Endovascular treatment of medium and large intracranial aneurysms with large volume coils: A single-center experience
- Department of Neurosurgery, Hospital Nacional Guillermo Almenara Irigoyen, La Victoria, Lima, Peru,
- Department of Radiology University of Washington, Seattle, Washington, United States,
- Department of Neurosurgery, University of Washington, Seattle, Washington, United States,
- Department of Neurosurgery, Clínica Tezza, Santiago de Surco, Lima, Peru.
Giancarlo Saal-Zapata, Department of Neurosurgery, Hospital Nacional Guillermo Almenara Irigoyen, La Victoria, Lima, Peru.
DOI:10.25259/SNI_947_2021Copyright: © 2022 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Giancarlo Saal-Zapata1, Basavaraj Ghodke2, Melanie Walker3, Ivethe Pregúntegui-Loayza4, Rodolfo Rodríguez-Varela1. Endovascular treatment of medium and large intracranial aneurysms with large volume coils: A single-center experience. 12-Jan-2022;13:9
How to cite this URL: Giancarlo Saal-Zapata1, Basavaraj Ghodke2, Melanie Walker3, Ivethe Pregúntegui-Loayza4, Rodolfo Rodríguez-Varela1. Endovascular treatment of medium and large intracranial aneurysms with large volume coils: A single-center experience. 12-Jan-2022;13:9. Available from: https://surgicalneurologyint.com/?post_type=surgicalint_articles&p=11343
Background: Large volume coils are an alternative to conventional coils for the treatment of intracranial aneurysms. However, there are no published reports documenting occlusion and complication rates in medium and large intracranial aneurysms. Therefore, we present our results in this subgroup of aneurysms.
Methods: A single-center, retrospective analysis of consecutive patients treated with Penumbra coils 400 in aneurysms ≥7 mm was performed. Demographics, aneurysm features, procedural details, intraoperative complications, clinical outcomes, and occlusion rates were analyzed.
Results: Thirty-three patients were included for analysis, and a total of 33 intracranial aneurysms were analyzed. Mean age was 57.6 years (SD ± 12.4) and 85% of the patients were women. Large aneurysms represented 46% of cases. Paraclinoid (55%) followed by posterior communicating (30.3%) aneurysms was the most frequently treated. Ruptured and saccular aneurysms were found in 49% and 63% of the cases, respectively. The mean aneurysmal dimensions were 14.2 mm width, 11.9 mm length, 5.4 mm neck, and 2.4 dome-to-neck ratio. A dome-neck ratio
Conclusion: Endovascular treatment with PC400 coils is an effective and safe option for medium and large intracranial aneurysms with high occlusion rates, few complications, and good clinical outcomes at follow-up.
Keywords: Coils, Intracranial aneurysm, Large aneurysm, Paraclinoid aneurysm, Wide neck
Thirty years ago, Guglielmi detachable coil embolization was introduced as an alternative method for treating patients with intracranial aneurysms. Since that time, devices and techniques for endovascular repair of aneurysms have continued to evolve.[
Penumbra PC400 coils (Penumbra, Inc., Alameda, CA, USA) were approved for endovascular repair of intracranial aneurysms in 2011, and since then, studies have consistently reported increased packing density, fewer coils per aneurysm, decreased operative time, and superior cost-effectiveness.[
Herein, we present our experience in the treatment of medium and large intracranial aneurysms with PC400 coils and report efficacy in terms of occlusion rates as well as safety in terms of complications and clinical outcomes.
Between November 2017 and September 2019, consecutive patients who underwent embolization of ruptured and unruptured intracranial aneurysms with PC400 in the Hospital Nacional Guillermo Almenara Irigoyen from Peru were selected for this study. All patients signed a detailed informed consent before surgery. Medical records, angiographic images, and brain computed tomography scans were retrospectively analyzed. All patients who underwent embolization with PC400 presented with medium (7– 12 mm), large (>12–25 mm), and giant (>25 mm) aneurysms per International Study of Unruptured Intracranial Aneurysms trial criteria.
Age, sex, preoperative clinical status, angiographic aneurysm characteristics, endovascular techniques employed, intraoperative complications, postoperative clinical outcomes, and angiographic follow-up variables were included in the analysis. Angiographic features included (a) aneurysm location, (b) status of rupture, (c) length and width of the sac, (d) neck diameter, (e) number of coils, (f) dome-neck ratio, (g) presence of blebs, and (h) morphology (saccular or dysplastic). A wide-neck aneurysm was defined as a dome-neck ratio <2. Barami classification was employed for paraclinoid aneurysms.[
Penumbra coils 400 main characteristics
The PC400 is a new generation of bare platinum coils with a 0.020" outer diameter which has a stretch resistant nitinol inner wire. The larger diameter of these coils compared to conventional coils allows for improved packing density and offers 400% more volume per unit length than traditional coils. A 0.025" inner diameter microcatheter (PX Slim; Penumbra) is required to deploy the coils within the aneurysm sac. A large guide catheter (Neuron Max 088 8F) should be used when remodeling or stenting is considered.
