The primary objective of this study is to evaluate the effect of different treatment modalities on clinical outcome of patients suffering from acute lower limb ischemia (ALI). Depending on clinical presentation, anatomical as well as technical considerations, different treatment options are available for revascularisation of affected limbs. Using an observational, international, multicentric study design (min. patient number of 500), the defined primary endpoint of the study, amputation-free survival 90 days after the diagnosis of ALI, will be evaluated.

Recently published clinical guidelines highlighted that the available evidence on the management of acute lower limb ischemia (ALI) is mostly outdated and includes only small patient cohorts. Depending on the patient's characteristics, the duration of ischemic symptoms as well as the cause of ALI and the anatomical lesion, different treatment options are available and need to be compared regarding clinical outcome.

With the knowledge about the heterogeneity of patients suffering from ALI, a multicentre observational study design has the potential to give results on influence of several factors (patient related factors, treatment related factors) on clinical outcome of patients with lower extremity ALI. In contrast, a randomized controlled trial would not be feasible as heterogeneity of patients would lead to limitations in the recruitment of patients.

The primary objective of this study is to evaluate the effect of different treatment modalities on clinical outcome of patients suffering from acutle lower limb ischemia. Depending on clinical presentation, anatomical as well as technical considerations, different treatment options are available for revascularisation of affected limbs. Using an observational, international, multicentric study design (min. patient number of 500), the defined primary endpoint of the study, amputation-free survival 90 days after the diagnosis of ALI, will be evaluated.

The secondary objectives of this study are the identification of factors having an effect on the primary endpoint . These factors are:

• Demographic data (age, gender, Body Mass Index,
• Cardiovascular risk factors (diabetes, arterial hypertension, dyslipidemia, smoking history)
• COVID-19 anamnesis (infectious status; vaccination status)
• Pre-existing diseases (Arterial fibrillation, chronic kidney disease, hemodialysis, coronary artery disease, COVID infection in medical history, pulmonary disease)
• Risk factors for ALI (peripheral arterial disease, aortic aneurysm or dissection, arterial embolization in medical history, malignant disease, peripheral arterial aneurysm, previous stroke, thrombophilia, revascularization procedure on ipsilateral limb)
• Pre-existing medication (antiplatelet, oral anticoagulation, statins)
• Clinical presentation (Rutherford ischemia classification, Cause of ALI, anatomical level of arterial occlusion, diagnostic imaging modality)
• Details on performed intervention (time of ischemia, periprocedural heparin administration, type of procedure, technical details on performed procedure, compartment syndrome with need for fasciotomy)
• Outcome parameters (Survival, Rutherford ischemia classification, residual sensory or motor deficit, impaired walking distance, need for reintervention, major bleeding periprocedural, access site complications, organ failure) 30 and 90 days after diagnosis of ALI.

Inclusion Criteria:

• Acute lower limb ischemia (Rutherford Categories I-III)

Exclusion Criteria:

• No informed consent

All patients with the diagnosis of acute lower limb ischemia treated at a participating study center.