Endovascular embolization of cerebral arteriovenous malformations: results of the Japanese Registry of Neuroendovascular Therapy (JR-NET) 1 and 2

Five Cases of High-grade Arteriovenous Malformation Treated by Presurgical Embolization through the Anterior Choroidal Artery

Objective

In cases of cerebral arteriovenous malformation (AVM) in which perforators are involved as feeder, hemostasis is difficult during surgical removal and postoperative hemorrhage may develop. If possible, presurgical embolization should be performed. However, when the anterior choroidal artery (AChA) is the feeder, the risk of embolization is particularly high, and there are few reports describing this situation. Authors report the treatment results of five cases of AVM in which a single operator performed presurgical embolization through the AChA and describe the technique with a review of the literature.

Case Presentations

Of the five total cases (three men and two women; average age was 43.4 years [28-68 years]), one case presented with hemorrhage, two with epilepsy, the other ones with headache and trigeminal neuralgia, respectively. The lesions were located in the frontal lobe in one case and in the temporal lobe in four cases. On the Spetzler-Martin (SM) grading scale, four cases were grade III and one was grade IV. The eloquent area was involved within the nidus in four cases. Multimodal treatment was planned because all cases were high-grade AVM. Authors thought that performing presurgical embolization through the AChA would reduce the overall risk of treatment and performed the presurgical embolization. The embolization was possible in all cases, and the AVM was not angiographycally visible through the AChA in three cases. The blood flow through the AChA was reduced in two cases. All cases were awake immediately after embolization and no case had neurological symptom after embolization. CT or MRI after embolization revealed asymptomatic infarction in two cases. The AVM was removed safely without difficulty including hemostasis.

Conclusion

In this series, there were no morbidity and embolization was performed relatively safely. Embolization through the AChA was suggested to be an effective treatment, but careful consideration is required in each individual case.

Complications of Endovascular Treatments for Brain Arteriovenous Malformations: A Nationwide Surveillance

BACKGROUND AND PURPOSE

Embolization is widely performed to treat brain arteriovenous malformations, but little has been reported on factors contributing to complications. We retrospectively reviewed a nationwide surveillance to identify risk factors contributing to complications and short-term clinical outcomes in the endovascular treatment of brain arteriovenous malformations.

MATERIALS AND METHODS

Data for endovascular treatment of brain arteriovenous malformations were extracted from the Japanese nationwide surveillance. Patient characteristics, brain arteriovenous malformation features, procedures, angiographic results, complications, and clinical outcomes at 30 days postprocedure were analyzed.

RESULTS

A total of 1042 endovascular procedures (788 patients; mean, 1.43 ± 0.85 procedures per patient) performed in 111 institutions from 2010 to 2014 were reviewed. Liquid materials were used in 976 procedures (93.7%): to perform presurgical embolization in 638 procedures (61.2%), preradiosurgical embolization in 160 (15.4%), and as sole endovascular treatment in 231 (22.2%). Complete or near-complete obliteration of brain arteriovenous malformations was obtained in 386 procedures (37.0%). Procedure-related complications occurred in 136 procedures (13.1%), including hemorrhagic complications in 59 (5.7%) and ischemic complications in 57 (5.5%). Univariate analysis identified deep venous drainage, associated aneurysms, infratentorial location, and preradiosurgical embolization as statistically significant risk factors for complications. Multivariate analysis showed that embolization of brain arteriovenous malformations in the infratentorial location was significantly associated with complications. Patients with complications due to endovascular procedures had worse clinical outcomes 30 days after the procedures than those without complications.

CONCLUSIONS

Complications arising after endovascular treatment of brain arteriovenous malformations are not negligible even though they may play a role in adjunctive therapy, especially in the management of infratentorial brain arteriovenous malformations.

