Prospective Multi-Center Longitudinal Study to Validate Accuracy of the Global Anatomic Staging System (GLASS) Score in Predicting Major Acute Limb Events in Patients With Chronic Limb Threatening Ischemia Undergoing Endovascular Intervention: The PROMOTE-GLASS Study Protocol

Introduction: Developed by the Global Vascular Guidelines committee, the Global Limb Anatomic Staging System (GLASS) is an angiographic scoring system used for quantifying infrainguinal disease extent and predicting treatment success with endovascular techniques (EVT). Currently, no other risk prediction model is available for patients with chronic limb threatening ischemia (CLTI) undergoing EVT. GLASS' validation and adoption outside academic institutions for research are limited. Thus, this longitudinal multicenter prospective study aims to examine GLASS' validity and reliability in predicting major acute limb events and overall survival (OS) in patients with CLTI undergoing EVT. Methods and analysis: This prospective, international, multicenter, observational study will include patients with CLTI undergoing EVT (PROMOTE-GLASS) (ClinicalTrials.gov; ID: NCT06186544) identified through routine clinical referrals and emergency visits to vascular units in participating centers. Only patients who are referred for EVT will be recruited. The primary outcomes are immediate technical success, immediate technical failure, and 1-year limb base patency. The secondary outcomes are major adverse limb events, major lower limb amputation, and OS in patients presenting with CLTI who undergo EVT up to 1 year after the procedure. Clinical and imaging data will be analyzed at the end of follow-up to validate risk prediction. This protocol outlines our approach for identifying cases, GLASS score calculation, outcome measures assessment, and a statistical analysis plan. Anticipated implications: PROMOTE-GLASS holds significant implications and can potentially revolutionize clinical decision-making by assisting clinicians in identifying patients who are likely to benefit from EVT. Ultimately, reduce the need for more invasive procedures and improve patient outcomes. Furthermore, PROMOTE-GLASS can provide useful information, including patient selection, for future randomized controlled trials (RCTs) investigating EVT for CLTI. PROMOTE-GLASS anticipated implications on the vascular community are rooted in its potential to improve patient care, inform future research, and address limitations in existing literature regarding CLTI treatment outcomes.