Development and validation of a prediction model for early mortality after transcatheter aortic valve implantation (TAVI) based on the Netherlands Heart Registration (NHR): The TAVI‐NHR risk model

Figures

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  Figure 1. Calibration graph (left) and AU‐ROC (right) of the final model. Performance measures of the internal validation of the prediction strategy in 10‐fold cross‐validation, and performance measures of the temporal validation of the prediction strategy on 2018 data set (n = 2289) (below). Abbreviations: AU‐ROC, area under the receiver operating characteristic curve = concordance c‐statistic; AU‐PRC, area under the precision‐recall curve; IQR, interquartile range; 95% CI, 95% confidence intervals. $On each of the training folds, we repeated the prediction strategy (including generating five multiple imputation sets, fitting logistic regression models, selecting variables by stepwise AIC, selecting the variables that appeared five times out of the five imputed data sets, and then pooling the coefficients' estimates for the final model). We tested the final model from each fold on the corresponding test fold. We evaluated the predictive performance in terms of discrimination (AU‐ROC), AU‐PRC, Brier score, Brier‐skill score, calibration intercept, and calibration slope.

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  Figure 2. Forest plot showing the AU‐ROC for different models, using different sets of variables from the final selected predictor variables by Akaike Information Criterion (AIC). Abbreviations: NYHA, New York Heart Association functional Classification; LVEF, left ventricular ejection fraction; DM, diabetes mellitus. The estimated early mortality risks derived from these models were evaluated in the test sets. Note that the five imputed data sets were stacked in one data set (where each observation gets a weight of 0.2), and then we split the data set into training and test sets. The variable list shown builds downwards, adding to the existing variables; for example, the c‐statistic (AU‐ROC) shown in the fifth row is for the model that includes body surface area, LVEF, NYHA, procedure acuteness status, and access route. [Color figure can be viewed at wileyonlinelibrary.com]