CHAPTER 61 ARTERIAL OCCLUSION Flashcards
Pain at rest, ulceration or gangrene exists
CRITICAL LIMB ISCHEMIA
Most important risk factors for PAD
Smoking and DM
Others: hyperlipidemia, hypertension, elevated blood homocysteine, elevated CRP
Most frequently diseased arteries
For The ABc
Femoropoplitieal
Tibial
Aortoiliac
Brachiocephalic
Pathophysiology of Acute Limb Ischemia
Sudden decrease in blood supply to a limb –> tissue hypoperfusion and threatening limb viability
Irreversible changes occurs within how many hours of vessel occlusion due to absence of collateral vessels
4 - 6 hours
What can happen following restoration of blood flow
REPERFUSION INJURY
- compartment syndrome, rhabdomyolysis, metabolic derangements
Most common cause of Acute Limb Ischemia
THROMBOTIC OCCLUSION
Thrombotic occlusion in lower limbs
> 80%
Thrombotic occlusion in upper limbs
half due to thrombosis
one third due to embolism
Other than plaque rupture, progression of ischemic injury can occur by:
(1) propagation of clot to occlude collateral vessels,
(2) ischemia related distal edema leading to high compartment pressures (compartment syndrome),
(3) fragmentation of clot into the microcirculation, and
(4) edema of the microvasculature cells.
Occlusion from embolism is MORE common than occlusion from thrombosis
FALSE
less common
The __________ is the predominant source of peripheral emboli, with ___________________ being responsible for most cases.
heart; atrial fibrillation
Noncardiac sources of arterial emboli
thrombi from aneurysms
atheromatous plaques
Most common location where emboli lodges
1) Bifurcation of the common femoral artery
2) Popliteal artery
An embolus may fragment and embolize distally, or it may propagate locally and create a larger clot.
Most commonly affected of embolism in the upper limb
Brachial artery
Patients with acute limb ischemia exhibit one or more of the “six Ps”
pain
pallor
paralysis
pulselessness
paresthesias
poikilothermia (for cold)
A lack of one or more of the 6Ps findings does not exclude ischemia
TRUE
__________ alone may be the earliest symptom of ischemia, localized in the limb distal to the site of obstruction.
PAIN
Skin changes
Pallor –> blotchy and mottled areas of cyanosis –> petechiae and blisters –> skin and fat necrosis (late)
Painful cyanotic discoloration of isolated portion of foot; remainder of the foot is warm
Trash foot or blue toe syndrome
Vasospasm in small arteries or arterioles provoked by cold or stressors;
Local pain, pallor, cyanosis, numbness, paresthesias in hands usually resolving in 30–60 min;
Rewarming, medications: calcium channel blockers, α-blockers, vasodilators
Raynaud’s disease
Young Asian women: peripheral ischemia and necrosis leading to pulseless phase; may have fever, rash, muscle aches, arthritis
Takayasu’s arteritis
Painful nodules, ulceration, and gangrenous digits in young adults (age 20–40 y);
Nonatherosclerotic segmental inflammation of small/medium vessels; typically, seen only in smokers
Thromboangiitis obliterans (Buerger’s disease)
Painful discoloration of one or more ulnar fingers with sparing of thumb;
Repeated trauma to the hypothenar area with hammering in laborers, as well as those using vibrational tools, causing narrowing of ulnar artery or aneurysmal degeneration
Hypothenar hammer syndrome
