Introduction/purpose Flow diversion technology has dramatically changed the spectrum of vascular lesions treatable via endovascular means. Despite this, there are still many lesions that are not straightforward to treat with the pipeline embolization device, the only flow diversion device FDA-approved and readily available within the United States. Other flow diversion devices are on the horizon for the U. S. or already available in Europe, and now the second generation of pipeline is available, the pipeline flex. While the pipeline device has not changed, the delivery system no longer has a distal capture coil and the device is resheathable until almost completely deployed. The authors here chronicle the early pipeline flex experience in the United States, treating aneurysms that would otherwise have been difficult with the first generation device.

Materials and methods Patients at two North American centers, Washington University in St. Louis, MO and Semmes-Murphey Clinic in Memphis, TN, with aneurysms treated with the pipeline flex device were retrospectively identified for inclusion in this study. Patients were selected for treatment with pipeline flex due to tortuous anatomy in proximity to the aneurysm requiring treatment, or because it was felt that there was a high likelihood the device would need to be resheathed and repositioned in the course of deployment. Aneurysm size and location, device size and number used, and procedural complications and follow up were recorded. Due to reports of early aneurysm rupture after flow diversion in certain aneurysms, patients with large or dysmorphic-appearing aneurysms or enlarging aneurysms were treated in our series with coil embolization in the same setting as flow diversion.

Results Nine patients in total had aneurysms treated with the pipeline flex embolization device. Age ranged from 12 to 75 years. Each patient had one aneurysm treated and each aneurysm was treated with a single device, with the exception of one patient who required two devices. The patient requiring two devices had a fusiform aneurysm of the A2 segment of the ACA, which required placing the flow diverters into a full 360-degree loop of the vessel. Three aneurysms were treated with coils in addition to flow diversion. In multiple cases, the device was resheathed and repositioned prior to full deployment. In at least one case, a device needed to be resheathed and removed without deployment, which was done without difficulty - this was also the patient with the fusiform ACA aneurysm. All nine aneurysm treatments were technical successes without procedural complication. To date, no aneurysms have ruptured following treatment.

Conclusion The pipeline flex device has an improved delivery system, allowing easier treatment of aneurysms in tortuous anatomy and allowing the device to be resheathed and repositioned if needed during the course of deployment. This allowed uncomplicated treatment of aneurysms that the authors felt would be difficult to treat with the first generation device. These aneurysms will need to be followed with formal angiogram, but as the implant itself has not changed from the first generation pipeline embolization device, one would expect follow up results to be similar.

Disclosures C. Nickele: None. C. Moran: 2; C; EV3 Covidien. 3; C; EV3 Covidien. A. Arthur: 1; C; Sequent, Siemens. 2; C; Codman, Microvention, Stryker, Medtronic, Penumbra, Sequent.