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25 Cards in this Set
- Front
- Back
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What is the pathogenesis of PAD?
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1. LDL moves into endothelium
2. LDL oxidized by macrophages 3. release growth factors and cytokines 4. additional monocytes are attraced 5. foam cell accumulation and smc proliferation result in growth of the plaque |
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Endothelial dysfunction progression and timeline
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progression-foam cells-->fatty streak-->intermediate lesion-->atheroma-->fibrous plaque-->complicated lesion/rupture
foam cells-atheroma: growth over 3 decades by lipid accumulation fibrous plaque-smooth muscle and collagen (after 3rd decade) complicated lesion/rupture-thrombosis/hematoma (after 3rd decade) |
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What are the precursors to endothelial dysfunction?
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Hypoxia/ischemia/reperfusion-->oxidative stress-->endothelial dysfunction
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What are risk factors that contribute to oxidate stress?
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smoking
dyslipidemia HTN diabetes |
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Why is it difficult to diagnose peripheral arterial disease?
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Most patient present with no symptoms or non-specific symptoms
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What does age have to do with PAD?
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risk increases with age
in females, there is a huge jump when they get into their 70s (higher risk than men) |
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What does diabetes have to do with PAD?
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increases risk
poor prognosis-higher rates of amputation and death |
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What clinical features do you look for in diagnosing PAD?
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Trophic signs-SubQ atrophy; Brittle toenails; Hair loss; Coolness
Pulses (DP, PT, POP, FEM, AA) Capillary filling time Femoral bruits Pallor on elevation Rubor on dependency |
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What does the vascular doppler examination do?
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listen for pulses: 2-3 beats is normal; 1 beat is abnormal
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What is the ankle brachial index? How do you interpret it?
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ABI=ankle systolic BP/brachial systolic BP
>1.2: noncompressible (could signify Monckeberg's medial calcific sclerosis) .9-1.2: normal .4-.9: mild/moderat PAD ,.4: severe PAD *this test is very sensitive and specific (predicts morbidity and mortality accurately)* |
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What are other non-invasive tests to do to assess for PAD?
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Toe brachial index
Segmental leg pressures/PVR transcutaneous oxygen skin perfusion pressures doppler ultrasound |
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How do you interpret a toe brachial index test?
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TBI > 0.75 normal
TBI < 0.25 severe PAD |
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How do you interpret segmental leg pressures/PVR tests?
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Localizes blocked segment
>20mmHg between segments = significant obstruction. > 40mmHg = occlusion (Less accurate in mulitlevel dz.) |
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How do you interpret a transcutaneous O2 test?
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> 55mmHg normal
< 30mmHg impaired healing 20mmHg predicts ischemic rest pain |
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How do you interpret skin perfusion pressures tests?
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>40-50mmHg nonischemic
<30mmHg poor healing |
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If a patient presents with clinical symptoms of PAD, what is the next step?
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measure ankle brachial index
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Patient presents w/ clinical symptoms of PAD, ABI is <.9
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patient has PAD
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Patient presents w/ clinical symptoms of PAD, ABI is .9-1.3. What's the next step?
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measure ABI after treadmill stress test
if normal ABI postexercise-->no PAD, evaluate other causes if ABI is decreased by >20% postexercis-->patient has PAD |
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Patient presents w/ clinical symptoms of PAD, ABI is >1.3. What is the next step?
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do other non-invasive tests:
pulse-volume recording; toe-pressure measurement; duplex ultrasound if tests are normal-->no PAD if tests are abnormal-->PAD |
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What anatomical testing can you do for PAD?
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Arterial angiogram (mostly by digital subtraction angiography – DSA)
Magnetic resonance angiogram (MRA) Computed tomography angiogram (CTA) |
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What are treatment options for PAD?
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Medical therapy-statins seem to work best
Surgery-PTA; bypass; atherectomy |
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What has the highest success rate for quitting smoking?
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bupropion (30%)
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What is the treatment algorithm for PAD?
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1. assess/modify cardiovascular risk factors
2. assess severity and limitation of claudication (lower leg cramping) 3. assess for critical leg ischemia |
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What is the therapy for claudication?
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supervised exercise
cilostazol If symptoms improve-->continue treatment |
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What is the therapy in a patient with PAD that has worsening claudication or critical leg ischemia?
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localize the lesion using either hemodynamic localization or diagnotic imaging
once localized, revascularization is indicated (angioplasty or bypass) |
