Prediction of Technical Failure of Inframalleolar Angioplasty in Patients with Chronic Limb Threatening Ischaemia

Abstract

This study sought to: determine anatomically evaluated predictors of the technical failure of inframalleolar angioplasty (IMA), develop a predictive model for unsuccessful IMA, and investigate the effect of IMA on clinical outcomes in patients with chronic limb threatening ischaemia (CLTI). This single centre retrospective observational study enrolled 159 patients with CLTI who underwent IMA for de novo occluded lesions between November 2017 and May 2021. These patients were divided into two groups: the Failed IMA group (n= 62) and the Successful IMA group (n= 97). In multivariable analysis, no target vessel outflow (OR 39.8, 95% CI 10.7 - 148, p < .001), medial artery calcification (MAC) grade (OR 4.91, 95% CI 1.40 - 17.3, p= .010), and occluded pedal arch (OR 5.2, 95% CI 1.2 - 22.7, p= .030) were identified as independent predictors of IMA technical failure. The risk prediction model had an area under the receiver operating characteristic curve (AUC) of 0.93; after bootstrapping adjustment for optimism, this value represented a corrected AUC of 0.95. The patients in the Successful IMA group had a significantly higher proportion of wound healing at 12 months than those in the Failed IMA group (log rank p= .030). IMA technical failure was associated with a significant change in the proportion of wound healing (HR 0.59, 95% CI 0.37- 0.94, p= .030). No target vessel outflow, MAC grade, and occluded pedal arch were independent predictors of IMA technical failure. Additionally, successful IMA was associated with better wound healing outcomes at 12 months. Furthermore, a model incorporating these three predictors precisely predicted IMA technical failure.