Treatment outcomes of large and giant intracranial aneurysms according to various treatment modalities

CFD investigations of a shape-memory polymer foam-based endovascular embolization device for the treatment of intracranial aneurysms

The hemodynamic and convective heat transfer effects of a patient-specific endovascular therapeutic agent based on shape-memory polymer foam (SMPf) are evaluated using computational fluid dynamics studies for six patient-specific aneurysm geometries. The SMPf device is modeled as a continuous porous medium with full expansion for the flow studies and with various degrees of expansion for the heat transfer studies. The flow simulation parameters were qualitatively validated based on the existing literature. Further, a mesh independence study was conducted to verify an optimal cell size and reduce the computational costs. For convective heat transfer, a worst-case scenario is evaluated where the minimum volumetric flow rate is applied alongside the zero-flux boundary conditions. In the flow simulations, we found a reduction of the average intra-aneurysmal flow of > 85% and a reduction of the maximum intra-aneurysmal flow of > 45% for all presented geometries. These findings were compared with the literature on numerical simulations of hemodynamic and heat transfer of SMPf devices. The results obtained from this study provide a novel and practical framework for optimizing the design of patient-specific SMPf devices, integrating advanced computational models of hemodynamics and heat transfer. This framework could guide the future development of personalized endovascular embolization solutions for intracranial aneurysms with improved therapeutic outcome.

Pipeline Embolization device for the treatment of unruptured intracranial saccular aneurysms: a systematic review and meta-analysis of long-term outcomes

INTRODUCTION

The pipeline embolization device (PED) is commonly used for intracranial aneurysm treatment. While its effectiveness for certain types of aneurysms is well-established, its efficacy for saccular aneurysms remains controversial. We aimed to assess the long-term outcomes of PED treatment for unruptured intracranial saccular aneurysms.

METHODS

Systematic review and meta-analysis were conducted following PRISMA guidelines. Studies with at least one year of follow-up after PED treatment for saccular aneurysms were included. The primary endpoint was angiographic aneurysm occlusion at long-term follow-up (≥ 12 months), and the secondary outcome was long-term complications. We conducted a meta-regression analysis to explore potential sources of heterogeneity across studies.

RESULTS

Eleven studies of 797 patients with 963 aneurysms were included. Long-term angiographic occlusion rate was 85% (95% CI, 77-91%; p < 0.01), symptomatic ischemic stroke rate was 1% (95% CI, 0-3%; p < 0.01), rupture rate was 1% (95% CI, 0-2%; p = 0.02), and intracranial hemorrhage (ICH) rate was 0.2% (95% CI, 0-1%; p = 0.11). Meta-regression analysis revealed a non-significant decreasing trend per year for aneurysmal occlusion, ischemic stroke rate, delayed aneurysmal rupture, and ICH.

CONCLUSION

PED demonstrates high long-term occlusion and low complication rates, suggesting it is a safe and effective treatment option for saccular aneurysms. Additionally, newer devices exhibit reduced thrombogenic profiles and safety with decreasing trends in ICH, ischemic stroke, and delayed aneurysmal rupture.

CFD investigations of a shape-memory polymer foam-based endovascular embolization device for the treatment of intracranial aneurysms

The hemodynamic and convective heat transfer effects of a patient-specific endovascular therapeutic agent based on shape memory polymer foam (SMPf) are evaluated using computational fluid dynamics studies for six patient-specific aneurysm geometries. The SMPf device is modeled as a continuous porous medium with full expansion for the flow studies and with various degrees of expansion for the heat transfer studies. The flow simulation parameters were qualitatively validated based on the existing literature. Further, a mesh independence study was conducted to verify an optimal cell size and reduce the computational costs. For convective heat transfer, a worst-case scenario is evaluated where the minimum volumetric flow rate is applied alongside the zero-flux boundary conditions. In the flow simulations, we found a reduction of the average intra-aneurysmal flow of > 85% and a reduction of the maximum intra-aneurysmal flow of > 45% for all presented geometries. These findings were compared with the literature on numerical simulations of hemodynamic and heat transfer of SMPf devices. The results obtained from this study can serve as a guide for optimizing the design and development of patient-specific SMPf devices aimed at personalized endovascular embolization of intracranial aneurysms.

Flow diversion for compressive unruptured internal carotid artery aneurysms with neuro-ophthalmological symptoms: a systematic review and meta-analysis

BACKGROUND

Data on the safety and efficacy of flow diverters (FD) for the treatment of unruptured internal carotid artery (ICA) aneurysms with compressive neuro-ophthalmological symptoms (NOS) are scarce and comprise mainly small case series.

METHODS

We performed a search of three databases and included series with ≥10 patients, with unruptured aneurysms of the ICA and NOS, treated with FD. Random-effects analysis of treatment results and safety was performed.

