Peripheral Vascular Disease

1
Peripheral Vascular Disease

• Larry W Kraiss MD
• Associate Professor Chief
• Division of Vascular Surgery

larry.kraiss_at_hsc.utah.edu
2
Objectives

• Define the clinical role of a vascular surgeon
• Discuss the hemodynamics of peripheral arterial
  disease (PAD) and the use of the vascular
  laboratory in its assessment
• Discuss the clinical management of carotid
  atherosclerosis
• Discuss the clinical management of lower
  extremity PAD

3
The Circulatory System the Vascular Surgeon

• Arteries
• Occlusive disease
• Aneurysms
• Entrapment syndromes
• Veins
• Thrombosis
• Valvular insufficiency (reflux)
• Post-thrombotic syndrome
• Lymphatics (Lymphedema)
• Minimally invasive and traditional surgical
  treatment

4
Atherosclerosis the major cause of PVD

• Risk factors
• Smoking
• Diabetes
• Hyperlipidemia
• Family history
• Homocystinemia

• Pathophysiology
• Luminal stenosis
• Plaque rupture/erosion
• Embolization
• Thrombosis

5
Atherosclerotic Plaque Types
Adapted from Atherosclerosis Coronary Artery
Disease, 1996
6
Stenoses produce changes in pressure (DP) and flow
7
DP is proportional to velocity
Hemodynamics for Surgeons, 1975
8
Collateral circulation develops around
significant stenoses
Vascular Surgery (Rutherford, Ed) 1977
9
Vascular Laboratory

• Pressure testing (ABIs)
• Waveform analysis (PVRs)
• Doppler-based studies (duplex)

10
Continuous Wave (CW) Doppler
Practical Noninvasive Vascular Diagnosis, 1982
11
Doppler waveform analysis
Practical Noninvasive Vascular Diagnosis, 1982
12
Pressure testing calculating the ankle-brachial
index (ABI)
Practical Noninvasive Vascular Diagnosis, 1982
13
Plethysmography Pulse Volume Recording (PVR)
Practical Noninvasive Vascular Diagnosis,1982
14
Pulsed Wave Doppler
Allows sampling of velocities from a particular
reflector without interference from other
reflectors in the path of the sound beam.
Practical Noninvasive Vascular Diagnosis, 1982
15
Duplex Scanning combining real-time gray scale
imaging with pulsed doppler
Duplex Scanning in Vascular Disorders, 1993
16
Effect of stenosis on doppler waveforms
With increasing stenosis, the peak systolic
velocity (Df) increases and spectral broadening
(turbulence) appears
17
Questions?
18
Extracranial Carotid Atherosclerosis

• Atherosclerotic plaque at carotid bifurcation and
  origin of the internal carotid artery
• Stroke 3 cause of death in US
• Significant cause of stroke in patients
• with plaque and symptoms gtgt 80
• Pathophysiology vulnerable plaque
• Thrombosis
• Embolization

19
Symptoms of Carotid Atherosclerosis

• Stroke
• Transient Ischemic Attack (TIA)
• Stroke-like neurologic deficit
• Duration lt 24 hours
• Directly related to anatomy of the ICA
• Ipsilateral ophthalmologic
• (amaurosis fugax)
• Contralateral somatic
• Paralysis/paresis
• Sensory deficits
• Aphasia
• (if dominant hemisphere involved)

Vascular Surgery (Rutherford, Ed), 2000
20
Symptoms not (typically) due to carotid
atherosclerosis

• Posterior circulation
• Dizziness
• Ataxia
• Light-headedness
• Syncope (implies global cerebral hypoperfusion)
• Binocular visual disturbances

21
Physical findings of carotid atherosclerosis

• Carotid bruit (unreliable)
• Evidence of vascular disease in other areas
• Neurologic deficit
• Hollenhorst plaque (cholesterol emboli to the
  retina)
• Overall, history is most important in determining
  subsequent clinical evaluation (especially if TIA)

22
Carotid AtherosclerosisDiagnostic Imaging

• Duplex scanning
• Best screening tool
• Can be definitive diagnostic test
• Angiography
• Magnetic Resonance (MRA)
• Selective intra-arterial catheterization
• Useful to study lesions duplex cannot evaluate
• Calcification
• Unable to identify distal extent of lesion (not
  MRA)
• Discriminating more or less than 50 stenosis
  (not MRA)

23
Duplex Scanning of the Carotid Arteries
Duplex Scanning in Vascular Disorders, 1993
Surgical Management of Cerebrovascular Disease,
1995
24
Doppler waveforms from diseased carotid arteries
Surgical Management of Cerebrovascular Disease,
1995
25
Duplex-based classification of carotid stenosis
Surgical Management of Cerebrovascular Disease,
1995
26
Carotid Angiography
Surgical Management of Cerebrovascular Disease,
1995
27
Carotid MRA
Vascular Surgery (Rutherford, Ed) 2000
28
Carotid AtherosclerosisTreatment

