Purpose In the treatment of intracranial aneurysms using coil embolization, higher packing densities are inversely correlated with aneurysm recurrence.¹ In review of our single center data, we have noticed a trend towards decreased recurrence rates when the first coil volume is at least 15% of that of the aneurysm volume.² We hypothesize that, by prospectively selecting a first coil with a volume that is at least 15% of the aneurysm volume (First Coil Packing Density), higher final packing densities and decreased aneurysm recurrence rates can be achieved.

Methods 25 patients presenting with ruptured or unruptured intracranial saccular aneurysms 4-20 mm were consented for enrollment in the prospective arm. Inclusion criteria were used from the Matrix and Platinum Science (MAPS) trial for comparison purposes. All aneurysms were treated using Target Detachable Coils (Stryker Neurovascular), in which the first coil length was selected with a goal of the First Coil Packing Density being at least 15% of the aneurysm volume.

Historical data from 20 patients enrolled from our center in the MAPS trial served as the control arm. All target aneurysms in the control arm were packed using GDC Detachable Coils (Stryker Neurovascular). In the MAPS trial, packing density was not actively calculated prior to coil selection.

The independent core lab results from the MAPS trial were used to evaluate for aneurysm recurrences at one-year angiography. All patients in the prospective arm that returned for the one-year angiogram were adjudicated by an independent core lab.

Results While there was no significant difference in aneurysm size and dome-to-neck ratio between the two groups, there was a trend for larger aneurysms in the prospective arm (8.0 vs 7.2 mm). Additionally, the prospective arm had a higher proportion of ruptured aneurysms (36%) compared to the control arm (30%).

We showed a statistically significant increase in the mean final packing density from the control arm (22.4%) to the prospective arm (33.0%, p<0.001). We were able to achieve 15% first coil packing density in 72% of subjects, but this goal could not be met on larger aneurysms, as coil lengths are limited.

Seventeen patients returned for one year DSA follow up in each arm. There were no residual aneurysms with dome filling in the prospective arm, with only 1 neck remnant seen, yielding a recurrence rate of 6%. In the control arm, residual filling of the dome was seen in 2 patients, and a neck remnant was seen in 3 patients, yielding a recurrence rate of 29%.

Conclusion Prospectively choosing Target Detachable Coils that yield at least 15% First Coil Packing Density led to higher final packing densities overall and decreased target aneurysm recurrences.

References

1. Sluzewski M, et al. Relation between aneurysm volume, packing, and compaction in 145 cerebral aneurysms treated with coils. Radiology 2004;231:653-658.

2. Woodward B. O-009 prospective packing density: a single center study investigating the effects of prospectively measuring packing density prior to choosing coils for the treatment of intracranial aneurysms. Journal of NeuroInterventional Surgery 2014;6:A5-A6.

Disclosures A. Windsor: None. B. Woodward: 1; C; Stryker.