MI in young patients: myxoma and endocarditis, the pitfalls of coronary embolism

A diagnostic challenge: coronary embolism in young patients

Coronary embolism constitutes a rare and frequently underestimated non-atherosclerotic etiology of acute coronary syndrome (ACS). In young patients without a classic cardiovascular risk profile, this mechanism must imperatively be integrated into the differential diagnosis of myocardial infarction with non-obstructive coronary arteries (MINOCA). The clinical difficulty lies in the diversity of emboligenic substrates and in the precise identification of the source, often masked by the urgency of the ischemic presentation.

Study objectives and hypotheses

This case series details three rare clinical presentations of coronary embolisms occurring in patients aged 23, 35, and 38 years. The objective is to illustrate the etiological variability — septic, tumor, or thrombotic embolism — in order to raise awareness among practitioners regarding the importance of systematic cardiovascular imaging in this context. The authors test the hypothesis that the origin of the embolism (infective endocarditis with mitral valve perforation, left atrial myxoma, or severe mitral stenosis) dictates a tailored therapeutic strategy. Management must indeed decide between a conservative approach through anticoagulation and major surgical intervention (mass excision, valve replacement, or bypass grafting) depending on the nature of the embolized material and the site of the coronary obstruction.

Methodology of the clinical case series

This study is a clinical case series reporting three rare presentations of coronary embolisms responsible for acute coronary syndromes (ACS) in young subjects, without significant atherosclerotic heart disease.

The study population includes three specific patients:

• Case 1: A 23-year-old man presenting with an inferior wall myocardial infarction of septic origin.
• Case 2: A 35-year-old man presenting with an inferior infarction secondary to tumor embolism.
• Case 3: A 38-year-old woman presenting with a non-ST-segment elevation myocardial infarction (NSTEMI) associated with severe mitral stenosis.

The evaluation protocol was based on the analysis of the patients' clinical history and the use of cardiovascular imaging to identify the embolic source. Therapeutic procedures were adapted to the identified etiology:

• Cardiac surgery for case 1 (mitral valve replacement and aneurysm repair) and case 2 (myxoma excision, annuloplasty and bypass).
• Pharmacological and interventional approach for case 3 (anticoagulation and planning of a percutaneous mitral commissurotomy).

As this is a case presentation, no control group or comparative statistical analysis was used. The final diagnosis was confirmed by imaging and intraoperative findings.

Clinical observations and therapeutic outcomes

This case series reports three distinct presentations of coronary embolism in young patients (mean age 32 years), highlighting the etiological diversity of this pathology beyond classic atherosclerosis.

Qualitative and surgical observations detail specific pathological mechanisms for each patient:

• Case n°1: Septic coronary embolism resulted in major structural complications, including perforation of the anterior mitral leaflet (AML) and an inferior basal submitral aneurysm.
• Case n°2: The infarction was caused by the migration of fragments from a left atrial myxoma, requiring combined management including coronary artery bypass grafting (CABG) in addition to tumor excision.
• Case n°3: Despite the absence of atrial fibrillation (AF) or thrombus in the left atrial appendage (LAA) on imaging, severe mitral stenosis was identified as the likely embolic substrate.

From a therapeutic perspective, the authors emphasize that while thrombus aspiration and anticoagulation remain the standard for thromboembolic lesions, non-thrombotic etiologies (septic or tumoral) require an individualized surgical strategy. In these three cases, the source of the embolism was confirmed by cardiovascular imaging and medical history, allowing for the resolution of the acute phase of the coronary syndrome.

Clinical analysis: coronary embolism, an underestimated reality in young patients

These three case reports (23, 35, and 38 years old) illustrate an often overlooked clinical reality: acute coronary syndrome (ACS) in young subjects without risk factors may mask an embolic substrate rather than an atherosclerotic one. The authors demonstrate that the nature of the embolus radically dictates management. While thrombus aspiration and anticoagulation are the pillars for fibrino-cruoric embolisms, these cases prove that an individualized approach is imperative when facing non-thrombotic materials.

The case of the 23-year-old patient is particularly telling: the septic embolism not only caused an inferior infarction, but degenerated into a sub-mitral aneurysm and valve perforation, requiring major surgery. Similarly, tumour embolism from a myxoma (case 2) or embolism related to severe mitral stenosis without atrial fibrillation (case 3) serve as reminders that cardiovascular imaging and anamnesis are more decisive than the lipid profile in this population profile.

Limits and implications for practice

The main limitation of this study lies in its descriptive nature (n=3). Although it proposes a differentiated management approach according to the site of obstruction (distal vs. proximal), it does not allow for the establishment of a universal treatment algorithm for non-thrombotic emboli, which remain clinical rarities. Nevertheless, these results emphasize that coronary embolism must systematically be included in the differential diagnosis of MINOCA (myocardial infarction with non-obstructive coronary arteries) in young patients. For the practitioner, the detection of an identifiable embolic substrate — whether infectious, tumoral, or valvular — must take priority from admission to avoid deleterious diagnostic wandering.

Summary of results

This case series describes three acute coronary syndromes (ACS) in patients aged 23, 35, and 38 years, caused by coronary emboli of non-atheromatous origin. The diagnoses reveal a septic embolism from mitral endocarditis, a tumor embolism from a left atrial myxoma, and a probable embolism related to severe mitral stenosis without atrial fibrillation.

In concrete terms, for the practitioner:

• Systematic clinical suspicion: Faced with an ACS or MINOCA in a young subject without classic risk factors, coronary embolism must be integrated into the differential diagnosis, particularly in the presence of an identifiable embolic substrate.
• Targeted diagnostic imaging: Echocardiography is imperative to detect specific etiologies (vegetations, tumor masses, valvular stenosis) that are not always associated with atrial fibrillation.
• Personalized management: While aspiration thrombectomy and anticoagulation are the standards for thrombi, septic or tumor emboli require an individualized surgical approach (mass excision, valvular repair, or bypass).

Technical lexicon of the study on coronary embolism

Coronary embolism: a non-atherosclerotic cause of acute coronary syndrome (ACS), characterized by the occlusion of a coronary artery by circulating material (thrombus, tumor or septic debris) originating from a proximal source.

MINOCA (Myocardial Infarction with Non-Obstructive Coronary Arteries): clinical concept referring to a myocardial infarction occurring in the absence of significant obstructive coronary lesions (< 50% stenosis) on angiography, differential diagnosis including coronary embolism.

Septic coronary embolism: a complication of infectious endocarditis where bacterial vegetations migrate into the coronary circulation, potentially leading to myocardial infarction and structural complications such as aneurysms.

Left atrial myxoma: benign cardiac tumor that can cause systemic or coronary tumor embolism through fragmentation or release of surface thrombotic material.

AML (Anterior Mitral Leaflet) perforation: tissue destruction of the anterior mitral leaflet, identified in this study as a consequence of infective endocarditis complicating the clinical picture.

Sub-mitral aneurysm: aneurysmal dilation located below the mitral valve apparatus, reported in the study as a rare structural complication of septic embolism and endocarditis.

Thrombo-aspiration (Aspiration thrombectomy): percutaneous intervention procedure aimed at mechanically aspirating the embolic material obstructing the coronary artery, considered the gold standard treatment for thromboembolic lesions.

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