AMPREDICT: 1 Year Mortality Post-Amp. Evaluating the Prognostic Accuracy of AMPREDICT in Predicting One-Year Mortality Following Major Lower Limb Amputation.

OBJECTIVE: Accurately predicting postoperative outcomes is fundamental to informed clinical decision making, and alignment of 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. We aimed to evaluate the prognostic accuracy of AMPREDICT in our Veteran patient population. METHODS: Retrospective review of lower extremity amputations completed at the West Los Angeles Veterans Affairs hospital from 2000 to 2020. Staged open amputations, and previous minor amputations were excluded. Using the AMPREDICT tool, the probability of mortality one-year post-surgery for single stage transfemoral and transtibial amputations was calculated, then compared with observed patient outcomes. 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. Receiver operator curves were constructed to assess discriminatory capacity of the tool. Significance was set at p < 0.05. RESULTS: 423 patients underwent 650 lower extremity amputations during our study period. 267 patients underwent single stage transfemoral or transtibial amputations comprising our study cohort. The average age at amputation was 66 years with an average age of death at 71 years. AMPREDICT tool's prognostic capability varied across the two amputations studied. For single staged transfemoral amputations, prediction aligned closely with observed outcomes, as indicated by a significant p-value of 0.0002 (C.I. 12.73 - 36.37). 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 amputations. The predictive accuracy was found to be statistically significant for both single staged transfemoral and transtibial amputations. These findings suggest that AMPREDICT may be a valuable tool in the clinical setting for patients undergoing major lower limb amputation.

Scaling between cell cycle duration and wing growth is regulated by Fat-Dachsous signaling in Drosophila.

The atypical cadherins Fat and Dachsous (Ds) signal through the Hippo pathway to regulate growth of numerous organs, including the Drosophila wing. Here, we find that Ds-Fat signaling tunes a unique feature of cell proliferation found to control the rate of wing growth during the third instar larval phase. The duration of the cell cycle increases in direct proportion to the size of the wing, leading to linear-like growth during the third instar. Ds-Fat signaling enhances the rate at which the cell cycle lengthens with wing size, thus diminishing the rate of wing growth. We show that this results in a complex but stereotyped relative scaling of wing growth with body growth in Drosophila. Finally, we examine the dynamics of Fat and Ds protein distribution in the wing, observing graded distributions that change during growth. However, the significance of these dynamics is unclear since perturbations in expression have negligible impact on wing growth.

Scaling between cell cycle duration and wing growth is regulated by Fat-Dachsous signaling in Drosophila.

The atypical cadherins Fat and Dachsous (Ds) signal through the Hippo pathway to regulate growth of numerous organs, including the Drosophila wing. Here, we find that Ds-Fat signaling tunes a unique feature of cell proliferation found to control the rate of wing growth during the third instar larval phase. The duration of the cell cycle increases in direct proportion to the size of the wing, leading to linear-like growth during the third instar. Ds-Fat signaling enhances the rate at which the cell cycle lengthens with wing size, thus diminishing the rate of wing growth. We show that this results in a complex but stereotyped relative scaling of wing growth with body growth in Drosophila. Finally, we examine the dynamics of Fat and Ds protein distribution in the wing, observing graded distributions that change during growth. However, the significance of these dynamics is unclear since perturbations in expression have negligible impact on wing growth.