Initial Experience with a New Self-Expanding Open-Cell Stent System with Antithrombotic Hydrophilic Polymer Coating (pEGASUS Stent) in the Treatment of Wide-Necked Intracranial Aneurysms

Abstract

Purpose: We report our initial experience with endovascular embolization of intracranial aneurysms using this new self-expanding open-cell stent system (pEGASUS stent system) with the antithrombogenic hydrophilic polymer coating.

Materials and methods: We retrospectively reviewed all patients treated with stent-assisted coiling or the Woven EndoBridge device using the pEGASUS stent system between September 2022 and June 2023. Demographic, clinical, and angiographic data were analyzed as well as short-term follow-up, including procedural complication rates and aneurysmal occlusion rates using the Raymond-Roy occlusion classification (RROC).

Results: Twelve patients with 12 wide-necked intracranial aneurysms were treated with the pEGASUS stent system, including 2 acutely ruptured aneurysms embolized in an emergency setting. The treated aneurysms were located at the anterior communicating artery (25.0%), the basilar artery (50.0%), the middle cerebral artery (16.7%), and the internal carotid artery (8.3%). All stents were deployed successfully. Immediate complete aneurysmal occlusion (RROC class I) was achieved in 83.3% (10/12) and near-complete occlusion (RROC II) in 16.7% (2/12). No periprocedural complications occurred in patients treated in the elective setting. A single case of intraoperative in-stent thrombus formation occurred during the treatment of an acutely ruptured basilar aneurysm and was resolved with intravenous Tirofiban. No other periprocedural complications occurred. Eleven out of 12 patients were available for follow up (mean 7.4 months). Complete aneurysmal occlusion without in-stent stenosis (ISS) was seen in 10 patients (90.9%). One patient (9.1%) showed aneurysmal reperfusion (RROC IIIb) with asymptomatic moderate ISS.

Conclusion: Our initial results demonstrate that the pEGASUS stent system appears to be a safe and effective device for stent assisted embolization of wide-necked intracranial aneurysms. More data is necessary to evaluate long-term follow-up.

Keywords: Aneurysm; Hemorrhage; Stent.

Fig. 1.

Middle aged patient with an unruptured wide-necked anterior communicating artery aneurysm (arrowheads in A, B) in 3-dimensional-angiography (A) and frontal oblique digital subtraction angiography (DSA) (B) via the left internal carotid artery. Successful placement of the pEGASUS stent (Phenox) from the left A2 into the left A1 segment (white arrow in C indicates soft distal wire tip in the left A2 during the placement of the stent; black arrows in (C–E) indicate distal and proximal stent markers). Stable complete occlusion of the aneurysm (Raymond–Roy occlusion classification I) without in-stent stenosis in DSA follow-up after 8 months (F).

Fig. 2.

Middle aged patient with an initially ruptured and coiled basilar artery (BA) aneurysm at the left superior cerebellar artery origin. (A) Frontal oblique digital subtraction angiography via left vertebral artery shows a wide necked aneurysmal recanalization (white arrow in A). (B) After placement of a pEGASUS stent (Phenox) from the P2 segment of the left posterior cerebral artery into the BA (black arrow in B indicates distal stent markers), coiling led to an occlusion of the aneurysmal recanalization (white arrow in B). Four-month follow-up (C) shows an aneurysmal recanalization (Raymond–Roy occlusion classification IIIb, white arrow in C) and distal in-stent stenosis (black arrow in C). Note the dysplastic configuration of the basilar tip (white arrowhead in A).

Fig. 3.

Elderly patient with an acutely ruptured wide-necked bassilar tip aneurysm (white arrow in A). Digital subtraction angiography in Towne view (A, C) and in frontal working projection for coiling after stent placement (B). After successful placement of the pEGASUS stent (Phenox) from the P2 segment of the left posterior cerebral artery into the basilar artery (white arrowheads in B), thrombi led to an occlusion of the superior cerebellar artery (SCA) on both sides (black arrows in B). With intraarterial tirofiban administration after complete aneurysmal occlusion (white arrow in C), the thrombi could be resolved in large parts with complete recanalization of the left SCA and partial recanalization of the right SCA with a remaining distal occlusion (black arrows in C).