Aggregate Index of Systemic Inflammation and Risk of Early Adverse Outcomes in Acute Limb Ischemia

Acute limb ischemia (ALI) is associated with high risks of mortality and major amputation despite advances in endovascular therapy. In patients treated with catheter-directed thrombolysis (CDT), early risk stratification is clinically important. The Aggregate Index of Systemic Inflammation (AISI) reflects systemic inflammatory burden, but its prognostic role in this setting remains unclear.

We retrospectively analyzed consecutive patients with Rutherford class IIa ALI treated with CDT between January 2016 and December 2024. Admission AISI was calculated from routine complete blood count parameters. The primary outcome was a composite of in-hospital mortality and/or major amputation. Multivariable logistic regression analyses using log-transformed AISI were adjusted for relevant clinical covariates. Discrimination was assessed using receiver operating characteristic analysis.

A total of 219 patients were included, and the composite outcome occurred in 24.7%. Higher AISI was associated with a significantly increased rate of adverse outcomes (40.5% vs. 8.3%, P < 0.001). AISI demonstrated moderate discriminatory ability (area under the curve = 0.74). In multivariable analysis, log-transformed AISI independently predicted the composite outcome (odds ratio 2.49, 95% confidence interval 1.52-4.10; P < 0.001).

Elevated admission AISI is independently associated with early adverse outcomes in ALI patients undergoing CDT and may support early risk stratification.