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Basic Science Peripheral Vascular Disease. Peripheral Arterial Occlusive Disease. Basic Considerations. Atherosclerosis - Risk factors. Hypercholesterolemia Diabetes Hypertension Smoking

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atherosclerosis risk factors
Atherosclerosis - Risk factors
  • Hypercholesterolemia
  • Diabetes
  • Hypertension
  • Smoking
  • Relative factors - advanced age, male gender, hypertriglyceridemia, hyperhomocysteinemia, sedentary lifestyle, family history
pathophysiology of atherosclerosis
Pathophysiology of Atherosclerosis
  • Atheroma – porridge; Sclerosis – hardening
  • Response to endothelial injury hypothesis
    • Loss of barrier function, antiadhesive properties and antiproliferative influence on underlying SMCs
    • Migration and proliferation of SMCs  production of ECM
    • Oxidized lipid accumulation in vessel walls
    • Recruitment of macrophages and lymphocytes
    • Adherence of platelets to dysfunctional endothelium, exposed matrix, and macrophages
critical diameter
Critical Diameter

Adaptive arterial enlargement preserves luminal caliber until a critical plaque mass is reached

diagnostic modalities
Diagnostic Modalities
  • Non-invasive
    • ABIs
    • Segmental limb pressures
    • Limb plethysmography
    • Exercise testing
    • Doppler & duplex ultrasound
    • MR angiography
  • Invasive
    • Contrast arteriography
    • CT angiography
ankle brachial index
Ankle-Brachial Index
  • Comparison of ankle pressure to brachial SBP
  • Reproducible, useful for long term surveillance
  • Normal 0.85-1.2
  • Claudicants 0.5-0.7
  • Critical ischemia < 0.4
  • May be falsely elevated in calcified vessels (DM)
slide9
PVR
  • Calibrated air plethysmographic wave form recording system
  • Helps localize site of obstruction
  • Placement of cuffs at levels of proximal and distal thigh, calf and ankle
medical therapy
Medical Therapy
  • Risk factor management
    • Lipid-lowering therapy
    • Smoking cessation
  • Exercise regimen
  • Antiplatelet therapy - ASA, ticlodipine, clopidogrel
  • Vasoactive - Cilostazol (Pletal), pentoxyfilline (Trental)
question
Question

A patient with symptomatic 85% carotid stenosis is

found to have asymptomatic 50% stenosis on the

contralateral side. Appropriate initial treatment includes:

A. Simultaneous bilateral CEA

B. Staged bilateral CEA with 1 week interval between stages

C. CEA on symptomatic side only

D. CEA on side of greatest stenosis regardless of symptoms

question1
Question

A patient with symptomatic 85% carotid stenosis is

found to have asymptomatic 50% stenosis on the

contralateral side. Appropriate initial treatment includes:

