Investigating the diagnostic value of cardiogoniometry in identifying patients with non-st segment elevation myocardial infarction (NSTEMI) and unstable angina pectoris (UAP) in the emergency department

INTRODUCTION: Emergency medicine physicians have a vast majority of experiences in ischemic heart diseases, which are well-known to be one of the most common causes of mortality in the World, as they are often the first group of physicians in encountering these diseases. It is important to diagnose the life-threatening acute coronary syndromes promptly and accurately in the emergency departments, which accept more than 40% of patients arriving at hospitals in our country. OBJECTIVE: The aim of the study is to investigate the diagnostic value of cardiogoniometry (CGM) in identifying patients with non-ST segment elevation acute myocardial infarction (NSTEMI) and patients with unstable angina pectoris in the emergency department. METHOD: Our study was conducted between November 2016 and April 2018 after the approvals of Ege University Ethics Committee and of Turkish Medicines and Medical Devices Agency had been granted. A total of 341 patients presenting in the emergency department with chest pain and correlated complaints, who were diagnosed with either NSTEMI or UAP, and who were hospitalized to undergo a coronary angiogram were included in the study at three study sites (Ege University, Faculty of Medicine, Department of Emergency Medicine; Ümraniye Training and Research Hospital, Department of Emergency Medicine; and Ankara Yıldırım Beyazıt University, Medical Faculty, Department of Emergency Medicine). After collecting the informed consent forms from all volunteering patients, CGM was performed in each patient. Other diagnostic or treatment procedures, which the study patients would undergo, were not intervened in the emergency department. The patients were excluded at baseline if they were diagnosed with STEMI, ventricular fibrillation or ventricular tachycardia; if they developed a respiratory arrest or cardiac arrest, if they had severe changes in consciousness, if they had unstable tachycardia or unstable bradycardia, had a severe cardiac failure or pulmonary edema not allowing the patient to lie flat, if they were in cardiogenic shock, if they had significant cardiac ectopic beats, had cardiac pacemakers, had tachycardia (150 beats/min, bundle branch block and/or atrial fibrillation), had a contraindication for performing CGM (patients who cannot lie down still and who cannot comply with the orders of not to breathe), if they did not or was not able to undergo a coronary angiogram, if they were unwilling to participate in the study and if they did not consent to the study. Coronary angiograms were interpreted by a cardiologist blinded to the results of CGM results. The diagnostic efficacy was investigated by comparing the results of the coronary angiogram, which is a golden standard in diagnosing an acute coronary syndrome, with those of CGM and of the other diagnostic tests. RESULTS: Of the 6205 patients who presented at the emergency department with the complaints of chest pain and correlated symptoms; a total of 341 patients were included in the study because 5356 patients were excluded as they did not comply with the inclusion criteria and as the remaining patients were excluded because they did not undergo a coronary angiogram due to various reasons (patients who were decided to be followed-up medically due to patient's rejection, due to the age of the patients or due to presence of comorbidities. The patients were excluded, too, if their coronary angiograms were unavailable). The mean age of the patients was 59.5±12.5 years. The ratio of the patients under the age of 65 was 69.5% (n=237) of the study population. The patients who were diagnosed with NSTEMI were aged older statistically significantly (p<0.001). The number of patients over the age of 65 and who were identified with a stenosis of more than 50% in the coronary angiograms were statistically significantly higher (p<0.001). Of the patients in the study, 67.4% (n=230) were males and 32.6% (n=111) were females. Male patients below 65 years of age constituted 73% of the study patients, therefore, it was determined that the number of diagnoses of NON-STE-acute coronary syndrome (ACS) in patients under 65 years was statistically significantly higher in males (p=0.001). Evaluation of the coronary angiogram results by gender revealed that 77.8% (n=179) of male patients were identified with a stenosis of more than 50% in the coronary angiograms, therefore, it was determined that the number of critical stenoses identified at the coronary angiograms was statistically significantly higher in males (p=0.001). The most frequent complaint in the study patients was the chest pain with a rate of 88.3% (n=284). The patients having at least one comorbid disease constituted 80.9% (n=276) of the study population. The most common comorbid diseases were hypertension, a previous coronary disease, and