The aim of the study is to assess the frequency of Peripheral Arterial Disease (PAD) and cardiovascular risk factors in patients with unprovoked Deep Vein Thrombosis (DVT) of the lower limbs, comparing them with patients who have provoked DVT or cancer-related DVT. Additionally, the study aims to examine the association between the Ankle-Brachial Index (ABI) and Carotid Intima-Media Thickness (IMT) in the different patient groups. This is an observational, spontaneous, monocentric, non-pharmacological study conducted on outpatient, non-hospitalized patients diagnosed with lower limb DVT, including both unprovoked and provoked DVT, as well as cancer-related DVT. The patients are followed at the Vascular Day Service of the SSD U.O. Angiology and Coagulation Disorders Unit at the Sant'Orsola Malpighi Polyclinic in Bologna. The study has a retrospective design for patients with DVT diagnosed between October 1, 2020, and the date of project approval, and a prospective design for patients diagnosed with DVT after this date. The study is expected to conclude by December 31, 2027.