RESULTS

A total of 22 studies reporting on 594 patients were included. Pooled proportions of NOS recovery, improvement, transient and permanent worsening were: 47.4% (95% CI 35.0% to 60.1%); 74.5% (95% CI 67.9% to 80.2%); 7.1% (95% CI 3.3% to 14.7%); and 4.9% (95% CI 3.2% to 7.4%), respectively. Rates of complete recovery and improvement in patients with isolated visual symptoms were 30.6% (95% CI 12.5% to 57.7%) and 56.6% (95% CI 42.3% to 69.9%). Isolated oculomotor symptoms recovered completely in 47.8% (95% CI 29.9% to 66.3%) and improved in 78% (95% CI 69.2% to 84.9%). Morbidity occurred in 5% (95% CI 2.8% to 9%) and mortality in 3.9% (95% CI 2% to 7.5%) of patients. An increased likelihood of symptom improvement was observed when treatment was performed early (<1 month) after symptom onset (OR=11.22, 95% CI 3.9% to 32.5%).

CONCLUSION

Flow diversion promotes recovery or improvement of compressive symptoms in a large proportion of patients but is associated with significant rates of morbidity and mortality. Transient and permanent NOS worsening is not uncommon. Early treatment is of utmost importance, as it increases the likelihood of symptom improvement more than 10-fold.

Microsurgical Treatment of Previously Coiled Giant Aneurysms: Experience with 6 Cases and Literature Review

OBJECTIVE

Surgical treatment of insufficiently embolized (coiled) or recurrent giant aneurysms has not been well established in the literature. The aim of this study is to bring up the surgical difficulties of these rare aneurysms and to offer solutions.

METHODS

A database was queried for giant aneurysms that had been previously embolized and subsequently required surgical treatment. We only found 29 aneurysms in the literature and here, we report 6 more surgical cases with patient characteristics, radiological studies, applied surgical techniques, and outcomes which were reviewed retrospectively.

RESULTS

Four females and 2 males, with a mean age of 45.6 years took part in the study. The most common aneurysm location was the middle cerebral artery. While 5 aneurysms were successfully clipped, 1 was excised and the neck was closed with micro sutures. The coils were compulsorily removed in 3 patients. Postoperative digital subtraction angiography confirmed total occlusion of the aneurysms in all cases. Overall morbidity was 16.6%. There was no mortality. No recurrence was observed in the angiographic follow-up (mean 22.6 months, range 7-47 months). The literature review also determined that 97.1% of 35 previously coiled giant aneurysms (including ours) were occluded using various surgical techniques, with 82.8% good outcome.

CONCLUSIONS

Surgical clipping is a safe and effective procedure for the treatment of insufficiently embolized or recurrent giant aneurysms after coiling. If possible, the coils should not be removed. However, if safe clipping is not possible due to the coils, the removal of the coils should not be avoided.

Endovascular treatment of pediatric basilar artery aneurysms: case series and literature review

PURPOSE

Pediatric basilar artery aneurysms are rare and challenging to treat. Microsurgical options and standard endovascular coiling are often undesirable choices for treatment of this pathology. Additional endovascular strategies are needed.

METHODS

Presentation, diagnosis, and management of pediatric basilar aneurysms were reviewed, with an emphasis on endovascular treatment strategies. Our case series of 2 patients was presented in detail, one treated with flow diversion and vessel sacrifice and one treated with stent-assisted coiling. An extensive review of the literation was performed to find other examples of pediatric basilar artery aneurysms treated with endovascular techniques.

RESULTS

Twenty-nine studies met inclusion criteria. Fifty-nine aneurysms in 58 patients were treated using endovascular techniques. Mortality rate was 10.3% (6/58) and a poor outcome (GOS 1-3) occurred in 15.5% (9/58). There were 4 reported recurrences requiring retreatment; however, only 46.5% of patients had reported follow-up of at least 1 year. 71.1% (42/59) were dissecting aneurysms.

CONCLUSION

Basilar artery aneurysms in the pediatric population are rare, commonly giant and fusiform, and often not amenable to microsurgical or coiling techniques. The surrounding vasculature, location, size, and morphology of the aneurysm along with the durability of treatment must be considered in treatment decisions. With proper patient selection, stent-assisted coiling and flow diversion may increase the durability and safety of endovascular treatment in this population.

Recovery from Cranial Nerve Symptoms after Flow Diversion without Coiling for Unruptured Very Large and Giant ICA Aneurysms

BACKGROUND AND PURPOSE

Cranial nerve symptoms, including visual impairment and ophthalmoplegia, are one of the most common presentations of very large and giant (≥15 mm) ICA aneurysms. In this study, we evaluated the treatment outcomes of flow diversion and conventional coiling in terms of recovery from cranial nerve symptoms and postoperative complications.

