Objectives: This study aimed to evaluate the importance and relevance of the AB index before and after endovascular intervention in patients with a high degree of peripheral vascular disease. Subjects and methods: A single-centre retrospective study was performed. Patients (N=18) who had their ABI measured before and after the intervention in time period from February 17th to July 8th 2022 were included in this study. Measuring device used for this study was MESI ABPI MD. The case files of those subjects were studied thoroughly for researched paramteres such as age, sex, comorbidities, clinical, radiological and angiographic reports. Results: The fact that the majority of patients (83%) with a high degree peripheral vascular disease had more severe forms of calcification of the walls of the arteries of the pelvis and legs stood out the most in the research. In all patients (N=18), we found that if there were severe calcifications of the artery walls, they were found in both legs. In patients who did not have calcifications, symmetry on the other leg was also confirmed. Thus, we confirmed our first hypothesis that patients with a high degree peripheral vascular disease have significant calcifications in the arteries of the pelvis and legs. CTA did not help us distinguish between two types of calcifications: atherosclerotic plaque and Mönckeberg arteriosclerosis due to the insufficiently high resolution of the device for such an analysis, therefore the division was not carried out in the results. Our hypothesis about the unreliability of the AB index was confirmed in 15 patients (83%) with pronounced arterial calcifications who underwent morphologically successful endovascular intervention. Namely, the ABI both before and after the intervention varied from completely normal values to below 0.5 in patients with the same Rutherford degree of clinical disturbances. Conclusion: AB index measurement is a simple, non-invasive test and screening method in the diagnosis of peripheral vascular disease. According to our research, the AB index in patients with severe forms of peripheral vascular disease can be a valuable contribution in monitoring the success of endovascular intervention, but only in patients without significantly calcified arterial walls. In patients with Fanelli grade 3 and 4 calcifications, ABI is unreliable and not recommended. Before each interventional procedure, a CTA is performed, on which, by simply measuring the severity of calcifying lesions according to Fanelli, it can be determined in advance whether the patient should have an AB index measured.