Nomogram for Predicting In-stent Stenosis After Pipeline Embolization Device Treatment in Patients with Intracranial Aneurysm: a Multicenter, Retrospective Model Development and Validation Study

Intracranial aneurysms (IAs) are the primary cause of non-traumatic subarachnoid hemorrhage with high morbidity and mortality. Flow diverters, such as pipeline embolization devices (PEDs), are among the most effective methods for treating IAs in recent years due to the maturity of interventional devices and minimally invasive techniques. Unlike conventional stents, PEDs modify the hemodynamics within the parent artery and aneurysm sac, allowing blood flow from the aneurysm sac, thus facilitating endothelialization of the aneurysm neck. As a result, aneurysms are completely removed from circulation with time. However, about 5.1%-38.5% of IA patients develop in-stent stenosis (ISS) even after successful PED implantation. ISS increases the risk of retreatment and ischemic complications, thereby affecting the long-term prognosis of IA patients. Therefore, preoperative determination of the patient's suitability for PED implantation can enhance patient-centered decision-making and improve the long-term prognosis of IA patients.

Although previous studies have evaluated the correlation between certain individual variables and ISS, there are few comprehensive models predicting ISS after PED treatment. Nomograms have been widely used for prediction of tumor survival and cardiovascular events. Nomograms incorporate multiple risk factors for predicting the patient's potential prognosis based on their individual risks. This study aimed to identify the predictors for ISS after PED treatment and to create and verify a nomogram for assessing individual risk.