MATERIALS AND METHODS

Seventy-nine patients with unruptured ICA aneurysms of >15 mm who were treated with flow diversion or conventional coiling between December 2009 and December 2020 were retrospectively evaluated. We compared the radiologic and clinical outcomes, including recovery from cranial nerve symptoms, between the 2 groups.

RESULTS

Twenty-eight of 49 patients (57.1%) treated with flow diversion and 10 of 30 patients (33.3%) treated with conventional coiling initially presented with cranial nerve symptoms (P = .068). In the clinical follow-up, the symptom recovery rate was significantly higher in those treated with flow diversion (15 [50%] versus 3 [25%] with conventional coiling, P = .046). Multivariate logistic regression analysis demonstrated that flow diversion was significantly associated with symptom recovery (OR, 7.425; 95% CI, 1.091-50.546; P = .040). The overall postoperative complication rate was similar (flow diversion, 10 [20.4%]; conventional coiling, 6 [20.0%], P = .965), though fatal hemorrhagic complications occurred only in patients with intradurally located aneurysms treated with flow diversion (4 [8.2%] versus 0 [0.0%] with coiling, P = .108).

CONCLUSIONS

Flow diversion without coiling for very large and giant ICA aneurysms yielded a higher rate of recovery from cranial nerve symptoms, but it may be related to an increased hemorrhagic complication rate, especially for intradurally located aneurysms.

A Single Flow Re-direction Endoluminal Device for the Treatment of Large and Giant Anterior Circulation Intracranial Aneurysms

PURPOSE

The purpose of this study was to report the author's experiences in treating large (10-25 mm) and giant (>25 mm) intracranial aneurysms (IAs) using a single Flow Re-direction Endoluminal Device (FRED) without assistant coiling, with a focus on procedure-related complications.

MATERIALS AND METHODS

A total of 33 patients who were treated with FRED between January 2018 and July 2020 were retrospectively reviewed. The timing of procedure-related complications was chronologically categorized as acute (within 7 days), subacute (8 to 21 days), and delayed (after 21 days) periods. Follow-up angiography was performed at 2 to 27 months (mean 9.7 months), and clinical follow-up was performed at 1 to 31 months (mean 14.1 months) in all patients.

RESULTS

Six (18.2%) patients experienced procedure-related complications, including 2 (6.1%) in acute period, 1 (3.0%) in subacute period, and 3 (9.1%) in delayed period. Thromboembolic complications occurred in 5 (15.2%) patients and hemorrhagic complications in 1 (3.0%). Permanent morbidity and mortality rates were 3.0% each. Non-internal carotid artery (ICA) location of IAs (odds ratio 6.532; 95% confidence interval, 1.335-17.816; p=0.034) was the only independent risk factor for procedure-related complications on multivariate logistic regression analysis.

CONCLUSION

The procedure-related complication rate was 18.2% in this study. Procedure-related complications might increase when treating large and giant IAs located on a non-ICA, especially on the middle cerebral artery. Therefore, it may be suggested that neurointerventionists and endovascular neurosurgeons should pay attention to the location of IAs when treating large and giant IAs with a single FRED.

Predictors of the Effects of Flow Diversion in Very Large and Giant Aneurysms

BACKGROUND AND PURPOSE

The treatment paradigm for very large and giant aneurysms has recently changed to flow diversion, in light of the results of the Pipeline for Uncoilable or Failed Aneurysms trial. However, the effects of flow diversion were definitely unknown. We explored this topic and identified the predictors of such effects.

MATERIALS AND METHODS

We retrospectively reviewed 51 patients with unruptured aneurysms admitted to our institution for flow diversion between February 2014 and August 2019. Patients were categorized into an effect group (no filling or remnant entry) and a no-effect group (subtotal or total filling). We evaluated the aneurysm size and shape, incorporation vessel, parent artery stenosis and curvature, stagnation of contrast medium within the aneurysm, use of balloon angioplasty, and intra-aneurysm thrombus as potential predictors of the effects of flow diversion.

RESULTS

The effect group comprised 34 patients (66.7%, 34/51; no filling, 35.3%, 18/51; and remnant entry, 31.4%, 16/51). The no-effect group comprised 17 patients (33.3%, 17/51; subtotal filling, 29.4%, 15/51; and total filling, 3.9%, 2/51). An incorporation vessel and balloon angioplasty were independent risk factors for the no-effect group in multivariate logistic regression analyses (OR = 0.13 and 0.05; 95% confidence intervals, 0.02-0.62 and 0.00-0.32; P values, .021 and .004, respectively).

CONCLUSIONS

Flow diversion is effective for very large and giant aneurysms, but the outcomes require further improvement. The results of this study show that an incorporated vessel and excessive balloon angioplasty might compromise flow diversion. This finding can help improve the outcomes of flow diversion.