WIFI,GLASS, and Ambulatory Status Predicts Level of Amputationin aHigh-RiskPopulation in Chronic Limb-Threatening Ischemia
Darshan Randhawa, Kevin Kim, Quingwen Kawaji, Jason Howard, Michael Rouse, David Martin, Jason Crowner, Raghuveer Vallabhaneni
MedStar Health, Baltimore, MD
Introduction: The Global Limb Anatomic Staging System (GLASS) has been developed to quantify patterns of ischemia in chronic limb-threatening ischemia(CLTI). The wound, ischemia, and foot infection(WIfI) grading system assesses the combination of these factors to classify and predict patients that are at risk for one-year major amputation. These models are robustly generalizable for CLTI patients, but their ability to predict level of amputation has not been evaluated. Black patients with end-stage renal disease and CLTI have been shown to be a high-risk population. Our goal of this study was to evaluate the use of GLASS and WIfI classification as a predictor for level of amputation in this high-risk population.
Methods: A retrospective cohort study was performed within a single healthcare system spanning multiple hospitals over a five-year period from 2014-2019. Black patients with ESRD and who had undergone a lower extremity amputation (AKA, BKA, Chopart, and TMA) were included in our study. WIfI classification, demographics, and comorbidities were recorded. Pre-amputation initial angiographic images were obtained to calculate GLASS scores. Standard univariate and multivariate statistical methods were performed using IBM SPSS.
Results: 174 patients met inclusion criteria. Of these, 59 had complete data, including all components of the GLASS and WIfI scoring system. The majority of patients were male (63%), with a median age of 64 (IQR: 59,74), had diabetes (96%), and were ambulatory at baseline(65%). The mean follow-up time period after amputation was 2.4 ±0.6 years. Among angiograms performed, the rate of endovascular intervention was as follows; AKA 50%, BKA 60%, Chopart 75%, TMA 70%(p=.545).The mean WIfI composite score and GLASS stage correlated to the level of amputation(p<.001) (Table 1). GLASS scoring: femoral-popliteal scoring yielded no significant differences among amputation levels, whereas infra-popliteal, infra-malleolar, and GLASS staging demonstrated a significant difference when comparing level of amputation (p<.005). A Spearman's rank-order correlation demonstrated a positive correlation between WIfI composite score and GLASS stage (rs(8) = .498, p = .004). A multiple regression analysis was run to predict the level of amputation from ambulatory status, WIfI composite score, and GLASS stage. All of these variables predicted level of amputation, F(5, 39) = 41.37, p < .001, R2 = .899; all 3 variables added to the prediction, p <.005 (Table 2).
Conclusions: The utilization of ambulatory status, GLASS, and WIfI scoring to determine the level of amputation demonstrates promise as a prognostic tool for Black patients with ESRD and CLTI. The ability to predict the level of amputation may help with shared decision-making and prevent multiple surgeries in this high-risk group. 
Back to 2022 Posters