embolism dan infark , slide

7/29/2019 embolism dan infark , slide

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An embolus is adetached intravascular

solid, liquid, or gaseousmass that is carried bythe blood to a sitedistant from its pointof

origin


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In more than 95% of cases, PEs originate from legdeep vein thromboses (DVTs)

Most pulmonary emboli (60% to 80%) areclinically silent because they are small

Sudden death, right heart failure (cor pulmonale),

or cardiovascular collapse occurs when emboliobstruct 60% or more of the pulmonarycirculation


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Embolic obstruction of medium-sized arterieswith subsequent vascular rupture can result inpulmonary hemorrhage but usually does notcause pulmonary infarction

Embolic obstruction of small end-arteriolarpulmonary branches usually does result in

hemorrhage or infarction


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Emboli in the arterial circulation.

Most (80%) arise from intracardiac mural thrombi

2/3 of which are associated with left ventricular

wall infarcts 1/4 with left atrial dilation and fibrillation

The remainder originate from aortic aneurysms,thrombi on ulcerated atherosclerotic plaques, or

fragmentation of a valvular vegetation


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Arterial emboli can travel to a wide variety of sites

Major sites : lower extremities (75%)

brain (10%) intestines, kidneys, spleen, and upper extremities


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The consequences of embolization in a tissuedepend on: its vulnerability to ischemia,

the caliber of the occluded vessel,

collateral blood supply

In general, arterial emboli cause infarction of the

affected tissues


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after fractures of longbones (which havefatty marrow)

rarely in the setting of

soft tissue trauma andburns

characterized bypulmonary

insufficiency,neurologic symptoms,anemia, andthrombocytopenia


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Gas bubbles within the circulation can coalesce toform frothy masses that obstruct vascular flow(and cause distal ischemic injury).

Decompression sickness, occurs when individualsexperience sudden decreases in atmosphericpressure

Chronic form of decompression sickness is calledcaisson disease


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An infarct is anarea of ischemic

necrosis caused byocclusion of eitherthe arterial supplyor the venousdrainage


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Myocardial infarction

Cerebral infarction

Pulmonary infarction

Diabetic (gangrenous infarction)


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Thrombotic or embolic arterial occlusion

Other mechanism:

Local vasospasm

Extrinsic vessel compression (eg.tumor) Torsion of vessel (infark testis)

Vascular trauma

Edema (compartment syndrome)


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Red infarcts (1) with venous occlusions (e.g., ovary),

(2) in loose tissues (e.g., lung)

(3) in tissues with dual circulations

(4) in tissues previously congested by sluggishvenous outflow,

(5) when flow is re-established to a site of previousarterial occlusion and necrosis (e.g., following

angioplasty of an arterial obstruction).


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White infarcts arterial occlusions in solid organs with end-arterial

circulation (e.g., heart, spleen, and kidney)

where tissue density limits the seepage of blood

from adjoining capillary beds into the necroticarea.


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1) the nature of the vascular supply,

2) the rate at which an occlusiondevelops,

3) vulnerability to hypoxia

4) the oxygen content of the blood.


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embolism dan infark , slide