Introduction: Angio-architectural factors affecting early clinical and angiographic outcome after treatment of brain aneurysms using pipeline embolization device (PED) has not been fully studied.
Methods: Aneurysm size, aspect ratio (AR), aneurysm segment tortuosity (AST), aneurysm transition (junctional vs mid-segment), aneurysm-parent artery angle (APA), and number of pipeline curvatures (after deployment) were evaluated for impact on the primary outcome measure, early stagnation. Based on the duration of contrast stagnation inside the aneurysm after deployment of the pipeline, we graded stagnation status as follows: grade 1: arterial phase, grade 2: capillary phase, grade 3: venous phase, grade 4: persistence of crescent after end of venous phase, and grade 5: complete occlusion. Effect of aneurysm segment tortuosity on intraoperative and postoperative complications was further evaluated using a Chi2 method for the categorized data analysis. A multivariate analysis was also performed to report adjusted statistical outcomes.
Results: Forty-five patients with fifty-six aneurysm with mean age 56.25 (±9.74) years, 84.9% females, a mean aneurysm size of 8.93 (±6.11) mm and average aspect ratio (AR) of 1.75 (+1.12) were included in this analysis. Larger the size of aneurysm and higher the aspect ratio were both significantly associated with higher grades of early stagnation in both crude and multivariate analysis (p< 0.01). On the other hand, aneurysm transition (p=0.892), APA (p=0.513), AST (p=0.337), number of pipeline curvatures (p=0.592) was not significantly associated with higher rate of early stagnation. Moreover, AST was also not significantly associated with intraoperative complications or postoperative neurological deficit (p=0.226, p=0.259, respectively). Mean stagnation grade significantly increased from 3.54 in early postop period to 4.33 after a mean follow up of 5.14 months (Paired t-test p<0.01). However, there was no significant association between early and late stagnation grades (p=0.17).
Conclusions: Aneurysm size and aspect ratio are the only angio-architectural factors affecting the early stagnation status after treatment of brain aneurysms using flow diversion stents. Long term Follow up will be required to see if stagnation translate into continued occlusion of aneurysms.
Patient Care: This will affect patient selection process in a way that patients with larger aneurysm and smaller neck benefit more from this device. With better patient selection, we can increase success rate and decrease complication rate.
Learning Objectives: understanding Angio-architectural factors affecting early clinical and angiographic outcome after treatment of brain aneurysms using pipeline embolization device. Also, longer follow up angiography is very important for assessment of final success rate.