Duplex-ultrasound as a single imaging test for Global Limb Anatomic Staging System (GLASS) assignment stage and comparison with intraoperative arteriography.

Introduction: Obtaining a prognostic and predictive classification based on the risk of amputation is crucial in ischemic pathology of the lower limbs. Accurate anatomical characterization of arterial lesions is essential for optimal clinical decision-making. The Global Limb Anatomic Staging System (GLASS) provides a comprehensive anatomy assessment of the femoropopliteal and infrapopliteal arterial system. GLASS introduces concepts such as the target arterial path (TAP) and estimated limb-based patency (LBP), crucial for determining the best arterial route to restore blood flow.

Materials and methods: A prospective study conducted from May to December 2022 involved 66 patients undergoing revascularization surgery for Critical Limb-Threatening Ischemia (CLTI). Preoperative arterial mapping (PAM) using duplex ultrasonography was the sole imaging modality. The TAP was defined in each patient, and GLASS staging was determined. Intraoperative arteriography (IA) was used on the day of surgery for comparison. Agreement between PAM and IA was assessed using Cohen's kappa coefficient, and diagnostic metrics were compared using ROC curves.

Results: Doppler ultrasound demonstrated a sensitivity of 98%, specificity and PPV of 100%, and NPV of 94.7% in the femoropopliteal sector, with a Kappa coefficient of 0.98. For the infrapopliteal sector, sensitivity was 95%, specificity 96.5%, PPV 97.3%, and NPV 93.3%, with a Kappa coefficient of 0.89. Combining both sectors, the overall GLASS stage showed a 93.9% concordance with a Kappa coefficient of 0.91. ROC curves revealed no significant differences between ultrasound and arteriography in terms of staging.

Conclusion: This study demonstrates that Doppler Ultrasound can serve as the exclusive imaging modality for determining the preoperative GLASS stage.