Diagnostic and Prognostic Value of AISI, SII, and SIRI in Predicting Gangrenous Evolution of Acute Lithiasic Cholecystitis

<b>Background/Objectives:</b> Acute calculous cholecystitis remains one of the most frequent surgical emergencies, ranging from mild inflammation to gangrenous forms associated with necrosis and sepsis. Early differentiation between these stages is essential for timely surgical management. This study aimed to evaluate the diagnostic and prognostic value of hematological inflammatory indices-the Aggregate Index of Systemic Inflammation (AISI), the Systemic Immune-Inflammation Index (SII), and the Systemic Inflammation Response Index (SIRI)-in predicting the gangrenous evolution of acute calculous cholecystitis. <b>Methods:</b> A retrospective study was conducted on 435 patients who underwent cholecystectomy between 2016 and 2024 at a tertiary care center. Patients were divided into gangrenous (<i>n</i> = 145) and chronic (<i>n</i> = 290) cholecystitis groups. Preoperative hematological parameters were used to calculate AISI, SII, and SIRI. After histopathological confirmation, patients with GC (gangrenous calculous cholecystitis) were identified, and for each case, two age- and sex-matched controls with chronic CC (calculous cholecystitis) were selected, maintaining a GC:CC ratio of 1:2. Preoperative hematological parameters were used to calculate AISI, SII, and SIRI. <b>Results:</b> All three indices were significantly higher in the gangrenous group (<i>p</i> < 0.001). Logistic regression identified SIRI as the strongest independent predictor of gangrenous cholecystitis (OR = 1.976, <i>p</i> < 0.001). ROC analysis demonstrated excellent discriminative capacity for all markers (AUC > 0.8), with SII achieving the highest diagnostic accuracy (AUC = 0.889, sensitivity 79.5%, specificity 86.3%). <b>Conclusions:</b> AISI, SII, and SIRI represent reliable, easily obtainable, and noninvasive biomarkers for assessing inflammatory severity and predicting gangrenous transformation in acute calculous cholecystitis. Their integration into preoperative evaluation could improve early risk stratification, surgical planning, and patient outcomes.