Development and validation of a nomogram to predict the risk of type II endoleak after endovascular aneurysm repair

Figures

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  Figure 1. For estimating the probability of type II endoleak (T2EL) following endovascular aneurysm repair (EVAR). The nomogram incorporates six predictors including age, smoking status, intraluminal thrombus, number of patent lumbar arteries (LA), inferior mesenteric artery (IMA) diameter, and IMA patency. T2EL, type II endoleak; EVAR, endovascular aneurysm repair; LA, lumbar arteries; IMA, inferior mesenteric artery.

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  Figure 2. Calibration curves of the nomogram in the training and validation sets. (A) Calibration curve in the training set, showing strong agreement between predicted and observed probabilities (mean absolute error = 0.032, B = 1,000 bootstrap resamples). (B) Calibration curve in the validation set, also demonstrating good calibration (mean absolute error = 0.024, B = 1,000 bootstrap resamples). n, sample size; B, number of bootstrap iterations.

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  Figure 3. Receiver operating characteristic (ROC) curves of the nomogram predicting type II endoleak (T2EL) in the training and validation sets. (A) ROC curve in the training set. (B) ROC curve in the validation set. ROC, receiver operating characteristic; AUC, area under the curve; T2EL, type II endoleak.

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  Figure 4. Decision curve analysis (DCA) of the nomogram. (A) DCA curve in the training set, demonstrating positive net clinical benefit across threshold probabilities of 1%–66% and 79%–92% (B = 1,000 bootstrap resamples). (B) DCA curve in the validation set, showing benefit across a broader threshold range of 1%–84% (B = 1,000 bootstrap resamples). DCA, decision curve analysis; B, number of bootstrap iterations.