Patients with infrainguinal occlusive disease present with symptoms of claudication (Rutherford ischemia classification categories 1, 2, and 3), ischemic rest pain, or tissue loss (Rutherford categories 4, 5, and 6). When the atherosclerotic disease is limited to the infrapopliteal arterial segments, pain is mainly located in the forefoot. Advanced arterial insufficiency can also lead to ischemic ulceration, gangrenous changes, and nonhealing wounds. This constellation of symptoms represents CLI and typically occurs when the ankle pressure is less than 50 mmHg, the ankle-brachial index (ABI) is less than 0.4, and the great toe pressure is less than 30 mmHg (FIG 1A,B).

CLI with tissue loss often occurs in the setting of multilevel arterial occlusive disease. In the case of isolated diabetic tibial occlusive disease, femoral, and frequently popliteal, pulses remain palpable. In either circumstance, limb-threatening ischemia may ensue. In the latter circumstance, multilevel approaches to complete revascularization, either staged or simultaneous, should be pursued.

Neurovascular exam, with particular focus on the wound location and the extent of tissue loss, should be evaluated and documented. Probably, the most deterministic variable is the extent of tissue loss—Wagner wound classification, the presence and severity of osteomyelitis, exposure or involvement of the calcaneus bone, residual intact skin on either the dorsal or plantar foot. These conditions all impact decision making and clinical outcome.

Patient functional capacity also plays an important role in the therapeutic strategy. Options and outcome goals vary substantially between ambulatory and nonambulatory patients.

Pulse volume recordings (PVRs) (FIG 2)

Duplex (FIG 3)

Computed tomography (CT) and magnetic resonance (MR) angiograms can be obtained; however, their diagnostic use in planning tibial interventions is frequently limited by the imprecision of bolus timing with distal extremity crosssectional imaging techniques, heavy medial calcification frequently present in target arteries, and the diminutive size of reconstituted target arteries, which may be present in the peri- and inframalleolar regions.

Catheter-directed, intraarterial angiography remains the gold standard imaging study for tibial occlusive disease for both diagnostic and therapeutic purposes (FIG 4).

Technical skills, careful planning, and knowledge of the relevant arterial anatomy determine tibial revascularization strategies for limb salvage. Current controversies include the potential value of restoring patency in more than one tibial vessel to optimize blood flow and maximize the chances of
wound healing. Proponents of this approach reference the “angiosome” concept of the foot or the idea that specific skin regions derive primary perfusion from end-arterioles arising primarily from either the dorsal pedal or posterior tibial arteries as they cross the ankle. This practice is pursued in marked contradistinction to the open surgical imperative to restore in-line flow to the foot in the single largest, most continuous crural artery. The many advantages of endovascular reconstruction techniques in tibial reconstruction include restoring partial flow in multiple target arteries as compared to a single artery following surgical bypass, as well as opportunities to repeat procedures with relatively simple outpatient interventions as needed, to maintain patency and skin integrity. Treatment decisions regarding revascularization strategy in individual circumstances should be guided by patient-specific anatomic considerations, arterial runoff into the foot, patient habitus and ambulatory status as well as patency and feasibility considerations related to either open or endovascular options.

Currently available endovascular technology facilitates successful treatment of complex occlusive lesions at and below the malleolar level. Technical limitations remain, however, highlighted by risks of arterial perforation (FIG 5), difficulty in true lumen reentry in complete occlusions (FIG 6), procedure-related distal arterial embolization, and limited pedal vessel outflow in certain circumstance.

The retrograde or SAFARI (SubintimAl Flossing with Antegrade-Retrograde Intervention) tibial intervention technique may improve technical results in challenging lesions, particularly those resistant to ipsilateral antegrade access, including flush occlusions at the origin of the target artery or with large collateral arteries adjacent to the occluded origin. In nearly every circumstance, even chronic and recalcitrant occlusions may be crossed more easily from the retrograde rather than antegrade approach; this is true regardless of the chronicity of the lesion in question, degree of calcification, or length of occlusion.