Patient population
In this retrospective single-center study, 32 patients with 33 aneurysms treated from November 2015 to April 2019 for wide-necked unruptured intracranial aneurysms using the low profile Neuroform Atlas stent-assisted coiling were included.
Antiplatelet therapy
All patients underwent dual antiplatelet-therapy 7 days before the endovascular procedure with aspirin (100 mg) and clopidogrel (75 mg). After stent placement, double antiplatelet therapy has been continued for 3-6 months. Aspirin 100 mg was given until the 6th month.
Technique
All procedures were performed under general anesthesia; a bolus dose of 5000 IU of intravenous Heparin was administrated in all patients at the beginning of the procedure. The femoral artery was accessed through a 6F sheath introducer, usually combined with a 6F guide catheter (Envoy, Cordis, Bridgewater, New Jersey, USA) placed in the internal carotid or in the vertebral artery. A 3D-rotational angiography was performed in every patient to better define aneurysms’ dimensions and morphology, individuate the working projection and the stent size. Subsequently a microcatheter (Excelsior SL10, Stryker, Neurovascular, Fremont, CA, USA or Echelon 10, ev3 Inc., Plymouth, MN, USA) over a 0.014’’ neurovascular micro guidewire was used to reach the target vessel.
In most of the cases, the Neuroform Atlas stent was primarily placed across the aneurysmal neck, and then the microcatheter was used to recross the stent and to release the coils in the aneurysm sac; in some cases, a “jailing” technique was used.
The Neuroform Atlas stent is the first low-profile open-cell stent, with a hybrid design, that can be delivered through a 0.0165” or 0.017” catheter. The alternation of structures with open and closed cells makes the Atlas a hybrid design stent (Figure 1). As all nitinol-made stent, the Neuroform Atlas is not visible under fluoroscopy, but it has 3 proximal and distal radio-opaque markers.
It is suitable for vessels with a diameter range from 2 to 4.5 mm. Available stent diameters range from 3 to 4.5, with stent lengths of 15, 21, 24 and 30 mm.
Aneurysmal occlusion was first evaluated at the end of each procedure with final control angiograms according to the Raymond-Roy occlusion classification (RROC, [1]). This classification includes the degrees of occlusion: complete obliteration (1), residual neck (2), and residual aneurysm (3). Representative cases illustrating the procedure are shown in figure 2-7.
Follow up
All the patients enrolled underwent clinical evaluation at 3, 6 and 12 months. Radiological follow-up included contrast enhancement MRA at 3 and 6 months and DSA at 12 months, reproducing the working projections adopted during the treatment and performing a further RROC evaluation.
End Points
The primary endpoint was the recurrence rate, evaluated through the modified Raymond-Roy occlusion rate (RROC) at the end of each procedure and the 12 months DSA.
Safety endpoints were the morbidity rate, evaluated through the modified Ranking Scale (mRS) at 3, 6 and 12 months, and the mortality rate.