Acute Management of Brain Arteriovenous Malformations

Management of Brain Arteriovenous Malformations: A Review

Brain arteriovenous malformations (bAVM) are vascular malformations of the brain affecting all ages. The optimum management strategy is essentially devoid of high-quality evidence and is highly nuanced and embedded in local customs. This study summarizes the frequently employed management strategies, drawing conclusions on the utility of each method of treatment and delving into controversies surrounding them. A literature search on PubMed and Medline was done on January 3^rd, 2022. 11,767 articles were found, and abstracts were reviewed. Full-text review of 153 articles led to chapters from three books and 71 articles incorporated into a summative discussion. Spetzler-Ponce (S-P) Class A patients may be offered surgery if they are good surgical candidates and have a good number of high-quality years of life left. The exception is diffuse Spetzler-Martin (S-M) grade 2 in a patient older than 40 years: radiosurgery for unruptured and embolization for ruptured. S-P Class B may be offered surgery if a compact nidus or if younger than 40 years. If diffuse or age greater than 40, radiosurgery may be preferred if the Pollock-Flickinger score is less than 2.5. For the remainder of S-P Class B, conservative management may be preferred. S-P Class C is generally not treated unless young or those patients with poorly controlled seizures affecting their quality of life are willing to risk permanent neurological deficits. While the quality of studies is generally high, the level of evidence is concerning with only one randomized controlled trial (RCT). Most research output hails from high-income countries, i.e., perhaps not universally applicable to all settings owing to possible genetic, environmental, and resource differences. More research is needed: large volume studies in the pregnant population, validation of scoring systems in pediatric age groups, clinical trials focused on combination multi-staged treatment modalities, and studies originating from the developing world.

Radiomics Analysis for Predicting Epilepsy in Patients With Unruptured Brain Arteriovenous Malformations

Objectives: To investigate the association between radiomics features and epilepsy in patients with unruptured brain arteriovenous malformations (bAVMs) and to develop a prediction model based on radiomics features and clinical characteristics for bAVM-related epilepsy.

Methods: This retrospective study enrolled 176 patients with unruptured bAVMs. After manual lesion segmentation, a total of 858 radiomics features were extracted from time-of-flight magnetic resonance angiography (TOF-MRA). A radiomics model was constructed, and a radiomics score was calculated. Meanwhile, the demographic and angioarchitectural characteristics of patients were assessed to build a clinical model. Incorporating the radiomics score and independent clinical risk factors, a combined model was constructed. The performance of the models was assessed with respect to discrimination, calibration, and clinical usefulness.

Results: The clinical model incorporating 3 clinical features had an area under the curve (AUC) of 0.71. Fifteen radiomics features were used to build the radiomics model, which had a higher AUC of 0.78. Incorporating the radiomics score and clinical risk factors, the combined model showed a favorable discrimination ability and calibration, with an AUC of 0.82. Decision curve analysis (DCA) demonstrated that the combined model outperformed the clinical model and radiomics model in terms of clinical usefulness.

Conclusions: The radiomics features extracted from TOF-MRA were associated with epilepsy in patients with unruptured bAVMs. The radiomics-clinical nomogram, which was constructed based on the model incorporating the radiomics score and clinical features, showed favorable predictive efficacy for bAVM-related epilepsy.

MR characteristics of unruptured intracranial arteriovenous malformations associated with seizure as initial clinical presentation

Background

Patients with intracranial arteriovenous malformations (AVMs) are at increased risk of seizures.

Objective

To identify MRI characteristics of unruptured intracranial AVMs associated with seizures at presentation.

Materials and methods

A retrospective review was completed of patients diagnosed with unruptured intracranial AVMs on MRI between January 1, 2000 and December 31, 2016. Two blinded reviewers assessed demographics, lesion locality, and imaging and architectural characteristics of AVMs and surrounding parenchyma, including, but not limited to, AVM location, venous drainage pattern, venous varix, thrombosed venous varix, long draining vein, AVM-related gliosis, peri-AVM edema, and peri-AVM T2* signal. Findings were statistically analyzed for correlation with seizure using Student’s t-test for continuous variables and Χ2 test for categorical variables.

Results

Of 165 included patients, 57/165 (34.5%) patients were imaged as part of an investigation for seizures. Patients with seizures more commonly had peri-AVM edema (36.8%, compared with 11.1% of non-seizure patients, p<0.0001), peri-AVM T2* blooming (28.1% vs 7.4%; p=0.029), a venous pouch/varix (61.4% vs 31.5%, p=0.0003), long draining vein (91.2% vs 55.6%, p<0.0001), and larger size based on Spetzler-Martin grade categorization (p=0.006). By location, AVMs located in the frontal lobe, primary motor cortex, and primary sensory cortex were associated with seizures (p=0.004, p=0.001, and p=0.006, respectively); temporal lobe location was not associated with seizures (p=0.459).

Conclusions

Certain MRI characteristics of unruptured intracranial AVMs are associated with seizures. Such correlations may assist in identifying the pathophysiological mechanisms by which AVMs cause seizures.

Timing of surgery for ruptured supratentorial arteriovenous malformations

BACKGROUND

There are conflicting opinions regarding the optimal waiting time to perform surgery after rupture of supratentorial arteriovenous malformations (AVMs) to achieve the best possible outcome.

OBJECTIVE

To analyze factors influencing outcomes for ruptured supratentorial AVMs after surgery, paying particular attention to the timing of the surgery.

METHODS

We retrospectively investigated 59 patients admitted to our center between 2000 and 2014 for surgical treatment of ruptured supratentorial AVMs. We evaluated the effect of timing of surgery and other variables on the outcome at 2-4 months (early outcome), at 12 months (intermediate outcome) after surgery, and at final follow-up at the end of 2016 (late outcome).

RESULTS

Age over 40 years (OR 18.4; 95% CI 1.9-172.1; p = 0.011), high Hunt and Hess grade (4 or 5) before surgery (OR 13.5; 95% CI 2.1-89.2; p = 0.007), hydrocephalus on admission (OR 12.9; 95% CI 1.8-94.4; p = 0.011), and over 400 cm³ bleeding during surgery (OR 11.5; 95% CI 1.5-86.6; p = 0.017) were associated with an unfavorable early outcome. Age over 40 years (OR 62.8; 95% CI 2.6-1524.9; p = 0.011), associated aneurysms (OR 34.7; 95% CI 1.4-829.9; p = 0.029), high Hunt and Hess grade before surgery (OR 29.2; 95% CI 2.6-332.6; p = 0.007), and over 400 cm³ bleeding during surgery (OR 35.3; 95% CI 1.7-748.7; p = 0.022) were associated with an unfavorable intermediate outcome. Associated aneurysms (OR 8.2; 95% CI 1.2-55.7; p = 0.031), high Hunt and Hess grade before surgery (OR 5.7; 95% CI 1.3-24.3; p = 0.019), and over 400 cm³ bleeding during surgery (OR 5.8; 95% CI 1.2-27.3; p = 0.027) were associated with an unfavorable outcome at last follow-up. Elapsed time between rupture and surgery did not affect early or final outcome.

CONCLUSIONS

Early surgery in patients with ruptured supratentorial arteriovenous malformation is feasible strategy, with late results comparable to those achieved with delayed surgery. Many other factors than timing of surgery play significant roles in long-term outcomes for surgically treated ruptured supratentorial AVMs.