Occlusive Disease: Tibial & Pedal Arteries

Essentials of Diagnosis

• Severe pain of forefoot that is relieved by dependency (ischemic rest pain)

• Pain or numbness of foot with walking

• Ulcer or gangrene, and not claudication, is a frequent initial manifestation

• Pallor when foot is elevated

General Considerations

• Involves the tibial arteries of the lower leg and pedal arteries in the foot occur

• Occurs primarily in patients with diabetes

• There often is extensive calcification of the artery wall

Symptoms and Signs

• Foot ischemia without attendant claudication

• Ischemic rest pain or ulcers

  • May be first sign of severe vascular insufficiency

  • Termed "chronic limb-threatening ischemia" (formerly critical limb ischemia)

  • Associated with highest rate of amputation

• Characteristics of rest pain

  • Severe, usually burning

  • Awakens patient

  • Confined to the dorsum of the foot at the area of the metatarsal heads

  • Relieved with dependency

• Pedal pulses are absent

• Dependent rubor with pallor on elevation

• Skin of the foot is generally cool, atrophic, and hairless

Differential Diagnosis

• Diabetic neuropathic dysesthesia

Imaging Studies

• Digital subtraction angiography is the gold standard method to delineate the anatomy of the tibial-popliteal segment

• Magnetic resonance angiography or CT angiography is less helpful for detection of lesions in this location due to the small vasculature and other technical issues related to image resolution

Diagnostic Procedures

• Ankle-brachial index

  • May be quite low (in the range of 0.4 or lower)

  • May be falsely elevated due to calcification of the arterial media layer (Mönckeberg medial calcific sclerosis) and may not be compressible

• Toe brachial indexes are preferred for assessing perfusion and predicting wound healing

Surgery

BYPASS AND ENDOVASCULAR TECHNIQUES

• Bypass with vein to the distal tibial arteries or foot effective in

  • Treating rest pain

  • Healing gangrene

  • Healing ischemic ulcers of the foot

• These bypasses have good patency rates (70% at 3 years)

• In nearly all series, limb preservation rates are much higher than patency rates

• Endovascular treatment with plain balloon angioplasty is effective for short segment lesions

• The technical failure and reocclusion rates increase drastically with long segment disease in multiple tibial arteries

• Stents and drug-coated balloons have not been successful in the tibial vessels

AMPUTATION

• Patients with chronic limb-threatening ischemia or ulcers have a 30–40% 1-year risk for major amputation that increases if revascularization cannot be done

• Patients with diabetes and peripheral artery disease have a 4-fold risk of chronic limb-threatening ischemia compared with nondiabetic patients with peripheral artery disease and have a risk of amputation up to 20-fold when compared to an age-matched population

• Many patients who have below the knee or above the knee amputations due to vascular insufficiency never regain independent ambulatory status and often need assisted-living facilities

Therapeutic Procedures

• Blood flow studies (ankle-brachial index/toe-brachial index) are indicated if ulcerations appear and there is no significant healing within 2–3 weeks

• Poor blood flow and a foot ulcer or nightly ischemic rest pain requires expeditious revascularization to avoid a major amputation

• Any patient with an ulcer and a diabetic foot infection should be treated emergently with operative incision and drainage

• Broad-spectrum intravenous antibiotics should be given empirically to cover

  • Methicillin-resistant Staphylococcus aureus (such as vancomycin)

  • Gram-negative and anaerobic organisms (such as ertapenem or piperacillin/tazobactam)

Prognosis

• Good foot care may avoid ulceration

• Most diabetic patients do well with a conservative regimen

When to Refer

• Patients with diabetes and foot ulcers should be referred for a formal vascular evaluation

• Patients with an ulcer and a diabetic foot infection require emergent referral

• Centers that have a multidisciplinary limb preservation center staffed with vascular surgeons, podiatrists, plastic and orthopedic surgeons, prosthetics and orthotic specialists, and diabetes specialists should be preferentially sought