diabetes mellitus, respectively. The number of patients with a stenosis of more than 50% identified at the coronary angiogram and who had either of these comorbid diseases was statistically significantly higher (p= 0.015, p=0.004, and p<0.001 respectively for each of the above-mentioned three comorbidities). Of the study patients, 34.9% (n=119) were diagnosed with UAP and 65.1% (n=222) were diagnosed with NSTEMI. Compared to the patients who were diagnosed with UAP at the emergency department, the rate of identifying of a stenosis of more than 50% in the coronary angiograms was statistically significantly higher in the patients who were diagnosed with NSTEMI at the emergency department (p<0.001). The patients' duration of stay in the emergency department ranged from 1 hour to 31 hours. The mean duration of stay in the emergency department for the patients who were diagnosed with UAP was 5.7±2.9 hours while the mean duration of stay of patients who were diagnosed with NSTEMI was 7.4±4.9 hours. The duration of stay in the emergency department was statistically significantly longer for the patients diagnosed with NSTEMI compared to the patients with AAP (p=0.004). After obtaining these results; the sensitivities, specificities, positive predictive values, negative predictive values, and the diagnostic accuracies of the diagnostic tests were compared to those of coronary angiogram at identifying the patients with a stenosis of more than 50% in the coronary arteries. The sensitivity of CGM was found to be 93.5% compared to the coronary angiogram which is recognized as the golden standard in diagnosing an acute coronary syndrome. The sensitivity values of CGM were 92.4% and 98.8% in the patients with UAP characterized by a negative troponin finding and in the patients with UAP, respectively. The sensitivity of CGM was found out to be higher than the sensitivities of ECG and the first troponin tests in all sub-groups (57.9% for ECG, 59.1% for serial ECG, 73.6% for the first troponin levels in all patients. It was 86.9% for the serial troponin levels for the patients with an indication for this test). The specificity of CGM was found out to be 39.6% in all patients with NSTE-ACS. The positive predictive value of CGM was 80.2% and it was found out to be 92.3% in the NSTEMI patient group. The positive predictive value of a troponin test result only was found out to be 89.6% in the NSTEMI patients characterized by a positive troponin test. While the negative predictive value of CGM was 69.8% in all patients with NSTE-ACS, it was found out to be 85.7% in the UAP patient group and 52% in the NSTEMI patient group. Cardiogoniometry enhanced the diagnostic accuracy when it was used in combination with other diagnostic tests employed in making the diagnosis of an acute coronary syndrome. CGM positivity in patients with ischemic findings in ECG was 97.3% in patients with significant critical stenosis in the coronary angiography, which is the golden standard. This ratio was 57.9% only in patients with specific characteristic findings of ischemia in the ECG. Of the patients with a negative troponin value at the first test and in patients with a negative CGM, 87.1% were identified with a stenosis of less than 50% in the coronary angiogram. This ratio was 50% only in patients with a negative troponin value at the first test. The diagnostic accuracy of CGM was 88.2% in the patients with specific findings for ischemia in ECG and with a positive troponin value at the first test, however, it was 72.2% when ECG alone and the results of the first troponin tests were used in combination. By using the routine clinical criteria, of the study patients who were decided to undergo an early invasive intervention, 72.4% (n=247) of the patients were identified with a stenosis of more than 50% in the coronary angiogram, whereas, of the patients with positive CGM only, 80.2% (n=231) were identified with a stenosis of more than 50% in the coronary angiogram CONCLUSION: It is concluded that, because of its high sensitivity, cardiogoniometry (CGM) can be used as a screening test for the diagnosis of NSTE-ACS in patients presenting with chest pain and correlated complaints in the emergency departments, however CGM cannot be used in making the diagnosis of NSTE-ACS due to its lower specificity as 30.2% (N=16) of the CGM-negative patients were identified with a stenosis of more than 50% in coronary angiograms. Because 44.5% (n=53) of the patients diagnosed with UAP using the existing clinical criteria (n=119) were identified with a stenosis of less than 50% when they were referred to undergo a coronary angiogram and because CGM has a higher negative predictive value, it can be included in the diagnostic tests performed for discharging patients from the hospital. When CGM is used in conjunction with other diagnostic tests, it enhances the sensitivity and diagnostic accuracy of these tests. KEYWORDS: Cardiogoniometri, myocardial enfarction without ST elevation, Unstabil angına pectoris, ECG, CGM