In the last 2 decades, several studies in the literature evaluated the possible role of covered stents in the treatment of TransAtlantic Inter-Society Consensus (TASC) C and D femoropopliteal lesions but, despite the encouraging results, the employment of these devices was never included in clinical guidelines. The aim of this study is to evaluate the role of the technical aspects in patients with TASC C or D lesions that were treated with the GORE VIABAHN endoprosthesis and to elaborate a computerized method to objectively estimate the post-stent run-off and predict stent-graft failure. In this monocentric retrospective study, we collected the patients who were treated in our department from December 2014 to May 2021. Inclusion criteria comprised: (1) patients who underwent endovascular treatment of a TASC C or D femoropopliteal lesions using one or more heparin-bonded covered stent(s) and (2) clinical follow-up >2 years. Exclusion criteria were clinical follow-up <2 years or missing. An in-house computerized analysis to estimate the post-stent run-off, CEVERO (Computerized Estimation of VEssel Run-Off), was elaborated. Sixty-six patients were enrolled in the study. Eleven patients had a TASC type C lesion, and 55 patients presented a type D lesion. The median follow-up time was 2.6 years. Twenty-nine patients (43.9%) experienced a major adverse limb event. Primary patency after 6, 12 and 24 months was 74.2%, 60.6%, and 57.6%; primary-assisted patency was 78.8%, 65.2%, and 59.1%. The presence of <2 run-off vessels (p<0.001) was correlated with stent-graft failure. The CEVERO analysis demonstrated an accuracy of 90.0% in predicting stent-graft failure. The treatment of TASC C and D femoropopliteal lesions remains technically challenging. Our study supported the hypothesis that run-off is the most critical factor in determining the outcome of the procedure and that concomitant angioplasty of the tibial vessels might improve the patency of the covered stent. The CEVERO analysis could permit a real-time, objective estimation of the distal run-off using conventional angiographic images, and it might be employed as a tool in the intraprocedural decision-making process, but its clinical applicability should be evaluated on external validation cohorts. The endovascular treatment of TASC C and D femoropopliteal lesions is technically challenging and run-off seems to be the most critical factor in determining the outcome. Concurrent angioplasty of the tibial vessels can create adequate run-off to avoid stent failure. The CEVERO analysis is a computerized estimation of run-off that might be a useful tool in the decision-making process.