A. Simultaneous bilateral CEA

B. Staged bilateral CEA with 1 week interval between stages

C. CEA on symptomatic side only

D. CEA on side of greatest stenosis regardless of symptoms

stroke
Stroke
  • Third leading cause of death
  • Major modifiable risk factors
    • HTN
    • Smoking
    • Carotid stenosis
    • Cardiac diseases - a-fib, endocarditis, MS, recent MI
  • Atherosclerosis = leading cause of ischemic stroke
    • Artery-to-artery emboli
    • Thrombotic occlusion
    • Hypoperfusion from advanced stenosis
carotid stenosis
CarotidStenosis
  • Causes of atherosclerosis at bifurcation
    • Low wall shear stress
    • Flow separation
    • Complex flow reversal along posterior wall of sinus
  • Sequence of events
    • b. Establishment of plaque
    • c. Soft, central necrotic core with overlying fibrous cap
    • d. Disruption of cap - necrotic cellular debris and lipid material become atherogenic emboli
    • e. Empty necrotic core becomes a deep ulcer = thrombogenic  thromboembolism
presentation
Presentation
  • Asymptomatic bruit
  • Amaurosis fugax – transient monocular visual disturbance
  • Lateralizing TIA
  • Crescendo TIA
  • Stroke-in-evolution
  • CVA
duplex scanning
Duplex Scanning
  • B-mode scan – Anatomic information
  • Doppler – Flow velocities
    • Plague  Increased peak and range of velocities
indications for cea
Indications for CEA
  • Symptomatic – TIA, AF, small stroke
    • Proven – Stenosis > 70%
    • Acceptable – Stenosis 50-69%
    • Lesser symptoms, failed medical therapy
  • Asymptomatic
    • Proven – Stenosis > 60%, good risk
    • Uncertain
      • High risk patient
      • Surgeon morbidity-mortality >3%
      • Combined carotid coronary operation
      • Non-stenotic ulcerative lesions
  • Presence of ulceration or contralateral occlusion may lower threshhold for surgery
peripheral arterial occlusive disease2

Peripheral Arterial Occlusive Disease

Chronic Occlusive Disease of the Lower Extremities

question2
Question

Which of the following is an indication for bypass?

A. Claudication within ½ block

B. ABI of 0.5

C. Rest pain

D. Occlusion of the superficial femoral and anterior tibial arteries

question3
Question

Which of the following is an indication for bypass?

A. Claudication within ½ block

B. ABI of 0.5

C. Rest pain

D. Occlusion of the superficial femoral and anterior tibial arteries

prevalence and survival
Prevalence and survival
  • 2-3% population >50y, 10% > 70y
  • Lower extremity ischemia associated with decreased 5-yr survival
    • 97.4 % intermittent claudication
    • 80% claudication requiring surgery
    • 48% limb-threatening ischemia
    • 12% re-op for limb-threatening ischemia
signs and symptoms
Signs and symptoms
  • Claudication
    • Extremity pain, discomfort or weakness
    • Consistently produced by the same amount of activity
    • Relieved with rest
  • Rest pain
    • Localized to metatarsal heads and toes
    • Worse with elevation or recumbent position
    • Improved with foot dependency
slide26
Temperature
  • Hair loss
  • Pallor
  • Nail hypertrophy
  • Ulcer
  • Gangrene
    • Dry - non infected black eschar
    • Wet - tissue maceration and purulence
question4
Question

Late vein graft failure is due to:

A. Atherosclerotic changes in the vein

B. Vein thrombosis

C. Fibrointimal hyperplasia

D. Kinking of the vein graft

question5
Question

Late vein graft failure is due to:

A. Atherosclerotic changes in the vein

B. Vein thrombosis

C. Fibrointimal hyperplasia

D. Kinking of the vein graft

graft
Graft
  • Autologous Vein Graft - SV, arm vein
  • Synthetic - PTFE, Decron
  • Graft failure
    • 30 days - Technical error
    • 30 days to 2 years - Intimal hyperplasia
    • >2 years - Progression of atheresclerosis
  • Surveillance
    • Duplex 6 wks peri-op, 3 months/2 yrs, q 6 month
peripheral arterial occlusive disease3

Peripheral Arterial Occlusive Disease

Acute Thromboembolic Disease

question6
Question

86 yo F with PMHx CAD, HTN, DM, A fib

presents w/ sudden onset left lower extremity pain.

Palpable femoral pulses. No palpable or doppler

signals on left. Nl on right. Where is her obstruction?

A. Common femoral artery

B. Popliteal artery

C. Iliac bifurcation

D. Superficial femoral artery

question7
Question

86 yo F with PMHx CAD, HTN, DM, A fib

presents w/ sudden onset left lower extremity pain.

Palpable femoral pulses. No palpable or doppler

signals on left. Nl on right. Where is her obstruction?

