EXAM2/CH17- PAD Flashcards
PVD
peripheral vascular disease
where does PVD occur
arteries + veins
PAD
peripheral artery disease
where does PAD occur
ONLY the arteries
are PVD + PAD the same thing
no
peripheral artery disease (PAD)
blockage of the leg arteries by plaque, leading to gradual narrowing of the arteries in the lower extremities
-leads to decreased blood flow to muscles of the leg
PAD is the same issue seen in ____
CVD
PAD in arms is less/more severe
MORE SEVERE
what is the prevalence of PAD
202 million cases
more than ____ adults have PAD in the United States
8 million
___% to ___% of PAD patients have intermittent claudication (IC)
35-40%
___% to ___% of PAD patients experience critical limb ischemia
1-2%
individuals with PAD are at high risk of developing ____
CVD
critical limb ischemia
most severe PAD that occurs when not taking care of your PAD
common risk factors of PAD
-diabetes
-smoking
-hypertension
-hypercholesterolemia
-increased blood viscosity (blood thickness)
blood viscosity
blood thickness
PAD has the same risk factors as what
CVD
patients with PAD have an increased risk of what 2 types of diseases
-cardiac
-cerebrovascular
pathophysiology of PAD
(same as pathophysiology for atherogenesis in CH13)
- endothelial injury (chronic or excessive injury)
- inflammatory response (monocyte, platelet, LDL-C aggregation)
- endothelial dysfunction (increased wall adhesiveness, impaired vasodilation)
- plaque formation (lesions progress from endothelium to intima)
2 signs + symptoms of PAD
-intermittent claudication
-critical limb ischemia
what is the most common symptom of PAD
intermittent claudication
-most common symptom once the disease process reaches a certain point
what % people with PAD experience intermittent claudication
35-40%
what is intermittent claudication caused by
ischemia
intermittent claudication
-pain, cramping, aching feeling
-tends to occur with physical exertion + diminish with rest
what is the most common location for intermittent claudication
calf (gastrocnemius)
-increased gastrocnemius O2 consumption during walking but those with PAD do not have O2 delivery capacity to the lower extremity
if PAD is not treated where does intermittent claudication move
thighs/hips
what is intermittent claudication of the thigh + buttock region indicative of
PAD in the profunda femoris + internal iliac
critical limb ischemia
chronic ischemia causing more severe PAD (arterial occlusive disease) + can lead to ischemia at rest, foot ulcers, or gangrene
-wounds don’t heal
gangrene
a serious condition that occurs when tissue dies due to a lack of blood flow or a bacterial infection
what may critical limb ischemia ultimately lead to
amputation
what % of PAD cases experience critical limb ischemia
1-2%
if PAD is suspected, what are the invasive + noninvasive procedures that occur in the initial assessments
-scales (Fontaine, Rutherford)
-imaging (angiography, ultrasound)
-hemodynamic (pressure) studies
scales for suspected PAD
-Fontaine
-Rutherford
imaging for suspected PAD
-angiography
-ultrasound
hemodynamics
pressure studies
treatment for if PAD is suspected
surgical interventions can be used in severe conditions
Fontaine scale
1.. asymptomatic (incomplete blood vessel obstruction)
2a.. mild claudication in limb
2b.. moderate to severe claudication in limb
3.. ischemic pain at rest, mostly in feet
4.. ulceration, gangrene, or necrosis of the limb
Fontaine scale is subjective/objective
100% subjective
-physician creates rating based on what the patient tells them
Rutherford scale
-grade 0, category 0
* asymptomatic–no hemodynamically significant occlusive disease
* objective test: normal treadmill or reactive hyperemia test
-grade 0, category 1
* mild claudication
* objective test: completes treadmill exercise; ankle pressure after exercise > 50 mmHg but at least 20 mmHg lower than resting value
-grade 1, category 2
* moderate claudication
* objective test: between categories 1 + 3
-grade 1, category 3
* severe claudication
* objective test: cannot complete standard treatmill exercise, + ankle pressure after exercise < 50 mmHg
-grade 2, category 4
* ischemic rest pain
* objective test: resting ankle pressure < 40 mmHg, flat or barely pulsatile ankle or metatarsal pulse volume recording; toe pressure < 30 mmHg
-grade 3, category 5
* minor tissue loss–nonhealing ulcer, focal gangrene with diffuse pedal sichemia
* objective test: resting ankle pressure < 60 mmHg, ankle or metatarsal pulse volume recording flat or barely pulsatile; toe pressure < 40 mmHg
-grade 3, category 6
* major tissue loss–extending above transmetatarsal level, functional foot no longer salvageable
* objective test: same as category 5
Rutherford scale is subjective/objective
subjective + objective
-SO, THIS SCALE IS MORE USEFUL
Fontaine or Rutherford scale is more useful
Rutherford- has both subjective + objective criteria
diagnostic testing for PAD- imaging (2)
-CT angiography
-MRI angiography
imaging studies for PAD
provide anatomic detail (of plaque buildup)
PAD imaging- CT angiography
-most common first-line option
-uses iodine contrast injection
-detailed image of blood vessels + tissue
PAD imaging- MRI angiography
-with/without contrast
-radio frequency waves give image of vessels
advantages of CT angiography
-widespread availability
-simplicity of imaging protocols
-higher spatial resolution
-rapid scanning times
-large gantry size
-ability to viasualize calcium
-ability to visualize lumen within stents
-lower cost
CT angiography disadvantages
