Commentary on “‘Real Angiosome’ Assessment from Peripheral Tissue Perfusion Using Tissue Oxygen Saturation (StO2) Foot-mapping in Patients with Critical Limb Ischemia”

Abstract

When choosing the target vessel for revascularization of an ischaemic foot, common clinical practice and recent guidelines, for example TASC-II, favour grafting of the “best vessel” that crosses the ankle. Although this strategy will most often offer the best run off for the graft or the endovascular reconstruction, it may not offer the best perfusion of the ischaemic area or the best chance of wound healing or limb salvage. As an example, 15% of heel ulcers do not heal even in the presence of a patent bypass graft to the dorsal pedal artery. In common with the rest of the body, the foot can be divided into a number of three-dimensional blocks of tissue, each with its own feeding artery and venous drainage, the so-called “angiosomes”. Plastic surgeons have identified small calibre vessels (“choke vessels”) between the angiosomes. Ligation of a feeding artery to an angiosome induces hyperplasia and dilatation of “choke vessels” from the neighbouring angiosomes to form functional collaterals. In this way, larger reconstruction flaps can be harvested in a later operation. In the ischemic foot, however, “choke vessels” are not recruited in a reproducible manner and the collaterals formed between the angiosomes are not always reliable. A number of recent retrospective comparisons have documented faster wound healing and better limb preservation after direct revascularization of the relevant angiosome than is the case after indirect revascularization of another angiosome. Particularly in patients with microangiopathy due to diabetes or nephropathy, connections between neighbouring angiosomes of the foot are sparse. Even in the absence of randomized trials, it seems fair to argue that current evidence leans towards the position that, when possible, the angiosome-specific artery should be chosen for revascularization rather than just the “best vessel”. This would also bring the practice of peripheral vascular surgery into line with that of other surgical specialities, for example coronary bypass surgery and plastic surgery.