The value of a new cardiac magnetic resonance imaging protocol in Myocardial Infarction with Non-obstructive Coronary Arteries (MINOCA) – a case-control study using historical controls from a previous study with similar inclusion criteria

Abstract

BackgroundMyocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA) is common with a prevalence of 6% of all patients fulfilling the diagnosis of myocardial infarction. MINOCA should be considered a working diagnosis. Cardiac Magnetic Resonance (CMR) imaging has recently been suggested to be of great value to determine the cause behind MINOCA. The objectives of this paper are to describe the rationale behind the second Stockholm Myocardial Infarction with Normal Coronaries (SMINC-2) study and to discuss the protocol for investigation of MINOCA patients in the light of the recently published position paper from the European Society of Cardiology.MethodsThe SMINC-2 study is an open non-randomised study using historical controls for comparison. The primary aim is to prove that MINOCA patients investigated with the latest CMR imaging technique can achieve a diagnosis in 70% of all cases entirely by imaging. By including 150 patients we will have >80% chance to prove that the diagnostic accuracy can be improved by 20 absolute % with a p-value of less than 0.05 when compared with CMR imaging in the SMINC-1 study. Furthermore, in addition to invasive coronary angiography, coronary arteries are evaluated by computed tomography angiography to investigate coronary causes and questionnaires are used to describe Quality-of-Life (QoL). By January 1st 2017, 75 patients have been included.DiscussionWhether CMR imaging can provide a diagnosis to an adequate proportion of MINOCA patients is unknown. Well-defined inclusion and exclusion criteria will be used to compare a MINOCA cohort from the population with an appropriate control group. Positive results are likely to influence future guidelines of the management of MINOCA. Furthermore, the study will give mechanistic insights into MINOCA in particular in patients with “true” myocardial infarction and describe QoL in this vulnerable group of patients.Trial registrationClinical Trials NCT02318498.

State of the art: Evaluation and prognostication of myocarditis using cardiac MRI

“…These entities may present with subendocardial or transmural LGE in a coronary territory. Further review of angiograms may be required to ensure an occluded arterial branch was not initially identified . Given recent injury, myocardial edema may be seen on T 2 ‐weighted imaging in the affected myocardium.…”

“…Further review of angiograms may be required to ensure an occluded arterial branch was not initially identified. 53 Given recent injury, myocardial edema may be seen on T 2weighted imaging in the affected myocardium. If stress perfusion MRI is performed, perfusion abnormalities may be present in the region of occlusion, if present.…”

Infarto agudo de miocardio sin enfermedad coronaria ateroesclerótica obstructiva

“…Para su diagnóstico, la ventriculografía y la RMC muestran anormalidades de la movilidad global y regional, características que la diferencian de Takotsubo (26). La RMC tiene muy buen rendimiento diagnóstico con una sensibilidad hasta del 100 %, y una especificidad del 90 %.…”

“…El estándar de oro diagnóstico es la biopsia endomiocárdica, la cual solo se indica en pacientes con falla cardiaca de reciente diagnóstico y de causa inexplicada, compromiso hemodinámico, sospecha de autoinmunidad o enfermedades infiltrativas como sarcoidosis y miocarditis eosinofílica. Estos pacientes no requieren de medidas anti isquémicas, el tratamiento se da con betabloqueadores, IECA, medidas de soporte ventricular, de ser necesarias, y trasplante cardiaco en casos seleccionados (26).…”

“…Un área de LGE subendocardico sugiere isquemia, si es epicárdico, sugiere cardiomiopatía, y en el caso de no tener apariencia isquémica puede sugerir miocarditis o desordenes infiltrativos. (26,32). En un estudio en el que se realizó RMC en 153 pacientes con MINOCA se encontró que el 67 % de ellos fueron normales, el 19 % tenían signos de necrosis miocárdica y el 7 % signos de miocarditis, con lo cual se comprobó su utilidad para diferenciar miocarditis, necrosis miocárdica y miocardio normal.…”