The Role of Cardiac Magnetic Resonance in the Diagnosis of Left Ventricular Anterior Wall Pseudoaneurysm After Myocardial Infarction: A Case Report (QF_FR_080)

Description of Clinical Presentation: A 47-year-old man with a history of hypertension presented to the emergency department with reports of dyspnea on mild exertion, tachycardic palpitations, bendopnea, and mild lower limb edema. Eight weeks prior to hospital admission, he experienced intense precordial pain for several hours, which later improved, although he did not seek medical attention at that time. However, he did report shortness of breath with moderate exertion. In the emergency department, he exhibited sinus tachycardia (HR: 102 bpm) and slightly reduced oxygen saturation (92%). Physical examination revealed normal heart sounds, mild pulmonary crackles, and minimal lower limb edema. He was thus diagnosed with acute heart failure with a previous myocardial infarction.

Diagnostic Techniques and Their Most Important Findings: After clinical stabilization, the diagnostic process began with an ECG showing an electrically inactive zone on the anterior wall associated with mildly ST segment elevation in the anterior wall. Subsequently, an echocardiogram revealed significant left ventricular dilation, a large apical aneurysm, extensive akinesia of the anteroseptal wall, and an apical thrombus, with significant systolic dysfunction of the left ventricle (LVEF of 24%). A cardiac catheterization showed proximal occlusion of the Left Anterior Descending (LAD) artery with distal filling via grade II collaterals, without other significant coronary lesions. Due to uncertainty about the nature of the aneurysm versus pseudoaneurysm, a Cardiac Magnetic Resonance (CMR) was performed. CMR findings revealed significant systolic dysfunction of the left ventricle (LVEF of 16%), along with thinning and akinesia in the apical and anterior wall regions of the left ventricle with adjacent intracavitary thrombi, indicating an abrupt transition from normal myocardium to the aneurysm. There was also observed ventricular wall discontinuity, thus characterizing a pseudoaneurysm in the LAD artery territory.
Additionally, there was pericardial edema, late gadolinium enhancement, and a small pericardial effusion without the presence of hemopericardium

Learning Points from this Case: This case highlights the role of CMR in differentiating between aneurysm and pseudoaneurysm. Morphologically, pseudoaneurysms are characterized by a narrow neck channel that connects the large aneurysmal sac with the ventricle. Pseudoaneurysms more commonly involve the posterior or inferior walls. The obliteration of the myocardium-pericardium interface and the late enhancement of the overlying pericardium are very useful clues for the diagnosis of pseudoaneurysm, influencing early or late surgical decision-making. However, in some cases, differentiating late enhancement of myocardium from adjacent pericardium can be challenging, as an enhancing pericardium containing a pseudoaneurysm can mimic an infarcted myocardium.  The chemical irritation of the pericardium by blood released of the myocardial rupture which induces an inflammatory reaction and pericardial neovascularisation.
In this case, evaluation with multiple sequences in MRI including: cine, first-pass perfusion, and late enhancement provides relevant information, thus allowing for a correct diagnosis. The patient underwent cardiac surgery during hospitalization, with left ventricular reconstruction and thrombectomy performed, while the left anterior descending artery was unreachable. The patient required decreasing doses of vasoactive drugs, was extubated early, and had a good clinical evolution after the procedure