Background: Critical limb ischemia (CLI) presented as a foot ulcer with or without gangrene requires the quick re-establishment of arterial blood supply. The recently introduced angiosome concept has offered a new perspective on the treatment of CLI. The idea of angiosome-targeted (direct) revascularization⎯the restoration of blood flow directly to the angiosome affected by an ischemic wound appeared among vascular surgeons.
The concept has rised interest among vascular specialists as several studies supported the hypothesis of a better clinical outcome after direct revascularization. Despite the promising results, the feasibility of the concept in endovascular treatment has not been addressed, nor has a comparison of revascularization methods, endovascular versus open surgical, been investigated. Furthermore, the methodology is not consistent, and the definition of direct revascularization is unclear, especially if the wound spreads over several angiosomes. Therefore, clinical value of the hypothesis is yet to determined.
Aim of the study: The aim of this study was to investigate the importance of the angiosome concept in the treatment of CLI with tissue loss (Rutherford 5,6). The main goals were to evaluate the feasibility of the concept in endovascular procedures; to compare the clinical outcomes of direct and indirect revascularization; and to obtain a consensus concerning the angiosome-targeted approach.
Patients and methods: The study comprises patients referred for infrapopliteal revascularization, endovascular or open surgical, between 2008 and 2013. We analyzed patient s records retrospectively, focusing on wound location, the feasibility of infrapopliteal direct revascularization, and differences in clinical outcome, with the main interest in wound healing and leg salvage. We also compared the clinical outcome of two existing definitions of angiosome-targeted revascularizations as they differ in revascularization approach of leasions located in forefoot and the heel. Definition A accepts into the direct group if any of the affected angiosomes is revascularized, while Definition B accepts only revascularization of posterior tibal artery.
Main Results: For the feasibility of the angiosome concept in endovascular infrapopliteal revascularization, the wound was isolated to a single angiosome in only 24% of the cases, and 33% of the patients had only one infrapopliteal artery suitable for revascularization. The success rate of direct revascularization, however, was 75.9%.
When comparing direct and indirect revascularization, the propensity score analysis yielded significantly better leg salvage (p=0.019) and a trend towards improved wound healing (p=0.058) for the direct approach, and when adjusted for revascularization method, direct bypass was associated with a significantly higher wound-healing rate than endovascular revascularization (HR 1.295, 95%CI 1.005 1.668).
Among diabetic patients, the findings showed that direct bypass yielded significantly better wound healing than indirect PTA (p=0.001, HR 2.83, 95%CI 1.35 3.04), and, furthermore, indirect PTA was associated with the poorest leg salvage rate. The analysis of the two different angiosome-targeted approaches revealed a significantly better feasibility of the conventional method (definition A) compared to definition B (p less than 0.05). Furthermore, the prognostic ability for better clinical outcome using definition A was confirmed by both the Cox proportional hazard analysis (p= 0.044 for wound healing, p= 0.047 for leg salvage) and the propensity score analysis (p= 0.037 for wound healing, p= 0.044 for leg salvage).
Conclusion: The tissue lesion affects several angiosomes in the majority of the cases, and a consensus on the accurate definition of angiosome-targeted revascularization needs to be achieved to standardize the methodology of arterial selection. Despite the inconsistent methodology in the literature, our findings seem to suggest that observing the angiosome concept in the decision-making yields better clinical outcomes, especially in endovascular therapy. In bypass surgery, however, the concept seems to be of less value, and the artery with the best runoff should be selected as the outflow artery.non
