Below-the-knee (BTK), or infrapopliteal, interventions address peripheral arterial disease affecting the tibial and peroneal arteries that supply the lower leg and foot. This vascular territory presents distinct anatomical and technical challenges compared to more proximal disease, and BTK interventions are particularly relevant in patients with critical limb ischemia (CLI) or diabetes-associated arterial involvement, where restoring flow to the foot can be a central treatment goal.
What Makes Below-the-Knee Disease Distinct?
Tibial and peroneal arteries are smaller in diameter than the femoropopliteal segment and often exhibit long, diffuse, and heavily calcified lesions, particularly in patients with diabetes or chronic kidney disease. Multivessel involvement is common, and disease frequently extends into the pedal arteries. These characteristics generally require smaller-profile devices, careful lesion assessment, and consideration of angiosome-based revascularization strategies, in which the physician targets the specific arterial territory feeding the area of tissue compromise.
How Is Below-the-Knee Disease Typically Evaluated?
Preprocedural evaluation commonly includes duplex ultrasound, CT angiography, or catheter-based angiography to characterize lesion length, calcification burden, and distal runoff. In patients with heavily calcified vessels, ankle-brachial index results can be unreliable, so toe-brachial index or other supplemental assessments are often used alongside clinical judgment.
What Endovascular Techniques Are Used Below the Knee?
Physicians may draw on several endovascular tools and techniques depending on lesion characteristics:
- Low-profile PTA balloon catheters sized appropriately for smaller tibial and peroneal vessels, used to dilate focal or diffuse narrowing
- Drug-coated balloons in select cases, intended to reduce restenosis by delivering an antiproliferative agent to the vessel wall
- Atherectomy for heavily calcified lesions that resist balloon dilation, used as vessel preparation to improve subsequent balloon or stent performance
- CTO guidewires designed to help navigate chronic total occlusions, which are common in this territory
- Selective stent placement, generally reserved for specific indications such as flow-limiting dissection after angioplasty, since stenting below the knee is used more selectively than in larger proximal vessels
Device availability and regulatory status vary by country. Please contact INVAMED or your authorized local distributor for current regulatory information applicable to your region.
What Role Does Vessel Preparation Play?
Because below-the-knee lesions are frequently calcified, vessel preparation — using atherectomy or specialty balloon techniques prior to definitive treatment — is an important consideration in procedural planning. Adequate lesion modification can influence how well a balloon or subsequent device performs within the calcified segment, though the specific approach is determined case-by-case by the treating physician based on lesion characteristics and available imaging.
What Are the Goals of Below-the-Knee Revascularization?
The overarching goal of BTK intervention is typically to restore adequate in-line or angiosome-directed blood flow to support wound healing and limb preservation in patients with CLI, or to relieve ischemic rest pain. Outcomes depend on numerous individual factors, including the extent of disease, wound severity, and patient comorbidities, and are determined by the treating clinical team on a case-by-case basis.
Frequently Asked Questions
Why are below-the-knee arteries treated differently than femoropopliteal disease?
Tibial and peroneal arteries are smaller, more prone to diffuse calcification, and more frequently involve multiple vessels simultaneously. These anatomical differences generally call for smaller, more flexible devices and a different procedural strategy compared to the femoropopliteal segment.
Is stenting common below the knee?
Stent placement below the knee is generally used more selectively than in larger, more proximal arteries, often reserved for specific situations such as suboptimal angioplasty results. Balloon angioplasty and atherectomy are more frequently used as primary strategies, though the appropriate approach depends on individual lesion characteristics.
Who typically needs below-the-knee intervention?
Patients being evaluated for BTK intervention often present with critical limb ischemia, non-healing foot wounds, or rest pain. Candidacy is determined by a vascular specialist after a comprehensive evaluation of symptoms, imaging, and overall health.
Related INVAMED Resources
- Peripheral Arterial Disease (PAD) Products
- Critical Limb Ischemia: Symptoms, Causes & Care Overview
- Contact INVAMED for More Information
Medical Disclaimer: This article is provided for general informational and educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendation. It is not a substitute for consultation with a qualified healthcare professional. Product indications, availability, and regulatory status vary by country. Always refer to the official Instructions for Use (IFU) and consult a licensed physician for guidance specific to your situation. INVAMED devices are intended for use by trained healthcare professionals.