Study Protocol of a Prospective Multicenter Observational Study Evaluating Acute Lower Limb Ischemia

Introduction: Acute lower limb ischemia (ALI) is a limb- and potentially life-threatening condition which requires urgent evaluation and treatment. Contemporary data on optimal therapy and prognosis of ALI are lacking, while surgical, hybrid, and foremost endovascular techniques have rapidly evolved over the past decades. Available clinical guidelines are not based on high-level evidence and do not fully reflect day-do-day practice. Contemporary data on etiology, procedural strategies as well as patient outcomes in ALI are urgently needed to improve care and prevent limb loss. The current study was initiated by the European Vascular Research Collaborative (EVRC), established by young European vascular specialists, and aims to provide insight into contemporary treatment strategies in ALI and its clinical results within Europe. In this manuscript we report the rationale and a detailed study protocol. Material and Methods: The proposed study is a prospective, international, multicenter, observational study on ALI (PROMOTE-ALI) (ClinicalTrials.gov - NCT05138679). Patients with ALI (Rutherford classification grade I -III) of one or both lower extremities will be included in the study. The primary endpoint of the study is amputation-free survival (AFS) at 30 d. Secondary endpoints are freedom from target limb reintervention, freedom from complications, clinical outcome of the index leg, and limb salvage and survival at 30 and 90 d after diagnosis of ALI. Conclusions: ALI remains a challenging condition and due to the heterogeneous etiology, clinical presentation and treatment strategies, a large multicenter study on this topic is needed to gain contemporary data on clinical outcomes and prognosis, especially for modern endovascular techniques. PROMOTE-ALI is expected to provide these data and set a benchmark for future randomized controlled trials (RCTs)