Introduction Coiling of very small (≤ 3mm) aneurysms is technically difficult and is reported to have a high intra-procedural rupture rate. This is related to both catheter stability inside the aneurysm and the small aneurysm size with inherent increased pressure on the aneurysm walls during coil delivery.

Recently, a new range of extra-soft platinum coils SMART coil [PENUMBRA] have been introduced, which are supposedly extremely soft, cause less catheter displacement and conform better to the shapes of the very small aneurysms.

We report the intraprocedural complication rates, angiographic results and clinical outcomes of 13 consecutive patients harbouring very small intracranial aneurysms (≤3 mm) treated with extra soft coils SMART(PENUMBRA) in a single neurosciences centre in NE England from Feb 2016 to Feb 2017.

Materials and methods: Retrospective analysis of the neurovascular database from 19 Feb 2016- 7 Feb 2017 identified 13 patients (with 13 very small aneurysms) treated with the extra-soft SMART (PENUMBRA) coil system.

The relevant case notes, angiography, cross-sectional imaging and follow up clinic data was reviewed. In this group of patients we looked at the incidence of intra-procedural complications, the use of adjunctive devices, clinical outcomes, angiographic recurrences.

Results 13 patients (8 Female and 5 male) harbouring very small intracranial aneurysms were treated with extra soft SMART (PENUMBRA) coils.

Age range was from 43–71 years (median 54 years). There were 7 acutely ruptured and 6 unruptured aneurysms (3 neck remnants) comprising of 5 ACOM, 1 A1,2 M1,3 MCA and 2 Basilar aneurysms.

7 aneurysms measured 3mm, 5 aneurysms measured 2 mm and 1 aneurysm measured 2.5 mm in size respectively.

22 extra soft SMART (PENUMBRA), 3 soft SMART (PENUMBRA) and 1 Axium Prime (MEDTRONIC) coils were used for the treatment. 10 aneurysms were treated purely with the extra soft coil range, the other three aneurysms were treated with either the soft SMART or the Axium PRIME coils in addition to the extra soft coils. The average number of coils used per case was 2 coils.

Adjunctive devices were used in 9 cases (6 balloons and 3 stents).

Coils were delivered into these small aneurysms from the neck of the aneurysm. There was no microcatheter displacement during coil delivery. No re-sheathing or redeployment was needed in these cases. No intraprocedural rupture, coil migration, coil stretching, failure of coil detachment or intra procedural thrombosis was noted. All coils were detached. There was no mortality or procedure related morbidity in these patients with no change in the baseline mRs after the procedure.

6 month FUMRA/ catheter angiogram is available in 7/13 patients which revealed complete aneurysm occlusion with no remnants in 6 patients and a tiny neck remnant in 1 patient which is under observation. There are no rebleeds in this cohort of patients.

Conclusion The extra soft SMART (PENUMBRA) coils appear to be safe and effective in the treatment of otherwise difficult to treat very small intracranial aneurysms. Selection of appropriate coil size and technique allows a favourable outcome in coiling of very small aneurysms.

Disclosures: R. Padmanabhan: 3; C; PENUMBRA.