Safety and Feasibility of Neuroendovascular Therapy for Elderly Patients: Analysis of Japanese Registry of Neuroendovascular Therapy 3

Japan has a rapidly aging population and the application of neuroendovascular therapy (NET) for cerebrovascular diseases among elderly patients has increased, but feasibility and safety of NET for elderly patients are still debated. Therefore, this study aimed to elucidate feasibility and safety of NET by analyzing the Japanese nationwide database, the Japanese Registry of Neuroendovascular Therapy 3 (JR-NET 3). In total, 35,972 patients in the JR-NET 3 were analyzed retrospectively. "Elderly patients" were defined as those aged ≥75 years. Approximately one-quarter of patients who received NET were elderly patients. The proportion of patients with modified Rankin Scale (mRS) 0-2 before treatment and 30 days after NET was significantly low across all diseases in the elderly patients. Technical success rates were generally high across all procedures, but complication rate was significantly higher among elderly patients; ischemic complications were significantly higher with NET for unruptured aneurysms (UA) and carotid artery stenosis (CAS). Multivariate analysis revealed that mRS 0-2 before treatment [odds ratio (OR): 0.56, 95% confidence interval (CI): 0.34-0.94, P = 0.03], middle cerebral artery aneurysm (OR: 0.33, 95% CI: 0.12-0.92, P = 0.04), and complete obliteration (OR: 0.66, 95% CI: 0.44-0.97, P = 0.03) were associated with ischemic complications with NET for UA. Moreover, mRS 0-2 before treatment (OR: 0.55, 95% CI: 0.36-0.86, P < 0.01), high intensity with time-of-flight magnetic resonance angiography (OR: 1.55, 95% CI: 1.03-2.32, P = 0.04), open-cell stent (OR: 2.20, 95% CI: 1.50-3.22, P <0.01) were associated with ischemic complications with NET for CAS. Taken together, our findings indicate that cautious and precise selection of patients suitable for NET is necessary.

A comparison of the prevalence and risk factors of complications in intracranial tumor embolization between the Japanese Registry of NeuroEndovascular Therapy 2 (JR-NET2) and JR-NET3

BACKGROUND

The Japanese Registry of NeuroEndovascular Therapy 2 (JR-NET2) and 3 (JR-NET3) were nationwide surveys that evaluated clinical outcomes after neuroendovascular therapy in Japan. The aim of this study was to compare the prevalence and risk factors of complications of intracranial tumor embolization between JR-NET2 and JR-NET3.

METHODS

A total of 1018 and 1545 consecutive patients with intracranial tumors treated with embolization were enrolled in JR-NET2 and JR-NET3, respectively. The prevalence of complications in intracranial tumor embolization and related risk factors were compared between JR-NET2 and JR-NET3.

RESULTS

The prevalence of complications in JR-NET3 (3.69%) was significantly higher than that in JR-NET2 (1.48%) (p = 0.002). The multivariate analysis in JR-NET2 showed that embolization for tumors other than meningioma was the only significant risk factor for complication (odds ratio [OR], 3.88; 95% confidence interval [CI], 1.13-12.10; p = 0.032), and that in JR-NET3 revealed that embolization for feeders other than external carotid artery (ECA) (OR, 3.56; 95% CI, 2.03-6.25; p < 0.001) and use of liquid materials (OR, 2.65; 95% CI, 1.50-4.68; p < 0.001) were significant risks for complications. The frequency of embolization for feeders other than ECA in JR-NET3 (15.3%) was significantly higher than that in JR-NET2 (9.2%) (p < 0.001). Also, there was a significant difference in the frequency of use of liquid materials between JR-NET2 (21.2%) and JR-NET3 (41.2%) (p < 0.001).

CONCLUSIONS

Embolization for feeders other than ECA and use of liquid materials could increase the complication rate in intracranial tumor embolization.

Interval angioarchitectural evolution of brain arteriovenous malformations following rupture

OBJECTIVE

The goal of this study was to describe changes in the angioarchitecture of brain arteriovenous malformations (bAVMs) between acute and delayed cerebral digital subtraction angiography (DSA) obtained after hemorrhage, and to examine bAVM characteristics predicting change.

