Patterns, Clinical Management, and Short-Term Outcomes of Acute Limb Ischemia (ALI) Seen In In-Hospital and Out-of-Hospital Onset.

Background Acute limb ischemia (ALI) is a vascular emergency associated with high morbidity and mortality. While most studies focus on community-onset ALI, some patients develop ALI during hospitalization for other medical conditions, where outcomes and decision-making may differ. Data on the in-hospital onset ALI remain limited. Aims This study aimed to evaluate the clinical characteristics and outcomes of patients with in-hospital onset ALI compared with those with out-of-hospital onset at a single center. Methods We retrospectively reviewed patients who underwent emergency surgical thrombectomy for ALI at a single center between April 2019 and August 2025. Patients with vascular access-related ALI, iatrogenic ALI, or bypass graft occlusion were excluded. ALI was classified as an in-hospital or out-of-hospital onset. Outcomes included 30-day mortality, in-hospital mortality, and major amputation. Results Twenty-five limbs in 25 patients were analyzed (right: 18, left: seven): 19 with out-of-hospital onset and six with in-hospital onset ALI. The in-hospital onset group had a higher prevalence of active cancer and infection. Operative variables and time from onset to revascularization were similar between groups. No major amputations were performed. However, one in-hospital onset patient developed irreversible dry gangrene and died from terminal cancer. Thirty-day mortality was significantly higher in the in-hospital onset group (50% vs. 0%). Conclusion In-hospital onset ALI is associated with markedly higher early mortality despite comparable limb-related outcomes. Prognosis appears to be driven primarily by systemic conditions rather than limb ischemia alone. Although in-hospital onset ALI represents a high-risk subgroup, outcomes are not uniformly fatal, underscoring the importance of individualized treatment decisions based on overall clinical status.