Endovascular treatment: Technical considerations
All procedures were performed in a biplane angiography unit (Philips Allura Xper FD20/10, Philips Medical Systems, Best, The Netherlands) under general anesthesia. The femoral approach was used in all cases.
For coiling only, a 6F guide catheter was navigated into the artery of interest, whereas for balloon-assisted coiling (BAC) and stent-assisted coiling (SAC) cases, the Neuron Max 088 (Penumbra, Inc., Alameda, CA, USA) guide catheter was employed. The PX Slim microcatheter (ID = 0.025", Penumbra, Inc., Alameda, CA, USA) over a 0.014" microwire was used for navigation and catheterization of the aneurysm sac. Once the coil was completely deployed within the aneurysm sac, it was detached mechanically with the Penumbra Coil Detachment Handle (Penumbra, Inc., Alameda, CA, USA). For stenting in cases of coil protrusion into the parent artery, intraoperative dual antiplatelet therapy with 300 mg of aspirin and 300 mg of clopidogrel was initiated through a nasogastric tube. Low-profile Visualized Intraluminal Support Device (LVIS; MicroVention, Tustin, CA, USA), LEO (Balt, Montmorency, France), and Neuroform EZ (Stryker Neurovascular, Fremont, CA, USA) stents were employed. For remodeling cases, the Scepter XC balloon (MicroVention, Tustin, CA, USA) was employed.
In cases of complex anatomy of the carotid siphon and difficult catheterization of the aneurysm sac, reshaping of the microcatheter was performed. In cases of unruptured aneurysms, the size and length of the coil were chosen based on the maximum diameter of the aneurysm. For ruptured aneurysms, the coil was 1 mm undersized based on the maximum diameter. The mean number of coils per aneurysm was determined according to the size of the aneurysm.
Categorical variables were expressed as percentages whereas continuous variables as mean ± standard deviation. Differences among groups were obtained by t-test and Chi-square if variables were continuous or categorical, respectively. P < 0.05 was defined as statistically significant. The statistical software Stata v14.0 (StataCorp, Texas, USA) was used for analysis.
Baseline characteristics of the patients
Thirty-three patients harboring 33 aneurysms were analyzed. The mean age was 57.6 ± 12.4 years (27–81 years). Women represented 85% of the patients. At admission, patients with unruptured aneurysms presented a good preoperative mRS, except one patient with a pre-existing neurological deficit. Four patients (12%) with ruptured aneurysms showed a poor functional status, with a median Hunt-Hess of 2 (1–4). Three recanalized aneurysms were treated (9%), in which conventional coils were used. Overall, a good preoperative mRS was found in 28 patients (85%) and five patients presented a poor functional preoperative status. Detailed patient information is shown in [
Large aneurysms (>12 mm) represented 46% of the study cohort. Paraclinoid aneurysms were found in 18 cases (55%) followed by posterior communicating artery aneurysms in 10 cases (30%). Using Barami classification for paraclinoid aneurysms, the most frequent aneurysm was type 1A in 33% of the cases, followed by type 1B and type 3A, representing 28% and 17% of the cases, respectively. Sixteen aneurysms (49%) were ruptured. Saccular aneurysms were found in 21 cases (64%), followed by dysplastic aneurysms (36%). Only one aneurysm was located in the posterior circulation (ruptured basilar tip aneurysm). Overall, blebs were found in 40% of the aneurysms and in 69% of the ruptured cases. Differences among ruptured and unruptured aneurysms are shown in [
The mean aneurysm length was 14.2 mm ± 5.7 mm (7–26.8) and the mean width of the aneurysm sac was 11.9 mm ± 4.97 mm (3.1–22.5). The mean neck diameter was 5.4 mm. A neck diameter >4 mm was found in 25 aneurysms (76%). The mean dome-neck ratio was 2.4. Wide-neck aneurysms were found in 13 cases (39%) and most of them were between 7 mm and 12 mm (92%). The right-sided aneurysms were found in 63% of the cases. Differences among dome-neck ratios are shown in [
Intracranial navigation of the PX Slim microcatheter was successful in 100% of the cases, achieving the catheterization of the aneurysm sac. Coiling alone was performed in 15 cases (46%) followed by SAC in 14 cases (42%). Five of 14 SAC cases were done following coil protrusion or migration. Remodeling was employed in 4 cases (12%). Coiling was used in 46% of the ruptured cases, whereas SAC was used in 53% of unruptured cases. Three recanalized aneurysms were treated with stenting. Endovascular treatment with coil assistance was performed in 55% of the cases. The mean number of coils per aneurysm was 4.8, with a slight difference among wide necked (3.9 coils/aneurysm) and the rest (5.3 coils/aneurysm) which was not significant (P = 0.233). In five cases (9, 25, 28, 30, and 31), conventional coils were used to improve the occlusion. Two representative cases are shown in [
Endovascular treatment of a middle cerebral artery (MCA) aneurysm. (a) Three-dimensional rotational angiography of a right MCA aneurysm. (b) Navigation of PX Slim microcatheter into aneurysms sac. (c-f) Deployment of PC400 into the aneurysm sac and immediate angiographic control shows an adequate obliteration. (g and h) Follow-up angiographic control with 3D reconstruction shows a complete obliteration of the aneurysm (modified Raymond–Roy 1) with patency of distal vessels.
