A proposed grading system to evaluate the endovascular curability of deep-seated arteriovenous malformations

The Efficacy and Disadvantages of Endovascular Therapy for Deep-Seated Cerebral Arteriovenous Malformations: A Long-Term Follow-Up Study

Arteriovenous malformations (AVMs) in the basal ganglia, the thalamus, and the insular lobe of the brain are rare and difficult-to-treat diseases that require integrated multimodal management. This study aimed to determine the safety and disadvantages of embolization as an independent therapy for deep-seated AVMs. The authors reviewed 76 patients from a single center with cerebral deep-seated AVMs from 2010 to 2020. Clinical hemorrhage refers to the initial clinical presentation with bleeding, the first occurrence of bleeding, and delayed postoperative hemorrhage refers to subsequent bleeding following the initial hemorrhage. After interventional therapy, 8 patients experienced delayed postoperative hemorrhage during the total follow-up of 94,631 person-years, with an annual postoperative hemorrhage rate of 3.1%. Compared with the overall clinical hemorrhage rate before treatment (15.9%/person-year), 11 patients experienced clinical hemorrhage during 25,238 person-years, indicating a significantly decreased risk of clinical hemorrhage after treatment. A total of 28.9% (22/76) of patients achieved angiographic obliteration. Multivariate analysis showed that pretreatment limb weakness and a high Spetzler-Martin grade predicted poor clinical outcomes (P = 0.043 and 0.005). Fewer feeding arteries predicted AVMs' obliteration (P = 0.048). Endovascular procedure-related complications, mortality, and morbidity were, respectively, reported in 7.9% (6/76), 1.3% (1/76), and 14.8% (8/54) of patients. Endovascular embolization significantly lowered the risk of clinical deterioration and delayed hemorrhage, indicating it to be a safe and effective therapy for deep-seated AVMs. Lesions with a simple angioarchitecture were more likely to be completely obliterated.

Outcome prediction for treatment of brain arteriovenous malformations: performance of endovascular predictive scores in a single-center population

BACKGROUND

Endovascular embolization is an accepted treatment modality for brain arteriovenous malformations (bAVM); however, treatment outcomes are highly variable, warranting accurate prediction for adequate patient selection. Several predictive scores have been proposed for this purpose. The objective of this study was to externally validate these scores for embolization of bAVM.

METHODS

This study involved bAVM patients treated with transarterial embolization. Endovascular predictive scores were identified through literature search. Relevant data for scoring of included patients was extracted. Primary study outcomes were radiological cure and neurological complications. The performance of the scores was evaluated by analyzing calibration (z-scores from logistic regression), discrimination (area under the receiver operating characteristic curve, AUROC), and classification (Youden's index and corresponding sensitivity and specificity). Additionally, sensitivity analyses were performed restricting the study population by size, location, and embolization intent.

RESULTS

A total of 198 bAVM (190 patients) were included. The rates of radiological cure and neurological complications were 18.2% and 14.1%, respectively. The literature search identified seven predictive scores. In the overall analysis, the Toronto score showed the best performance for radiological cure (AUROC 0.905). No significant difference was observed between the performance of the assessed scores for neurological complications. The sensitivity analysis showed improved performance of most scores. The Toronto score exhibited the highest performance for radiological cure (AUROC 0.857). The AVM Embolization Prognostic Risk Score (AVMEPRS) showed the highest performance for neurological complications (AUROC 0.751). The AVM Embocure Score (AVMES) showed fair to good performance for both efficacy and safety outcomes.

CONCLUSION

Among the selected scores, the Toronto, AVMEPRS, and AVMES scores showed the best performances.

Endovascular Management of Arteriovenous Malformations in the Thalamic and Basal Ganglia: A Systematic Review

Arteriovenous malformations (AVMs) in the thalamic and basal ganglia present significant challenges due to their deep-seated location and complex vessel architecture. This systematic review outlines the efficacy and outcomes of endovascular management of these lesions. A comprehensive analysis of seven studies including 53 patients revealed high technical success rates, with complete obliteration in 46.7-100% of cases, using advanced embolization agents, such as ethylene vinyl-alcohol copolymer, and precipitating hydrophobic injectable liquid. Adjunctive therapies, mainly stereotactic radiosurgery, further improved results in complex cases. The complications were highly variable, and again, the need for the performance of the technique to be as meticulous as possible was pointed out, tailoring the treatment strategies. This review underlines the potential of endovascular interventions in optimizing outcomes in patients with AVMs in these critical brain regions.

Reporting of angiographic studies in patients diagnosed with a cerebral arteriovenous malformation: a systematic review

A cerebral arteriovenous malformation (cAVM) is an abnormal tangle of cerebral blood vessels. The consensus document by the Joint Writing Group (JWG) highlighted which cAVM features should be recorded. Subsequent publications have reported cAVM angioarchitecture, but it is unknown if all followed the JWG recommendations. The aim of this systematic review was to describe use of the JWG guidelines. A database search, using the PRISMA checklist, was performed. We describe the proportion of publications that used JWG reporting standards, which standards were used, whether the definitions used differed from the JWG, or if any additional angiographic features were reported. Out of 4306 articles identified, 105 were selected, and a further 114 from other sources. Thirty-three studies (33/219; 15%) specifically referred to using JWG standards. Since the JWG publication, few studies have used their standards to report cAVMs. This implies that the angioarchitecture of cAVMs are not routinely fully described.

