Myocardial infarction with nonobstructive coronary arteries: a puzzled story

Abstract

Introduction. Myocardial infarction with non-obstructive coronary arteries (MINOCA) in contemporary practice involves a large amount of causes and the same number of therapies. MINOCA should be considered as a working diagnosis in order to determine physicians find the specific causes of its appearance, clarify the underlying individual mechanisms and achieve patient-specific treatments, although the mechanism of the myocardial damage in these patients remains unclear. Aim of the study. This review aims to better understanding the clinical diagnosis of MINOCA Materials and methods. The article is based on international publication data and on-line materials. Results. Myocardial infarction without obstructive coronary artery disease (MINOCA) is a syndrome defined by the presence of the universal acute myocardial infarction (AMI) criteria among with normal or near normal coronary arteries and no clinically overt specific cause for the acute presentation. As different clinical studies have reported a prevalence with a range between 4 - 25% of AMI cases, physicians have been regularly confronting with many questions on its management. The demographic and clinical characteristics of MINOCA are different from patients with AMI, being more common in younger and in women, having a lower prevalence of traditional cardiovascular disease risk factors. Studies made pointed a different profile with previous history of depression, emotional stress, inflammatory conditions and malignancy. The diagnosis of MINOCA should exclude first other causes for elevated troponin, overlooked obstructive coronary disease, nonischemic causes for myocardial injury, including Takotsubo syndrome. There are disparate aetiologies causing MINOCA, including: coronary disorders (coronary plaque disruption, coronary dissection, coronary spasm, coronary thrombus/embolus, microvascular dysfunction); myocardial disorders; non-cardiac disorders (e.g.pulmonary embolism). Failure to identify the underlying cause may result in inappropriate therapy in these patients. As the plaque disruption, spontaneous coronary artery dissection are common in MINOCA, it is recommended to use optical coherence tomography or intravascular ultrasound imaging to confirm it. Coronary vasospasm and microvascular dysfunction are other frequent findings in MINOCA patients undergoing provocative testing with acetylcholine – the gold standard technique. Multiple diagnostic pathways have been proposed to evaluate patients with MINOCA, considering as priority cardiac magnetic resonance imaging. Rational treatment fallows from etiologic diagnosis, since same therapy will not be appropriate for all MINOCA patients. The outcome of MINOCA depends on the underlying cause, but its overall prognosis is serious with a 1 year mortality about 3,5%. Conclusions. MINOCA is a distinct clinical diagnosis with different pathophysiological causes. It is essential that healthcare professionals become familiar with it, use proper diagnostic criteria, additional investigation techniques and determine target therapies for each patient, in order to improve their clinical outcome.