Narrowing of the angle of the parent artery after coil embolization increases the risk for aneurysm recurrence

Abstract

Objective: Aneurysm recurrence after coiling is a major complication in some cases, including cases of repeated recurrences. In this study, we identified a relationship between the recurrence of a coiled aneurysm and angle change of the parent artery.

Methods: From April 2008 to December 2019, we performed 283 coil embolizations to treat 256 aneurysms in 251 patients. Among these, 21 cases of recurrent saccular aneurysms were selected. The parent artery angle changes between the initial treatment and the first re-treatment were compared between those who underwent single re-treatment and showed no recurrence after the first re-treatment (Group SR, n = 14) and those who required multiple re-treatments (Group MR, n = 7).

Results: The parent artery angles at the first treatment [medians (interquartile ranges)] were 121.6° (109.3-135.6°) in Group SR and 104.9° (89.9-131.0°) in Group MR; at the second treatment, these angles were 121.2° (105.5-132.7°) and 81.9° (67.0-111.4°), respectively, revealing angle changes of -2.2° (-4.0 to -0.4°) and -16.4° (-30.1 to -8.6°) in Groups SR and MR between the first and second treatments. The between-group differences in the parent artery angles at the second treatment and the changes in the parent artery angle between the first and second treatments were statistically significant.

Conclusion: In patients with recurrent aneurysms, simple aneurysm coiling is not effective when the angle of the parent artery becomes narrower after treatment, relative to that before treatment. Stent placement should be considered for straightening the parent artery or diverting blood flow.

Keywords: Aneurysmal coiling; Narrowing of the angle of the parent artery; Repeated recurrence; aggressive stent placement.