EMBOLIC STROKE

Embolic stroke refers to the blockage of an artery by an embolus, a traveling particle or debris in the arterial blood stream originating from elsewhere.

An embolus is most frequently a blood clot, but it can also be a number of other substances including :

• fat ( e.g. from bone marrow in a broken bone )
• Air
• Cancer cells
• Clumps of bacteria ( usually from infectious endocarditis )

Emboli most commonly arise from the heart ( especially inatrial fibrillation ) but may originate from elsewhere in the arterial tree. In paradoxical embolism, a deep vein thrombosis embolises through an atrial or ventricular septal defect in the heart into the brain.

Cardiac causes can be distinguished between high and low risk :

High risk :

• Atrial fibrillation and paroxysmal atrial fibrillation
• Rheumatic disease of the mitral or aortic valve disease
• Artificial heart valves
• Cardiac thrombus of the atrium or vertricle
• Sick sinus syndrome
• Atrial flutter
• Myocardial infarction
• Chronic myocardial infarction together with ejection fraction <>
• Symptomatic congestive heart failure with ejection fraction<>
• Dilated cardiomyopathy
• Libman-Sacks endocarditis
• Marantic endocarditis
• Infective endocarditis
• Papillary fibroelastoma
• Left atrial myxoma
• Coronary artery bypass graft ( CABG ) surgery

Low risk / potential :

• Calcification of the annulus ( ring ) of the mitral valve
• Patent foramen ovale ( PFO )
• Atrial septal aneurysm
• Atrial septal aneurysm with patent foramen ovale
• Left ventricular aneurysm without thrombus
• Isolated left atrial "smoke" on echocardiography (no mitral stenosis or atrial fibrillation )
• Complex atheroma in the ascending aorta or proximal arch

Because an embolus arises from elsewhere, local therapy only solves the problem temporarily. Thus, the source of the embolus must be identified. Because the embolic blockage is sudden in onset, symptoms usually are maximal at start. Also, symptoms may be transient as the embolus is partially resorbed and moves to a different location or dissipates altogether.

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