The association between self-reported exercise intensity and acute coronary syndrome in emergency department chest pain patients.

BACKGROUND: Regular exercise is thought to be protective against coronary artery disease. As a result, some physicians believe that the likelihood of acute coronary syndrome (ACS) in patients with acute chest pain is reduced in those who exercise regularly. We studied the association between self-reported frequency of exercising and the likelihood of ACS in patients presenting to the Emergency Department (ED) with chest pain. METHODS: A multi-center prospective, descriptive, cohort study design was used in ED patients to determine whether the risk of ACS was reduced in patients who self-reported regular exercise. RESULTS: There were 1093 patients enrolled. Median (interquartile range) age was 57 (48-67) years; 506 (45.7%) were female. ACS was diagnosed in 248 (22.7%) patients. Patients who did not exercise at least monthly were more likely to be diagnosed with ACS than those who did (129/466 [27.7%] vs. 119/627 [19.0%]; odds ratio 1.63, 95% CI 1.23-2.17). After adjusting for age, gender, body mass index, smoking, and prior history, limited exercise was still associated with ACS (adjusted odds ratio 1.52, 95% CI 1.10-2.10). There was no apparent association between frequency and intensity of exercise and risk of ACS. CONCLUSION: Although self-reported frequency of exercise was significantly associated with a decrease in ACS in ED patients with chest pain, it should not be used to exclude ACS in symptomatic ED patients.

Diagnostic accuracy of a point-of-care troponin I assay for acute myocardial infarction within 3 hours after presentation in early presenters to the emergency department with chest pain.

BACKGROUND: Guidelines recommend that serial cardiac marker testing to rule out acute myocardial infarction (AMI) be performed for 8 to 12 hours after symptom onset. We aim to determine the diagnostic accuracy of a contemporary point-of-care (POC) troponin I (TnI) assay within 3 hours for patients presenting within 8 hours of symptom onset. METHODS: The MIDAS study collected blood from patients presenting with suspected acute coronary syndrome at presentation and at 90 minutes, 3 hours, and 6 hours in whom the emergency physician planned an objective cardiac ischemia evaluation. Criterion standard diagnoses were adjudicated by experienced clinicians using all available medical records per American Heart Association/American College of Cardiology criteria. Reviewers were blinded to the investigational marker, Cardio3 TnI POC. The Cardio3 TnI reference value was defined as >0.05 ng/mL. Measures of diagnostic accuracy are presented with 95% CI. RESULTS: A total of 858 of 1107 patients met the inclusion criteria. The study cohort had 476 men (55.5%) with median age of 57.0 years (interquartile range 48.0-67.0 years). Median time from symptom onset to initial blood draw was 3.9 hours (interquartile range 2.7-5.2 hours). Acute myocardial infarction was diagnosed in 82 patients (9.6%). The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio over 3 hours were 84.1, 93.4, 12.8, and 0.17, respectively. There was no significant improvement in diagnostic accuracy associated with adding 6-hour serial testing to the 3-hour sample. CONCLUSION: In suspected patients with acute coronary syndrome presenting to the emergency department within 8 hours of symptom onset, 3 hours of serial testing with the Cardio3 TnI POC platform provides similar diagnostic accuracy for AMI as longer periods.

Myeloperoxidase in the diagnosis of acute coronary syndromes: the importance of spectrum.

BACKGROUND: Myeloperoxidase (MPO) is proposed for risk stratification in patients with suspected acute coronary syndromes (ACSs). We determined if MPO has diagnostic value in patients being evaluated for ACS. METHOD: MIDAS was an 18-center prospective study enrolling suspected ACS emergency department patients who presented <8 hours after symptom onset and in whom serial cardiac markers and objective cardiac perfusion testing were planned. Blinded MPO (Biosite, Inc, San Diego, CA) and troponin I (Triage Cardio 3; Biosite, Inc) were drawn at arrival, and Troponin I (TnI) was measured at 90, 180, and 360 minutes. Final diagnoses were adjudicated by the local investigator blinded to study assay. RESULTS: Of 1,018 patients, 54% were male, 26% black, with a mean age of 58 ± 13 years. Diagnoses were ACS in 288 (23%) and noncardiac chest pain (NCCP) in 788 (77%). Of patients with ACS, 94 (9.2%) had a myocardial infarction (MI) at presentation (69 non-ST-elevation MI, 25 ST-elevation MI), and 136 had unstable angina. Using a cutpoint of 210 ng/mL to provide 90% specificity, MPO had a sensitivity of 0.18; negative predictive value, 0.69; positive predictive value, 0.47; negative likelihood ratio, 0.91; and a positive likelihood ratio of 1.83 to differentiate ACS and NCCP. Because of the large overlap of quartiles, MPO was not clinically useful to predict serial TnI changes. The C statistics ± 95% CI for MPO differentiating ACS from NCCP and for AMI versus NCCP were 0.629 ± 0.04 and 0.666 ± 0.06, respectively. CONCLUSIONS: Myeloperoxidase has insufficient accuracy for decision making in patients with suspected ACS.

