Prevalence and characteristics of non-ST-segment elevation in acute myocardial infarction with insignificant coronary artery disease

Type of funding sources: Public hospital(s). Main funding source(s): King Chulalongkorn Memorial Hospital

 Acute myocardial infarction is mostly associated with obstructive coronary artery disease. 8% to 12% of patients have insignificant coronary artery disease. Prognosis for patients with insignificant coronary artery disease is better than patients with obstructive coronary artery disease who presented with non-ST elevation myocardial infarction (NSTEMI). Prevalence of patients with non-ST elevation myocardial infarction (NSTEMI) related insignificant coronary artery disease in Thailand remains unknown.

 A retrospective cohort analysis was performed in all patient who admitted for NSTEMI and underwent coronary angiography presenting to our hospital in admission (January 2018 to October 2020). The primary end point was to study the prevalence of insignificant coronary artery disease in NSTEMI patients, the secondary end point was to find associated factors of the insignificant coronary artery disease and create new scoring system for predicting insignificant coronary artery disease.

 A total 522 subjects were enrolled. 74 patients (14.2%) had insignificant coronary artery disease. The median age was 68.37 years (female 37.4%), smoking 14%, diabetes 46.7%, hypertension 85.1%, dyslipidemia 78%, history of stroke 8.4% and ESRD 7.3%. There are many predictors of insignificant coronary artery disease in NSTEMI patients: Absence of regional wall motion abnormalities from echocardiogram had the strongest association with insignificant coronary artery disease (OR = 5.057, 95% CI, 2.54-10.06 ; p-value < 0.001). Other variables were; no ST segment deviation in the ECG (OR = 4.29, 95% CI, 2.16-8.52 ; p-value < 0.001), female sex (OR = 3.43, 95% CI, 1.77-6.66 ; p-value < 0.001) and the absence of dyslipidemia (OR = 2.48, 95% CI, 1.23-4.97 ; p-value = 0.01). By using multivariate analysis, a scoring system was made to predict insignificant coronary artery disease, which consist of 2 points for female, 2 points for not having history of dyslipidemia, 3 points for no ST segment deviation form the ECG and 3 points for no regional wall motion abnormalities from the echocardiogram. As shown in the ROC curve, the AUC = 0.804 and 5 is the cut point score with 72.1% sensitivity, 72.3% specificity and 72.3% accuracy.

 Prevalence of non-ST-segment elevation acute myocardial infarction with insignificant coronary artery disease is 14.2%. Absence of regional wall motion abnormalities from echocardiogram, no ST segment deviation in the ECG, female sex and absence of dyslipidemia were all statistically associated with insignificant coronary artery disease. With the predicting score ≥5, the patient may be considered not to proceed the coronary angiogram.