Role of Multimodality Imaging in the Assessment of Myocardial Infarction With Nonobstructive Coronary Arteries: Beyond Conventional Coronary Angiography

Abstract

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a heterogeneous clinical entity, encompassing multiple different causes, and a cause of substantial morbidity and mortality. Current guidelines suggest a multimodality imaging approach in establishing the underlying cause for MINOCA, which is considered a working diagnosis. Recent studies have suggested that an initial workup consisting of cardiac magnetic resonance and invasive coronary imaging can yield the diagnosis in most patients. Cardiac magnetic resonance is particularly helpful in excluding nonischemic causes that can mimic MINOCA including myocarditis and Takotsubo cardiomyopathy, as well as for long-term prognostication. Additionally, intracoronary imaging with intravascular ultrasound or optical coherence tomography may be warranted to evaluate plaque composition, or evaluate for plaque disruption or spontaneous coronary dissection. The role of noninvasive imaging modalities such as coronary computed tomography angiography is currently being investigated in the diagnostic approach and follow-up of MINOCA and may be appropriate in lieu of invasive coronary angiography in select patients. In recent years, many strides have been made in the workup of MINOCA; however, significant knowledge gaps remain in the field, particularly in terms of treatment strategies. In this review, we summarize recent society guideline recommendations and consensus statements on the initial evaluation of MINOCA, review contemporary multimodality imaging approaches, and discuss treatment strategies including an ongoing clinical trial.

Keywords: angiography; computerized tomography; magnetic resonance imaging; myocardial infarction; optical coherence tomography.

Figure 1. Diagnostic criteria of MINOCA.,

FFR indicates Fractional flow reserve; LBBB, left bundle‐branch block; and RWMA, regional wall motion abnormality.

Figure 2. Suggested diagnostic algorithm for the workup of MINOCA.

Imaging modalities are in white, and corresponding diagnoses in gray. *Triple‐vessel intracoronary imaging is recommended to increase diagnostic yield. ^†Functional assessment can be considered at any time if the history is suggestive of vasospasm or the patient has other vasospastic disease such as Raynaud’s phenomenon or cerebral vasospasm. ^‡If embolism to the coronary arteries is strongly suspected clinically, then thrombophilia workup and transesophageal echocardiogram to evaluate for intracardiac clot or valvular vegetation may be considered if results would change management. ^§Assessment of microvascular dysfunction on CMR may require the use of rest and stress perfusion analysis. CMR indicates cardiac magnetic resonance; IVUS, intravascular ultrasound; MINOCA, myocardial infarction with nonobstructive coronary arteries; OCT, optical coherence tomography; and TEE, transesophageal echocardiogram.

Figure 3. Case of a 55‐year‐old woman with hypertension presenting with chest tightness and T wave inversion in lateral leads and abnormal cardiac biomarkers.

A, Coronary angiogram demonstrated nonobstructive lesion in mid LCX (red arrow). B, OCT images demonstrated a plaque rupture (green arrow). Reprinted by permission from Springer Nature Customer Service Centre GmbH: Springer Nature, Current Cardiology Reports, The Imaging Toolbox to Assess Patients with Suspected Myocardial Infarction in the Absence of Obstructive Coronary Artery Disease (MINOCA), Soheila Talebi, Pedro Moreno, Abel Casso Dominguez, and Jacqueline E. Tamis‐Holland. Copyright ©2020. LCX indicates left circumflex artery; and OCT, optical coherence tomography.

Figure 4. Case of a 66‐year‐old man with no past medical history who presented with chest pain and dyspnea, ST elevation in lateral and inferior leads, and elevated cardiac biomarkers.

A, OCT images demonstrating a thrombus overlying an intact fibrous cap in mid‐LAD, consistent with plaque erosion (red arrow). B, Coronary angiogram with nonobstructive lesion in mid‐LAD (yellow arrow). Reprinted by permission from Springer Nature Customer Service Centre GmbH: Springer Nature, Current Cardiology Reports, The Imaging Toolbox to Assess Patients with Suspected Myocardial Infarction in the Absence of Obstructive Coronary Artery Disease (MINOCA), Soheila Talebi, Pedro Moreno, Abel Casso Dominguez, and Jacqueline E. Tamis‐Holland. Copyright ©2020. LAD indicates left anterior descending artery; and OCT, optical coherence tomography.

Figure 5. Case of a 42‐year‐old man without past medical history presenting with chest pain, mild T wave abnormalities in the anterior wall, and elevated cardiac biomarkers.

A, Coronary angiogram demonstrated nonobstructive lesion in the mid‐LAD (red arrow). B, IVUS imaging demonstrated classical findings of SCAD with true lumen (T) and false lumen (white arrow) (F). Reprinted by permission from Springer Nature Customer Service Centre GmbH: Springer Nature, Current Cardiology Reports, The Imaging Toolbox to Assess Patients with Suspected Myocardial Infarction in the Absence of Obstructive Coronary Artery Disease (MINOCA), Soheila Talebi, Pedro Moreno, Abel Casso Dominguez, and Jacqueline E. Tamis‐Holland. Copyright ©2020. IVUS indicates intravascular ultrasound; LAD, left anterior descending artery; and SCAD, spontaneous coronary dissection.

Figure 6. Case of a 42‐year‐old woman who presented with syncope, ventricular tachycardia, and elevated troponin.

Coronary angiography indicated an ulcer crater in the left main coronary artery with 40% stenosis which extended into the origin of the LAD and the LCX. CMR showed delayed transmural gadolinium enhancement in the anterior and lateral walls as well as the lateral aspect of the inferior wall, suggestive of a vascular insult. CCTA was performed to further evaluate the lesions seen on angiography, finding 30% to 40% stenosis of distal left main, with surrounding hypodense material causing vessel enlargement, suggestive of SCAD with intramural hematoma. Similar findings were seen in the very proximal portions of the LAD and LCX. No atherosclerosis was observed. CCTA indicates coronary computed tomography angiography; CMR, cardiac magnetic resonance; LAD, left anterior descending artery; LCx, left circumflex artery; and SCAD, spontaneous coronary dissection.