Left internal iliac artery stenosis as a risk factor for anastomotic leakage after left-sided colorectal surgery

Purpose To evaluate association of stenosis of celio-mesenteric and internal iliac arteries with anastomotic leakage (AL) following left-sided colorectal resection in patients with primary colorectal cancer. Methods This single-center study included consecutive patients undergoing left-sided colorectal resection for primary colorectal cancer between 2014 and 2024. Patients with and without AL were matched by propensity scores. Two radiologists independently assessed preoperative computed tomography (CT) scans for arterial stenosis (<50% vs. ≥50%). Weighted multivariate logistic regression identified independent predictors of leakage. Results Among 367 consecutive left-sided colorectal resections, 37 patient with AL were eligible and matched to 60 controls for detailed vascular analysis. Baseline characteristics were well balanced after matching. Vascular assessment on CT showed a prevalence of significant stenosis ranging from 9.3% to 23.7%, with good to excellent interrater agreement ( κ ≥0.71, p < 0.001). Propensity matching achieved covariate balance for most of variables (SMDs <0.1). Weighted multivariate regression identified left internal iliac artery (LII) stenosis as significantly associated with AL (OR 4.13, p = 0.026). No association was observed between AL and the celiac artery, superior mesenteric artery, inferior mesenteric artery, or right internal iliac. Conclusion LII stenosis emerged as the most relevant vascular predictor of AL after left-sided colorectal surgery. Incorporating preoperative arterial assessment on routine contrast-enhanced CT may therefore improve risk stratification and guide preventive strategies in selected patients. Statement This study identifies left internal iliac artery stenosis as an independent vascular predictor of anastomotic leakage after left-sided colorectal resection. Incorporating preoperative arterial assessment into routine CT may therefore improve risk stratification and guide preventive strategies in selected patients.