HEART Score vs Clinical Gestalt for Diagnosing ACS in the ED
HEART Score vs Clinical Gestalt for Diagnosing ACS in the ED
A single-centre prospective cohort study of all adult patients presenting with chest pain to the ED was performed in the Medical Center Leeuwarden, a teaching hospital with 23 000 ED visits yearly. Data were collected during an 8-month study period (from 1 December 2012 until 31 July 2013). Patients admitted to the ED during the study period with chest pain were eligible for inclusion in the study when they were at least 18 years old and had experienced at least 5 min of chest pain that could be related to an ACS. Patients presenting with only syncope, shortness of breath, dyspnoea, palpitations or atypical complaints like fatigue, nausea or dizziness were excluded, as were patients with an ST elevation MI on the ECG, interhospital referrals and patients that had been included on prior visits. As our study only involved evaluation of routinely recorded patient data, this type of study was determined to be exempt research by our local institutional review board.
During the study, data were collected on a Case Report Form (CRF) by the treating physician while the patient was in the ED. Treating physicians were either emergency medicine consultants or residents (emergency medicine or internal medicine in their 1st year until their 4th year of training). The CRF consisted of separate entries for age, gender, level of training of the physician seeing the patients, medication administration in the ED and final discharge diagnosis from the ED. Furthermore, the treating physician was asked to rate the clinical gestalt based probability (low, intermediate or high) of the presence of an ACS as the cause of the patient's chest pain symptoms at presentation. All available information (history, physical exam, ECG and laboratory results) could be used by the physician to determine clinical gestalt-based probability. Finally, the HEART score (Table 1) and its five component subscores (history, ECG, age, number of risk factors and troponin) had to be filled in. Two points were assigned to the ECG subscore when ST-depression (defined as ST-segment depression ≥0.05 mV in two or more contiguous leads in the appropriate clinical context) was present on the ECG. One point was assigned when non-specific repolarisation disturbances or a left bundle branch block were present. The HEART score and the probability of ACS according to clinical gestalt were assessed as soon as the first lab results and ECG were obtained.
ECGs were recorded for all patients and electronically stored for review purposes. High sensitivity troponin T (hsTropT) measurements were performed in all patients at presentation, with results being available within 60 min (Roche Modular E170, Roche Diagnostics Mannheim, Germany; 99th centile 14 ng/L). When the patient had chest pain for more than 6 h at presentation with a normal ECG and a normal initial hsTropT, no serial hsTropT was ordered, which is in line with the most recent European Society of Cardiology (ESC) guideline recommendations. Otherwise, serial hsTropT was ordered 6 h after presentation. In case of serial troponin measurements, only the troponin T value of the first blood sample was used for the HEART score calculation.
Follow-up data were retrieved from the electronic patient records and included discharge letters, revascularisation reports and documentation from follow-up visits in the outpatient clinic.
The diagnostic reference standard in our study was ACS, which was defined as acute MI at presentation or MACE within 6 weeks of presentation in the ED, since the occurrence of MACE in a patient without AMI at presentation would suggest the diagnosis at presentation was ACS with MI. MACE was defined as either MI, or PCI, or CABG, or coronary angiography revealing significant stenosis or death by any cause. AMI was defined according to the ESC-American Heart Association-WHO task force for the redefinition of MI as: 'a rise and fall of troponin values with at least one value above the 99th centile of the upper reference limit together with evidence of myocardial ischaemia'.
Descriptive statistics are represented as average (95% CI) or absolute numbers. Differences in prevalence of ACS between various risk groups were tested by one-way analysis of variance with post hoc multiple comparisons (Tukey Kramer). In order to compare diagnostic accuracy of HEART score and clinical gestalt c-statistics were calculated and compared with the Hanley and McNeil method. For all tests, statistical significance was accepted at the 95% CI. All statistical analyses were done with the SPSS V.22.0 for Windows statistical package (SPSS, Chicago Illinois, USA) and the MedCalc V.12.7.8 statistical program.