• Medical
• Antiplatelet therapy (ASA, others)
• Statins
• Aggressive risk factor management
• Lesion-based intervention
• Surgical (carotid endarterectomy - CEA)
• Angioplasty/stenting
• Choice of therapy depends on presence of symptoms
  and the degree of stenosis

29
Carotid Endarterectomy
Wylies Atlas of Vascular Surgery, 1992
30
North American Symptomatic Carotid Endarterectomy
Trial (NASCET)

• Symptomatic patients (CVA, TIA, amaurosis fugax)
• Carotid stenosis 30-70 and gt70
• Randomized, prospective trial of best medical
  therapy (ASA) vs CEA (Level 1 evidence)

31
NASCET (1991) Results 70-99 stenosis
CEA provides better stroke protection and
survival compared to ASA
NASCET Collaborators, N Engl J Med, 1991
32
NASCET (1998) Results 30 - 99 stenosis

• CEA better for lesions gt50
• No benefit for CEA if lesion lt50

Barnett, N Engl J Med, 1998
33
Asymptomatic Carotid Atherosclerosis Study (ACAS)

• Natural history increased risk of stroke as
  stenosis worsens, especially gt 80
• Can CEA prevent CVA?
• ACAS trial randomized asymptomatic patients with
  gt60 stenosis to CEA or ASA

34
ACAS (1995) - Results
ASA 11 risk of stroke _at_ 5 yrs CEA 5 risk of
stroke _at_ 5 yrs
ACAS, JAMA, 1995
35
Current Recommendations for Patients with Carotid
Atherosclerosis

• Symptomatic
• gt70 gtgt CEA
• 50-70 gtgt probable CEA
• lt50 gtgt medical therapy (antiplatelet)
• Asymptomatic ?
• Depends on surgeon/center perioperative stroke
  rate
• Patient preference

36
Carotid Atherosclerosis Future Directions

• What is the optimal role of angioplasty/stenting?
• Better antiplatelet agents?
• Clopidogrel (Plavix)
• ASA/dipyridamole (Aggrenox)
• Identification of the vulnerable plaque?
• MRA
• duplex
• Plaque regression?
• Statins
• Angiotensin II inhibition

37
Questions?
38
Peripheral Arterial Disease (PAD)

• Chronic
• Slow, gradual luminal stenosis 2 plaque
  enlargement
• Collateral development compensates
• Symptoms proportional to disease burden
• Exertional symptoms may appear first
• Acute
• Sudden occlusion in the absence of adequate
  collaterals
• Embolization (cardiogenic, proximal arteries)
• Thrombosis superimposed on occlusive disease
• plaque rupture
• failure of a previous vascular reconstruction
• Injury

39
Distribution of Chronic PAD

• Extremities
• Lower
• Upper?
• Mesenteric
• Celiac
• SMA
• IMA
• Renal (limited collateral potential)

40
Chronic PAD of the Lower Extremities

• Aorto-iliac
• Femoropopliteal (SFA most common)
• Tibial (especially diabetics)

Vascular Surgery (Rutherford, Ed), 2000
41
Chronic LE PAD Symptoms

• None
• Intermittent claudication
• Exertional muscular ischemia (calf, thigh,
  buttock)
• Analogous to stable angina
• Rest pain
• Blood supply inadequate to meet resting metabolic
  needs
• Affects tissue furthest from the heart
• May be relieved by dependency
• Tissue loss
• Non-healing traumatic ulcer
• Spontaneous gangrene

42
Chronic LE PAD Physical Findings

• Pulse exam (especially femoral)
• Distinguish normal vs abnormal
• Symmetry
• Bruit or thrill
• Aneurysm
• Evaluate non-palpable pulses with CW doppler
• Trophic signs (Muscular atrophy, absent hair
  growth)
• Dependent rubor/elevation pallor
• Tissue loss (ulceration, gangrene)

43
Chronic LE PAOD Non-invasive evaluation

• Ankle-Brachial Index (ABI)
• Best brachial SBP/Ankle SBP
• Normal value 1.0
• Claudication 0.4 - 1.0
• Limb-threatening 0.4
• Calcified vessels produce inaccurately high ABIs
• Common in diabetes and renal failure
• ABI should be consistent with other measures (PE,
  PVR)
• Exercise (treadmill) testing
• reveals pressure drop in claudication when ABI
  normal
• can identify pseudoclaudication (i.e. spinal
  stenosis)