METHODS

This is a retrospective study of a prospective institutional bAVM database. The authors included all patients with ruptured bAVMs who had DSA in both acute and delayed phases, with no interval treatment of their bAVM, between January 2000 and April 2017. The authors evaluated the existence or absence of angioarchitectural changes. Demographic data, radiological characteristics of hemorrhages, and angioarchitectural features of the bAVMs of the two patients' groups were analyzed. Univariate and multivariate logistic analyses were performed to identify predictors of angioarchitectural change.

RESULTS

A total of 42 patients were included in the series. Seventeen (40.5%) patients had angioarchitectural changes including bAVM only visible on the delayed DSA study (n = 8), spontaneous thrombosis of the AVM (n = 3), or alteration of the size or the opacification of the nidus (n = 6). The factors associated with angioarchitectural changes were a small nidus (3.8 ± 7.9 ml vs 6.1 ± 9.5 ml, p = 0.046), a superficial location (94.1% vs 5.9%, p = 0.016), and a single superficial draining vein (58.8% vs 24.0%, p = 0.029).

CONCLUSIONS

Angioarchitectural changes can be seen in 40% of ruptured bAVMs between the acute- and delayed-phase DSA. A small nidus, a superficial location, and a single superficial draining vein were statistically associated with the occurrence of angioarchitectural changes. These changes included either enlargement or spontaneous occlusion of the bAVM, as well as subsequent diagnosis of a bAVM following an initial negative DSA study.

Indications for the Performance of Intracranial Endovascular Neurointerventional Procedures: A Scientific Statement From the American Heart Association

Intracranial endovascular interventions provide effective and minimally invasive treatment of a broad spectrum of diseases. This area of expertise has continued to gain both wider application and greater depth as new and better techniques are developed and as landmark clinical studies are performed to guide their use. Some of the greatest advances since the last American Heart Association scientific statement on this topic have been made in the treatment of ischemic stroke from large intracranial vessel occlusion, with more effective devices and large randomized clinical trials showing striking therapeutic benefit. The treatment of cerebral aneurysms has also seen substantial evolution, increasing the number of aneurysms that can be treated successfully with minimally invasive therapy. Endovascular therapies for such other diseases as arteriovenous malformations, dural arteriovenous fistulas, idiopathic intracranial hypertension, venous thrombosis, and neoplasms continue to improve. The purpose of the present document is to review current information on the efficacy and safety of procedures used for intracranial endovascular interventional treatment of cerebrovascular diseases and to summarize key aspects of best practice.

Effectiveness of Preradiosurgical Embolization with NBCA for Arteriovenous Malformations - Retrospective Outcome Analysis in a Japanese Registry of 73 Patients (J-REAL study)

Purpose

Recent reports have posed doubts about the effect of preradiosurgical embolization in brain arteriovenous malformation (AVM) because it makes the planning of stereotactic radiosurgery (SRS) difficult and has the risk of recanalization out of the target. We investigated whether the performance and quality of embolization may influence the success of SRS based on a retrospective case cohort study.

Materials and Methods

Seventy-three patients who underwent embolization followed by SRS between 2003 and 2012 in eight institutes with neurointerventionists were considered. They were divided into the following two groups at 3 years of follow up after the final SRS: “successful occlusion group” (S group), with radiologically complete occlusion of AVM; and “non-successful occlusion group” (N group) with persistent remnant nidus or abnormal vascular networks. Patient background, AVM profile, embolization performance grade and complications were compared in each group. The quality of embolization was evaluated with the new grading system: embolization performance grade (E grade), specializing the achievement of nidus embolization. E grade A was defined as sufficient nidus embolization with more than half of the total number of feeders achieving nidus penetration. E grade B was defined as less than half achievement of nidus embolization, and E grade C was defines as failure to perform nidus embolization.

Results

Forty-three patients were included in the S group, and 29 patients were included in the N group. The size and Spetzler-Martin grade of AVM and the rate of diffuse type was higher in the N group without statistical significance. The embolization performance level according to E grade indicated a significantly higher rate of successful embolization with more than 50% of nidus penetration in the S group (P<0.001). This difference was also confirmed in the subanalysis for limited cases, excluding smaller AVMs with complete occlusion with SRS alone (P=0.001).

