b"Scientific Session Abstracts SATURDAY APRIL 20, 2024 5: EVALUATING THE PROGNOSTIC ACCURACY OF AMPREDICT IN PREDICTING ONE-YEAR MORTALITY FOLLOWING MAJOR LOWERLIMB AMPUTATIONKristina Rudio, MD, Gabrielle Daso, MD, Hugh A. Gelabert, MD,David A. Rigberg, MD, Nina Bowens, MD, Mark Archie, MD,Jessica B. OConnell, MD, Jesus G. Ulloa, MDHarbor-UCLA Medical Center, Torrance, CAGreater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CABackground: Anticipating outcomes in patients undergoing major lower limb amputations is a critical aspect of preoperative planning and postoperative care. Accurately predicting postoperative outcomes is fundamental to informed clinical decision making, enhancing patient management, and aligning with patient, and family expectations. The AMPREDICT Decision Support Tool is a predictive tool designed to assess the probability of mortality one year after major and minor amputations. AMPREDICT may play a vital role in the collaborative decision- making process between physicians and patients; therefore, we aimed to evaluate its application in our particular patient population.Methods: A retrospective review of lower extremity amputations completed at an academic affiliated, regional hospital from 2000 to 2020. Staged open amputations, and previous minor amputations were excluded. Using the AMPREDICT tool, we predicted the probability of mortality one year post-surgery for single stage transfemoral and transtibial amputations, then compared the results with actual patient outcomes. Descriptive statistics of our study cohort were calculated. The observed to predicted mortality was compared through boxplots, at one year after surgery, confidence intervals were calculated, and group means were compared using Students T-test. Significance was set at p0.05.Results: We identified 423 patients that underwent 650 lower extremity amputations during our study period. 267 patients that underwent single stage transfemoral or transtibial amputations comprised our study cohort. The average age at amputation was 66 years with an average age of death at 71 years (Table 1). Our analysis indicated that the AMPREDICT tool's prognostic capability varied across the two amputations studied. For single staged transfemoral amputations, (Figure 1) the prediction aligned closely with actual outcomes, as indicated by a significant p-value of 0.0002 (C.I. 12.73 - 36.37). The predictions for transfemoral amputation demonstrated a higher median predicted risk for patients who died within one year, which is supported by fewer outliers, indicating a more concentrated prediction range that closely aligned with actual mortality rates. For single stage transtibial amputations, the predictions were also significant, p-value 0.0017 (C.I. 5.25 - 21.20), though had a wider prediction range.Conclusions: Our study confirms the reliability of the AMPREDICT tool in predicting one-year mortality for patients undergoing major lower limb 42SOUTHERN CALIFORNIA VASCULAR SURGICAL SOCIETY"