Risk factors for lower limb ischemia in minimally invasive and robotic-assisted cardiac valve surgery: a retrospective cohort study

Background: Lower limb ischemia is a critical complication of femoral cannulation during minimally invasive and robot-assisted cardiac surgery. We aimed to evaluate the validity of our intraoperative near-infrared spectroscopy (NIRS) monitoring strategy and identify risk factors for distal perfusion. Methods: We retrospectively analyzed 329 patients who underwent minimally invasive or robotic-assisted cardiac surgery with ipsilateral femoral arteriovenous cannulation between 2014 and June 2025. The primary outcome was intraoperative Tissue oxygenation index (TOI) desaturation requiring distal perfusion, defined as a >10% decline from baseline in the cannulated limb. Femoral artery (FA) diameter and femoral vein (FV) cross-sectional area were measured on preoperative computed tomography (CT). Risk factors were assessed by logistic regression, and receiver operating characteristic (ROC) analysis determined optimal cut-off values. Results: Intraoperative TOI desaturation requiring distal perfusion occurred in 34 patients (10.3%). Multivariable analysis revealed that age (P=0.03) and FA-cannula diameter difference (P