USING POINT-OF-CARE CARDIAC MARKERS IN LOW RISK CHEST PAIN IN THE EMERGENCY DEPARTMENT

Introduction: We sought to (1) classify patients who underwent stress echocardiography in an emergency department observation unit based on their pretest probabilities of obstructive CAD using the Diamond-Forrester criterion, (2) to compare observed versus expected frequencies of obstructive CAD based on the Diamond-Forrester risk categories of low (<25%), intermediate (25-75%), and high (>75%) pretest probability of disease, and (3) to test the association of traditional cardiovascular risk factors (age, gender, hypertension, diabetes, high cholesterol, and smoking) with obstructive CAD. METHODS: Retrospective review of the electronic medical record for patients who presented to the emergency department with chest pain and underwent observation followed by stress echocardiography between the period January 1, 2012 to December 31, 2012. Patients were classified as low, intermediate, or high risk for obstructive CAD using the Diamond-Forrester criterion. Main outcome measures were stress echocardiography results as well as receipt of cardiac catheterization and results. RESULTS: A total of 504 patients were included in the final analysis. Overall, 4.8% had a positive stress test and only 1.2% had angiographic evidence of obstructive CAD. In each category of risk, the observed frequency of obstructive CAD was significantly lower than expected. Having a high pretest probability as defined by the Diamond-Forrester criterion was significantly associated with obstructive CAD. Age, gender, diabetes, hypertension, high cholesterol, and smoking were not independently associated with evidence of obstructive CAD; nor were any composites of these risk factors. CONCLUSIONS: The traditional Diamond-Forrester criterion significantly overestimates the probability of obstructive CAD in ED observation unit patients. Reliance on the Diamond-Forrester criterion and other traditional risk factors associated with obstructive CAD in the outpatient setting could lead to faulty Bayesian reasoning, overuse of non-invasive imaging, and improper interpretation of test results in an ED population of low-risk chest pain patients. Further work is required to determine an optimal risk-assessment strategy for this patient population.

Download Full-text

P2674Rapid rule-out of myocardial infarction with a novel high precision point-of-care troponin assay appears safe and effective

European Heart Journal ◽

10.1093/eurheartj/ehz748.0992 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

S Aldous ◽

J Pickering ◽

J Young ◽

P George ◽

A Watson ◽

...

Keyword(s):

Myocardial Infarction ◽

Decision Making ◽

Emergency Department ◽

Chest Pain ◽

High Precision ◽

Primary Outcome ◽

Point Of Care ◽

High Sensitivity ◽

Research Fellowship ◽

Rule Out

Abstract Background High sensitivity troponin assays were developed to improve analytical sensitivity and precision at the decision cut-points for the diagnosis and rule out of acute myocardial infarction (AMI). Central laboratory assays have achieved this but point of care assays, which have the ability to accelerate decision making due to much shorter turnaround times, have remained lacking. Purpose To ascertain the threshold for decision making and subsequent clinical utility for ruling out AMI on presentation in patients attending the emergency department acutely with chest pain, using a high precision point of care troponin assay (TnI Nx), (i-STAT, Abbott). Methods We measured arrival TnI-Nx concentrations in stored plasma samples in adults presenting acutely to the emergency department with chest pain. The primary outcome was an AMI or cardiac death on index admission or within 30 days. We used 2000 bootstrapped data sets to derive and validate a suitable threshold for TnI-Nx before calculating diagnostic test performance. We pre-specified this threshold must have a <1% false negative rate for the primary outcome. We compared this with a core laboratory high sensitivity troponin I (hs-TnI) (Abbott Architect) using the early rule-out cut-point (European Society of Cardiology) at the limit of detection (2 ng/L). Results We recruited 1320 patients of whom 192 (14.1%) had the primary outcome. The TnI-Nx threshold was determined to be 8 ng/L with subsequent sensitivity of 99.0% (95% confidence interval: 97.3% to 100%), negative predictive value of 99.7% (99.2% to 100%) and specificity of 59.0% (56.0% to 62.0%). The hs-TnI had a sensitivity of 99.5% (98.2% to 100%), negative predictive value of 99.7% (99.0% to 100%), and specificity of 28.4% (25.8% to 31.2%) at 2ng/L. Conclusion A high precision point of care assay, TnI-Nx, with a decision threshold of 8ng/L, has comparable rule out performance compared with a core laboratory high sensitivity assay and therefore could potentially be used for early decision making in the assessment of acute chest pain. Acknowledgement/Funding Research grant from Abbott Point of Care. Senior Research Fellowship from ECF, CMRF and CDHB. Clinical Research Fellowship from NZ HRC

Download Full-text