Endovascular Treatment of TASC C- D Aorto-Iliac Occlusions: Analysis of Pre-Operative CT-Scan Can Predict Technical Failure

Abstract

Introduction - While the outcomes of recanalization of TASC C-D aorto-iliac chronic total occlusions (CTO) are satisfying in high-volume centers, the risk of technical failure and the fear of iliac rupture especially in heavily calcified lesions limit the widespread use of this technique. To our knowledge, risks factor of technical failure or iliac rupture were poorly studied in the literature. We hypothesized that features of occlusion analyzable on pre-operative CT-scan could predict risks of technical failure or iliac rupture of endovascular treatment of TASC C-D aorto-iliac CTO. Methods - This is a retrospective study of a prospective cohort. All patients treated in our department by endovascular techniques for aTASC C-D aorto-iliac CTO between December 2009 and June 2016 were analyzed. Patients with no pre-operative CT-scan were excluded. We included 107 patients and 148 iliac arteries. All CT-scan were analyzed by 2 independent surgeons. Each side was analyzed independently. We evaluated the location of the occlusion and the degree of arterial calcifications. For this factor, patients were divided into 3 groups : the Black occlusion group (BO) defined by the presence of mild non protrusive calcifications or the complete absence of calcifications in all the aorta and iliac artery, the white occlusion group (WO) defined by moderate calcifications of more of 50 % of the arterial circumference but little or no protrusive in all the occlusion and the white protrusive occlusion group (WPO) defined by the presence of heavy endoluminal calcifications of more of 50 % of the arterial lumen in the occluded arterial segment. All patients had antegrade approach in case of failure of transfemoral approach. Primary endpoint was technical failure rate and secondary was iliac rupture rate. Wilcoxon, fisher exact test, univariate and multivariate regression model were performed. Results - CTO are located on the external iliac artery (EIA) in 37 cases, on the common iliac artery (CIA) in 41 cases, on both in 42 cases and on the aortic bifurcation in 14 cases. There were 66 iliac artery in the BO group, 45 in the WO group and 37 in the WPO group. Technical failure occurred in 8 patients that’s 11 iliac arteries. Per-operative iliac rupture occurred in 6 patients. In univariate analysis, only the location in the EIA is a significate risk factor of technical failure (OR = 9,93 and p = 0,0012). In multivariate analysis, this parameter is also an independant significate risk factor (OR = 15,26 and p = 0,0006). The presence of heavy calcifications is a further significate risk factor (OR = 13,88 and p = 0,0365). Rupture rate was comparable between the 3 groups (p = 0,881). Iliac rupture occur more for long lesions when both EIA and CIA were occluded but this is no significate (p = 0,282). Conclusion - The location of the CTO in the EIA is the major risk factor of technical failure of endovascular treatment for TASC C-D aorto-iliac CTO. The presence of heavy endoluminal calcifications is also a risk factor of technical failure. However, this parameter is not a risk factor of iliac rupture. The detailed analysis of pre-operative CT-scan can permit a better selection of patients for endovascular treatment of aorto-iliac CTO especially in low-volume centers. Referencesendovascular treatment, chronic total occlusion, aorto-iliac, technical failure, iliac rupture, predictors