Grades of brain arteriovenous malformations and risk of hemorrhage and death

Analysis of the role of perfusion parameters in predicting rupture of brain arteriovenous malformations: a multi-center study

This study aimed to investigate the potential correlation between the perfusion parameters of brain arteriovenous malformations (bAVMs) as determined by multiphase CT angiography and bAVM rupture. Based on the occurrence of bAVM-related hemorrhage, 480 diagnosed bAVM patients were divided into hemorrhage (n = 220) and non-hemorrhage (n = 260) groups in this retrospective multi-center study spanning 2010 to 2020. On initial rupture CT images, the bAVM nidus and major draining vein were segmented, and time-density curves were extracted to compute perfusion parameters including mean transit time (MTT), time to peak (TTP), blood volume (BV), and blood flow (BF). To examine the potential correlation between these parameters and bAVM rupture, logistic regression was utilized to analyze multifactorial data and compare differences between the two groups. The ruptured group demonstrated a bAVM nidus characterized by an increased BF, a shorter TTP and MTT, and a higher peak density. The veins that were draining exhibited a reduced TTP, MTT, and peak density. A nidus TTP of less than 4s was identified by the multifactorial analysis as a critical risk factor for bAVM rupture. The statistical results highlight the noteworthy correlation between nidus TTP and bAVM rupture, presenting an original framework for assessing the risk of rupture.

CT Angiography Radiomics Combining Traditional Risk Factors to Predict Brain Arteriovenous Malformation Rupture: a Machine Learning, Multicenter Study

This study aimed to develop a machine learning model for predicting brain arteriovenous malformation (bAVM) rupture using a combination of traditional risk factors and radiomics features. This multicenter retrospective study enrolled 586 patients with unruptured bAVMs from 2010 to 2020. All patients were grouped into the hemorrhage (n = 368) and non-hemorrhage (n = 218) groups. The bAVM nidus were segmented on CT angiography images using Slicer software, and radiomic features were extracted using Pyradiomics. The dataset included a training set and an independent testing set. The machine learning model was developed on the training set and validated on the testing set by merging numerous base estimators and a final estimator based on the stacking method. The area under the receiver operating characteristic (ROC) curve, precision, and the f1 score were evaluated to determine the performance of the model. A total of 1790 radiomics features and 8 traditional risk factors were contained in the original dataset, and 241 features remained for model training after L1 regularization filtering. The base estimator of the ensemble model was Logistic Regression, whereas the final estimator was Random Forest. In the training set, the area under the ROC curve of the model was 0.982 (0.967-0.996) and 0.893 (0.826-0.960) in the testing set. This study indicated that radiomics features are a valuable addition to traditional risk factors for predicting bAVM rupture. In the meantime, ensemble learning can effectively improve the performance of a prediction model.

A Microsurgical Arteriovenous Malformation Model on Saphenous Vessels in the Rat

Arteriovenous malformation (AVM) is an anomaly of blood vessel formation. Numerous models have been established to understand the nature of AVM. These models have limitations in terms of the diameter of the vessels used and the impact on the circulatory system. Our goal was to establish an AVM model that does not cause prompt and significant hemodynamic and cardiac alterations but is feasible for follow-up of the AVM's progression. Sixteen female rats were randomly divided into sham-operated and AVM groups. In the AVM group, the saphenous vein and artery were interconnected using microsurgical techniques. The animals were followed up for 12 weeks. Anastomosis patency and the structural and hemodynamic changes of the heart were monitored. The hearts and vessels were histologically analyzed. During the follow-up period, shunts remained unobstructed. Systolic, diastolic, mean arterial pressure, and heart rate values slightly and non-significantly decreased in the AVM group. Echocardiogram results indicated minor systolic function impact, with slight and insignificant changes in aortic pressure and blood velocity, and minimal left ventricular wall enlargement. The small-caliber saphenous AVM model does not cause acute hemodynamic changes. Moderate but progressive alterations and venous dilatation confirmed AVM-like features. The model seems to be suitable for studying further the progression, enlargement, or destabilization of AVM.