A. Common femoral artery

B. Popliteal artery

C. Iliac bifurcation

D. Superficial femoral artery

epidemiology
Epidemiology
  • Incidence: 1.7 cases / 10,000 people / Yr.
  • Elderly
  • Male > female
  • Mortality 15%, Amputation 10-30%
  • Medical co-morbidities common
    • CVD 12%, CAD 45%, DM, 31%, HTN 60%, CHF 13%
sites of embolization
Sites of Embolization
  • Bifurcations
    • Femoral - 40%
    • Aortic - 10-15%
    • Iliac - 15%
  • Popliteal - 10%
  • Upper extremities - 10%
  • Cerebral - 10-15%
  • Mesenteric/visceral - 5%
history
History
  • The onset and duration of symptoms
  • Pain
    • Sudden onset - embolic
    • Long-standing before acute event - thrombotic
  • Previous revascularization
  • Risk factors for atherosclerotic heart disease
slide38
6 Ps
  • Pain
  • Pallor
  • Pulselessness
  • Paresthesia
  • Paraparesis
  • Poikilothermia
slide39

Palpable Pulses

Location of Obstruction

Femoral

Popliteal

Pedal

-

-

-

Aortoiliac segment

+

-

-

Femoral segment

+

+ +

-

Distal popliteal ± tibials

(Popliteal anerysm)

+

+

-

Distal popliteal ± tibials

management
Management
  • Arteriography
    • Operative planning – target vessel
    • Therapeutic – thrombolysis, angioplasty
    • Should not delay revascularization & may be obtained intra-operatively
  • Rapid systemic anticoagulation
    • Heparin bolus/drip
    • Prevent propagation of thrombus, distal thrombosis, venous thrombosis
  • Surgery- Embolectomy
  • Percutaneous Thrombectomy
question8
Question

6 hours after a femoral-tibial artery bypass for

advanced acute ischemia, the lower leg is

swollen and painful with palpable pulse. The

likely etiology is:

A. DVT

B. Reperfusion injury

C. Thrombosis

D. Arterial spasm

question9
Question

6 hours after a femoral-tibial artery bypass for

advanced acute ischemia, the lower leg is

swollen and painful with palpable pulse. The

likely etiology is:

A. DVT

B. Reperfusion injury

C. Thrombosis

D. Arterial spasm

reperfusion injury
Reperfusion injury
  • Local effects
    • Oxygen radicals accumulate
    • Compound cellular insult
  • Systemic effects
    • Acid, potassium, cytokines, cardiodepressants accumulate in ischemic limb
    • Sudden cardiac arrhythmias
    • Renal failure
    • Acute lung injury
prevention and management
Prevention and management
  • Hydration
    • UO 100cc/hr
  • Alkalinization of urine
    • Prevent myoglobin precipitation in renal tubules
  • Mannitol
    • Antioxidant, osmotic diuretic
  • Insulin/glucose
  • Fasciotomy
question10
Question

Regarding compartment syndrome, which of the

following is correct?

A. The leg is divided into two compartments--anterior and posterior

B. The most commonly affected compartment is the posterior

C. The earliest manifestation of acute compartment syndrome is pain

D. Patients with compartment pressures greater than 15 mm Hg should undergo fasciotomy

question11
Question

Regarding compartment syndrome, which of the

following is correct?

A. The leg is divided into two compartments--anterior and posterior

B. The most commonly affected compartment is the posterior

C. The earliest manifestation of acute compartment syndrome is pain

D. Patients with compartment pressures greater than 15 mm Hg should undergo fasciotomy

slide47

Anatomic Compartments of leg

4 compartments:

Anterior

Lateral (Peroneal)

Deep Posterior

Superficial Posterior

pathophysiology
Pathophysiology

CELL INJURY

CELL SWELLING

TRANSUDATION OF FLUID

 INTRACOMPARTMENT PRESSURE

 CAPILLARY TRANSUDATE

TISSUE PRES. = CAP. HYDR. PRES.

