Optimizing the Volume of the Initial Framing Coil to Facilitate Tight Packing of Intracranial Aneurysms.

Background During endovascular treatment of an aneurysm, the importance of the initial coil volume for facilitating tight packing is unclear. We retrospectively studied the relationships between initial packing density (PD; initial coil volume divided by aneurysm volume), final PD (volume of all coils divided by aneurysm volume). Methods We reviewed 105 aneurysms in 98 patients who underwent endovascular coiling between April 2011 and March 2014. The initial coil was defined as the first coil in the single-catheter method and the first 2 coils in the double-catheter method. The patient data were divided into groups with or without a final PD ≥20%, and the significant predictors of a final PD ≥20% were determined using multivariable logistic regression. The optimal cutoff value for the initial PD was determined using a receiver operating characteristic curve. Results Of 105 aneurysms, 56 and 49 were treated with single- and double-catheter methods, respectively. Statistically significant differences in rupture status, neck size, dome/neck ratio, and initial PD were observed between aneurysms with and without a final PD ≥20% (all P P  = 0.025; odds ratio, 1.22) and rupture status ( P  = 0.002; odds ratio, 0.19) were significantly associated with a final PD ≥20%. Using receiver operating characteristic curve analysis, the cutoff points of initial PD to achieve a final PD ≥20% were 8.0% and 10.0% in single- and double-catheter groups, respectively. Conclusions Initial PD appears to be a critical factor for achieving tight packing.