General pathology · Hemodynamic disorders
Systemic (arterial) thromboembolism !
- Mechanism
Emboli that travel in the arteries nearly always start in the left heart and end up in the legs, brain, gut, kidney or spleen.
Updated 2026-11-01
What it is
Systemic thromboembolism is the arrival of emboli in the arterial circulation. Most come from mural thrombi in the left heart: an infarcted or dilated ventricle, or a left atrium in atrial fibrillation. Other sources are valve vegetations, aortic aneurysms and plaques, and paradoxical embolism. Unlike venous emboli, they nearly always cause infarction, because they reach end arteries.
Step by step
- A thrombus forms in the left heart or the aorta.
- A fragment breaks off and follows the arterial flow.
- It lodges where the vessel becomes narrower than the embolus, often at a branch point.
- Without enough collateral circulation, the territory becomes ischemic.
- Without reperfusion, an infarct follows within minutes to hours.
Sources of arterial emboli
| Source | Why the thrombus forms | Common destination |
|---|---|---|
| Left ventricular infarct | Akinetic wall and damaged endocardium | Brain, limbs |
| Atrial fibrillation | Stasis in the left atrial appendage | Brain (cardioembolic stroke) |
| Chagas cardiomyopathy | Apical aneurysm with mural thrombus | Brain |
| Valve vegetations | Infective or nonbacterial endocarditis | Brain, spleen, kidney; septic emboli |
| Aortic aneurysm or plaque | Mural thrombus or ulcerated atheroma | Lower limbs, kidney, gut |
| Paradoxical embolism | Venous thrombus crossing a patent foramen ovale | Brain |
Clinical notes
- In Colombia, Chagas disease (Trypanosoma cruzi) is a cause of cardioembolic stroke in people from endemic areas, sometimes as the first sign of the cardiomyopathy.
- Rheumatic mitral stenosis with a dilated left atrium is still a source of emboli in Latin America.
- Embolic occlusion of the central retinal artery causes sudden, painless loss of vision.
Test yourself
Think of the answer, then tap the question to see it.
Where do most systemic arterial emboli come from?
From mural thrombi in the left heart, above all after a myocardial infarction or in atrial fibrillation.
What is the commonest destination of arterial emboli?
The lower limbs, followed by the brain.
What does the pathologist see in renal atheroembolism?
Long, needle-shaped clefts where the cholesterol crystals were, inside small arteries.
Why does Chagas disease cause stroke?
Because Chagas cardiomyopathy forms ventricular aneurysms and mural thrombi that embolise to the brain.
Related
- Arterial vs venous thrombi; mural thrombi and lines of Zahn
- Infarction: red vs white, and what decides the damage
- Fat, air and amniotic fluid embolism
- Pulmonary thromboembolism: where it comes from and what it does
Related conditions
- Ischaemic stroke
- Atrial fibrillation
- Acute limb ischaemia
- Acute mesenteric ischaemia
- Myocardial Infarction (Heart Attack)
- Infective endocarditis
- Chagas cardiomyopathy
- Transient ischaemic attack
- Central retinal artery occlusion
- Mitral stenosis
- Dilated cardiomyopathy
- Atheroembolic renal disease (cholesterol crystal embolism)
Elsewhere in DurgiPedia
Microorganisms
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Arterial embolism: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); Stroke: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025); Acute Mesenteric Ischemia (StatPearls (NCBI Bookshelf), 2026).
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Representative model, for educational purposes only.