Nomogram for predicting in-stent stenosis after pipeline embolization device treatment in patients with unruptured intracranial aneurysm: a multicenter model development and validation study

Background Some intracranial aneurysms (IAs) still develop in-stent stenosis (ISS) even after successful pipeline embolization device (PED) implantation. ISS increases the risk of retreatment and ischemic complications, thereby affecting the long-term prognosis of IA patients. This study aims to identify predictors for ISS after PED treatment of IAs, and develop a nomogram for assessing individual risk.Materials and Methods This analysis included unruptured IA patients treated with PEDs between April 2016 and October 2023 at three institutions. The patients were grouped into the training cohort and validation cohort according to the admission institution. Predictors were identified via least absolute shrinkage and selection operator analysis and multivariable regression analysis. A nomogram was then developed to predict ISS after PED implantation in the training cohort. The area under the receiver operating characteristic curve (AUC), calibration curves, and decision curve analysis (DCA) were used to evaluate the predictive accuracy and clinical value of the nomograms.Results A total of 1335 IA patients were included in this study (1049 in the training cohort and 286 in the validation cohort). A total of 139 (13.3%) and 41 (14.3%) patients developed ISS in the training cohort and validation cohort, respectively. A nomogram with five predictors (difference between the proximal and distal parent artery diameters, distal stent-to-vessel diameter ratio, overlapping devices, balloon angioplasty, and dissecting aneurysms) was developed via multivariate logistic regression analysis. AUCs of the nomogram in the training cohort and validation cohort were 0.836 (95%CI, 0.801–0.870) and 0.829 (95%CI, 0.770–0.888), respectively. Calibration curve and DCA analysis confirmed the utility and clinical applicability of this nomogram.Conclusion This nomogram showed high accuracy and clinical utility in predicting ISS after PED treatment, indicating that the nomogram can guide the identification of high-risk patients and the development of improved treatment strategies.