Method
Study Setting and Study Population
A single-centre prospective cohort study of all adult patients presenting with chest pain to the ED was performed in the Medical Center Leeuwarden, a teaching hospital with 23 000 ED visits yearly. Data were collected during an 8-month study period (from 1 December 2012 until 31 July 2013). Patients admitted to the ED during the study period with chest pain were eligible for inclusion in the study when they were at least 18 years old and had experienced at least 5 min of chest pain that could be related to an ACS. Patients presenting with only syncope, shortness of breath, dyspnoea, palpitations or atypical complaints like fatigue, nausea or dizziness were excluded, as were patients with an ST elevation MI on the ECG, interhospital referrals and patients that had been included on prior visits. As our study only involved evaluation of routinely recorded patient data, this type of study was determined to be exempt research by our local institutional review board.
Data Acquisition
During the study, data were collected on a Case Report Form (CRF) by the treating physician while the patient was in the ED. Treating physicians were either emergency medicine consultants or residents (emergency medicine or internal medicine in their 1st year until their 4th year of training). The CRF consisted of separate entries for age, gender, level of training of the physician seeing the patients, medication administration in the ED and final discharge diagnosis from the ED. Furthermore, the treating physician was asked to rate the clinical gestalt based probability (low, intermediate or high) of the presence of an ACS as the cause of the patient's chest pain symptoms at presentation. All available information (history, physical exam, ECG and laboratory results) could be used by the physician to determine clinical gestalt-based probability. Finally, the HEART score (Table 1) and its five component subscores (history, ECG, age, number of risk factors and troponin) had to be filled in. Two points were assigned to the ECG subscore when ST-depression (defined as ST-segment depression ≥0.05 mV in two or more contiguous leads in the appropriate clinical context) was present on the ECG. One point was assigned when non-specific repolarisation disturbances or a left bundle branch block were present. The HEART score and the probability of ACS according to clinical gestalt were assessed as soon as the first lab results and ECG were obtained.
ECGs were recorded for all patients and electronically stored for review purposes. High sensitivity troponin T (hsTropT) measurements were performed in all patients at presentation, with results being available within 60 min (Roche Modular E170, Roche Diagnostics Mannheim, Germany; 99th centile 14 ng/L). When the patient had chest pain for more than 6 h at presentation with a normal ECG and a normal initial hsTropT, no serial hsTropT was ordered, which is in line with the most recent European Society of Cardiology (ESC) guideline recommendations. Otherwise, serial hsTropT was ordered 6 h after presentation. In case of serial troponin measurements, only the troponin T value of the first blood sample was used for the HEART score calculation.
Follow-up
Follow-up data were retrieved from the electronic patient records and included discharge letters, revascularisation reports and documentation from follow-up visits in the outpatient clinic.
Diagnostic Reference Standard
The diagnostic reference standard in our study was ACS, which was defined as acute MI at presentation or MACE within 6 weeks of presentation in the ED, since the occurrence of MACE in a patient without AMI at presentation would suggest the diagnosis at presentation was ACS with MI. MACE was defined as either MI, or PCI, or CABG, or coronary angiography revealing significant stenosis or death by any cause. AMI was defined according to the ESC-American Heart Association-WHO task force for the redefinition of MI as: 'a rise and fall of troponin values with at least one value above the 99th centile of the upper reference limit together with evidence of myocardial ischaemia'.
Statistical Analysis
Descriptive statistics are represented as average (95% CI) or absolute numbers. Differences in prevalence of ACS between various risk groups were tested by one-way analysis of variance with post hoc multiple comparisons (Tukey Kramer). In order to compare diagnostic accuracy of HEART score and clinical gestalt c-statistics were calculated and compared with the Hanley and McNeil method. For all tests, statistical significance was accepted at the 95% CI. All statistical analyses were done with the SPSS V.22.0 for Windows statistical package (SPSS, Chicago Illinois, USA) and the MedCalc V.12.7.8 statistical program.
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