- Department of Neuroradiology, The Royal London Hospital, London, UK
- Neuroradiological Clinic, Neurocenter, Leipzig, Germany
- Department for Neuroradiology, University Hospital Leipzig, Leipzig, Germany
- Neurological Clinic, Neurocenter, Leipzig, Germany
- Neurosurgical Clinic, Neurocenter, Klinikum Stuttgart, Leipzig, Germany
- Medical Faculty, University Duisburg-Essen, Duisburg, Germany
Neuroradiological Clinic, Neurocenter, Leipzig, Germany
DOI:10.4103/sni.sni_243_18Copyright: © 2018 Surgical Neurology International This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms.
How to cite this article: Pervinder Bhogal, Elina Henkes, Stefan Schob, Muhammad AlMatter, Victoria Hellstern, Hansjörg Bäzner, Oliver Ganslandt, Hans Henkes, Marta Aguilar Pérez. The use of flow diverters to treat small (≤5 mm) ruptured, saccular aneurysms. 30-Oct-2018;9:216
How to cite this URL: Pervinder Bhogal, Elina Henkes, Stefan Schob, Muhammad AlMatter, Victoria Hellstern, Hansjörg Bäzner, Oliver Ganslandt, Hans Henkes, Marta Aguilar Pérez. The use of flow diverters to treat small (≤5 mm) ruptured, saccular aneurysms. 30-Oct-2018;9:216. Available from: http://surgicalneurologyint.com/?post_type=surgicalint_articles&p=9051
Background:There is limited published literature on the use of flow diverting stents (FDS) to treat ruptured intracranial aneurysms in the acute stage. We present our experience of using FDS to treat small (≤5 mm) ruptured aneurysms.
Methods:We retrospectively identified all patients with ≤5 mm ruptured aneurysms treated exclusively with FDS between February 2009 and February 2016. We recorded demographic data, the Hunt and Hess score, aneurysm location and size, therapeutic intervention, immediate angiographic and clinical result, and clinical and radiological follow-up information.
Results:We identified seven patients (four females) with average age 59.8 ± 10 years (range 48–75). The average aneurysm fundus size was 2.7 ± 0.76 mm (range 1–4 mm). The average time from ictus to treatment was 6.3 days (range 1–14 days) and there were no cases of repeat rupture prior to treatment or intraoperative rupture. Angiographic follow-up was available in five patients. At initial follow-up, aneurysms (100%) were completely occluded raymond roy classification 1 (RRC 1). None of the aneurysms re-ruptured following treatment. Clinically, six patients were discharged with good functional outcome modified Rankin Score (mRS ≤2). There were no mortalities.
Conclusion:The use of FDS to treat small, ruptured, saccular aneurysms is feasible; however, the use of FDS should not be considered first-line treatment. Further studies are required to determine the safety and efficacy of the use of FDS in the acute situation.
Keywords: Flow diverter, ruptured aneurysm, subarachnoid haemorrhage
The introduction of flow diverting stents (FDS) represented a paradigm shift in the way intracranial aneurysms were treated and for the first time a treatment option that allowed reconstruction of the diseased parent artery became available. Although the exact mechanism of action by which flow diverters act is debated, there is a general consensus that initially these devices alter the intra-aneurysmal hemodynamics to promote thrombosis with subsequent formation of neo-intima over the braided stent wires and complete exclusion of the aneurysm from the circulation.[
In this study, we present our data on the treatment of acutely ruptured, small (≤5 mm), saccular aneurysms with FDS.
We searched our prospectively maintained database, for patients treated in our institution between February 2009 and February 2016, with ruptured, saccular aneurysms ≤5 mm in maximal size treated with FDS in the acute and early subacute period (≤14 days). Patients treated prior to the acute rupture with clipping, for example, ruptured remnant, were also included. Exclusion criteria included fusiform, blister, and dissecting aneurysms. We excluded aneurysms that were coiled acutely and then treated with flow diversion either during the same hospital admission or at a later date.
For each patient, we recorded demographic data, clinical presentation, aneurysm location, therapeutic intervention, immediate angiographic and clinical result, and clinical and radiological follow-up information.
All treatments were performed under general anesthesia. A single type of flow diverter, the p64 (Phenox, Bochum, Germany), was used in all cases and this was based upon the higher mesh density compared to the Pipeline Embolization Device (PED) (Medtronic, Dublin, Ireland) which is the only other flow diverter available in our department.
