New device is “equivalent to, or better than” known flow diverters in initial experience

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In the first study to be published reporting on endovascular aneurysm treatment with the p64 flow modulation device (Phenox), Francesco Briganti and colleagues have found that the device provides a safe procedure with no technical complications.

Given that the experience with the endovascular treatment of cerebral aneurysms by flow diverters is limited to four devices, Briganti and colleagues sought to study and describe their initial experience with the p64 flow modulation device. The study was published in the Journal of NeuroInterventional Surgery.

The p64 flow modulation device is a braided mesh tube, composed of a 64 nickel-titanium alloy with radiopaque markers along the length of the device and eight proximal bundle markers. In their experience, the study authors note that “the option of retrieving the device after complete deployment is a clear advantage, owing to a controlled mechanical detachment; the p64 can be retrieved into the microcatheter and removed or repositioned until its complete length has been extruded.”

Between December 2014 and February 2015, six intracranial aneurysms in five patients (four women, mean age of 63 years) were treated with the device. Inclusion criteria were aneurysms difficult to treat by both coiling and clipping because of their anatomical configurations (wide neck, fusiform, posterior circulation). The endpoints were an assessment of periprocedural technical complications and early morbidity and mortality. The procedure was considered successful if the p64 completely covered the aneurysm (0.5–1cm proximal and distal to the aneurysm neck).

The authors report that, “no intraprocedural and periprocedural technical complications occurred. The device was retrieved and repositioned in in three patients. Immediate post-procedural angiography demonstrated reduced flow into all aneurysms. One patient harbouring a fusiform basilar artery aneurysm, treated in the subacute phase of subarachnoid haemorrhage showed clinical and radiological improvement and was discharged with no disability. In another patient with a large aneurysm at the basilar artery fenestration, treated with p64 and coils, MR showed decreased compression and oedema of the brainstem. The procedural disability score was unchanged (left hemiparesis, mRS 3). No neurological morbidity was seen immediately after the procedure and at discharge in the other three patients.”

At last follow-up, (ranges from 15 to 60 days), clinical conditions were stable with mRS 0 in four patients and unchanged mRS 3 in one. Further, there was no early or delayed aneurysm rupture, no subarachnoid haemorrhage, and no deaths.

Commenting on their initial experience, Briganti et al state: “The p64 has undoubted benefits over other flow diverter devices. These include the good radial force, the 100% retrievability, and the mechanical detachment. In our small series, we could deploy the device as intended in all cases; the flexibility of the system was good and its visibility allowed controlled manipulation. No adverse events related to the device occurred. Thus p64 is equivalent to, or better than, other known flow diverter devices, which have similar functions but only partial retrievability.”

The p64 flow modulation device received CE mark approval in 2012.