1. Lower Extremity Vascular Disease

2. Anatomy

3. Anatomy

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

5. 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

6. 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.

7. 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

8. 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.

9. 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

10. Risk Factors Diabetes Smoking #1 preventable cause HTN Genetics
Obesity
Hyperlipidemia
Hypercholesterolemia

11. 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

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

13. 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%

14. 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

15. Invasive Techniques
Angiography is the gold standard for evaluating lower extremity ischemic disease
Done before OR for precision
From aorta to feet

16. 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 (<3%), local and distal complications (<1-2%)
Not done if no intervention planned!

17. 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?

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

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

20. Drugs Decrease in viscosity
Increases blood flow in the lower extremity and increases muscle oxygen tension

21. 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

22. 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

23. 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

24. 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.

25. 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.

26. Surgical Therapy

27. Surgical Therapy Optimize other medical problems
Debride and treat infections
Angiogram

28. Surgical Therapy Endarterectomy, bypass, amputation
Bypass is indicated for the patient with critical ischemia and, in specific instances, the patient with claudication

29. 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!

30. Surgical Therapy Inflow and outflow vessels Runoff
Vein (reversed or in-situ)
Graft

31. 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?)