What is the best management for an elderly lady with uncontrolled DM, severe limb ischemia, and complete occlusion of popliteal and infra-popliteal arteries?

Management of Severe Limb Ischemia in an Elderly Diabetic Patient

Below knee amputation is the most appropriate management for this elderly diabetic patient with extensive necrosis, complete occlusion of popliteal and infrapopliteal arteries, and no distal runoff. 1

Assessment of the Current Situation

This patient presents with:

• Elderly female with uncontrolled diabetes mellitus
• Blackish discoloration of left foot for 2 weeks (gangrene)
• No palpable anterior or posterior tibial pulses
• Leukocytosis (suggesting infection)
• CTA findings:
  • Severe stenosis of distal superficial femoral artery
  • Complete occlusion of popliteal and infrapopliteal arteries
  • No collaterals
  • No distal runoff

Decision-Making Algorithm

1. Assess limb viability and revascularization potential:

   • Complete occlusion of popliteal and infrapopliteal arteries
   • No collaterals or distal runoff
   • Established gangrene (blackish discoloration)
   • Leukocytosis indicating infection

2. Consider patient factors:

   • Elderly patient with uncontrolled diabetes
   • Presence of infection (leukocytosis)
   • Established gangrene for 2 weeks

3. Evaluate revascularization options:

   • Bypass graft: Not feasible due to no distal runoff vessels
   • Endovascular therapy: Not suitable with complete occlusion and no runoff

Rationale for Below Knee Amputation

According to the 2017 ESC Guidelines, "Patients with extensive necrosis or infectious gangrene and those who are non-ambulatory with severe comorbidities may be best served with primary major amputation. This remains the last option to avoid or halt general complications of irreversible limb ischemia" 1.

In this case:

• The patient has established gangrene (blackish discoloration for 2 weeks)
• Complete occlusion of popliteal and infrapopliteal arteries with no runoff makes revascularization futile
• Leukocytosis indicates infection, which can lead to sepsis if not addressed
• Uncontrolled diabetes further complicates wound healing potential

Why Below Knee Rather Than Above Knee Amputation

The ESC guidelines specifically state: "In any case, infragenicular amputation should be preferred, because the knee joint allows better mobility with a prosthesis" 1. Preserving the knee joint offers significant functional advantages:

• Better mobility with prosthesis
• Lower energy expenditure during ambulation
• Improved rehabilitation potential
• Better quality of life

Why Not Bypass Graft

Bypass grafting requires:

1. Adequate inflow (present with stenosis but not complete occlusion of SFA)
2. Adequate outflow/target vessel (absent - complete occlusion of infrapopliteal vessels)
3. No distal runoff (confirmed by CTA)

The ESC guidelines indicate that "infra-popliteal revascularization is indicated for limb salvage" 1, but this requires viable target vessels, which are absent in this case.

Common Pitfalls to Avoid

1. Delaying definitive treatment: Continuing medical management without addressing the necrotic tissue can lead to sepsis and increased mortality.

2. Attempting futile revascularization: With no distal runoff, revascularization attempts are unlikely to succeed and may delay necessary amputation.

3. Choosing above-knee amputation first: Preserving the knee joint significantly improves functional outcomes and should be the first choice when possible.

4. Inadequate infection control: Ensure appropriate antibiotic coverage before and after amputation.

5. Poor glycemic control: Optimize diabetes management to improve healing potential.

Post-Amputation Management

Following below knee amputation:

• Optimize glycemic control
• Appropriate antibiotic therapy for infection
• Early rehabilitation and prosthesis fitting
• Regular follow-up to monitor the contralateral limb
• Risk factor modification to prevent similar issues in the remaining limb