Endovascular embolization of small ruptured intracranial aneurysms using a biplane angiographic system with three-dimensional rotational digital subtraction angiography

Conventional endovascular treatment of small intracranial aneurysms is not associated with additional risks compared with treatment of larger aneurysms

BACKGROUND

Endovascular treatment of small intracranial aneurysms has historically been technically challenging and has been associated with high rates of complications and intraprocedural rupture. In this study, we compared complication and recurrence rates for treatment of small aneurysms (≤ 4 mm) versus large aneurysms in the context of the advent of improvements in endovascular techniques and technologies.

METHODS

A retrospective cohort study was performed to include all patients who underwent coiling of an intracranial aneurysm between 2005 and 2012. Small aneurysms were defined as any aneurysm 4.0 mm or smaller in all dimensions. The primary outcome was a composite outcome of the occurrence of an intraoperative rupture or a perioperative thromboembolic event. The secondary outcome of interest was aneurysm recurrence.

RESULTS

During the study period, 483 patients were treated using endovascular techniques; 85 (17.6%) of these patients had small aneurysms. In the small aneurysm group, there was only one (1.2%) intraoperative rupture, three (3.5%) perioperative thromboembolic events, and 11 (12.9%) incidents of aneurysm recurrence. Both the primary and secondary outcomes of interest were similar in patients presenting with small or large aneurysms. Small aneurysm size was not a risk factor for either the composite primary outcome or aneurysm recurrence in multivariate analysis.

CONCLUSIONS

Treatment of small intracranial aneurysms via conventional endovascular coiling techniques is not inferior to endovascular treatment of larger aneurysms based on our single institution experience. While technically challenging, such aneurysms may be treated safely and effectively with acceptable rates of complications and recurrence.

Endovascular treatment of very small intracranial aneurysms

The endovascular treatment of intracranial aneurysms 3 mm or less is considered controversial. The purpose of this study is to report angiographic and clinical results following coiling of such aneurysms and compare them to those of larger aneurysms (> 3 mm).Between November 1999 and November 2009 endovascular treatment was attempted in 956 consecutive intracranial aneurysms. Of 956 aneurysms, 111 aneurysms were very small aneurysms with a maximal diameter of 3 mm or less. We conducted a retrospective analysis of angiographic and clinical outcome following coiling of very small aneurysms and subsequently comparing it to the results of larger aneurysms.Coiling initially failed in eight aneurysms. In the remaining 103 aneurysms endovascular treatment was accomplished and immediate angiographic results showed complete aneurysm occlusion in 43 aneurysms, nearly complete aneurysm occlusion in 54 aneurysms and less than 90% aneurysm occlusion in six aneurysms. Complications occurred in the treatment of 15 aneurysms, including eight procedural ruptures, six thromboembolic events and one case of early hemorrhage. Compared with larger aneurysms, treatment of very small aneurysms was associated with a higher rate of procedural ruptures (7.2% versus 4.4%) and procedural mortality (4.7% versus 2.7%) but a lower procedural morbidity (1.9% versus 4.0%). However none of these differences reached statistical significance (p = 0.186, p= 0.388, respectively). The retreatment rate was higher for the larger aneurysms (8.2% and 6.3%), but this was not significant either (p= 0. 496). At nine-month follow-up significantly more small aneurysms were found to have a stable occlusion grade compared to large aneurysms.Endovascular treatment of very small aneurysms is feasible with a lower retreatment rate compared to large aneurysms (> 3 mm). However the data also suggest that endovascular treatment of very small aneurysms might be associated with an increased risk of procedural ruptures and mortality. At nine-month follow-up results indicate significantly less compaction in the very small aneurysms.