The Foot Angiosomal Source-arteries as Integrated Level of Fractal Vascular Distribution in the Inferior Limb

Introduction: The angiosome concept was pioneered by Taylor and Palmer and defines specific vascular territories in the human body owing topographic distribution. This model appears to integrate a harmonious and much larger arterial irrigation system based on fractal branches distribution. Specific arterial pathologies enhance characteristic branches affectation at precise levels of segmentation, including the angiosomal source arteries and their appended collaterals.

Methods: The present study proposes a succinct description of six Levels of arterial division in the inferior limb, including the angiosomal rank. Based on succeeding perioperative angiographic observation, these Levels (I - VI) were analyzed (including the angiosomal Level III) and further stratified in attached tables. The angiographic features of 341 chronic limb threatening ischemic (CLTI) foot wounds (Rutherford 5-6) were retrospectively reviewed. For each anatomical Level the more complex atherosclerotic lesions were selected, then compared with adjacent levels in same CLTI anatomical patterns. For each ramification, the heaviest angiographic occlusive lesions (GLASS grades “3-4”) were defined as “dominant”, in comparison with parallel “associate” atherosclerotic changes. A comparison between 206 diabetic, against 135 non-diabetic CLTI vascular patterns was further performed at each of the six Levels of arterial branching.

Results: Significant differences in dominant distribution of the occlusive disease were observed between the two groups. Specific “Level I” iliac and common femoral lesions (10%), adding “Level II” superficial femoral (16%) and femoro-popliteal (33%) dominant occlusions in non-diabetics prevailed against parallel iliac (2%), superficial femoral (5%), and femoro-popliteal (14%) occlusive lesions in diabetic CLTI subjects. Conversely, “Level II” popliteal and tibial occlusions (33%), adding “Level III” pedal-angiosomal, (34%), and foot arches occlusions (12%) in diabetic patients, overruled correspondent popliteo-tibial (28%), pedal-angiosomal (9%), and specific foot arches (4%) occlusions in non-diabetics. These tendencies were confirmed by meaningful differences for the iliac (p=0.004), the femoro-popliteal (p=0.012), the angiosomal branches (p<0.0001), the foot arches and large collaterals (p=0.017) atherosclerotic affectation between groups.

Conclusion: The whole vascular tree of the body holds a harmonic and balanced degressive distribution. Several Levels (I-VI) of inferior limb arterial ramifications can be individualized as part of a wider vascular network owing fractal and topographic distribution to the tissues. These Levels bear specific atherosclerotic arterial changes that differentiate diabetic versus non-diabetic CLTI patients.