11/15 Peripheral Arterial Occlusive Disease - Corbett Flashcards
peripheral arterial occlusive diseaes
presence of flow-limiting lesion in an artery providing blood supply to limbs
etiology
- atherosclerosis (most common)
- thromboembolism
- vasculitis
15-20% pts over 70
blood flow to extremities
resting vs exercise
WHY
resting blood flow to extremities: 300-40mm/min
exercise kicks this up up to 10x
why?
- incr in CO
- compensatory vasodilation
end of exercise → return to normal flow w/in minutes
atherosclerotic limb
what happens in exercise?
clinical presentation
in general, stenotic segment reduces the pressure experienced by distal muscle groups
during exercise, the peripheral vasodilation that takes place near the distal muscle groups leads to even greater/more significant reduction in pressure
- inadequate perfusion → can’t maintain good oxygen delivery to muscles
clinical presentation
- claudication: pain with exertion (most common clinical manifestation of periph arterial disease)
- rest pain
- non-healing wounds
intermittent claudication
“reproducible ischemic muscle pain”
occurs during physical activity, relieved after short rest (2-5min, even just standing still)
need to ask!
- 50-90% of pts who have it don’t mention it (think its a regular sx of old age)
need to quantify!
- relate onset of pain to walking distance in terms of street blocks
neurogenic claudication
caused by spinal stenosis → progressive narrowing of spinal canal
lumbar spine:
- pain, weakness, numbness in legs while walking
- intensified due to incr metabolic demands of compressed nerve roots that have become ischemic due to stenosis
pain relieved when patient flexes spine by sitting!
correlation between location of pain and affected artery
anatomical location of arterial lesion is linked to location of pain
- common: disease in distal superficial femoral artery → claudication in ankle
- disease in aortoiliac area → claidication in thigh, buttock & male erectile dysfx
risk factors: peripheral arterial disease
pathology of atherosclerotic PAD is identical to coronary artery disease
key risk factors:
- HTN
- hyperlipidemia
- smoking
- diabetes mellitus
- family hx
40% of pt with PAD have clinically significant CAD
physical findings: arterial insufficiency
- absent or diminished pulses
- atrophy of calf muscles
- thickened toes/nails
- loss of hair below knees
- thin, shiny skin
- non-healing wounds
-
dependent rubor
- limb become hyperemic when you hang it over the side of the exam table → indicative of dermal arterioles’ inability to constrict in presence of incr hydrostatic pressure
- lift leg? becomes white!
muscle adaptation to ischemia
what happens? what does it look like?
- change in muscle structure and fx
- denervation
- dropout of muscle fibers
consequence: muscle wasting and loss of strength
ankle-brachial index
at baseline: can have higher measured ankle pressure than arm pressure (1:1.4 normal)
on exercise: healthy extremities show NO CHANGE in measurements
in patients with stenosis, exercise induces significant drop in pressure in stenotic limb
intermittent claudication tx
- adjust modifiable risk factors
- progressive exercise program
- medications: ASA, trental, plavix, statins
when should you intervene?
when sx begin to interfere with QofL or employment
- might manifest as rest pain (indicative of critical narrowing/thrombus)
- limb-threatening ischemia
- pain waking pt at night
- pain in forefoot/foot, relieved by dangling foot over bed
acute limb ischemia
most common cause/where
mnemonic
most common cause: EMBOLI
- often cardiac origin (80%), proximal atheroma
- emboli lodge at artery bifurcations or in areas where vessels narrow abruptly
- femoral artery bifurcation
- iliac arteries
- aorta
- popliteal arteries
5 Ps
- pain
- pulseless
- paresthesias
- paralysis
- poikylothermia
EMERGENCY!!!