Identifying patients for early discharge: performance of decision rules among patients with acute chest pain.

BACKGROUND: The HEART score and North American Chest Pain Rule (NACPR) are decision rules designed to identify acute chest pain patients for early discharge without stress testing or cardiac imaging. This study compares the clinical utility of these decision rules combined with serial troponin determinations. METHODS AND RESULTS: A secondary analysis was conducted of 1005 participants in the Myeloperoxidase In the Diagnosis of Acute coronary syndromes Study (MIDAS). MIDAS is a prospective observational cohort of Emergency Department (ED) patients enrolled from 18 US sites with symptoms suggestive of acute coronary syndrome (ACS). The ability to identify participants for early discharge and the sensitivity for ACS at 30 days were compared among an unstructured assessment, NACPR, and HEART score, each combined with troponin measures at 0 and 3h. ACS, defined as cardiac death, acute myocardial infarction, or unstable angina, occurred in 22% of the cohort. The unstructured assessment identified 13.5% (95% CI 11.5-16%) of participants for early discharge with 98% (95% CI 95-99%) sensitivity for ACS. The NACPR identified 4.4% (95% CI 3-6%) for early discharge with 100% (95% CI 98-100%) sensitivity for ACS. The HEART score identified 20% (95% CI 18-23%) for early discharge with 99% (95% CI 97-100%) sensitivity for ACS. The HEART score had a net reclassification improvement of 10% (95% CI 8-12%) versus unstructured assessment and 19% (95% CI 17-21%) versus NACPR. CONCLUSIONS: The HEART score with 0 and 3 hour serial troponin measures identifies a substantial number of patients for early discharge while maintaining high sensitivity for ACS.

Implementation of an emergency department based transient ischemic attack clinical pathway: a pilot study in knowledge translation.

OBJECTIVES: To assess the feasibility of implementing an emergency department (ED)-based transient ischemic attack (TIA) clinical pathway that uses computer-based clinical support, and to evaluate measures of quality, safety, and efficiency. METHODS: This was a prospective cohort study of adult patients presenting to a community ED with symptoms consistent with acute TIA. Adherence to the clinical pathway served as a test of feasibility. Compliance with guideline recommendations for antithrombotic therapy and vascular imaging were used as process measures of quality. The 90-day risk of recurrent TIA, stroke, or death provided estimates of safety. Efficiency was assessed by measuring the rate of uneventful hospitalization, defined as a hospital admission that did not result in any major medical event or vascular intervention such as endarterectomy or stent placement. RESULTS: Of the 75 subjects enrolled, physician adherence to the clinical pathway was 85.3%, and 35 patients (46.7%) were discharged home from the ED. Antithrombotic agents were prescribed to 68 (90.7%), and vascular imaging was performed in 70 (93.3%). The 90-day risk of recurrent TIA was seven out of 75 (9.3%; 95% confidence interval [CI] = 4.6% to 18.0%), one patient experienced stroke (1.3%; 95% CI = 0.2% to 7.2%), and three patients died (4.0%; 95% CI = 1.4% to 11.1%). Uneventful hospitalization occurred in 38 of 40 patients (95.0%). CONCLUSIONS: Implementation of a clinical pathway for the evaluation and management of TIA using computer-based clinical support is feasible in a community ED setting. This pilot study in knowledge translation provides a design framework for further studies to assess the safety and efficiency of a structured ED-based TIA clinical pathway.