Dependent upon the clinical state of the patient, premedication was given either on table or orally at least 3 h prior to the operation for patients able to take oral medications. For patients able to take oral medications, loading doses of aspirin (500 mg) and ticagrelor (180 mg) were given on the morning of the surgery. The effectiveness of the antiplatelet medication was tested using both the VerifyNow (Accumetrics) and Multiplate (Roche) analyzers to ensure adequate anti-aggregation prior to the operation and at least 3 h post-medication. For patients unable to take oral medication prior to the operation, an intravenous bolus dose of weight-adjusted eptifibatide was given on table. Subsequently, loading doses of ticagrelor via NG tube (180 mg) and IV aspirin (500 mg) were given at the end of the procedure. In both situations, the effectiveness of the antiplatelet medication was tested 24-h post-procedure using the VerifyNow and Multiplate analyzers.
The post-procedural antiplatelet regimen consisted of ticagrelor (90 mg twice daily) continued for 12 months following treatment and aspirin (100 mg once daily) continued for life.
The preoperative brain imaging was carefully assessed to determine if an external ventricular drain (EVD) was required or may be required. Signs of obstructive hydrocephalus, intraventricular blood, or evidence of raised intracranial pressure were used as markers to guide the insertion of an EVD. The EVD was inserted prior to the initiation of antiplatelet medication. Following insertion of the EVD, repeat imaging was performed to assess both the positioning of the EVD and to exclude hemorrhage along the EVD tract. Antiplatelet medication was commenced only after hemorrhage following drain insertion had been excluded.
All procedures were performed via the right common femoral route using a 6-Fr access system as standard. All procedures were performed under heparin anticoagulation with a 5000-IU bolus dose at the start of the procedure and subsequent 1000-IU bolus doses every hour to maintain the activated clotting time between 2 and 2.5 times the baseline.
Procedural assessment and follow-up
Patency and flow characteristics within the aneurysm and parent artery were assessed angiographically immediately after placement of the FDS and during follow-up. Follow-up axial imaging, either CT or MRI, were performed prior to the discharge of the patient. A CT angiogram was routinely performed if the patient developed signs or symptoms of delayed cerebral vasospasm.
Procedural follow-up was performed initially at 3–6 months, again at 9–12 months, and then once per year. Standard angiographic projections were used to assess the patency of the vessels and the aneurysms in addition to angiographic projections that repeated those used during the treatment. Aneurysm occlusion was graded as either completely excluded, minor remnant, major remnant, or unchanged (patent) and additionally using the 3-point Raymond–Roy classification.[
In total, we identified 320 patients with ruptured aneurysms ≤5 mm in size. We identified seven patients (four females) that met our inclusion and exclusion criteria. The average age of the patients was 59.8 ± 10 years (range 48–75). The average aneurysm fundus size was 2.7 ± 0.76 mm (range 1–4 mm). The average neck width was 2.5 ± 0.5 mm (range 1–5 mm) with average aspect ratio 1.1. The majority of aneurysms were located in the anterior circulation (n = 5) with three aneurysms located in the clinoidal or supraclinoidal segment of the internal carotid artery (ICA), one aneurysm located at the A1/A2 junction, and one aneurysm on the pericallosal artery. In the posterior circulation, one aneurysm was located on the superior cerebellar artery and one aneurysm on the posterior cerebral artery. None of the aneurysms was previously treated.
In terms of clinical presentation, three patients presented with Hunt and Hess grade 1, two patients with Hunt and Hess grade 2, one patient with Hunt and Hess grade 3, and one patient with Hunt and Hess grade 5 subarachnoid hemorrhage. One patient had an EVD inserted and in one patient a lumbar drain was inserted. There were no cases of hemorrhage secondary to drain insertion or following initiation of antiplatelet medication. The results are summarized in
Delivery of the flow diverter was feasible in all cases. The p64 was used in all cases. In a single patient, two p64 flow diverters were used. In the remaining six patients, a single FDS was deployed. The average time from ictus to treatment was 6.3 days (range 1–14 days) and there were no cases of repeat rupture prior to treatment. Treatment was significantly delayed in two patients (patient 4 and 7). In patient 4, this was due to unsuccessful surgical attempt at clipping and then the development of vasospasm. In the patient 7, the patient presented in a delayed fashion and initially remained undiagnosed in a nonspecialist hospital.