Ruptured bilateral brain arteriovenous malformations in a young woman with early pregnancy: a case report

BACKGROUND

Brain arteriovenous malformations (AVMs) are rare congenital developmental vascular lesions, and often presents with symptoms upon rupture. The controversy exists as to whether pregnancy confers an increased risk of intracranial hemorrhage. The diagnosis of brain AVMs, in the absence of brain imaging, is challenging in resource-limited settings, particularly in sub-Saharan Africa.

CASE PRESENTATION

A 22-year old black African woman, primigravida at 14 weeks of gestation, presented with a history of persistent throbbing headache which was treated at primary health care facilities with analgesics and anti-migraine medications without relief. She later developed severe headache 2 weeks prior to admission and one-day history of serial partial generalized tonic-clonic seizures which were followed by post-ictal confusion and persistent right upper limb weakness. Initial evaluation revealed her to be pregnant and she later underwent a brain magnetic resonance angiography (MRA) at a university teaching hospital which revealed bleeding bilateral parietal AMVs with intracerebral haematoma and associated perilesional vasogenic oedema. The patient was managed conservatively using antifibrinolytic drugs and prophylactic anti-seizure drugs. Seven months later, she underwent a control brain MRA which revealed resolution of intracranial haematoma and associated vasogenic oedema and had her seizures well controlled. The headache had subsided and the pregnancy was allowed to continue to term under close obstetric and neurological observation. On follow up visits she reported episodes of nasal bleeding which upon ENT examination revealed nasal AVMs, suggesting the diagnosis of hereditary hemorrhagic telangiectasia (HHT).

CONCLUSION

AVMs are rare but should prompt suspicion in young patients with atypical Central Nervous System (CNS) manifestations without evident underlying causes.

Venous Rupture Following Transcatheter Arterial Embolization for Inferior Mesenteric Type II Arteriovenous Malformation

We treated a 64-year-old man who had an inferior mesenteric arteriovenous malformation with multiple shunts. As multiple varicosities in the draining vein became enlarged, two dilated shunts on the superior rectal and sigmoid colon arteries were coil embolized. Two days after embolization, a varicosity near the shunt (65 mm diameter) ruptured, causing intra-abdominal hemorrhage and surgical hemostasis. There were thrombi in the ruptured varicosity and its draining vein. The likely cause was a pressure increase in the incompletely thrombosed varicosity due to shunt blood flow from the remaining shunts after embolization.

Untangling the Modern Treatment Paradigm for Unruptured Brain Arteriovenous Malformations

Brain arteriovenous malformations (AVMs) often present treatment challenges. Patients with unruptured AVMs must consider not only whether they want to be treated, but what treatment modality they would prefer. Vascular neurosurgeons, neurointerventional surgeons, and stereotactic radiosurgeons must in turn guide their patients through the most appropriate treatment course considering the risk of AVM rupture, an individual AVM’s characteristics, and patient preferences. In this review we will look at how the clinical trial “A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA)” has influenced the approach to unruptured brain AVMs and the treatment modalities available to clinicians to deal with these formidable lesions.

Microsurgical Treatment of Deep and Eloquent AVMs

Over the past 30 years, the treatment of deep and eloquent arteriovenous malformations (AVMs) has moved away from microneurosurgical resection and towards medical management and the so-called minimally invasive techniques, such as endovascular embolization and radiosurgery. The Spetzler-Martin grading system (and subsequent modifications) has done much to aid in risk stratification for surgical intervention; however, the system does not predict the risk of hemorrhage nor risk from other interventions. In more recent years, the ARUBA trial has suggested that unruptured AVMs should be medically managed. In our experience, although these eloquent regions of the brain should be discussed with patients in assessing the risks and benefits of intervention, we believe each AVM should be assessed based on the characteristics of the patient and the angio-architecture of the AVM, in particular venous hypertension, which may guide us to treat even high-grade AVMs when we believe we can (and need to) to benefit the patient. Advances in imaging and intraoperative adjuncts have helped us in decision making, preoperative planning, and ensuring good outcomes for our patients. Here, we present several cases to illustrate our primary points that treating low-grade AVMs can be more difficult than treating high-grade ones, mismanagement of deep and eloquent AVMs at the behest of dogma can harm patients, and the treatment of any AVM should be tailored to the individual patient and that patient's lesion.

