Initial Experience with p64: A Novel Mechanically Detachable Flow Diverter for the Treatment of Intracranial Saccular Sidewall Aneurysms

Abstract

Background and purpose: Flow diverters are important tools for the treatment of intracranial aneurysms. We report a retrospective evaluation of the safety and efficacy of p64, a fully resheathable, detachable flow diverter, in the endovascular treatment of intracranial sidewall aneurysms.

Materials and methods: Results of 121 patients with 130 aneurysms (median neck size, 3 mm; median fundus size, 4 mm), treated from April 2012 through October 2014, were analyzed. Aneurysms were unruptured or beyond the acute SAH phase. Thirteen aneurysms were located in the posterior circulation. Twenty-three aneurysms had previous saccular treatment but no previous parent vessel stent placement. In 19 aneurysms, a combination of coiling and flow diversion was performed.

Results: Successful p64 deployment was achieved in 127/130 aneurysms. The average number of p64s used was 1.1 per aneurysm. The rates of transient and permanent morbidity and mortality were 5%, 1.7%, and 0.8%, respectively. Three-month DSA follow-up in 123/130 aneurysms showed complete occlusion in 58.5%. Nine-month DSA follow-up in 93/106 (87.7%) eligible aneurysms showed complete occlusion in 79.6%. Late follow-up (median, 496 days) has already been performed in 35 aneurysms, showing complete occlusion in 30 (85.7%).

Conclusions: p64 offers an efficacious treatment option for intracranial sidewall aneurysms with a high aneurysm occlusion and an acceptable complication rate. The possibility of repositioning or removing the device was an advantage. The higher attenuation may lead to fewer devices per case and early aneurysm occlusion. Long-term follow-up data are pending.

© 2015 by American Journal of Neuroradiology.

Figures

Fig 1.

Detachment mechanism of the p64. Eight bundles, each containing 8 wires, are attached to a slotted crown (A) and released from there by pulling a polymer hypotube in the proximal direction (B). Image courtesy of phenox.

Fig 2.

Manual detachment of the p64. The p64 comes with a torque device, which is locked over the hypotube to hold this hypotube in position (A). The detachment starts with unlocking the torquer, repositioning it, and again locking it approximately 15 mm proximally (B). A handle on the hypotube is then moved proximally (C).

Fig 3.

De novo unruptured paraclinoid aneurysm (7 × 5 mm) in a 63-year-old woman with a history of 2 spontaneous SAHs from 2 MCA bifurcation aneurysms, which had been clipped. The paraclinoid aneurysm was not considered ideal for coil occlusion alone (A), and the patient was reluctant to undergo surgery again. A single Morpheus 7 × 21 cm 3D coil (Medtronic, Dublin, Ireland) was inserted into the aneurysm. The aneurysm neck was then covered by a 4 × 18 mm p64 (B). DSA follow-up 93 days later reveals complete occlusion of the aneurysm (C).

Fig 4.

A small saccular aneurysm of the basilar trunk (4 × 3 mm) (A) in a 56-year-old woman. Both surgery and coil occlusion were not considered suitable treatment options. A 4.5 × 15 mm p64 was deployed in the basilar artery with complete coverage of the aneurysm (B). Although the procedure was well-tolerated, the patient developed a hemiparesis and dysarthria (mRS 3) 26 days later. MR imaging shows an ischemic pontine lesion (C); a Multiplate test (not shown) confirmed insufficient platelet function inhibition. Antiaggregation was switched to ticagrelor, and the patient subsequently recovered (mRS 1). Follow-up DSA after 28 days (D) and after 421 days (E) shows complete occlusion of the aneurysm.