Introduction: Anaemia due to iron and vitamin deficiency among patients with critical limb ischemia is high (\>50%). The prevalence of a higher rate of anaemia extends into the three months prior to revascularization surgery, it is associated with longer hospital stays and more transfusions in addition to being a factor in poor prognoses. Study and treatment of anaemia within the perioperative period could improve the surgical outcomes, including the recovery and the quality of patients' lives. There are several types of intravenous iron preparations with different administration protocols, but there is not a consensus on the timing and type of the appropriate iron therapy. To the best of our knowledge, there is no data on the performance of intravenous iron in the management of preoperative anaemia in patients with peripheral artery disease (PAD) in vascular surgery. Methods and analysis: The IRONPAD Study is a phase IV randomised controlled trial with two branches of treatment on the efficacy of intravenous iron therapy for the optimisation of blood use and prognosis in the perioperative period of patients with anaemia undergoing revascularisation for chronic lower limb ischemia. The study randomises 240 patients with anaemia to: treat with a single intravenous dose of ferric carboxymaltose (1000 mg) or no treatment vs oral iron supplements (if severe anaemia) a minimum of two days prior to lower limb revascularisation surgery. The primary outcome is to reduce the incidence of transfusion from randomisation up to 30+7 days after the main surgery. The secondary outcomes will be included to establish the optimal preoperative moment of increased intravenous iron administration, to raise haemoglobin levels; to study the evolution of haemoglobin from inclusion to 30+7 days after surgery; and to determine the impact of anaemia and its treatment on the length of hospital stay, morbidity and mortality, as well as the quality of life in this period.