Conclusion

The cause of the unsuccessful result of post-embolization SRS might be the large, diffuse angioarchitecture, but proper embolization with a high rate of nidus penetration to avoid recanalization is more important. Effective embolization is essential to contribute to and promote the effect of radiosurgery.

Safety of neuroangiography and embolization in children: complication analysis of 697 consecutive procedures in 394 patients

OBJECT

The safe treatment of children using catheter-based angiography and embolization poses unique challenges because of the technical factors regarding the size and fragility of access and target vessels, as well as unique pediatric cerebrovascular pathologies. The complication rates for neurointerventional procedures in children have not been established.

METHODS

The records of a consecutive cohort of pediatric patients who underwent neuroangiography and/or embolization between 2007 and 2013 were reviewed retrospectively to identify both intraprocedural and postprocedural complications. Demographic and clinical risk factors were analyzed with a multivariate logistic regression model.

RESULTS

The 697 consecutive procedures consisted of 429 diagnostic angiograms and 268 embolizations (mean age of patients 11.1 years; range 4 days to 18 years; 217 females). There were 130 intracranial, 122 extracranial, and 16 spinal embolizations. Pathologies included 28 intracranial arteriovenous malformations (AVMs), 12 spinal AVMs, 19 aneurysms, 29 vein of Galen malformations, 29 dural arteriovenous fistulas, 96 extracranial AVMs, 39 tumors, 3 strokes, and 13 others. Overall, 2 intraprocedural and 1 postprocedural complication (0.7%) occurred in the diagnostic group, all of which were nonneurological events. In the embolization group, 7 intraprocedural and 11 postprocedural complications (6.7%) were observed. Of these complications, 15 were nonneurological events (5.6%), 1 was a short-term neurological event (0.4%), and 2 were long-term neurological events (0.7%).

CONCLUSIONS

Neither the technical challenges posed by children's access and target vessels nor the unique neuro-vascular pathologies seen in children need result in an elevated morbidity rate related to neuroangiography and embolization. At a dedicated high-volume center, the complication rates may be lower than those for comparable procedures performed in adults.

Management of intracranial aneurysms associated with arteriovenous malformations

Intracranial or brain arteriovenous malformations (BAVMs) are some of the most interesting and challenging lesions treated by the cerebrovascular neurosurgeon. It is generally believed that the combination of BAVMs and intracranial aneurysms (IAs) is associated with higher hemorrhage rates at presentation and higher rehemorrhage rates and thus with a more aggressive course and natural history. There is wide variation in the literature on the prevalence of BAVM-associated aneurysms (range 2.7%–58%), with 10%–20% being most often cited in the largest case series. The risk of intracranial hemorrhage in patients with unruptured BAVMs and coexisting IAs has been reported to be 7% annually, compared with 2%–4% annually for those with BAVM alone. Several different classification systems have been applied in an attempt to better understand the natural history of this combination of lesions and implications for treatment. Independent of the classification used, it is clear that a few subtypes of aneurysms have a direct hemodynamic correlation with the BAVM itself. This is exemplified by the fact that the presence of a distal flow-related or an intranidal aneurysm appears to be associated with an increased hemorrhage risk, when compared with an aneurysm located on a vessel with no direct supply to the BAVM nidus. Debate still exists regarding the etiology of the association between those two vascular lesions, the subsequent implications for patients’ risk of hemorrhagic stroke, and finally the determination of which patients warrant treatment and when. The ultimate goals of the treatment of a BAVM associated with an IA are to prevent hemorrhage, avoid stepwise neurological deterioration, and eliminate the mortality risk associated with recurrent hemorrhagic events. The treatment is only justifiable if the risks associated with an intervention are lower than or equivalent to the long-term risks of disability or mortality caused by the lesion itself. When faced with this difficult decision, a few questions need to be answered by the treating neu-rosurgeon: What is the mode of presentation? What is the symptomatic lesion? Which one of the lesions bled? What is the relationship between the BAVM and IA? Is it possible to safely treat both BAVM and IA? The objective of this review is to discuss the demographics, natural history, classification, and strategies for management of BAVMs associated with IAs.