-artifact in presence of severe calcium
-exposure to ionizing radiation
-use of nephrotoxic contrast
MRI angiography advantages
-absence of ionizing radiation
-no interference from calcium
-ability to obtain some information with specialized protocols without use of contrast agents
MRI angiography disadvantages
-higher cost
-more complicated imaging protocols
-contraindicated in patients with ferromagnetic materials (pacemakers, orthopedic hardware, shrapnel)
-small gantry size, limiting studies for patients with claustrophobia or marked obesity
-scanning times prolonged, requiring greater degree of patient cooperation
-venous contamination in legs
-difficulty visualizing stents; artifact from previously placed stents
diagnostic testing for PAD- hemodynamics (4)
-ankle-brachial index (ABI)
-toe pressure (toe-brachial index)
-segmental limb pressures
-transcutaneous oxygen pressure
diagnosing PAD- hemodynamic studies
-provide FUNCTIONAL information
-uses pressure measurements
what is the GO TO diagnostic tool for PAD
hemodynamics
what is the most common diagnostic subtool of hemodynamics
ankle-brachial index (ABI)
ankle-brachial index (ABI)
assesses pressure differences between the brachial artery + dorsalis pedis + posterior tibial arteries using BP cuffs + a Doppler probe (ultrasound)
-aka pressure difference between ankle + arm
larger pressure difference between ankle + arm in ABI =
more severe PAD
if you had PAD, pressure will be lower in the ankle/arm
ankle
diagnostic testing for PAD- segmental limb pressures
BP cuff measures at segments of the leg
-ankle -> calf -> thigh
-looking for changes between segments
diagnostic testing for PAD- transcutaneous oxygen pressure
skin sensor detects O2 delivery to tossie
transcutaneous oxygen pressure- lower value of O2 saturation in toe means +/- PAD
+
2 categories of treatment for PAD
-optimal medical treatment
-revascularization (surgical bypass vs. endovascular techniques)
the 2 categories of treatment for PAD are the same as for what disease
acute coronary syndrome
-same medications
-same revascularizaton proecedures
PAD treatment- optimal medical treatment
-minimizing risk factors (HTN, smoking, diabetes, high cholesterol)
-antiplatelet agent (aspirin or clopidogrel)
-claudication improvement (not gaurenteed to go away)
what is the ONLY drug shown to improve intermittent claudication
cilostazol
-only current drug shown to improve IC walking distance (54%)
-has HORRIBLE side effects so not commonly prescribed
what other medication helps to relieve IC
ACE inhibitors
PAD treatment- revascularization
similar to that of heart revascularization (CH14)
4 methods of revascularization for PAD
-percutaneous transluminal angioplasty
-stenting
-atherectomy
-bypass
is it possible for claudication to persist after treatment (either medication or revascularization)?
YES
-claudication may persist after treatment
what is helpful in diagnosing PAD
exercise testing
-can do a sign/symptom limited test for claudication + angina
what will typically be done BEFORE + AFTER exercise testing
ABI
goals of exercise testing
define functional limitations
-can they walk? (walking + walking FAST may be very hard for PAD patients; it encourages IC which is painful)
-do they have a prosthetic (due to amputation)?
cardiovascular testing for PAD
-presence of intermittent claudication?
-at what point (time, intensity) does claudication set in?
exercise testing protocol for PAD
e
treadmill (2-2-2)
-constant speed of 2 mph
-2% grade increase every 2 min (change in intensity is via change in GRADE)
-endpoint is patient’s intolerance to leg pain
when is pre/post ABI abnormal
when the ankle pressure drops by 30 mmHg or more OR drops by >20% from baseline + takes >3 min to normalize
other exercise testing- 6 min walk
patient self selects their speed
-useful in predicting functional capacity based on the distance that can be completed
what % of patients with PAD are unable to complete treadmill walking for various reasons
16%
other modalities for patients that cannot complete treadmill walking
-arm + leg ergometry
-recumbent stair stepping
Dr. Gardner’s take away **know
-no 2 clinical patients are exactly alike
-start with program that is doable for patient + then progress
Dr. Gardner’s minimum program requirements **know
cardiorespiratory
* 10 min per bout of exercise
* 2-3 days per week
resistance training
* 2-3 days per week
flexibility + balance
* as often as possible
for PAD, low or high intensity training is more beneficial
low intensity is more beneficial
ExRx intensity should be guided by what
IC symptoms
-patients must exercise below the ischemic threshold (before the pain kicks in)
____ training is preferred
supervised
in PAD patients doing ExRx, always assess for what
angina
-due to link to atherosclerosis
as PAD patients exercise at higher intensities, attention should be focused on what
potential CVD symptoms due to high incidence of CAD
benefits of exercise training for PAD
-walking distance increases
-higher ischemia threshold (distance to claudication onset increases)
-adverse CV event risks are reduced
**PRIMARY goal of training for PAD
increase walking distance
increased walking distance in PAD patients
-increased angiogenesis + collateral circulation, resulting in increased blood flow
-reduction in blood viscosity
-attenuation of atherosclerosis
-increased extraction of oxygen + metabolic substrates resulting from improvements in skeletal muscle oxidative metabolism
-increasd pain tolerance
-improved endothelial function