Predicting intraoperative major blood loss in microsurgery for brain arteriovenous malformations

Objective

Intraoperative blood loss poses a great challenge for brain arteriovenous malformation (AVM) microsurgery, although systematic researches are still lacking. This study aimed to identify factors predicting intraoperative major blood loss in brain AVM microsurgery and to investigate its impact on patient outcome. To deal with the fierce bleeding, we introduced a modified hemostatic method, bone-wax (BW) coated bipolar electrocoagulation.

Methods

The authors retrospectively analyzed the clinical data of 131 patients (50/81 in intraoperative major/non-major blood loss cohort) with brain AVMs who underwent microsurgery in our center during the period between January 2018 and April 2023. According to previous studies, major blood loss was defined as blood loss of at least 1,000 mL. The accuracy and objectivity of our grouping methodology were validated by comparing the hemoglobin mass loss, hematocrit loss and factors associated with intraoperative bleeding. Potential clinical and radiological predictors for intraoperative major blood loss were evaluated using a multivariate stepwise logistic regression. And outcomes of patients in the two cohorts were also compared. At last, the performance of BW coated bipolar electrocoagulation in brain AVM microsurgery was illustrated by the case presentation, histological staining and transmission electron microscopy of the coagulated nidus vessels.

Results

Hemoglobin mass loss, hematocrit loss and factors associated with intraoperative bleeding were significant different between the two cohorts. five independent factors predicting intraoperative major blood loss were identified: (1) clinical manifestations; (2,3) location and size of the nidus; (4) deep venous drainage; and (5) the number of draining veins. And the intraoperative major blood loss can not only adversely affect the surgical progression, but also predict poor perioperative outcomes for patients. Regarding the application of BW coated bipolar electrocoagulation, we found the novel hemostatic method exerted efficient hemostatic effect and reduced the damage to the vascular structure in brain AVM microsurgery.

Conclusion

This study proposed a nomogram for neurosurgeons to predict intraoperative major blood loss in brain AVM microsurgery preoperatively. And intraoperative major blood loss is associated with poor patient outcomes. In addition, BW coated bipolar electrocoagulation, can be applied to control ferocious bleeding during brain AVM microsurgery, which still remains further researches.

Susceptibility weighted imaging for qualitative grading of persistent arteriovenous shunting in deep-seated arteriovenous malformations after stereotactic radiation surgery

BACKGROUND AND PURPOSE

To investigate Susceptibility Weighted Imaging (SWI) signal changes in the draining vein of deep-seated arterio-venous malformations (AVMs) following stereotactic radiosurgery (SRS).

METHODS AND MATERIALS

This is a retrospective study of 32 patients with deep-seated AVMs who were treated with SRS. Pre-SRS treatment and post-SRS treatment MRI were performed at 6, 12, and 24-month intervals. Deep-seated AVMs were classified based on their anatomical location and venous drainage pattern. AVM nidal volume (cm3) was estimated using the ABC/2 method. AV shunting of the AVM draining veins were graded according to its SWI signal intensity: hyperintense (grade III), mixed signal intensity (grade II), hypointense (grade I) and absent (grade 0). Conventional time-of-flight (TOF)-MRA and contrast enhanced (CE)-MRA sequences were performed to document the patency of the vein.

RESULTS

Pre-SRS treatment AVM draining veins were either grade III 18/32 (56%) or grade II 14/32 (44%). Using mixed effects analysis, we demonstrate that each month following the SRS treatment nidal volumes decreased at the rate of 0.51 cm3/per month (CI -0.61 to (-0.40)) p =.00. Following the treatment, there was a clinically significant relationship between the signal and nidal volume: signal 0 corresponded with average nidal volume of 1.81 cm3 (CI 1.40-2.21), signal 1 with nidal volume of 2.06 cm3 (CI 1.69-2.44), signal 2 with nidal volume 2.73 cm3 (CI 2.35-3.11) and signal 3 with nidal volume 3.13 cm3 (CI 2.70-3.56) p = .00.

CONCLUSION

Post-SRS AVM draining veins shows a stepwise regression of the SWI signal grades which can be reliably used as a surrogate to monitor the reduction of AV shunting.

Brain Arteriovenous Malformations Classifications: A Surgical Point of View

Brain arteriovenous malformations (AVMs) classification has been the subject of extensive discussion. The aim of our work was to review the main classification schemes proposed in the literature, which can be summarized in four main groups: (a) traditional schemes oriented to evaluate the operability of AVMs have been joined by (b) specific classifications that evaluate the outcome and the predictability of obliteration of other treatment modalities and (c) others that evaluate the outcome of intracerebral hemorrhages in ruptured AVMs. Eventually, (d) topographical classifications that categorize the subtypes of AVMs located in specific anatomical regions have been drawn. For each classification, we discuss the implications on surgical management.

Modern radiosurgical and endovascular classification schemes for brain arteriovenous malformations

Stereotactic radiosurgery (SRS) and endovascular techniques are commonly used for treating brain arteriovenous malformations (bAVMs). They are usually used as ancillary techniques to microsurgery but may also be used as solitary treatment options. Careful patient selection requires a clear estimate of the treatment efficacy and complication rates for the individual patient. As such, classification schemes are an essential part of patient selection paradigm for each treatment modality. While the Spetzler-Martin grading system and its subsequent modifications are commonly used for microsurgical outcome prediction for bAVMs, the same system(s) may not be easily applicable to SRS and endovascular therapy. Several radiosurgical- and endovascular-based grading scales have been proposed for bAVMs. However, a comprehensive review of these systems including a discussion on their relative advantages and disadvantages is missing. This paper is dedicated to modern classification schemes designed for SRS and endovascular techniques.