Below-knee arterial occlusion (infrapopliteal artery disease) is the narrowing or blockage of the tibial arteries below the knee due to atherosclerosis. It is particularly common in diabetic patients and is one of the most important causes of critical limb ischemia.
Infrapopliteal Artery Anatomy#
The below-knee (infrapopliteal) arteries consist of three main branches as a continuation of the popliteal artery.
Anatomical Structure:
Popliteal Artery
↓
Tibioperoneal Trunk
↓
┌──┴──┐
↓ ↓
Posterior Peroneal
Tibial Artery
Artery ↓
↓ Ankle
Medial lateral
Plantar branches
Anterior Tibial Artery
↓
Dorsalis Pedis
↓
Dorsum of foot
Vessel Characteristics:
| Artery | Diameter | Length | Area Supplied |
|---|---|---|---|
| Anterior Tibial | 3-4 mm | ~30 cm | Dorsum of foot |
| Posterior Tibial | 3-4 mm | ~25 cm | Sole of foot |
| Peroneal | 3-4 mm | ~25 cm | Lateral ankle |
Why Are Below-Knee Vessels Important?#
Critical Limb Ischemia#
Below-knee vascular disease is the most important cause of critical limb ischemia (CLI):
- CLI definition: Rest pain or tissue loss
- Amputation risk: 25-40% at 1 year without treatment
- Mortality: 50-70% at 5 years
Diabetes and Below-Knee Disease#
Below-knee involvement is very common in diabetic patients:
- 80% of diabetic PAD patients have below-knee involvement
- Medial calcification (Mönckeberg)
- Diffuse, multisegmental disease
- Poor collateral development
Risk Factors#
| Risk Factor | Characteristic |
|---|---|
| Diabetes | Most important risk factor |
| Chronic kidney disease | Severe calcification |
| Smoking | Disease progression |
| Advanced age | >70 years |
| Hyperlipidemia | Plaque formation |
Symptoms of Below-Knee Arterial Occlusion#
Critical Limb Ischemia Findings#
Rutherford Classification:
| Category | Clinical Finding |
|---|---|
| 4 | Rest pain |
| 5 | Minor tissue loss |
| 6 | Major tissue loss |
Typical Symptoms#
Rest Pain:
- Night pain (decreases when leg is lowered)
- In toes and forefoot
- May require opioid analgesics
Tissue Loss:
- Non-healing wounds
- Dry/wet gangrene
- Infection risk
Diabetic Foot:
- Neuropathic ulcers
- Charcot foot
- Osteomyelitis
Diagnostic Methods#
Physical Examination#
- Dorsalis pedis and posterior tibial pulse
- Capillary refill time (>3 sec pathological)
- Foot color and temperature assessment
- Wound/ulcer examination
Non-invasive Tests#
ABI (Ankle-Brachial Index):
| ABI | Interpretation |
|---|---|
| >1.30 | False high (calcification) |
| 0.91-1.30 | Normal |
| ≤0.40 | Critical ischemia |
TBI (Toe-Brachial Index):
- Digital arteries are less calcified
- TBI <0.70: PAD presence
- TBI <0.30: Critical ischemia
Transcutaneous Oxygen Measurement (TcPO2):
- Evaluates tissue perfusion
- <30 mmHg: Critical ischemia
- <10 mmHg: Difficult wound healing
Imaging#
Doppler Ultrasound:
- First step
- Flow patterns
- Limited imaging (calcification)
CT Angiography:
- Detailed anatomical map
- Calcification assessment
- Run-off vessel imaging
DSA (Digital Subtraction Angiography):
- Gold standard
- Foot arch assessment
- Treatment in same session
Angiosome Concept#
The foot is divided into regions (angiosomes) supplied by different arteries:
| Angiosome | Feeding Artery |
|---|---|
| Dorsum of foot | Dorsalis pedis (Anterior tibial) |
| Sole (medial) | Medial plantar (Posterior tibial) |
| Sole (lateral) | Lateral plantar (Posterior tibial) |
| Heel (medial) | Calcaneal branch (Posterior tibial) |
| Heel (posterior) | Calcaneal branch (Peroneal) |
Treatment Strategy:
- Priority is opening the artery feeding the angiosome where the wound is located
- “Direct revascularization” principle
- Increases wound healing and limb salvage rates
Endovascular Treatment#
Treatment Principles#
- Opening at least one tibial artery (to the foot arch)
- Angiosome-directed revascularization
- Wound-directed approach
Balloon Angioplasty#
Standard Treatment:
- Primary choice in below-knee vessels
- Good results without stenting
- Repeatable
Drug-Coated Balloon (DCB):
- Paclitaxel or Sirolimus
- Reduces restenosis rate
- Advantageous in long segment disease
Special Balloons#
| Type | Feature | Indication |
|---|---|---|
| Scoring balloon | Controlled dissection | Calcified lesion |
