Predictors of In-Stent Stenosis Following the Implantation of Pipeline Embolization Devices for the Treatment of Aneurysms Located at or beyond the Circle of Willis in the Anterior Circulation.

BACKGROUND AND PURPOSE: In-stent stenosis is commonly observed after stent implantation. There is no consensus on the contributing factors for in-stent stenosis, especially for aneurysms located at or beyond the circle of Willis in the anterior circulation. This study aimed to investigate the morbidity and determinants of in-stent stenosis in distal anterior circulation aneurysms following the implantation of Pipeline Embolization Devices.

MATERIALS AND METHODS: Patients who underwent Pipeline Embolization Device treatment at our center between January 1, 2018, and June 15, 2023, were enrolled. Distal anterior circulation aneurysms were defined as those occurring at or beyond the circle of Willis, including anterior communicating artery aneurysms, anterior cerebral artery aneurysms, and MCA aneurysms. Baseline information, aneurysm characteristics, and follow-up data of patients were analyzed. Patients were divided into 2 groups: the in-stent stenosis group (patients with a loss of >25% of the lumen diameter of the parent artery) and the non-in-stent stenosis group. Binary logistic regression and restricted cubic spline curves were used to explore risk factors.

RESULTS: We included 85 cases of 1213 patients treated with flow-diverter devices at our hospital. During an average follow-up period of 9.07 months, the complete occlusion rate was 77.64%. The overall incidence of in-stent stenosis was 36.47% (31/85), of which moderate stenosis accounted for 9.41% (8/85), and severe stenosis, 5.88% (5/85) (triglyceride-glucose index ≥ 8.95; OR = 6.883, P  = .006). The difference in diameters between the stent and parent artery of ≥0.09 mm (OR = 6.534, P  = .015) and 55 years of age or older (OR = 3.507, P  = .036) were risk factors for in-stent stenosis. The restricted cubic spline curves indicated that the risk of in-stent stenosis increased as the difference in diameter between stent and parent artery and the triglyceride-glucose index increased.

CONCLUSIONS: Compared with the on-label use of Pipeline Embolization Devices, the rate of in-stent stenosis did not obviously increase when treating distal anterior circulation aneurysms with these devices. The incidence of in-stent stenosis was 36.47% when defined as a lumen diameter loss of >25%, and 15.2% when defined as a lumen diameter loss of >50%. Stent-size selection and biochemical indicators can potentially impact the incidence of in-stent stenosis.