Lower Extremity Vascular Disease

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Lower Extremity Vascular Disease

• Vic V. Vernenkar, D.O.
• St. Barnabas Hospital
• Dept. of Surgery

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Anatomy
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Anatomy
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Pathophysiology

• Most predominant cause is atherosclerotic disease
  
• Other causes include antiphospholipid syndrome,
  popliteal aneurysms, adventitial cystic disease,
  popliteal artery entrapment, and trauma.

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Pathophysiology

• Collateral circulation allows for blood flow to
  all areas of the lower extremity in the face of
  localized occlusive disease
• Muscle arterial resistance can be decreased to
  allow a large increase in blood flow. This is
  physiologic during exercise and compensatory
  during ischemia
• As occlusive disease progresses, it usually
  involves multiple sites in the lower extremity
  vasculature

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Pathophysiology

• The first symptoms are noted by the patient
  during exercise because the leg is no longer able
  to increase blood delivery in the normal fashion
• Claudication, is reproducible lower extremity
  muscle pain on walking that is relieved by rest
• Most commonly, it involves the calf.

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Pathophysiology

• As ischemia progresses, pain is encountered at
  rest.
• With critical ischemia, the patient experiences
  rest pain and wounds are unable to heal, so that
  the patient is predisposed to infection,
  gangrene, and limb loss

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Pathophysiology

• Rest pain initially begins in the forefoot
  (metatarsalgia) and toes and progresses
  proximally.
• Patients often notice a beneficial effect of
  gravity on their arterial blood flow.

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Pathophysiology

• Many let their legs hang over the side of the bed
  in a dependent fashion to increase the effect of
  gravity, which augments minimal perfusion and
  decreases pain.
• Conversely, symptoms of rest pain are provoked
  and worsened when the extremity is elevated

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Risk Factors

• Diabetes
• Smoking 1 preventable cause
• HTN
• Genetics
• Obesity
• Hyperlipidemia
• Hypercholesterolemia

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Patient Evaluation

• History of pain (type, location position)
• Non-healing ulcer, infection
• Past medical history of diabetes, HTN, cardiac,
  hypercholesterolemia, hypercoagulable states
• Social history (smoking, activity level)
• Family history

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Physical Exam

• Full vascular examination
• Appearance (color, hair, muscle, nails, skin)
• Touch (temp, refill, tenderness, elevation)
• Pulses
• Stethoscope
• Neck, Abdomen
• Heart

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Non-invasive Techniques

• Ankle-Brachial Index
• Useful in predicting the likelihood of wound
  healing
• Amputations healed in all patients with an ABI
  above 70
• Healing did not occur in 25 of those with an ABI
  below 70

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Non-invasive Techniques

• Simple and inexpensive
• In diabetics is often unreliable because of
  abnormal wall calcification and
  noncompressibility
• Additional information can be obtained by
  measuring pressures at various levels of the
  lower extremity
• Gradients of more than 20 mm Hg are diagnostic of
  a hemodynamically significant lesion
• Duplex Ultrasound
• Exercise stress test can be performed

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Invasive Techniques

• Angiography is the gold standard for evaluating
  lower extremity ischemic disease
• Done before OR for precision
• From aorta to feet

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Invasive Techniques

• Hemodynamically significant lesions are
  identified by a reduction in the cross-sectional
  area of 75 or more or a 50 decrease in diameter
  
• Dye load a problem for renal patients,
  anaphylaxis (lt3), local and distal complications
  (lt1-2)
• Not done if no intervention planned!

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Treatment

• Claudication or limb threatening?
• When limb-threatening, intervention is necessary
• Claudication lifestyle limiting?
• Co-existing problems, high or good risk patient?
• Surgery or endovascular?

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Conservative

• Stop smoking
• Walk
• Preventative foot care in diabetics
• Control of blood glucose level
• Decrease cholesterol levels
• Drug therapy

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Drugs

• Pentoxyphyllin (Trental), a hemorrheologic drug
• Increases blood filtration and decreases platelet
  aggregation and plasma fibrinogen

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Drugs

• Decrease in viscosity
• Increases blood flow in the lower extremity and
  increases muscle oxygen tension

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Drugs

• Cilostazol (Pletal), a phosphodiesterase
  inhibitor that suppresses platelet aggregation
  and acts as a direct vasodilator
• Ticlopidine, an adenosine diphosphate inhibitor,
  also decreases blood viscosity

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Endovascular Therapy

• Discrete lesions of the superficial and deep
  femoral arteries have been successfully treated
  with percutaneous transluminal angioplasty
• Balloon causes the atherosclerotic intima to
  rupture and stretches the media
• Increased blood flow allows for continued patency

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Endovascular Therapy

• The atherosclerotic lesion can also re-form over
  time
• Best results are observed in those with short
  focal lesions
• Success rates are higher in larger vessels

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Endovascular Therapy

• Good runoff is important for patency
• Distal disease increases the risk for restenosis
  and failure, and the consequences would be
  devastating if acute thrombosis were to occur
  during the procedure.

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Endovascular Therapy

• PTA has also been used successfully as an adjunct
  to surgery to improve inflow for a more distal
  bypass and outflow for a more proximal bypass
• Stenosis in bypass grafts is also amenable to PTA
  
• In the event of acute lower extremity ischemia,
  an immediate angiogram is optimal and
  fibrinolytic therapy may be warranted
• Catheter is inserted into the clot and the
  fibrinolytic agent is infused into the clot
  during the ensuing hours along with heparin.

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Surgical Therapy
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Surgical Therapy

• Optimize other medical problems
• Debride and treat infections
• Angiogram

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Surgical Therapy

• Endarterectomy, bypass, amputation
• Bypass is indicated for the patient with critical
  ischemia and, in specific instances, the patient
  with claudication

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Surgical Therapy

• Both the physician and the patient must be
  certain that the disease is truly incapacitating
  and limits the activities of daily living
• That conservative and medical management have
  been unsuccessful, and that the mortality risk
  and threat of limb loss as a complication of
  surgery are worth the possible relief of symptoms
  
• Remember! claudication progresses to critical
  ischemia and limb loss in relatively few cases
• All interventions in the peripheral circulation
  can be complicated by limb loss!

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Surgical Therapy

• Inflow and outflow vessels
• Runoff
• Vein (reversed or in-situ)
• Graft

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Complications

• Perioperative mortality has been reported to be
  between 2 and 5
• Perioperative myocardial infarction rates have
  been reported as 3
• If silent and unnoticed myocardial infarctions
  are included, they may be as high as 10 to 15
• Hemorrhage, hematoma, thrombosis, infection, and
  edema
• Primary amputation (when?)

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