Extravascular incidental findings in computed tomography angiography are associated with lower amputation-free survival in patients with acute lower limb ischaemia.

Abstract

Emergency computed tomography angiography (CTA) is the most important imaging modality to visualize arterial occlusions in patients with acute lower limb ischaemia (ALI). Extravascular incidental findings (EVIFs) have received less attention. The aims of this study were to evaluate the incidence of EVIFs of immediate clinical relevance in patients with ALI undergoing CTA and evaluate the association between EVIFs and emergency revascularization and amputation-free survival at 1 year. Retrospective cohort study. Emergency CTA in patients with ALI between 2015 and 2018 were independently scrutinized by two senior radiologists. EVIFs were classified into immediate (category I), potential (category II) or no clinical relevance (category III). Multi-variable binary logistic regression analysis was expressed in Odds ratios (OR) with 95% confidence intervals (CI). The intra-class correlation (ICC) coefficient for EVIF category I between the raters was 0.94 (95% CI 0.92-0.96). Among 118 patients with ALI, 78 patients underwent emergency revascularization. Forty-six EVIFs (34 patients) were category I, of which 63% were found in the chest, including pleural effusion (n = 12), pneumonia (n = 8) and cardiac thrombus (n = 4). Ascites (n = 4) and cancer disease (n = 4) were other category I findings. Category I EVIFs were associated with reduced rate of emergency revascularization (OR 0.26, 95% CI 0.10-0.66) and increased rate of combined major amputation/mortality at 1year (OR 2.9, 95% CI 1.1-8.2) in adjusted analysis. It is important to evaluate EVIFs in emergency CTA in patients with ALI since these findings are both common and associated with reduced emergency revascularization and amputation-free survival at 1year.