641 likes | 1.21k Views
Peripheral Arterial Occlusive Disease. Basic Considerations. Atherosclerosis - Risk factors. HypercholesterolemiaDiabetesHypertensionSmokingRelative factors - advanced age, male gender, hypertriglyceridemia, hyperhomocysteinemia, sedentary lifestyle, family history. Pathophysiology of Atherosclerosis.
E N D
1. Basic Science Peripheral Vascular Disease Kashaf Sherafgan
PGY 2
November 17th 2005
2. Peripheral Arterial Occlusive Disease Basic Considerations
3. Atherosclerosis - Risk factors Hypercholesterolemia
Diabetes
Hypertension
Smoking
Relative factors - advanced age, male gender, hypertriglyceridemia, hyperhomocysteinemia, sedentary lifestyle, family history
4. 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
5. Critical Diameter Adaptive arterial enlargement preserves luminal caliber until a critical plaque mass is reached
6. Diagnostic Modalities Non-invasive
ABIs
Segmental limb pressures
Limb plethysmography
Exercise testing
Doppler & duplex ultrasound
MR angiography
Invasive
Contrast arteriography
CT angiography
7. 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)
8. ABI algorithm
9. 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
10. Medical Therapy Risk factor management
Lipid-lowering therapy
Smoking cessation
Exercise regimen
Antiplatelet therapy - ASA, ticlodipine, clopidogrel
Vasoactive - Cilostazol (Pletal), pentoxyfilline (Trental)
11. Surgical Interventions
12. Peripheral Arterial Occlusive Disease Carotid Stenosis
13. 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
14. 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
15. 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
16. 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
17. Presentation Asymptomatic bruit
Amaurosis fugax – transient monocular visual disturbance
Lateralizing TIA
Crescendo TIA
Stroke-in-evolution
CVA
18. Diagnostic Algorithm
19. Duplex Scanning B-mode scan – Anatomic information
Doppler – Flow velocities
Plague ? Increased peak and range of velocities
20. 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
21. Peripheral Arterial Occlusive Disease Chronic Occlusive Disease of the Lower Extremities
22. Question Which of the following is an indication for bypass?
A. Claudication within ˝ block
B. ABI of 0.5
C. Rest pain
D. Occlusion of the superficial femoral and anterior tibial arteries
23. Question Which of the following is an indication for bypass?
A. Claudication within ˝ block
B. ABI of 0.5
C. Rest pain
D. Occlusion of the superficial femoral and anterior tibial arteries
24. 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
25. 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
26. Temperature
Hair loss
Pallor
Nail hypertrophy
Ulcer
Gangrene
Dry - non infected black eschar
Wet - tissue maceration and purulence
28. Diagnostic algorithm
29. 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
30. 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
31. 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
32. Peripheral Arterial Occlusive Disease Acute Thromboembolic Disease
33. 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
34. 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
35. 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%
36. Sites of Embolization Bifurcations
Femoral - 40%
Aortic - 10-15%
Iliac - 15%
Popliteal - 10%
Upper extremities - 10%
Cerebral - 10-15%
Mesenteric/visceral - 5%
37. 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
38. 6 Ps Pain
Pallor
Pulselessness
Paresthesia
Paraparesis
Poikilothermia
40. 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
41. 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
42. 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
43. 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
44. Prevention and management Hydration
UO 100cc/hr
Alkalinization of urine
Prevent myoglobin precipitation in renal tubules
Mannitol
Antioxidant, osmotic diuretic
Insulin/glucose
Fasciotomy
45. 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
46. 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
47. 4 compartments:
Anterior
Lateral (Peroneal)
Deep Posterior
Superficial Posterior
48. Pathophysiology
49. 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
50. 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
51. Fasciotomy
52. Thoracic Outlet Syndrome
53. 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
54. 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
55. Anatomy Interscalene triangle - artery and nerves
Costoclavicular space - vein
Subcoracoid area - artery, vein, nerves
56. 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
57. 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
58. 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
59. Buerger’s Disease
60. 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
61. 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
62. 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
63. 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
64. Buerger’s Disease - Management Revascularization options are limited
Clinical remission with smoking cessation
Sympathectomy has a limited role in patients with ulcerations