How do you differentiate and manage chronic venous insufficiency (CVI) vs peripheral arterial occlusive disease (PAOD)?

Differentiating and Managing Chronic Venous Insufficiency vs Peripheral Arterial Occlusive Disease

The key to distinguishing CVI from PAOD lies in the symptom pattern, pulse examination, and ankle-brachial index (ABI): PAOD presents with exertional claudication relieved by rest within 10 minutes, absent pulses, and ABI ≤0.90, while CVI presents with aching/heaviness worsened by standing and improved with elevation, normal pulses, edema, and skin hyperpigmentation. 1

Clinical Presentation Differences

Peripheral Arterial Occlusive Disease (PAOD)

• Pain pattern: Claudication characterized by fatigue, discomfort, or pain in buttocks, thigh, or calf during exercise that is quickly relieved by rest (typically within 10 minutes) due to exercise-induced ischemia 1
• Physical findings: Diminished or absent pulses at femoral, popliteal, dorsalis pedis, and posterior tibial sites; pallor on elevation; delayed capillary refill (>3 seconds); cool extremities; arterial bruits on auscultation 2, 1
• Skin changes: Atrophic skin, hair loss, nail changes, and ulcers typically located on toes, foot, or pressure points 1
• Distribution: Symptoms affect specific muscle groups depending on occlusion level—buttock/thigh pain suggests aortoiliac disease, calf pain suggests femoral-popliteal disease 1

Chronic Venous Insufficiency (CVI)

• Pain pattern: Aching, heaviness, and throbbing pain that worsens with prolonged standing and improves with leg elevation 1
• Physical findings: Normal pulses (critical distinguishing feature), edema (particularly ankle/lower leg), varicose veins, and skin changes including hyperpigmentation and lipodermatosclerosis 1
• Skin changes: Brownish discoloration (hemosiderin deposition), thickened indurated skin, and ulcers typically located at the medial malleolus 3
• Progression: May present with leg swelling, skin changes (CEAP C3-C6), and venous ulceration in advanced cases 4

Diagnostic Algorithm

Step 1: Initial Vascular Assessment

• Comprehensive pulse examination: Palpate brachial, radial, ulnar, femoral, popliteal, dorsalis pedis, and posterior tibial pulses bilaterally 2
• Bilateral arm blood pressure: Measure in both arms to detect interarm asymmetry suggesting subclavian stenosis 2
• Vascular review of symptoms: Document walking impairment, claudication characteristics, ischemic rest pain, nonhealing wounds, and symptom relationship to position 2, 1

Step 2: Ankle-Brachial Index (ABI) - Mandatory First Test

• Perform resting ABI as the first-line diagnostic test with 68-84% sensitivity and 84-99% specificity for PAOD 2, 5
• ABI interpretation 2, 5:
  • ≤0.90: Confirms PAOD diagnosis
  • 0.91-0.99: Borderline, consider exercise ABI
  • 1.00-1.40: Normal range

  • 1.40: Non-compressible arteries (calcified vessels, common in diabetes)

• For non-compressible arteries: Obtain toe-brachial index (TBI), with TBI <0.70 confirming PAOD 2
• Normal ABI with venous findings: Suggests CVI as primary diagnosis 1

Step 3: Duplex Ultrasound

• For PAOD: Duplex ultrasound confirms lesion location, assesses stenosis severity, and evaluates below-knee vessels 2, 1
• For CVI: Duplex ultrasound assesses venous reflux (>0.5 seconds in superficial veins, >1 second in deep veins), identifies incompetent perforators, and detects deep vein thrombosis or obstruction 6, 3

Step 4: Advanced Imaging (When Indicated)

• CT angiography or MR angiography: For PAOD patients being considered for revascularization to define anatomic detail and plan intervention 2, 1
• Ascending/descending phlebography: For CVI patients with complex anatomy or when considering surgical intervention to demonstrate valve competence and postthrombotic changes 6

Management Approaches

PAOD Management

Risk factor modification (all patients) 1:

• Smoking cessation (mandatory)
• Statin therapy targeting LDL-C <55 mg/dL
• Blood pressure control <130/80 mmHg
• Diabetes management with HbA1c <7%

Supervised exercise therapy 1:

• 30-45 minute sessions, 3 times weekly for minimum 12 weeks
• Walking to near-maximal pain, then rest, then resume

Antiplatelet therapy 1:

• Aspirin 100 mg daily or clopidogrel 75 mg daily for symptomatic PAOD

Revascularization 1:

• Consider for patients remaining symptomatic despite optimal medical therapy and exercise
• Endovascular procedures (angioplasty/stenting) or open surgical bypass depending on anatomy

CVI Management

Compression therapy (mainstay) 3:

• Graduated compression stockings (20-30 mmHg for mild-moderate, 30-40 mmHg for severe CVI)
• Multi-layer compression wraps for active ulcers

Lifestyle modifications 3:

• Leg elevation above heart level when resting
• Weight reduction if obese
• Regular walking to activate calf muscle pump

Pharmacologic therapy 3:

• Micronized purified flavonoid fraction (MPFF) for symptom relief
• Avoid diuretics as monotherapy—associated with treatment failure 4

Interventional therapy 3:

• Endovenous thermal ablation (radiofrequency or laser) for saphenous vein reflux
• Sclerotherapy for varicose veins
• Iliac vein stenting for May-Thurner syndrome or postthrombotic obstruction

Critical Pitfalls to Avoid

• Do not assume leg pain is venous without checking pulses and ABI—missing PAOD can lead to limb loss 2, 1
• Do not rely on ABI alone in diabetics or elderly—obtain TBI if ABI >1.40 due to arterial calcification 2
• Do not prescribe diuretics for CVI-related edema—associated with persistent swelling despite endovenous therapy 4
• Do not delay vascular surgery referral for patients with ABI <0.40, ischemic rest pain, nonhealing wounds, or tissue loss 5
• Recognize mixed disease—approximately 15-20% of patients have both PAOD and CVI requiring combined management strategies 2

Follow-Up Recommendations

• PAOD patients: At least annual follow-up to assess clinical status, medication adherence, limb symptoms, and repeat ABI 1
• CVI patients: Regular monitoring for ulcer development, compression compliance, and consideration for interventional therapy if conservative measures fail 3