Effects of Preoperative Embolization on Spetzler-Martin Grade I and II Arteriovenous Malformations: A Propensity-Adjusted Analysis

BACKGROUND

Cerebral arteriovenous malformations (AVMs) with low Spetzler-Martin grades (I and II) are associated with good neurological outcomes after microsurgical resection; however, the use of preoperative embolization for these lesions is controversial.

OBJECTIVE

To compare the neurological outcomes of preoperative embolization with no embolization in patients with low-grade AVMs.

METHODS

Patients with a Spetzler-Martin grade I or II AVM who underwent microsurgical resection during January 1, 1997, through December 31, 2019, were analyzed. Patients undergoing preoperative embolization were compared with patients not undergoing embolization. A propensity score was constructed from baseline characteristics and used to match intervention (embolization) and control (nonembolization) groups in a 1:1 ratio. The primary outcome was poor neurological status on last follow-up examination, defined as a modified Rankin Scale score >2 and a modified Rankin Scale score worse at follow-up than at the preoperative examination.

RESULTS

Of the 603 patients analyzed, 310 (51.4%) underwent preoperative embolization and 293 (48.6%) did not. Patients in the embolization cohort compared with those in the nonembolization cohort had a higher percentage of Spetzler-Martin grade II AVMs (71.6% vs 52.6%, P < .001) and a lower percentage of hemorrhage (41% vs 55%, P = .001). After propensity score matching, no differences were found between paired cohorts (each N = 203) for baseline characteristics with a significant reduction in absolute standardized mean differences. No significant differences were found in primary outcomes between treatment groups in the matched or unmatched cohorts.

CONCLUSION

Preoperative embolization of low-grade Spetzler-Martin AVMs is not associated with improved neurological outcomes after microsurgical resection.

Exclusion treatment of ruptured and unruptured low-grade brain arteriovenous malformations: a systematic review

PURPOSE

To assess the obliteration rate, functional outcome, hemorrhagic complication, and mortality rates of exclusion treatment of low-grade brain arteriovenous malformations (BAVMs) (Spetzler and Martin grades (SMGs) 1 and 2), either ruptured or unruptured.

METHODS

Electronic databases-Ovid MEDLINE and PubMed-were searched for studies in which there was evidence of exclusion treatment of low-grade BAVMs treated either by endovascular, surgical, radiosurgical, or multimodality treatment. The primary outcome of interest was angiographic obliteration post-treatment and at follow-up. The secondary outcomes of interest were functional outcome (mRS), mortality rate, and hemorrhagic complication. Descriptive statistics were used to calculate rates and means.

RESULTS

Eleven studies involving 1809 patients with low-grade BAVMs were included. Among these, 1790 patients treated by either endovascular, surgical, radiosurgical, or multimodality treatment were included in this analysis. Seventy-two percent of BAVMs were Spetzler-Martin grade II. The overall (i.e., including all exclusion treatment modalities) complete obliteration rate ranged from 36.5 to 100%. The overall symptomatic hemorrhagic complication rate ranged from 0 to 7.3%; procedure-related mortality ranged from 0 to 4.7%.

CONCLUSION

Our systematic review of the literature reveals a high overall obliteration rate for low-grade BAVMs, either ruptured or unruptured, with low mortality rate and an acceptable post-treatment hemorrhagic complication rate. These results suggest that exclusion treatment of low-grade BAVMs may be safe and effective, regardless of the treatment modality chosen.

Hemorrhagic Pseudocyst: A Rare Cerebral Mass Lesion Causing Death. A Case Report and Brief Review of Literature

ABSTRACT

Mass lesions in the brain encompass a wide range neoplastic and nonneoplastic entities. These can present as a diagnostic pitfall, with nonspecific, overlapping symptoms and similar appearances on radiology. They may cause death through varied mechanisms, either specific to the underlying pathophysiology or due to the space-occupying effect of the lesion. We report a case of fatal hemorrhagic cerebral pseudocyst, a rare mass lesion, associated with a cerebral varix, causing death in a morbidly obese individual. To the best of our knowledge, there is no previous documentation in the postmortem literature of this entity as a cause of death. This case aims to document this rare entity in the differential diagnosis of a tumor-like lesion in the brain, highlight the clinical difficulty in its assessment, and demonstrate an uncommon mechanism of death, of a mass lesion acting as a focus causing seizures, with resulting hypoxia due to effects of morbid obesity and heart failure.