Combination of ECG and Cardiovascular Risk Factors Could Increase Diagnostic Performance Of Chest Pain Triage at ED
Conditions: Chest Pain
Sponsor: Université Catholique de Louvain

CECIDOC Study 
Combination of ECG and Cardiovascular risk factors could Increase 
Diagnostic performance Of Chest pain triage at ED 
 
 
Study Protocol and Statistical Analysis Plan 
04-09-2019 
 
 
 
Gregoire C., Casarin C., Pirot A.S., Van Der Haert L., Vanden Berghe P., Penaloza A., Castanares-
Zapatero D., Dechamps M.. 
Université Catholique de Louvain 
St Luc University Hospital 
PI : Melanie Dechamps  
melanie.dechamps@uclouvain.be 
 
 
 
 
 
 
 
 
 
 
 

 
Background 
 
Acute chest pain triage in the Emergency Department (ED) may prove challenging, since similar 
symptoms can reveal both mild or life-threatening disorders, and the clinical presentation itself is 
known not to be reliable for evaluating the risk of acute coronary syndrome (ACS)1,2.  
The first priority in patients with suspected ACS is to identify those with ST-elevation myocardial 
infarction (STEMI), since these patients require urgent reperfusion therapy. Both European and 
American cardiology guidelines recommend implementation of a 12-lead electrocardiogram (ECG) 
within 10 min of arrival in the ED3,4.  
In contrast, in the absence of electrocardiographic changes consistent with ischemia, the ACS rate is 
low (1–8% depending on the number of risk factors)3, and ACS are associated with lower in-hospital 
mortality 4,5,6.  
Emergency Department (ED) triage systems for acute chest pain are either based on clinical features 
or on a 12-lead ECG. A recent study showed the systems having a similar diagnostic performance but 
different characteristics since clinical-based triage had a higher sensitivity and ECG-based triage had a 
higher specificity7. The lack of sensitivity of ECG based triage was explained by the fact that patients 
with a normal or non-ischemic ECG were assigned to a low-acuity triage score, defined as inadequate 
(false negative) for ACS patients. Conversely, the lack of specificity of clinical based triage was due to 
a large number of patients with benign pathology assigned to a high-acuity triage score to perform a 
12-lead ECG within the 10 minutes after the first medical contact as required. 
We therefore hypothesized that combination of 12-lead ECG and cardiovascular risk factor could 
increase the sensitivity of ECG based triage for chest pain patients with a normal or non-ischemic 
ECG. 
Methods 
Selection of participants  
All consecutive patients above 18 years of age, presenting at ED with acute non-traumatic chest pain 
as main complaint will be systematically included in the study.   
Study design  
We plan a prospective, single-center, observational study in a teaching hospital in Brussels, Belgium.  
Triage of chest pain patients will be performed using the “French Emergency Nurses Classification 
version 2” (FRENCH) triage system8, which is currently used in our ED. FRENCH score is a 5-levels 
triage system classifying patients from category 1 corresponding to the “immediately life-threatening 
condition” to category 5 corresponding to the “less or non-urgent situations”. Maximum authorized 
waiting period before first medical assessment according to severity category are respectively: 
immediate response, 20 minutes, 60 minutes, 120 minutes and undefined. Initial triage of chest pain 

patients is based on vital signs, than if normal patients with a normal or unmodified ECG are sorted 
into category 3, those with an abnormal ECG without evidence of ischemia are classified into 
category 2, while those with ECG showing signs of ischemia (ST elevation, ST depression, new onset 
of a left bundle branch block, or T-wave inversions) are classified into category 1. Patients with 
lateral chest pain of a probable musculoskeletal nature are sorted into category 4 without 
performing an ECG. 
The FRENCH triage (ECG-based triage) will be compared to a modified FRENCH triage system (ECG 
Score- based triage)  upgrading high-risk patients with a normal ECG from category 3 to category 2. 
We defined high-risk patients as patients having a Systemic Coronary Risk Estimation (SCORE) above 
10 % according with the 2016 European Guidelines on cardiovascular disease prevention in clinical 
practice9. To facilitate calculation of the SCORE at triage, we defined one major or four minor criteria 
required to upgrade the patients. 
The major criteria are:  
1. History of Cardio-vascular disease  
a. acute coronary syndrome 
b. stroke or IAT. 
c. aterial revascularization procedure of peripheral artery. 
2. Diabetes  
3. End-stage renal disease or dialysis 
The minor criteria are:  
1. Man 
2. Above 60 years of age 
3. Hypertension 
4. Smoker 
5. Dyslipidemia 
The above criteria will be collected by the triage nurse using a computerized form designed for the 
study. On this basis, the computer will additionally sort the patients using our modified triage scale, 
with blinded result avoiding bias in the initial nurse triage. This modified triage will therefore not be 
taken into account and management of the patients will not be modified. 
Medical data will also be collected by physicians using a dedicated computerized form, particularly 
cardiovascular risks factors and complications occurring during the ED stay (arrhythmia, heart failure, 
shock).   
The final diagnosis will be determined at the end of a 30-day follow-up, by either reviewing patient’s 
files or a phone call to patients or relatives. ECG interpretation and diagnosis of acute myocardial 
infarction will be based on the universal definition of myocardial infarction10. Pulmonary embolism 
and aortic dissection will be substantiated by computed tomography (CT), chest infection by relevant 
positive biomarkers and a chest X-ray, gastroesophageal reflux by gastroscopy or positive therapeutic 
test with a proton pump inhibitor, and abdominal pathology by biology, imaging, or both. 
Musculoskeletal pain will be diagnosed if all of the above-mentioned investigations are normal, and 
movement and palpation enhanced superficial pain. Finally, patients with a normal physical 

examination, ECG, chest X-ray, and blood tests who did not report any event during the 30-day 
follow-up, and who therefore have no definite cause for their chest pain, will be sorted into a 
dedicated group called ‘unclear diagnosis’. 
The local hospital ethics committee approved the study protocol (CEHF 2017/18AOU/407), and 
patients will provide their written informed consent to participate in this study.  
 
