Module 4: Arterial Insufficiency

describe the arterial layers

innermost layer is the tunica intima, then the tunica media, and finally the tunica adventitia

what are capillaries?

a single layer of endothelial cells on thin basement membrane, typically 1 mm long and 9 micrometer wide. most tissues are only 0.1 mm from the nearest capillary- oxygen and nutrients in blood diffuse along capillary concentration gradients into the tissue

what is the etiology of arterial insufficiency?

are caused by decrease in arterial blood supply- causes include: trauma, acute embolism, DM, RA, thromboangiitis (Buerger’s disease), arteriosclerosis. lipids, calcium deposits, and scar tissue accumulate on the intimal layer, causing progressive stenosis (high LDLs enhance cholesterol deposition)

what is arteriosclerosis?

thickening/hardening of the arterial walls

what is atherosclerosis?

systemic, degenerative process, arterial lumen is gradually and progressively encroached upon

what is the role of HDLs in arterial insufficiency?

carry cholesterol and serve a protective function

what is teh role of the LDLs in arterial insuffiency?

carry cholesterol and when high enhance cholesterol deposition

what is intermittent claudication?

activity specific discomfort due to local ischemia, pain stops within 1-5 minutes of ceasing of activity. 50% of stenosis pts have it. Pain location is usually distal to the site of occlusion.

what does iliofemoral artery obstruction cause?

buttock, thigh, or calf pain (claudication)

what does infrapopliteal artery obstruction cause?

foot pain (claudication)

what is ischemic rest pain?

burning pain exacerbated with elevation and relieved by dependency positioning, more significant arterial disease, increasing tissue O2 demand can upset the balance between O2 supply and tissue demand, causing ulceration

what can repeated bouts of ischemia and reperfusion lead to?

arterial insufficiency ulceration

what is the progression of an ulcer?

arterial insufficiency → intermittent claudication → ischemic rest pain → ulcer

what is gangrene?

dead tissue that is dry, dark, cold, and contracted. potential for limb loss. results when O2 requirements for tissue exceeds perfusion

what are risk factors that contribute to arterial ulceration?

• hyperlipidemia and elevated LDL

• smoking (#1 modifiable risk factor)

• diabetes

• hypertension

• trauma

• advancing age

what are the PT tests and measures for arterial insufficiency?

• pulses

• doppler ultrasound

• ankle-brachial index

• rubor of dependency

• venous filling time

what needs to be done if there is an absence of pulses?

should be followed up with more sensitive testing (doppler)

when testing pulses, should you check the pulse on the side of the injury only or bilaterally?

BILATERALLY

where is the most common site for occlusion?

the bifurcation of the common femoral artery

which arteries supply the foot?

posterior tibial artery as the main blood supply, and the dorsalis pedis

what is the purpose of the doppler ultrasound?

helpful in further assessing arterial patency, handheld probe that prodcues an audicle signal over moving fluid, method of assessment when pulses are NOT EASILY palpable

can also be used to assess venous perfusion (but harder to do)

what is the ankle brachial index?

should be the first line of testing, reliable, non-invasice, specific method to diagnose PAD, is the systolic pressure of the LE/ the systolic pressure of the upper extremity

what do lower values of ABI correlate with?

increased severity of atherosclerosis and CAD, indicator of poor healing potential

what does an ABI greater than 1.1 denote?

vessel calcification and is not a valid indicator of peripheral perfusion- in this case pulse volume waveforms may be used to better identify PAD. also TBI (toe brachial index) should be performed to assess for arterial disease with diabetes or with abnormally high ABIs due to vessel calcification

what is TBI used for (toe brachial index)?

for pts with diabetes or with abnormally high ABIs due to vessel calcification

describe the interpretation of the ABI

see image

why do we used segmental pressure measurements?

helps localize areas of decreased arterial blood flow, best for identifying distal arterial occlusion or stenosis

what does a pressure drop of more than 20 mmHG in adjacent segments indicate?

arterial occlusion

what are additional vascular tests and measures?

• capillary refill

• rubor of dependency

• venous filling time

what are some classification systems for AI?

• fontaine

• WIFI (wound, ischemia, and foot infection)- prefered by APTA division for wound management

• rutherford

what is involved in the classification of arterial ulcers?

• depth of tissue involvement

• wound etiology (when possible)

what would you expect with pain with arterial ulcers?

• may be severe, is correlated to mental and physical QOL

• described as cramping, aching, or fatigue

• cause of pain is tissue ischemia

• positions that further compromise tissue perfusion (leg elevation) may also increase pain

what are the general characteristics of arterial ulcers?

• almost always located in the LE (rarely above the knee)

• commonly found on toes (on distal non-plantar aspect of the foot should be considered ischemia unless proven otherwise)

• other location usually caused by trauma

what is the wound presentation of AUs?

begin small and shallow, round and regular to conform to trauma, pale or gray granulation tissue, necrotic tissue desiccated with black eschar, minimal or no wound drainage even with infection

what does the periwound and extrinsic tissue look like of AUs?

• signs of decreased perfusion

• epidermis thin, shiny, anhydrous, loss of hair growth

• affected limb appears pale, dusky, cyanotic in color esp with elevation

• dependent rubor

  • edema is unusual

what might the temperature of AUs be like?

cool or cold to touch- need to have pt remove shoes and socks and rest of 5 minutes before testing

what is the prognosis for AUs?

need to consider wound size and depth, consider local tissue perfusion, a rapid decline in wound status warrants immediate reassessment and referral

what are the PT interventions for AUs?

• coordination, communication, and documentation

  • address etiology, risk factors as able

• pt education on how to modify risk factors and protect at-risk limbs from ulceration

what injury prevention techniques should you educate the pt on?

protect from

• trauma

• chemicals

• excessive heat/cold

• open wounds

• when to call clinician

what are the precautions for AUs?

avoid compression and compression dressings. PT of limited value for patients with low ABIs without prior revasc, reassess care plan if wound healing does not significantly progress within 2-6 weeks

when should the PT request for further medical testing?

invalid ABI measurements (greater than 1.1), or wounds that fail to progress as expected

what are some protective techniques?

therex, gait and mobility training, orthoses and specialized footwear, bandaging, therapeutic heat

what are medical and surgical interventions used for AI?

• pharmacological interventions

• sympathetic block (eliminates CNS control over vasoconstriction)

• surgical interventions like debridement, revascularization, percutaneous balloon angioplasty

• amputation