Cardiovascular · Year 1 · from Cardiovascular

Case 1: Critical Limb Ischemia - Advanced Peripheral Arterial Disease

Clinical Image

Source: Wikimedia Commons - Peripheral arterial disease - CC BY-SA 3.0

Patient Presentation

A 68-year-old man presents with worsening pain in his right foot that has been present for 3 weeks. The pain is constant, worst at night, and only partially relieved by hanging his leg over the side of the bed. He has a non-healing ulcer on his right great toe that developed 6 weeks ago after he stubbed his toe. He has a 50-pack-year smoking history and quit 2 years ago after a "mini-stroke."

Demographics

  • Age: 68 years
  • Sex: Male
  • Past Medical History: Type 2 diabetes, hypertension, hyperlipidemia, TIA 2 years ago
  • Medications: Metformin, lisinopril, atorvastatin, aspirin
  • Social History: Former smoker (50 pack-years), quit 2 years ago

Chief Complaint

Rest pain in right foot and non-healing toe ulcer

Physical Examination

  • Blood pressure: 148/82 mmHg
  • Heart rate: 78 bpm
  • Right lower extremity:
  • Dependent rubor, elevation pallor
  • Cool to touch compared to left
  • Hair loss on lower leg and foot
  • Shiny, atrophic skin
  • Ulcer on plantar surface of great toe (2 cm, punched-out, pale base)
  • Femoral pulse: 2+ (palpable)
  • Popliteal pulse: 1+ (diminished)
  • Dorsalis pedis and posterior tibial: Absent
  • Left lower extremity: Reduced but palpable pedal pulses

Workup

  • Ankle-brachial index (ABI): Right 0.32, Left 0.68
  • Toe-brachial index: Right 0.25 (severe disease)
  • Arterial duplex ultrasound: Severe stenoses in right superficial femoral and popliteal arteries, occluded anterior tibial artery
  • CT angiography: Confirms multilevel disease; AT artery occluded, PT artery 90% stenosed, peroneal artery patent
  • HbA1c: 8.2%
  • Wound culture: No evidence of osteomyelitis on MRI

Diagnosis

Critical Limb Ischemia (Rutherford Category 5) with tissue loss, secondary to multilevel peripheral arterial disease

Treatment

  1. Pain management and wound care
  2. Urgent revascularization consultation:
  • Options: Endovascular intervention vs. surgical bypass
  • Decision based on anatomy (TASC classification) and patient factors
  1. Antiplatelet therapy (aspirin + clopidogrel perioperatively)
  2. High-intensity statin therapy
  3. Strict glycemic control
  4. Smoking cessation reinforcement (already quit)
  5. Wound care with offloading
  6. If revascularization not possible or fails: amputation consultation

Physiological Principles Demonstrated

  • Critical limb ischemia criteria: Rest pain plus tissue loss (ulceration or gangrene) indicates blood flow insufficient to meet metabolic demands even at rest.
  • Dependent rubor: Maximally dilated capillaries from chronic ischemia fill with deoxygenated blood when dependent, producing the characteristic color that blanches with elevation.
  • ABI interpretation: ABI <0.40 indicates severe disease. Values <0.5 are associated with rest pain, and values <0.3-0.4 often indicate critical ischemia.
  • Limb salvage urgency: Without revascularization, CLI has a 1-year amputation rate of 25-40% and mortality of 20-25%. Prompt intervention is essential.

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