Statistical methods  
 
To evaluate triage system’s diagnostic performance, we will compare the triage score of patients 
with ACS (final diagnosis of STEMI, non-ST-elevation myocardial infarction [NSTEMI] or unstable 
angina [UA]) to a control group made up of patients with chest pain from mild severity diseases 
(including digestive diseases, chronic obstructive pulmonary disease (COPD) exacerbation, 
musculoskeletal chest pain, and all unclear diagnoses without any medical event in the follow-up 
period). Patients with other severe diseases, abnormal heart rate, abnormal blood pressure, 
respiratory distress, or hypoxemia will be excluded from the control group having a triage score 
driven by these conditions rather than by the ECG.  
Since for ACS most of the arrhythmic events occur within 12 h of symptom onset11,12 and ACS patients 
should be monitored13, we defined for ACS a triage Score of  1 or 2 (high-acuity triage score) as 
adequate (true positive), and a triage Score of 3, 4, or 5 (low-acuity triage score) as inadequate (false 
negative). Conversely, for the control group with mild severity diseases, we defined a triage Score of 
1 or 2 (high-acuity triage score) as inadequate (false positive), and a triage Score of 3, 4 or 5 (low-
acuity triage score) as adequate (true negative). Receiver operating characteristic (ROC) curves will 
be generated to assess each triage system’s accuracy in classifying a patient in ACS versus control 
group. 
Capability of triage nurses to collect cardiovascular risk factors will be assessed comparing data 
collected at triage to these collected by the physician in the medical computerized file.  
Sample Size 
 
Based on our previous study (7), FRENCH score AUC under the ROC curve was 0.69. We hypothesized 
a correlation of 0.9 between the two tests. To show a difference of 0.06 between the AUC of the 
tests with a power of 0.8 (alpha 0.05) we calculated a sampled size of 233 patients. Given the 
uncertainty of the correlation, we planned to enrol 500 patients. 
 
 
 
 
 

 
References 
                                                          
1 Ramsay G, Podogrodzka M, McClure C et al (2007) Risk prediction in patients presenting with 
suspected cardiac pain: the GRACE and TIMI scores versus clinical evaluation. QJM 100:11–18 
2 Body R, Carley S, Wibberley C et al (2010) The value of symptoms and signs in the emergent 
diagnosis of acute coronary syndromes. Resuscitation 81:281–286 
3 Lee Thomas H, Goldman Lee (2000) Evaluation of the patient with acute chest pain. NEJM 
342:1187–1195 
4 Cannon CP, McCabe CH, Stone PH et al (1997) The electrocardiogram predicts one-year outcome of 
patients with unstable angina 
and non–Q wave myocardial infarction: results of the TIMI III Registry ECG Ancillary Study. J Am Coll 
Cardiol 30:133–140 
5 Kaul Padma, Yuling Fu, Chang Wei-Ching et al (2001) Prognostic value of ST segment depression in 
acute coronary syndromes: 
insights from PARAGON-A applied to GUSTO-IIb1. J Am Coll Cardiol 38:64–71 
6  Barrabe´s JA, Figueras J, Moure C et al (2000) Prognostic significance of ST segment depression in 
lateral leads I, aVL, V5 and V6 on the admission electrocardiogram in patients with a first acute 
myocardial infarction without ST segment elevation. JACC 
35(7):1813–1819 
7 Melanie Dechamps, Diego Castanares-Zapatero,Patrick Vanden Berghe,,Philippe Meert,  Alessandro 
Manara1 (2016) Comparison of clinical-based and ECG-based triage of acute chest pain in the 
Emergency Department. Intern Emerg Med DOI 10.1007/s11739-016-1558-8 
8 Taboulet P, Moreira V, Haas L et al (2009) Triage with the French emergency nurses classification in 
hospital scale: reliability 
and validity. Eur J Emerg Med 16(2):61–67 
9 Massimo F. Piepoli (Italy),ArnoW. Hoes  and all. 2016 European Guidelines on cardiovascular 
disease prevention in clinical practice. European Heart Journal, Volume 37, Issue 29, 1 August 2016, 
Pages 2315–2381 
10 Thygesen K, Alpert JS, Jaffe AS et al (2012) Third universal definition of myocardial infarction. 
Circulation 126:2020 
11 Rahimi K  Incidence, time course, and predictors of early malignant ventricular arrhythmias after 
non-ST-segment elevation myocardial infarction in patients with early invasive treatment. Eur Heart J 
2006 
12 Piccini  JPSustained ventricular tachycardia and ventricular fibrillation complicating non-ST-
segment-elevation acute coronary syndromes. Circulation 2012 
13 Marco Roffi, Carlo Patrono and all ; 2015 ESC Guidelines for the management of acute coronary 
syndromes in patients presenting without persistent ST-segment elevation (ESC), European Heart 
Journal, Volume 37, Issue 3, 14 January 2016, Pages 267–315.