Tibial, Pedal, and Inframalleolar Disease

38.1Definition and presentation

Tibial, pedal, and inframalleolar arterial disease becomes clinically urgent when it presents as chronic limb-threatening ischemia (CLTI). CLTI is defined by the presence of objectively documented peripheral artery disease accompanied by tissue threat ACC/AHA 2024 · GVG 2019. The clinical endpoints of treatment are wound healing, relief of ischemic rest pain, preservation of function, and avoidance of major amputation Infrapopliteal Review 2025.

Clinical presentation includes:

• Ischemic rest pain.
• Gangrene (toe, forefoot, or heel).
• A lower-limb ulcer persisting for more than 2 weeks.

38.2Pathophysiology and risk factors

Disease in this segment is strongly associated with diabetes mellitus, end-stage renal disease, and medial arterial calcification. The anatomic pattern is characterized by long tibial occlusions, diffuse calcified stenoses, total occlusions, multisegment disease, and lesions extending below the ankle into the pedal arch ACC/AHA 2024 · Infrapopliteal Review 2025. A technically successful tibial revascularization fails clinically if nonarterial contributors are not controlled; successful tissue preservation requires integrating arterial flow restoration with structured multidisciplinary foot care, including offloading, infection control, and ongoing wound management IWGDF 2024 · IWGDF/ESVS 2023.

38.3Diagnosis and staging

The ankle-brachial index is frequently falsely elevated or incompressible in tibial and pedal CLTI due to calcification. Hemodynamic assessment relies on toe pressures and transcutaneous oxygen pressure (TcPO2) to provide objective perfusion data and guide revascularization necessity GVG 2019. Ischemic rest pain is corroborated by an ankle-brachial index below 0.40, an ankle pressure below 50 mmHg, a toe pressure below 30 mmHg, or a TcPO2 below 30 mmHg (equivalent to WIfI ischemia grade 3); toe pressure is the preferred measure here because tibial and pedal calcification makes the ankle index unreliable, and these numbers are read in clinical context rather than as rigid pass-or-fail lines.

Limb and anatomic staging frameworks stratify risk and replace perfusion-only evaluation. The WIfI classification grades Wound extent, Ischemia, and foot Infection on 0 to 3 scales to estimate 1-year amputation risk and the likelihood of benefit from revascularization GVG 2019 · SVS WIfI 2014. Anatomic complexity is graded by the Global Limb Anatomic Staging System (GLASS), which incorporates an inframalleolar modifier to quantify below-the-ankle anatomic risk and predict outcomes GLASS Inframalleolar · 2023.

38.4Treatment decision and revascularization thresholds

Revascularization is standard care for nonhealing wounds or gangrene in patients fit enough to benefit, aiming to establish in-line flow and maximize wound-bed perfusion ACC/AHA 2024. An unsalvageable limb (WIfI stage 4, a non-ambulatory patient, or prohibitive procedural risk) is the exception: primary amputation or palliation with medical therapy, not revascularization, is appropriate when in-line flow cannot deliver a functional, healable limb GVG 2019 · SVS WIfI 2014. Modality selection turns on anatomy, conduit availability, procedural risk, and local expertise.

The management logic proceeds stepwise:

1. Define the clinical limb threat (WIfI stage) and document objective tissue perfusion (toe pressures or TcPO2).
2. Initiate comprehensive structured foot care, including mandatory offloading and infection control.
3. Grade the anatomic complexity using the GLASS framework, including the inframalleolar segment.
4. Assess great saphenous vein quality and target-vessel outflow serving the wound territory.
5. Select surgical bypass if single-segment great saphenous vein is adequate; select an endovascular-first approach if vein is inadequate or disease is isolated to the infrapopliteal segment without proximal inflow disease requiring bypass.

38.5Endovascular and surgical modalities

The relative advantage of surgical bypass versus endovascular therapy depends directly on conduit and lesion extent. In BEST-CLI, patients with CLTI and infrainguinal disease who had an adequate single-segment great saphenous vein experienced fewer major adverse limb events or death after surgical bypass (42.6%) compared with endovascular therapy (57.4%) over a median of 2.7 years (HR 0.68) BEST-CLI · 2022. This advantage was not seen in the cohort lacking adequate vein. In BASIL-2, which strictly required infrapopliteal target revascularization, an endovascular-first strategy lowered the composite risk of major amputation or death relative to a vein-bypass-first strategy (adjusted HR 1.35), establishing endovascular-first as the favored entry approach for this specific anatomy BASIL-2 (2023).

Device selection for infrapopliteal endovascular intervention is distinct from femoropopliteal algorithms. Paclitaxel-coated balloon angioplasty for infrapopliteal CLTI demonstrated no durable 5-year patency benefit in the IN.PACT DEEP trial and showed an early major-amputation signal that resolved by study completion IN.PACT DEEP (2020). Conversely, LIFE-BTK demonstrated a 1-year primary efficacy advantage for an everolimus-eluting resorbable scaffold over standard angioplasty (74% versus 44% event-free) with non-inferior safety profiles, supporting its use in selected single-device anatomic patterns LIFE-BTK · 2024.

Below-the-ankle angioplasty and ultra-distal bypass are used for limb salvage when isolated inframalleolar anatomy dictates the approach. While supported predominantly by synthesis and cohort data, ultra-distal bypass for tissue loss reports a 12-month freedom from graft failure of 68% and freedom from major amputation of 92% Huizing 2019 · Ultra-distal Bypass 2026 · Inframalleolar Bypass 2021.

38.6Post-revascularization surveillance

Follow-up criteria depend on clinical progress at the foot. Surveillance evaluates the resolution of rest pain, demarcation of gangrene, and progressive ulcer healing within the boundaries of structured diabetic foot management ACC/AHA 2024 · IWGDF 2024. Best medical therapy runs in parallel: every CLTI patient needs antiplatelet therapy, and after lower-extremity revascularization low-dose rivaroxaban 2.5 mg twice daily plus aspirin reduces major adverse limb events (VOYAGER PAD), alongside a high-intensity statin, smoking cessation, and glycemic and blood-pressure control. Wound stagnation prompts immediate re-evaluation of target-vessel patency, adequacy of collateral pedal arch support, infection control, and mechanical offloading Angiosome Review 2025.

38.7Areas of controversy

The necessity of strict direct revascularization to the corresponding anatomic angiosome remains debated. Angiosome-directed flow is preferred when feasible, but successful healing is frequently achieved via indirect pathways when collateral networks or the pedal arch are intact Angiosome Review 2025.

Techniques such as retrograde pedal or distal access are widely used for below-the-knee intervention, but high-quality randomized evidence directly comparing distal and formal antegrade approaches is currently lacking Cochrane Distal Access 2024. The generalizability of drug-eluting resorbable scaffolds to complex, multi-vessel infrapopliteal disease and their durability beyond 1 year remain areas of active investigation Infrapopliteal DES Meta-analysis 2022 · LIFE-BTK · 2024 · Infrapopliteal Scaffolds 2024.

The headline infrapopliteal question is conduit versus anatomy, and the two landmark trials point in different directions. BEST-CLI favored surgical bypass when an adequate single-segment great saphenous vein was available, whereas BASIL-2, which required an infrapopliteal target, favored an endovascular-first strategy. Reconciling them turns on how much weight to give vein quality against the specific below-the-knee anatomy of the individual limb BASIL-2 (2023) · BEST-CLI · 2022.