Characteristics of patients presenting with acute myocardial injury with non-obstructive coronary arteries in Sfax, Tunisia

Abstract

In approximately 4–10% of patients with acute myocardial infarction, coronary angiography does not reveal an obstructive coronary stenosis. This is known as myocardial infarction with non-obstructive coronary arteries (MINOCA). Therefore, mechanisms are not unequivocal and there are a variety of aetiologies grouping ischemic and non-ischemic causes, for this reason the generic term for MINOCA should be replaced with acute myocardial injury with non-obstructive coronary arteries (aMINOCA). Prospective study including all patients presenting aMINOCA, between 2019 and 2020. Other imaging tests such as echocardiography and CMR were used to better support the aetiological diagnosis. Among 1032 consecutive patients admitted for acute myocardial infarction, aMINOCA was identified in 31 (4%) patients and clinical presentation was more often STEMI than NSTEMI (52% vs. 48%). Median age was 47.3 years, male predominance (81%). Two patients presented with cardiogenic shock. Tobacco use was the most noted risk factor (67.7%). According to a clinical diagnostic algorithm using 2D STE and CMR imaging, diagnostic accuracy was 90% to identify causes of aMINOCA (38.7% myocarditis, 32.3% MI, and 19.4% Takotsubo cardiomyopathy). Peak troponin levels were significantly higher in the MI group (21.5 ± 29.24 vs. 10 ± 21.4, P = 0.035). However, CRP was significantly higher in myocarditis group (36 ± 45 vs. 4.7 ± 4, P = 0.007). There was no difference between MI and myocarditis groups in clinical presentation with or without ST elevation, in the mean left ventricular ejection fraction and in the LV Global longitudinal systolic strain. At follow-up, one death was noted in Takotsubo group. Non-obstructive coronary myocardial injury is a rare clinical entity that affects a particularly young population, with a predominance of men in our country. Clinical diagnosis algorithm with echocardiography and CMR imaging established a diagnosis in almost 9 of 10 cases.