VENULAR PRESSURE

NO NUTRIENT FLOW

ISCHEMIA

signs and symptoms1
Signs and symptoms
  • Pallor and pulselessness
    • Not always reliable
    • Distal pulses may be present
  • Paralysis - Late symptom
  • Pain - Severe and out of proportion, increased on passive motion
  • Paresthesia - Numbness, weak dorsiflexion, numbness in 1st dorsal web space
  • Tender, swollen, tense muscle compartments
indications for fasciotomy
Indications for fasciotomy
  • Classically > 40-45 mm Hg at any point

or > 30 mm Hg for 3-4 hrs

  • Arterial perfusion pressure is paramount
    • Mean arterial pressure - interstitial pressure < 30 mm Hg is critical
    • Diastolic pressure - compartment pressure < 20 mm Hg is critical
question12
Question

The most common finding associated with

thoracic outlet syndrome is:

A. Signs of brachial plexus nerve injury

B. Subclavian vein thrombosis

C. Subclavian artery aneurysm

D. Presence of cervical rib on chest XR

question13
Question

The most common finding associated with

thoracic outlet syndrome is:

A. Signs of brachial plexus nerve injury

B. Subclavian vein thrombosis

C. Subclavian artery aneurysm

D. Presence of cervical rib on chest XR

anatomy
Anatomy
  • Interscalene triangle - artery and nerves
  • Costoclavicular space - vein
  • Subcoracoid area - artery, vein, nerves
thoracic outlet syndrome1
Thoracic Outlet Syndrome
  • Upper extremity symptoms due to compression of the neurovascular bundle in the thoracic outlet area
  • 3 Types
    • Neurogenic - most common (95%)
    • Venous 2-3%
    • Arterial 1%
  • Exacerbated by elevation, abduction, hyperextension of arm
etiology
Etiology
  • Bone - cervical rib, long transverse process of C7, abnormal first rib, osteoarthritis
  • Muscles - scalene anomalies
  • Trauma - neck hematoma, bone dislocation
  • Fibrous bands - congenital and acquired
  • Neoplasm
  • Narrowing of the costoclavicular space
    • Subclavius muscle, costoclavicular ligament, hypertrophic callus
management1
Management
  • Conservative
    • Improvements in postural sitting, standing, and sleeping position
    • Behavior modification at work
    • Muscle stretching and strengthening exercises
    • Successfully treats 50-90% of patients
  • Surgery - Transaxillary first rib resection
question14
Question

Which of the following characteristics of Buerger’s

disease is true?

A. Most commonly observed in young non-smoking females

B. It affects mainly the large arteries of the upper ext

C. Is characterized by sharply segmental acute and chronic vasculitis of medium-sized and small arteries

D. Vascular reconstructive surgery is the main therapy

E. Arterial involvement progresses in a proximal to distal fashion

question15
Question

Which of the following characteristics of Buerger’s

disease is true?

A. Most commonly observed in young non-smoking females

B. It affects mainly the large arteries of the upper ext

C. Is characterized by sharply segmental acute and chronic vasculitis of medium-sized and small arteries

D. Vascular reconstructive surgery is the main therapy

E. Arterial involvement progresses in a proximal to distal fashion

buerger s disease thrombangiitis obliterans
Buerger’s Disease Thrombangiitis Obliterans
  • Exclusively associated with cigarette smoking
  • More prevalent in Middle East and Asia
  • Occlusive lesions seen in muscular arteries, with a predilection for tibial vessels
  • Presentation - rest pain, gangrene and ulceration
buerger s disease1
Buerger’s Disease
  • Recurrent superficial thrombophlebitis (“phlebitis migrans”)
  • Young adults, heavy smokers, no other atherosclerotic risk factors
  • Angiography - diffuse occlusion of distal extremity vessels
  • Progression - distal to proximal
buerger s disease management
Buerger’s Disease - Management
  • Revascularization options are limited
  • Clinical remission with smoking cessation
  • Sympathectomy has a limited role in patients with ulcerations