The p48MW Flow Diverter-Initial Human Experience

Abstract

Background and purpose: The use of flow diverters to treat aneurysms arising from small caliber parent vessels has been reported. This article reports the results of the first in experiences with the p48MW (p48 Movable Wire) in humans, a device specifically designed to target vessels 1.75-3 mm in diameter.

Methods: This monocentric study retrospectively reviewed the prospectively maintained database to identify all patients treated with the p48MW device between January 2017 and January 2019 at this institution. Patient demographics, aneurysm characteristics, angiographic and clinical follow-up were recorded as well as complications.

Results: A total of 25 patients (20 female) with an average age of 55 ± 12.9 years (range 34-84) with 25 aneurysms were identified. The majority of the aneurysms was located in the anterior circulation (19/25, 76%). The average aneurysm dome width was 3.98 ± 3.6 mm (range 1.2-13 mm). Complete occlusion was seen in 18/24 (75%) aneurysms with neck remnants in 1/24 (4.2%) and continued aneurysm filling seen in the remaining cases (5/24, 20.8%). Adequate occlusion was seen in 79.2% of aneurysms (Raymond Roy Classification [RRC] grade I or II) during the follow-up period. There was a single technical complication with inappropriate deployment of the first p48MW. There was a single clinical complication (4%); however, the patient made a complete recovery (modified Rankin Scale [mRS] 0) and one patient died secondary to uncontrollable status epilepticus following acute subarachnoid hemorrhage unrelated to the treatment.

Conclusion: The p48MW is safe and effective for the treatment of aneurysms including those arising from distal vessels.

Keywords: Aneurysm; Flow diverter; New devices; P48 MW; Stent.

Fig. 1

The p48MW has an independently movable central wire with an atraumatic tip (a, black arrow) that is clearly visualized under fluoroscopy (b, black arrow). There is a radio-opaque marker that delineates the point of no return after which the stent cannot be recapture (b, white arrow). One of the key features of the p48MW is the central, independently movable wire. The atraumatic tip can be advanced/withdrawn by the operator during the procedure (c, d, black arrow). The radio-opaque marker (c, d, white arrow) delineates the point of no-return for device deployment

Fig. 2

The atraumatic distal tip can be clearly seen within the delivery microcatheter (a, black arrow) as well as during deployment (b, black arrow). The proximal marker (a, b, black circle) can also be easily seen within the microcatheter and after deployment allowing for accurate device positioning

Fig. 3

A patient (patient no. 25) with multiple intracranial aneurysms found during investigation for a stroke underwent treatment of a pericallosal aneurysm (a) using a single p48MW 2 × 12 mm. There were no intraprocedural complications. Persistent flow was seen within the aneurysm at the end of the procedure (b). The device is well seen on flat panel rotational angiography (c) thanks to the DFT construction and flow can be seen within the covered branches as well as the treated aneurysm. On follow-up angiography the aneurysm is completely excluded from the circulation (d)

Fig. 4

Patient 5 had an unruptured right MCA bifurcation aneurysm that was found incidentally (a). After discussion with the patient they opted for endovascular treatment despite the low risk of rupture. A single p48MW 3.0 × 9 mm was deployed with evidence of good wall apposition and continued filling in the covered branch (b, c). The device is clearly visualized on both flat panel rotational angiography (c) and fluoroscopic imaging (d). There was persistent filling of the aneurysm dome on the follow-up angiography performed at 12 months; however, this had decreased following treatment (e)

Fig. 5

An incidental carotid bifurcation aneurysm (a) was found in a patient (patient no. 19) undergoing investigation for headache. After discussion with the patient endovascular treatment for the aneurysm was performed that involved deployment of a single p48MW 3.0 × 18 mm from the A1 and back into the terminal ICA crossing the aneurysm origin (b, c, white arrow). There were no intraoperative complications; however, the patient was found to have unilateral weakness postoperatively. An urgent MRI revealed diffusion restriction within the caudate head (d, dashed white arrow) suggestive of infarction within the territory of the artery of Heubner. A repeat catheter angiogram was performed which revealed patency of the FDS and the Heubner artery (e, dashed black arrow). The patient made a complete recovery and the mRS was 0 at 90 days and at last clinical follow-up (12 months). The aneurysm was completely excluded from the circulation at follow-up angiography (12 months) (f)