Patients
Our radiological database was reviewed for FDS implantations in the last 2 years, which had been performed including the anchoring employment of a pREset stent retriever. A sum of 213 cases of FDS implantations were performed in this period, however, in only 14 cases (6 male, 8 female patients, mean age of 59 years, ranging from 36 to 69 years) the use of a pREset was eventually necessary. In five cases the anchoring maneuver was performed in the posterior circulation - four times for FD treatment of ruptured dissecting aneurysms of the intradural vertebral artery, one time for treatment of a ruptured basilar artery blister. In nine cases, stent retriever anchoring was performed in the anterior circulation. In two cases the aneurysms were located in the intradural ICA, in five cases at the AcomA complex, in one case at the MCA and in another case at the PcomA origin.
A detailed overview of individual clinical and demographic information is provided in Additional file 1: Table S1.
Interventional procedure
Oral dual antiplatelet medication (ASA 500 mg and ticagrelor 180 mg) was started the day before the procedure in elective cases. At the day of the procedure the standard regimen, consisting of aspirin 100 mg (once a day, life-long) and ticagrelor 90 mg (twice a day, for 12 months), was inititated.
In case of emergency treatments, intravenous dual platelet inhibition was initiated after interdisciplinary consent was gained for FDS implantation. For this purpose, 500 mg aspirin and 180 μg eptifibatide (Integrilin, GSK) / kg bodyweight were given prior intervention, followed by oral administration of 180 mg ticagrelor after the procedure. The abovementioned standard regimen was continued accordingly.
All endovascular procedures were performed under general anaesthesia using a bi-planar angiography suite. Endovascular access was established via the right femoral artery using an 8-French introducer sheath. A bolus of heparin (5000 IU) was administered via the sheath initially. All procedures were performed by 2 each of 3 available neurointerventionalists with 5, 14 and 18 years of experience.
The stent-retriever-anchoring maneuver
All cases featured a distinctly curved or otherwise challenging vascular anatomy, which impeded primary catheterization via the microcatheter required for FDS implantation. Except for one case (Prowler Select Plus: Codman Neurovascular, USA), in all remaining patients the Excelsior SL-10 (Stryker Neurovascular, USA) was used for the comparatively demanding catheterization of the target segment in combination with a Traxcess 0.014″ 200 cm microwire (MicroVention Terumo, USA). After reaching the desired segment and confirmation of the correct intraluminal position of the flexible, first microcatheter by contrast injection, the respective pREset / pREset LITE stent-retriever was most carefully deployed for anchoring in a secure, distal location. This way a stable position of the exchange device (pREset / LITE) was achieved and otherwise potentially uncontrollable microcatheter-dislocations or microwire cam-outs were avoided. Figures 12, 3, and 4 illustrate the individual steps of the whole maneuver, Additional file 2: Video S1 shows the whole procedure as animation.
Only in one case – for treatment of an extradurally located dissecting aneurysm of the left handed ICA – a conventional pREset (Phenox, Germany) was carefully deployed in the distal ipsilateral M1 segment via the Prowler Select Plus to facilitate the insertion of larger 0.025″ microcatheter (Vasco+ 25, Balt, France), which eventually enabled the smooth implantation of a Silk FDS (Balt, France) for reconstruction of the injured segment.
In all remaining cases the smaller and significantly more versatile pREset LITE was used for microcatheter exchange as described above. Additional file 1: Table S1 provides the individual combination of the microcatheter of all treatments.
The Additional file 2: Video S1 and S2 file illustrates all steps of the anchoring maneuver and FDS implantation in great detail.
Additional file 2: Additional video of the preset anchoring maneuver. The video demonstrates each step of the technique in detail.
As an important side note - the introduction and advancement of the second microcatheter along the pREset necessitate distinct preparation, as the push wire is too short for a conventional exchange step. Therefore, after removal of the first microcatheter, the second microcatheter needs to be connected to a 10 ml or 20 ml syringe filled with sterile saline before it is advanced over the short push wire of the stent retriever. This way, the second microcatheter is filled with sterile saline and advancement over the pusherwire – which becomes apparent when it enters the saline-filled body of the syringe – is possible without air embolism. For this specific step a secure anchoring position of the stentretriever, for example in the middle of the M2 segment, is required to prevent dislocation of the device when advancing the microcatheter over the wire without being in control of the pusher wire. Consecutively, as soon as the pusher wire of the pREset emerges from the advanced microcatheter, a flushed hemostatic valve is to be connected to the microcatheter prior pREset removal and subsequent FDS implantation.