 v 42.8%), prior AMI (23.0 v 7.2%), previous revascularization (31.1 v 10.5%), peripheral arterial disease (3.0 v 1.4%) and stroke (13.7 v 4.0%). Additionally, fewer patients with an abnormal ECG were ED discharged (36.5 v 51.7%, p<0.001) while patient sex and body mass index and with symptoms onset < 3 hours before first blood draw were not significantly different between these patient groups.
Conclusion: ED physicians do not discharge 1 hour AMI ruled out patients if they have many risk factors/comorbidities for coronary artery disease or have an abnormal ECG. There was no difference in 30 day outcomes for patients with low hs-cTnI values, regardless if hospitalized or not. These results indicate that additional rapidly ruled out patients may be safely discharged. Studies are needed to determine which of these do not benefit from hospitalization.