The other main concern with the treatment of small aneurysms (less than 4 mm) is safety, namely the concern of intraprocedural rupture or thromboembolic events. The ATENA Study showed that the risk of intraprocedural aneurysm rupture was significantly higher in small aneurysms (3.7% for 1-6 mm vs 7% for 7-15 mm; p= 0.008). The rate of failure of EVT was significantly higher in very small unruptured aneurysms compared to larger aneurysms (13.7% vs 3.3% respectively). This is likely related to several factors. Microcatheterization of the aneurysm sac may be challenging due to aneurysm size and placing even the smallest coils, maybe challenging in small aneurysms. In the same series as above [13 14], a 10.4% overall procedural complication rate was found. There were 24 embolic events, 11 coil protrusions and 4 aneurysm ruptures, while Oishi found a 3.8% thromboembolic event rate and a 1.4% risk of aneurysm rupture. Nguyen et al reported an intraprocedural rupture rate of 11.7% in aneurysms less than 3 mm in diameter [16]. In a meta-analysis, Brinjikji et al found a procedural rupture rate of 8.3% in small aneurysms while Spiotta et al demonstrated a 13.5% rate of intraprocedural rupture in ruptured aneurysms less than 4 mm [17] Other studies have found morbidity and mortality rates that range from 0.8%-7% and 0-1.4% [13 14 18]. The introduction of the Microvention HyperSoft® 3D line of coils with sizes from 1 to 5mm may help reduce these historical risks of failure to treat and intraprocedural rupture. The complex shape of the coils may allow for stable framing of the aneurysms followed by dense packing of the aneurysm sac and neck, therefore preventing recurrence. The softness of the coils may allow for increased confidence and safety when treating these aneurysms, which may be expressed as a reduction of intraprocedural complications.