44
Ankle-Brachial Index (ABI)
ABI falls as disease burden increases Life
expectancy falls with ABI
Vascular Surgery (Rutherford, Ed) 2000
45
PAD is a risk factor for overall cardiovascular
mortality
PAD patients are much more likely to die of MI
than undergo amputation
46
Chronic LE PAD Treatment Considerations

• PAD is a marker of diffuse atherosclerosis
• PAD identifies a need for risk factor
  intervention
• Claudication is a lifestyle-limiting (not
  typically limb-threatening) problem
• Be aggressive if ischemia is limb-threatening
• Risk/benefit decision

47
Chronic LE PAD Treatment Options

• Risk factor modification (almost always)
• Exercise (for claudication)
• Pharmacotherapy
• rarely for claudication
• not effective for limb-threatening ischemia
• Revascularization
• Endovascular (balloon angioplasty/stenting)
• Surgery
• Amputation
• failed revascularization
• may occasionally be appropriate 1 treatment

48
Intermittent Claudication

• Generally not limb-threatening
• Usually represents single-level disease (SFA most
  common)
• ABI 0.7
• Risk factors for progression to limb-threatening
  ischemia
• Smoking
• Diabetes
• Low ABI at presentation (lt0.50)
• First-line treatment
• Exercise
• Risk factor modification (especially smoking)
• Pharmacotherapy? (Good in theory, poor in
  practice)
• Revascularization? (Intolerable lifestyle
  limitation in good risk patient)

49
Claudication Smoking

• Risk factor for progression to limb-threatening
  ischemia
• Shortens walking distance at any given ABI
• Cessation will predictably double walking distance

50
Effect of exercise on claudication

• Predictably doubles walking distance
• The sedentary, smoking claudicant could quadruple
  walking distance with smoking cessation and
  exercise

51
Pharmacotherapy for claudication

• Cilostazol (Pletal) better than pentoxifylline
  (Trental)
• 50 improvement in walking distance with
  cilostazol
• Minimal benefit vs smoking cessation or exercise

52
Limb-threatening ischemia

• Rest pain or tissue loss
• Usually multi-level disease (Aorto-iliac,
  fem-pop, tibial)
• ABI typically lt0.4
• Nearly absolute indication for revascularization
• some type of operation is in the patients future
• Frail elderly patients poor candidates for
  prosthetic ambulation
• ?Primary amputation
• Non-ambulators
• Healthy with excellent potential for prosthetic
  function

53
Diabetes and PAD

• Risk factor for limb-threatening ischemia
• Higher likelihood of tibial artery disease
• Neuropathy predisposes to foot wounds
• Severe deep space foot infections
• Wound healing poorer at any given ABI vs
  non-diabetics
• Vascular calcification may artifactually elevate
  ABI
• Dismal prospects for limb-salvage if combined
  with renal failure

54
Chronic LE PAOD Role of Angiography?

• NOT for diagnostic purposes
• Used for planning therapy after decision to
  intervene has been made

55
Lower extremity revascularizationendovascular
options

• Balloon angioplasty/stenting
• Most commonly applied to aortoiliac segment
• Favorable lesion short, concentric stenosis
• Unfavorable lesion long, eccentric stenosis or
  occlusion
• Atherectomy (rarely)

56
Lower extremity revascularization surgical
options
Vascular Surgery (Rutherford, Ed) 2000
57
Lower extremity revascularization surgical
options
Wylies Atlas of Vascular Surgery, 1992
58
Lower extremity revascularization Graft patency
limb salvage
Graft patency (80-90 _at_ 5 yrs)
Limb salvage (90 _at_ 5 yrs)
Taylor, J Vasc Surg, 1990
59
Lower extremity revascularization Survival
Limb-threatening ischemia is a marker for a
malignant disease
Taylor, J Vasc Surg, 1990
60
Summary

• Vascular surgeons diagnose and treat
  atherosclerosis in non-coronary vascular
  territories (carotid, lower extremities, renal,
  mesenteric) using both endovascular and surgical
  techniques.
• Complete clinical evaluation possible in most
  patients with HP supplemented with vascular
  laboratory (common sense hemodynamic approach)
• CEA can prevent strokes in patients with gt50
  stenosis (Level 1 evidence)
• Lower extremity PAD (ABI) is a marker for heavy
  systemic atherosclerotic disease burden gtgt treat
  risk factors
• Primary treatment for claudication exercise,
  stop smoking
• Limb-threatening ischemia gtgt revascularization

61
Basic PAD Facts

• Which of the following statements regarding
  peripheral arterial disease is NOT true?
• PAD is a manifestation of atherosclerosis and has
  become recognized as a coronary disease
  equivalent
• PAD has a distinct set of risk factors that
  separate it from coronary artery disease.
• Vulnerable plaques are characterized by large
  necrotic cores and thin fibrous caps
• Lesions causing symptoms of PAD typically occur
  at major arterial bifurcations.

