A combination of embolization and radiosurgery is used as a common strategy for the treatment of large and complex cerebral arteriovenous malformations (AVMs).
Partially embolized AVMs are amenable to successful treatment with Gamma knife radiosurgery (GKS) . The volume of the nidus significantly influences the outcome of radiosurgical treatment. The Virginia RAS and Pollock-Flickinger score were found to be reliable scoring systems for selection of patient candidates and prediction of partially embolized AVM closure and complications for GKS 1).
Cerebral arteriovenous malformation embolization before stereotactic radiosurgery (SRS) has been shown to negatively affect obliteration rates.
The effect of prior embolization on AVM obliteration after SRS may be significantly confounded by nidus angioarchitectural complexity. Additionally, embolization could reduce the risk of radiation-induced changes. Thus, combined embolization and SRS may be warranted for appropriately selected nidi 2).
Preoperative use of the Onyx liquid embolic system in cerebral AVM treatment allows profound occlusion by targeted embolization and provides a basis for safe neurosurgical resection 3).
Staged endovascular embolization of large arteriovenous malformations (AVMs) is frequently performed to gradually reduce flow and prevent abrupt hemodynamic changes. While feeding artery aneurysms have been associated with increased risk of hemorrhage in the setting of AVMs, decisions regarding if and when to treat these aneurysms vary. Acute, fatal rupture of a feeding artery aneurysm following embolization of a large, unruptured AVM has been infrequently reported in the literature.
An increase in AVM feeding artery pressure following endovascular embolization may contribute to the rupture of a feeding artery aneurysm. For this reason, treatment of large arterial aneurysms on feeding pedicles should be considered prior to embolization of the AVM nidus 4).
General anesthesia prohibits neurological examination during embolization of cerebrovascular malformations when provocative testing prior to pedicle occlusion is needed. Intraoperative neurophysiological monitoring (IONM) has the potential to fill this gap 5).
A study aimed to explore the potential risk factors of recurrence in angiographically obliterated AVMs treated with endovascular embolization. This study reviewed AVMs treated with embolization only in a prospective multicenter registry from August 2011 to December 2021, and ultimately included 92 AVMs who had achieved angiographic obliteration. Recurrence was assessed by follow-up digital subtraction angiography (DSA) or magnetic resonance imaging (MRI). Hazard ratios (HRs) with 95% confidence intervals were calculated using Cox proportional hazards regression models. Nineteen AVMs exhibited recurrence on follow-up imaging. The recurrence rates after complete obliteration at 6 months, 1 year, and 2 years were 4.35%, 9.78%, and 13.0%, respectively. Multivariate Cox regression analysis identified diffuse nidus (HR 3.208, 95% CI 1.030-9.997, p=0.044) as an independent risk factor for recurrence. Kaplan-Meier analysis confirmed a higher cumulative risk of recurrence with diffuse nidus (log-rank, p=0.016). Further, in the exploratory analysis of the effect of embolization timing after AVM rupture on recurrence after the complete obliteration, embolization within 7 days of the hemorrhage was found as an independent risk factor (HR 4.797, 95% CI 1.379-16.689, p=0.014). Kaplan-Meier analysis confirmed that embolization within 7 days of the hemorrhage was associated with a higher cumulative risk of recurrence in ruptured AVMs (log-rank, p<0.0001). This study highlights the significance of diffuse nidus as an independent risk factor for recurrence after complete embolization of AVMs. In addition, we identified a potential recurrent risk associated with early embolization in ruptured AVMs 6).
This study makes a valuable contribution to the understanding of AVM recurrence after endovascular embolization. The prospective design, clear outcome measures, and identification of independent risk factors enhance the study's credibility. However, the findings should be interpreted cautiously, considering the limitations in sample size, generalizability, and the need for additional research to elucidate certain associations.
The management of arteriovenous malformations (AVMs) in the basal ganglia, insula, and thalamus is demanding for all treatment modalities.
A cohort of 22 patients with AVMs located in the basal ganglia, thalamus, and insula who underwent embolization between January 2008 and December 2013.
Eighteen of 22 (82%) patients had anatomic exclusion. The mean size was 2.98 ± 1.28 cm, and the mean number of sessions was 2.1 per patient. Most patients presented with hemorrhage (82%, n = 18), and 3 (14%) patients were in a deteriorated neurological status (modified Rankin Scale >2) at presentation. Sixty-eight percent of ruptured AVMs had size ≤3 cm. A single transarterial approach was performed in 9 (41%) cases, double catheterization was used in 4 (18%), and the transvenous approach was required in 8 (36%) cases. Procedure-related complications were registered in 3 (14%) cases. One death was associated with treatment, and complementary radiosurgery was required in 2 (9%) patients.
Embolization therapy appears to be safe and potentially curative for certain deep AVMs. The results demonstrate a high percentage of anatomic obliteration with rates of complications that may approach radiosurgery profile. In particular, embolization as stand-alone therapy is most suitable to deep AVMs with small nidus size (≤3 cm) and/or associated with single venous drainage in which microsurgery might not be indicated 7).
A total of 80 cases received interventional embolism treatment from December 2011 to July 2014. The patients all were confirmed by digital subtraction angiography. Risk factors of intracranial hemorrhage were analyzed by multivariate analysis. The factors included age, sex, AVM diameter, vein drainage types, embolism area, etc. Meanwhile, the patients were followed up for 60 months after interventional embolization, so as to assess the impact of related risk factors on prognosis.
By logistic regression analysis, it was found that age, AVM diameter, AVM combined with aneurysm, embolism area and venous drainage types were related risk factors those could lead to intracranial hemorrhage. Meanwhile, it was identified by receiver operating characteristic curve that embolism area, AVM diameter and AVM combined with aneurysm were risk factors had considerable influence on prognosis while the diagnosis significance of age and venous drainage types was poor (P > 0.05). The survival curves of embolism area and AVM diameter on prognosis had been identified by Kaplan Meier analysis and it showed that embolism area < 50% and AVM diameter ≥ 3 cm had a better prognosis than embolism area ≥ 50% and AVM diameter < 3 cm (P < 0.05).
A series of risk factors were related to intracranial hemorrhage and some of them had considerable influence on prognosis, which, could help to reduce the risk of intracranial hemorrhage and improve long-term survival rate 8).