| Cutting balloon | Micro-atherotome | Ostial stenosis |
| High-pressure | 20-30 atm | Resistant stenosis |
Stenting#
Below-Knee Stent Indications:
- Flow-limiting dissection
- Elastic recoil
- Suboptimal angioplasty result
Stent Types:
| Type | Feature |
|---|---|
| Coronary DES | Drug-coated, small diameter |
| Bioresorbable | Dissolves over time |
| Self-expanding | Long segment |
Atherectomy#
In calcified below-knee lesions:
- Orbital atherectomy (Diamondback)
- Rotational atherectomy
- Laser atherectomy
Advantage: Lumen preparation, increases balloon effectiveness
Chronic Total Occlusion (CTO) Techniques#
Approaches:
- Antegrade: From popliteal artery
- Retrograde (Pedal access): From dorsalis pedis or posterior tibial
- Subintimal: Controlled dissection
Success rate: 75-90% (in experienced centers)
Treatment Outcomes#
Technical Success#
- Balloon angioplasty: 90-95%
- CTO crossing: 75-90%
- Stenting: 95+%
Clinical Outcomes#
| Parameter | Rate |
|---|---|
| Limb salvage (1 year) | 80-90% |
| Wound healing | 60-80% |
| Amputation-free survival | 70-80% |
Patency Rates#
| Treatment | 1 Year |
|---|---|
| PTA | 50-60% |
| DCB | 70-80% |
| DES | 75-85% |
Hybrid and Combined Approaches#
Multi-level Disease#
Above-knee + below-knee disease often coexist:
Treatment Strategy:
1. First correct inflow (iliac/femoral)
2. Then open outflow (tibial)
3. Single session or staged
Hybrid Procedures#
- Femoral endarterectomy + Tibial angioplasty
- Iliac stent + Tibial DCB
- Bypass + Tibial angioplasty
Complications#
Specific Risks#
| Complication | Frequency | Management |
|---|---|---|
| Dissection | 10-20% | Long balloon, stent |
| Spasm | 5-10% | Vasodilator |
| Perforation | <1% | Long balloon |
| Distal embolism | 1-2% | Aspiration |
| No-reflow | 2-5% | Vasodilator |
Access Complications#
- In retrograde (pedal) access: Hematoma, AV fistula
- In antegrade access: Femoral complications
Medical Treatment#
Mandatory Components#
- Aspirin: 100 mg/day
- Clopidogrel: 75 mg/day (DAPT)
- Statin: High dose
- ACE inhibitor: Cardiovascular protection
Diabetes Management#
- Tight glycemic control
- Foot care education
- Regular podiatry check-ups
- Appropriate footwear
Wound Care#
- Debridement
- Infection control
- Offloading
- Multidisciplinary approach
Surgical Alternatives#
Indications#
- Long segment occlusion
- Failed endovascular intervention
- Autogenous vein availability
Bypass Options#
- Femoral-tibial bypass: With saphenous vein
- Popliteal-tibial bypass: Short bypass
- Distal bypass: To foot arteries
Follow-up Protocol#
Critical Limb Ischemia Follow-up#
| Period | Assessment |
|---|---|
| 2 weeks | Wound check |
| 1 month | Clinical + TcPO2 |
| 3 months | Doppler US |
| 6 months | Clinical + ABI/TBI |
| 12 months | Doppler US |
Wound Follow-up#
- Weekly wound photograph
- Signs of infection
- Granulation tissue assessment
- Debridement need
Multidisciplinary Approach#
Below-knee vascular disease treatment is a team effort:
- Interventional cardiologist: Revascularization
- Endocrinologist: Diabetes management
- Infectious diseases: Antibiotherapy
- Plastic surgery: Wound closure
- Orthopedics: Amputation decision (if needed)
- Podiatry: Foot care
Frequently Asked Questions#
What is below-knee arterial occlusion?
What are the symptoms of below-knee arterial occlusion?
What is the relationship between diabetic foot and below-knee vascular disease?
Is stenting performed in below-knee vessels?
Can the limb be saved with treatment?
Appointment and Contact#
To make an appointment for below-knee arterial occlusion evaluation and treatment:
📍 Avrasya Hospital - Beştelsiz Mah. 101. Sokak No:107, Zeytinburnu, Istanbul
📞 Phone: +90 212 665 50 50 (Ext: 4012)
This content has been prepared by Assoc. Prof. Dr. Habib Çil for general informational purposes. Please consult a cardiology specialist for definitive diagnosis and treatment.
Related Peripheral Interventions#
Other services related to below-knee arterial occlusion treatment:
- Above-Knee Arterial Occlusion - Femoropopliteal treatment
- Iliac Artery Treatment - Pelvic vessel treatment
- Peripheral Angiography - Vascular imaging
- Atherectomy - Plaque removal
- Peripheral Vascular Disease - General information