Is it okay to use Unna boots on a patient with Peripheral Artery Disease (PAD)?

Unna Boots in Peripheral Artery Disease: Not Recommended

Unna boots should NOT be used on patients with PAD due to the risk of compression-induced ischemia in already compromised arterial circulation. While compression therapy has a role in venous disease, applying compression to arterial insufficiency can worsen ischemia and lead to tissue necrosis, ulceration, or limb loss.

Critical Assessment Required Before Any Compression

Before considering any form of compression therapy in a patient with suspected PAD, you must:

• Measure the ankle-brachial index (ABI) immediately - this is the essential first step to determine arterial perfusion status 1
• Check toe pressures and transcutaneous oxygen pressure (TcPO2) in diabetic patients even if ABI appears normal, as calcified vessels can give falsely elevated readings 2
• Perform duplex Doppler ultrasound to evaluate the arterial system if PAD is suspected 2

Compression Contraindications Based on ABI

The safety of compression therapy is strictly determined by arterial perfusion:

• ABI <0.6: Absolute contraindication - never use any compression without first checking arterial status 2
• ABI 0.6-0.9: Reduced compression only - if compression is absolutely necessary for concurrent venous disease, limit to 20-30 mmHg graduated compression, which has been shown safe for healing venous ulcers in this range 2
• ABI ≥0.9: Standard compression permitted - 20-40 mmHg graduated compression can be used safely for venous insufficiency 2

Why Unna Boots Are Particularly Problematic in PAD

Unna boots are zinc oxide-impregnated bandages that provide sustained compression. In PAD patients, this creates several hazards:

• Fixed compression cannot be adjusted if ischemic symptoms develop, unlike removable compression stockings 3
• Masks deteriorating perfusion - the rigid bandage prevents visual inspection of skin changes that signal worsening ischemia 1
• Delays recognition of infection - PAD patients have subtle presentations of foot infection, and Unna boots obscure early warning signs like erythema, warmth, or drainage 1
• Prevents daily foot inspection - which is specifically recommended for all PAD patients to detect early ulceration 1

Alternative Management for PAD Patients with Edema

If your PAD patient has lower extremity edema requiring treatment:

• Identify the underlying cause - bilateral edema is rarely venous disease alone; exclude cardiac, renal, hepatic, and medication-related causes 2
• Optimize cardiovascular risk reduction - statins targeting LDL <55 mg/dL, antiplatelet therapy, blood pressure control to <140/90 mmHg 2, 1
• Implement proper foot care without compression - daily inspection, appropriate footwear, skin cleansing, topical moisturizing creams 1, 4
• Consider leg elevation when resting rather than compression 2
• Treat underlying cardiac conditions per heart failure guidelines if present, noting that absence of lung rales does not exclude heart failure 2

Special Consideration: Mixed Arterial-Venous Disease

In patients with both PAD and venous insufficiency (ABI 0.6-0.9):

• Reduced compression (20-30 mmHg) is safe and effective for healing venous ulcers in this population 2
• Diabetic foot ulcers typically heal if toe pressure >55 mmHg and TcPO2 >50 mmHg 2
• Initiate aggressive cardiovascular risk reduction alongside any compression therapy 2
• Use removable graduated compression stockings rather than fixed bandaging systems like Unna boots to allow daily inspection 2

Critical Pitfall to Avoid

Never assume edema is venous in origin without measuring ABI first - applying Unna boots to undiagnosed PAD can precipitate critical limb ischemia and lead to amputation 2. The consequences of compression-induced ischemia in PAD far outweigh any potential benefit from edema reduction.