The significance of stent sizing for parent vessel stenosis after flow diversion of MCA bifurcation aneurysms.

Background: Wide-necked bifurcation aneurysms (WNBA) of the middle cerebral artery (MCA) present significant therapeutic challenges. Flow-diverter stents have been increasingly adopted for their management, though they may give rise to adverse outcomes such as in-stent stenosis (ISS). This study explores the association between stent oversizing and the incidence of ISS following flow-diverter stent placement in MCA bifurcation aneurysms.

Methods: A retrospective study included 34 patients who underwent flow-diverter stent placement for MCA bifurcation aneurysms between 2020 and 2023. Data on patient demographics, aneurysm morphology, and stent sizing were collected. ISS was evaluated through follow-up imaging at 6-month post-procedure. Stent oversizing was determined by calculating the difference between the stent diameter and the proximal and distal parent vessel diameters. Statistical analyses included Pearson correlation and chi-square tests, with significance established at  < 0.05.

Results: The studied group had a mean age of 57.8 years, with 81.6% female patients. The average aneurysm neck size was 3.6 mm, with a mean dome-to-neck ratio of 1.6. ISS was detected in 64.7% of cases proximally and 88.2% distally. A statistically significant negative correlation ( = -0.496,  = 0.003) was observed between stent oversizing and ISS, indicating that increased stent oversizing was associated with a higher incidence of ISS, particularly in the distal vessel segments.

Conclusion: The findings indicate that stent oversizing is significantly associated with the development of ISS in MCA bifurcation aneurysms treated with flow-diverter stents. Careful consideration of stent sizing, particularly minimizing oversizing in distal segments, may mitigate the risk of ISS and improve clinical outcomes. These results underscore the importance of meticulous stent selection and procedural planning in neurointerventional practice.