The use of flow diversion was taken after multidisciplinary team discussion in six cases and based principally around the unfavorable morphology and anatomical configuration of the aneurysm. In all cases, the aneurysms had unfavorable aspect ratios, ≤1.3 in all cases, which would have likely necessitated the use of stent-assisted coiling. Furthermore, given the small size of the aneurysms (2.7 ± 0.75 mm), we felt that catheterization of the aneurysm, without the protection of a balloon, would pose a risk of intraoperative rupture. In one case, patient 4, the patient initially went to surgery. At the time of surgery, the rupture point of the aneurysm was found to be at neck of the aneurysm and therefore clipping of the aneurysm would have involved occlusion of the pericallosal artery. Similarly, because of the rupture point, endovascular coiling was also felt to be high risk.
There were no cases of intraoperative aneurysm rupture and there were no intraoperative complications.
Angiographic and clinical follow-up
Angiographic follow-up was available in five patients. At initial follow-up performed on average at 3.4 months after the procedure, five aneurysms (100%) were completely occluded (RRC 1). In two patients, there is no follow-up angiographic imaging available [Figures
Patient 4 presented with diffuse subarachnoid hemorrhage (a) and a solitary aneurysm of the A1/2 junction [(b and c) white arrows). After an attempted clipping, the patient was referred for endovascular treatment with a single p64 flow diverter (d and e). There were no intraoperative complications and there was no evidence of recurrent hemorrhage. Follow-up angiography at 4 months revealed complete exclusion of the aneurysm and asymptomatic, mild/moderate in stent stenosis (f)
Patient 6 presented with a localized subarachnoid hemorrhage (a, short white arrow) and a solitary aneurysm of the ICA (b, long white arrow). The wide neck would have necessitated stent-assisted coiling, and therefore, flow diversion was thought to represent a safer treatment option (c). Follow-up angiography at 3 months showed virtually complete exclusion of the aneurysm from the circulation (d). There was no evidence of repeat hemorrhage and no clinical or radiological complications following the implantation of the p64 flow diverter
None of the aneurysms re-ruptured following treatment. Clinically, six patients were discharged with good functional outcome (mRS ≤2), and the remaining patient was discharged with mRS 5, which was her baseline neurological status. There were no mortalities. The results are summarized in
Stent-assisted coiling is a widely used and accepted treatment option for unruptured intracranial aneurysms; however, the use of stents in the acute situation is generally avoided unless absolutely necessary. The use of stents, either alone or in conjunction with endovascular coiling, in the acute situation is believed to expose patients to an elevated risk of bleeding-related complications if interventions such as the insertion of an EVD are required.[
Several studies have documented the use of FDS in the acute situation,[
When considering the benefits and risks of FDS as a treatment option for small, ruptured aneurysms, it is important to compare with the risks of standard endovascular coiling. These risks relate to the difficulty in obtaining a stable microcatheter position as well as to the perceived increased risk of perforation related to the small, confined space. However, aneurysms smaller than 3 mm are routinely coiled and advances in imaging, increasing operator experience, and the widespread use of adjunctive devices have all assisted in making coiling of these tiny aneurysms feasible. Recently, Brinjikji et al.[
The introduction of surface-modified FDS with the requirement for only a single antiplatelet medication may prove particularly useful in the acute situation. We are aware of only a single publication documenting the use of these new devices in an acutely ruptured fusiform aneurysm.[
The retrospective design and small numbers limit our study. It is a single-center study and all the aneurysms were treated with a single type of FDS; extrapolation of these results to other types of FDS may not be feasible. Although we focused our analysis on small aneurysms, the technique could be used for larger aneurysms; however, again the applicability of our results is difficult to determine. Furthermore, as all the aneurysms are saccular, we are unsure of the applicability of the technique to fusiform aneurysms or to blister aneurysms.
The use of FDS to treat small, ruptured, saccular aneurysms is feasible, and in our small series, we achieved reasonable radiographic and clinical outcomes with no cases of re-rupture. Although the use of FDS should not be considered first-line treatment, it represents a potential alternative treatment option when standard endovascular coiling or neurosurgery may not be feasible.
Financial support and sponsorship
Conflicts of interest
PB and MAP serve as proctors and consultant for Phenox. HH is share holder and co-founder of Phenox.
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