Angiosome-directed revascularization in patients with critical limb ischemia

Abstract

Objective: Direct revascularization (DR), according to the angiosome concept, provides direct blood flow to the site of tissue loss in patients with critical limb ischemia (CLI). DR may lead to improved outcomes; however, evidence for this is controversial. This systematic review and meta-analysis investigated the outcomes of surgical and endovascular DR compared with indirect revascularization (IR) in patients with CLI.

Methods: A systematic review was undertaken using the Cochrane Collaboration specified tool, and a meta-analysis was done according to the MOOSE (Meta-analysis of Observational Studies in Epidemiology) criteria. The electronic databases of MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were systematically searched for studies of DR compared with IR in patients with CLI with tissue loss. All articles were critically assessed for relevance, validity, and availability of data regarding patient and lesion characteristics and outcomes. When possible, data were systematically pooled, and a meta-analysis was performed for wound healing, major amputation, amputation-free survival, and overall survival.

Results: Of 306 screened abstracts, 19 cohort studies with 3932 patients were included. Nine scored 7 or higher on the Newcastle-Ottawa score. DR significantly improved wound healing (risk ratio [RR], 0.60; 95% confidence interval [CI], 0.51-0.71), major amputation (RR, 0.56; 95% CI, 0.47-0.67), and amputation-free survival rates (RR, 0.83; 95% CI, 0.69-1.00) compared with IR. This significance was lost in major amputation on sensitivity analysis for bypass studies. No significant difference was found in overall survival. In studies stratifying for collaterals, no differences between DR and IR were found in wound healing or major amputations in the presence of collaterals.

Conclusions: DR significantly improves wound healing and major amputation rates after endovascular treatment in patients with CLI, supporting the angiosome theory. In the presence of collaterals, outcomes after IR are similar to outcomes after DR. Alternatively, patients without collaterals may benefit even more from DR as a primary treatment strategy. The angiosome theory is less applicable in bypass surgery, because bypasses are generally anastomosed to the least affected artery, with runoff passing the ankle to maintain bypass patency.