Non-compressible ABIs are associated with an increased risk of major amputation and major adverse cardiovascular events in patients with critical limb ischemia

Ankle-brachial indices (ABIs) are important for the assessment of disease burden among patients with peripheral artery disease. Although low values have been associated with adverse clinical outcomes, the association between non-compressible ABI (ncABI) and clinical outcome has not been evaluated among patients with critical limb ischemia (CLI). The present study sought to compare the clinical characteristics, angiographic findings and clinical outcomes of those with compressible (cABI) and ncABI among patients with CLI. Consecutive patients undergoing endovascular evaluation for CLI between 2006 and 2013 were included in a single center cohort. Major adverse cardiovascular events (MACE) were then compared between the two groups. Among 284 patients with CLI, 68 (24%) had ncABIs. These patients were more likely to have coronary artery disease (p=0.003), diabetes (p<0.001), end-stage renal disease (p<0.001) and tissue loss (p=0.01) when compared to patients with cABI. Rates of infrapopliteal disease were similar between the two groups (p=0.10), though patients with ncABI had lower rates of iliac (p=0.004) or femoropopliteal stenosis (p=0.003). Infrapopliteal vessels had smaller diameters (p=0.01) with longer lesions (p=0.05) among patients with ncABIs. After 3 years of follow-up, ncABIs were associated with increased rates of mortality (HR 1.75, 95% CI: 1.12-2.78), MACE (HR 2.04, 95% CI: 1.35-3.03) and major amputation (HR 1.96, 95% CI: 1.11-3.45) when compared to patients with cABIs. In conclusion, ncABIs are associated with higher rates of mortality and adverse events among those undergoing endovascular therapy for CLI.