Initial Raymond-Roy Occlusion Classification but not Packing Density Defines Risk for Recurrence after Aneurysm Coiling

Purpose After coil embolization of intracranial aneurysms, it is currently not well understood whether the initial coil packing density or the type of aneurysm residual perfusion, depicted by the modified Raymond-Roy occlusion classification, primarily effects the rate of aneurysm recurrence. We hypothesized that these factors interact and only one remains an independent risk factor. Methods In this single center retrospective study, 440 patients with intracranial ruptured and unruptured aneurysms between 2010 and 2017 were screened. A total of 267 patients treated with stand-alone coiling, with or without stent or balloon assistance were included (age 54.1 & x202f;+/- 12.2 years, sex 70.4% female). Flow diverter or Woven EndoBridge (WEB) device implantation were exclusion criteria. Results Using a binary logistic regression model, independent risk factors for aneurysm recurrence were postinterventional modified Raymond-Roy occlusion classification class (Odds ratio [OR] 1.747, 95% confidence interval [CI] 1.231-2.480) and aneurysm diameter (OR 1.145, CI 1.032-1.271). A trend towards a higher recurrence in ruptured aneurysms did not reach significance (OR 1.656, CI 0.863-3.179). Aneurysm localization, packing density, and neck width were not independently associated with aneurysm recurrence. Conclusion Independent risk factors for aneurysm recurrence after coil embolization with and without stent or balloon assistance were aneurysm diameter and postinterventional grading within the modified Raymond-Roy occlusion classification. Packing density interacted with the latter and was not independently associated to recurrence.

Automated summary

The independent risk factors for aneurysm recurrence after coil embolization are postinterventional modified Raymond-Roy occlusion classification and aneurysm diameter, while packing density and neck width are not associated with recurrence.