Transcript Lower_Extremity_Vascular_Disease

Lower Extremity
Vascular Disease
Anatomy
Anatomy
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
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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
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 crosssectional area of 75% or more or a 50%
decrease in diameter
 Dye load a problem for renal patients,
anaphylaxis (<3%), local and distal
complications (<1-2%)
 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
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
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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?)