62
Dopplers

• Which of the following statements about medical
  dopplers is true?
• The doppler will report greater frequency shifts
  as blood flow velocity increases.
• A duplex scan combines the technology of
  continuous wave doppler and plethysmography.
• A significant problem with pulsed dopplers is
  noise contributed by movement in adjacent
  anatomic structures.
• Dopplers are unable to detect blood flow in
  arteries that do not have a pulse.

63
Doppler Waveforms

• Which statement is FALSE?
• Extremity arteries distal to an occlusion may
  display continuous forward flow on doppler
  examination.
• The normal doppler waveform recorded from a
  healthy radial artery at rest will show reversal
  of flow at end-systole.
• Continuous forward flow throughout the cardiac
  cycle is characteristic of a high-resistance
  artery at rest.
• The normal internal carotid artery doppler
  waveform shows continuous forward flow.

64
Carotid Disease (1)

• A 64 year-old man with a history of smoking
  presents after 2 episodes of transient left
  monocular blindness. A left cervical bruit is
  present.
• Which of the following actions during the first
  clinic visit is NOT appropriate?
• Administer 325 mg ASA.
• Perform a complete neurological examination.
• Obtain a carotid duplex scan.
• Arrange for a stat carotid angiogram.

65
Carotid Disease (2)

• The carotid duplex scan reveals peak systolic
  velocities gt400 cm/sec in the left ICA consistent
  with a stenosis gt70. The patient returns to
  clinic the following day, reporting no new ocular
  symptoms.
• The most appropriate action at this time is
• Obtain a carotid angiogram to verify the duplex
  results.
• Maintain the patient on ASA and make plans to
  follow him carefully since he hasnt had any new
  symptoms since the initial visit.
• Refer the patient for carotid intervention in
  order to minimize the risk of future stroke.
• Obtain ophthalmologic consultation.

66
Carotid Disease (3)

• Regarding the NASCET and ACAS randomized trials
  of carotid stenosis treatment, which of the
  following statements is true?
• Carotid endarterectomy provides equivalent
  benefits in terms of absolute reduction of stroke
  risk in symptomatic and asymptomatic patients.
• Asymptomatic patients with carotid disease have a
  50 risk of stroke in one year with medical
  treatment.
• Symptomatic patients with gt70 stenosis derive
  the greatest benefit from carotid endarterectomy.
• Carotid angioplasty/stenting was shown to be
  superior to medical therapy in preventing future
  stroke.

67
PAD (1)

• Which of the following scenarios is most
  suggestive of limb-threatening ischemia?
• Forefoot pain when recumbent, monophasic pedal
  doppler signals, ABI 0.34.
• Exertional calf pain, absent pedal pulses,
  diminished hair growth below the knee.
• Leg cramps at night, non-palpable popliteal
  pulse, ABI 0.68.
• No symptoms, no palpable pulses at femoral or
  pedal locations, ABI 0.45.

68
PAD (2)

• Regarding patients with intermittent
  claudication, which of the following statements
  is true?
• The risk of progression to limb loss exceeds the
  risk of myocardial infarction.
• Pharmacotherapy is the best means to increase
  their walking distance.
• Revascularization is performed to prevent limb
  loss.
• Risk factor modification and exercise is the best
  means to increase their walking distance.

69
PAD (3)

• A 48 year-old construction worker with a 60
  pack-year smoking history presents with 50 right
  buttock claudication. He is in imminent danger
  of being fired because he cannot walk
  continuously around the job site. On physical
  exam, he has a weakly palpable right femoral
  pulse (the left is normal) and an ABI on the
  right of 0.65. After formulating a plan for
  smoking cessation and risk factor modification,
  which of the following additional measures is
  MOST appropriate in this situation?
• Supervised walking program
• Prescription for Pletal.
• Referral for vocational counseling and job
  retraining.
• Referral for angiography and possible
  revascularization.

70
PAD (4)

• A 68 year-old woman with diabetes presents with
  dry gangrene of the left 5th toe, no pedal pulses
  but an ABI 0.50. Five years ago, she underwent
  right below-knee amputation for diabetic foot
  sepsis. She is non-ambulatory but uses the left
  leg to transfer independently. She has had two
  previous MIs and underwent coronary stenting 6
  months ago. Despite treatment, she remains
  hypertensive with poor glycemic control and an
  LDL cholesterol of 170.
• Which of the following treatment plans is most
  appropriate?
• Intensified risk factor modification and careful
  observation of the gangrenous toe.
• Left below-knee amputation since she is already
  non-ambulatory.
• Revascularization of the left lower extremity.
• Left 5th toe amputation alone since the ABI
  indicates that she does not have limb-threatening
  ischemia.