Endovascular treatment of a paraclinoid aneurysm. (a) Three-dimensional rotational angiography of a large paraclinoid aneurysm. (b-f) Navigation of PX Slim microcatheter into aneurysm sac, PC400 deployment within the aneurysm sac, and immediate angiographic control with 3D reconstruction. (g and h) Follow-up angiography with 3D reconstruction shows complete occlusion of the aneurysm (modified Raymond–Roy 1).
Coil protrusion occurred in 5 cases (16%) which required stent placement to avoid parent artery occlusion. In one of these five patients, despite stenting, internal carotid artery thrombosis occurred without clinical consequences due to a patent anterior communicating artery. Coil migration occurred in one patient who required stent placement, without clinical consequences. One patient developed a middle cerebral artery thrombosis which was treated with mechanical thrombectomy with the Solitaire stent retriever (ev3) with an uneventful clinical evolution. Taking into consideration the two thrombotic events, the complication rate was 6% and mortality rate was 0%.
At discharge, a good postoperative mRS was achieved in 29 patients (88%). Thirteen cases were ruptured aneurysms (45%). Three out of the four patients with poor outcome were ruptured. At follow-up, 26 patients were evaluated with 96% of good clinical outcomes.
Immediate and follow-up occlusion rates
Immediate mRROC Grades 1, 2, and 3A were achieved in 15%, 21%, and 64% of the cases, respectively. No case of a Grade 3B occlusion was observed. Overall, an immediate adequate obliteration was achieved in 36% of cases, including the three recanalized aneurysms. Twenty-six patients were evaluated with a mean follow-up period of 11.1 months (4.9– 22.8). The most of the aneurysms (65%) were between 7 mm and 12 mm. An occlusion Grades 1, 2, and 3B were achieved in 58%, 35%, and 7% of the cases, respectively. Only one recanalized aneurysm was followed up (mRROC 1). Overall, an adequate obliteration was achieved in 92% of cases at follow-up. Occlusion rates among aneurysm sizes are shown in [
In our study, endovascular treatment of medium and large aneurysms with PC400 coils was most commonly performed in unruptured and paraclinoid aneurysms. We observed obliteration rates of 92% at mid-term follow-up, a complication rate of 6%, minor technical difficulties during the procedure, and good clinical outcomes. In this cohort, three recanalized aneurysms were successfully treated with PC400 coils in which conventional coils were previously used.
The physical and mechanical properties of different type of coils have been described previously.[
Because of a relatively high proportion of aneurysms >12 mm (46%), the most reliable parameter to identify a wide-neck aneurysm was a dome-neck ratio <2, which was present in 39% of the aneurysms. Other parameters to asses a wide-neck aneurysm have also been described and can predict the use of adjunctive devices.[
Two studies reported a variable proportion of medium and large aneurysms (100% and 83.8%, respectively) with obliteration rates between 55% and 72.2% at follow-up. Coiling with adjunctive devices was used in 22% and 27% of the cases, respectively.[
An immediate obliteration was considered adequate (mRROC1 and mRROC2) in 36% of our cases. Differences among ruptured and unruptured aneurysms were not found in this scenario in our cohort. These results are in accordance with the previous reported good obliteration rates (13.2%–94%). The highest immediate obliteration rate reported with PC400 was that of Berge et al. with 94% of total immediate occlusion, nevertheless, all the aneurysms were <10 mm.[
Regarding technical complications, Popiela et al. reported a failed catheterization due to the stiffness of the PX Slim microcatheter.[
This study has certain limitations: the number of aneurysms treated was small and there was no comparison group with other types of coils to determine statistical differences or associations with the main outcomes. Other types of treatments for these types of aneurysms such as flow diversion were not employed to make comparisons. The rationale to use PC400 was based on the interventionalist decision, with no randomized selection of the cases and according to the aneurysm size, shape, and location. Fluoroscopy times and packing density were not collected in this cohort. Longer follow-up periods are required to determine long-term occlusion rates when large volume coils are used in this group of aneurysms. The study was retrospective and further prospective studies must be performed when these large volume coils are selected for the treatment.
The results of this study showed that the selection of large volume coils for endovascular treatment of medium and large intracranial aneurysms was technically safe – with a low complication rate and good clinical outcomes – and effective, with high obliteration rate at mid-term follow-up. In resource-constrained settings, PC400 coils offer a safe and effective endovascular alternative for medium and large intracranial aneurysms. Further studies including long-term follow-up are needed to demonstrate the good obliteration rates shown at mid-term follow-up in this study.
Patient’s consent not required as patients identity is not disclosed or compromised.
There are no conflicts of interest.
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