What is the workup for a patient with multiple non-healing wounds on the lower extremities?

Workup for Multiple Non-Healing Lower Extremity Wounds

Immediately measure ankle-brachial index (ABI) bilaterally, obtain toe pressures with toe-brachial index (TBI), and assess transcutaneous oxygen pressure (TcPO2) or skin perfusion pressure (SPP) to determine if peripheral artery disease is preventing wound healing. 1

Initial Vascular Assessment (Perform First)

Mandatory Physiological Testing

• Measure resting ABI in both legs to establish baseline and confirm PAD diagnosis 1
• If ABI >1.40 (noncompressible arteries), immediately obtain toe pressure/TBI with waveforms as ABI alone is unreliable in this setting 1
• Obtain TcPO2 and/or SPP measurements in a warm room to prevent arterial vasoconstriction, as these predict wound healing potential 1

Critical Thresholds Requiring Urgent Vascular Intervention

• Toe pressure <30 mm Hg indicates severe ischemia and decreased likelihood of wound healing 1
• TcPO2 <30 mm Hg suggests inadequate perfusion for healing 1
• SPP <30-40 mm Hg predicts poor wound healing 1
• TBI ≤0.70 confirms PAD diagnosis 1

Important caveat: Nearly one-quarter of patients with chronic limb-threatening ischemia (CLTI) have ABI 0.90-1.40, and concordance between ABI and toe pressure is poor (only 58% of patients with abnormal toe pressures have abnormal ABIs). 1 Therefore, never rely on ABI alone when evaluating non-healing wounds.

Anatomic Imaging (If Revascularization Considered)

When Perfusion Assessment Indicates Inadequate Blood Flow

• Obtain duplex ultrasound, CTA, or MRA to define anatomic location and severity of arterial stenosis 1
• These imaging modalities are Class I recommendations for determining revascularization strategy in CLTI 1
• Catheter angiography is also acceptable for anatomic assessment 1

Segmental Pressure Studies

• Perform segmental limb pressures with pulse volume recordings (PVR) and/or Doppler waveforms to localize PAD anatomically (aortoiliac, femoropopliteal, or infrapopliteal disease) 1

Alternative Diagnoses (If Perfusion Normal)

If perfusion measures are normal or only mildly impaired, systematically evaluate for non-vascular causes of wound failure: 1

Infection Assessment

• Inspect for purulent drainage, erythema, warmth, swelling, and pain 2, 3
• Obtain deep tissue cultures after debridement (not surface swabs) to guide antibiotic therapy 2, 3
• Probe wounds with sterile blunt metal probe to assess depth and determine communication with joint cavities or tendon sheaths 2

Metabolic and Systemic Factors

• Assess glycemic control in diabetic patients (target HbA1c <7%) 4
• Document smoking status as smoking profoundly impairs wound healing through vasoconstriction 4
• Evaluate nutritional status as malnutrition impairs healing 1, 2

Venous Disease

• Examine for venous insufficiency signs: dependent edema, hemosiderin staining, lipodermatosclerosis, varicose veins 5, 6
• Venous ulcers typically occur in gaiter distribution (medial malleolus) with irregular borders 5, 6

Neuropathy

• Test sensation and motor function distal to wounds to identify peripheral neuropathy 2
• Neuropathic ulcers typically occur at pressure points (plantar metatarsal heads, heel) 5, 6

Pressure/Biomechanical Issues

• Assess for excessive or persistent pressure at wound sites 1, 2
• Evaluate foot structure and gait abnormalities in diabetic patients 1

Atypical Causes Requiring Biopsy

• Biopsy any atypical non-healing wound to exclude malignancy, vasculitis, pyoderma gangrenosum, or other inflammatory conditions 6

Comprehensive Wound Documentation

At initial assessment, systematically document: 2, 7

• Wound dimensions: length, width, depth (in centimeters)
• Wound location: specific anatomic site on each extremity
• Tissue type: percentage of granulation, slough, eschar, necrotic tissue
• Exudate: quantity (none, minimal, moderate, copious) and quality (serous, serosanguinous, purulent)
• Wound edges: attached, rolled, undermined, macerated
• Periwound skin: intact, erythematous, indurated, macerated
• Presence/absence of pedal pulses: dorsalis pedis and posterior tibial bilaterally

Common Pitfalls to Avoid

• Never delay vascular assessment in patients with non-healing wounds, as inadequate perfusion is the most common reversible cause of healing failure 4, 3
• Never rely solely on ABI in patients with diabetes or calcified vessels (ABI >1.40), as falsely elevated readings miss critical ischemia 1, 3
• Never obtain anatomic imaging (CTA/MRA/angiography) without first confirming inadequate perfusion through physiological testing, as imaging without revascularization intent is Class III (harm) 1
• Never attribute poor healing to "diabetic microangiopathy" without documenting macrovascular PAD, as this is not a validated cause of wound failure 3