Arteriovenous Malformations Patients Research Articles

Multimodal ultrasound imaging for patent foramen ovale and pulmonary arteriovenous malformation in patients with cryptogenic stroke or migraine: A prospective diagnostic study.

Right-to-left shunt (RLS) caused by patent foramen ovale (PFO) and pulmonary arteriovenous malformations (PAVM) have been associated with a variety of diseases, and reliable techniques for detecting RLS are essential for diagnosis. This study aimed to compare the diagnostic accuracy of multimodal ultrasound imaging, including transthoracic echocardiography (TTE) plus contrast transthoracic echocardiography (CTTE) and transesophageal echocardiography (TEE) plus contrast transesophageal echocardiography (CTEE) for PFO and PAVM in patients with cryptogenic stroke or migraine. This prospective study enrolled patients with cryptogenic stroke or migraine admitted to First Hospital of Shanxi Medical University between July 2018 and April 2023. The TTE + CTTE + TEE + CTEE multimodal ultrasound imaging was defined as the gold standard. A total of 230 patients with cryptogenic stroke (108) or migraine (122) were enrolled. The TEE + CTEE generated a better area under the receiver operator characteristic (ROC) curves (AUC) than TTE + CTTE [0.995 (0.988-1.000) vs 0.975 (0.767-0.984), P < .001], indicating better identification of PFO and PAVM. The sensitivity and specificity of the TTE + CTTE were 89.4% and 85.7%, respectively, whereas the sensitivity and specificity of TEE + CTEE were 99.1% and 100%, respectively. The missed diagnosis rate of TTE + CTTE and TEE + CTEE was 65.7 % and 12.5%, respectively. The combination of TEE + CTEE may be a more reliable and sensitive tool to detect PFO and PAVM than TTE + CTTE in patients with cryptogenic stroke or migraine.

Unforeseen outcomes: Unveiling cyst formation post stereotactic radiosurgery in brain arteriovenous malformations cases

IntroductionCyst formation after stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVMs) is a rare, delayed but important complication. Prompt recognition and appropriate treatment is essential for good outcome. MethodsWe analysed our institute’s Gamma knife treatment records from 2008 to 2023 and analysed AVM treated patients by gamma knife radiosurgery (GKRS). Patients with cyst formation and with adequate follow up were identified. Clinical details, management and prognosis of these patients was studied in detail along with prior literature review. ResultsA total of 921 AVM patients were treated in the above period and 7 patients were identified with cyst formation. The mean nidus volume was 12.98 ml, the mean radio surgical marginal dose was 23.57 Gy and maximal dose 47.21 Gy. The mean interval gap between SRS and cyst detection was 6.45 years. The mean volume of cyst cavity formed was 47.85 ml. Patients presented either with features of raised intracranial pressure (3) or focal neurological deficits (3) or seizures (1). 3 patients had achieved angiographic nidus obliteration at the time of cyst detection. Treatment was mostly on surgical lines with cyst fenestration(2 patients), excision (3 patients) and emergency decompressive craniectomy (1 patient). 1 patient required additional Ommaya insertion. Conservative management was followed for 1 patient. Residual nidus was treated either by concomitant excision or embolization or redo GKRS.Favourable outcome was seen in 6 out of 7 patients (85.71%) post cyst management with symptomatic and radiological improvement whereas 1 patient (14.28%) died due to refractory status epilepticus secondary to malignant cerebral edema. ConclusionCyst formation after GKRS for AVM treatment is an often-neglected complication due to its low incidence and often long latency period. Long term follow up of patients is hence necessary for prompt recognition. Diagnostic DSA should be done in all patients with cysts to look for residual nidus. Asymptomatic ones can be followed up conservatively while surgical treatment is required for symptomatic cases. Ventricular diversion like Ommaya or cystoperitoneal shunt may be necessary in some cases. Treatment outcome is usually favourable provided timely detection is done.

Stereotactic Radiosurgery With Versus Without Neoadjuvant Endovascular Embolization for Brain Arteriovenous Malformations With Associated Intracranial Aneurysms.

Stereotactic radiosurgery (SRS) with neoadjuvant embolization is a treatment strategy for brain arteriovenous malformations (AVMs), especially for those with large nidal volume or concomitant aneurysms. The aim of this study was to assess the effects of pre-SRS embolization in AVMs with an associated intracranial aneurysm (IA). The International Radiosurgery Research Foundation AVM database from 1987 to 2018 was retrospectively reviewed. SRS-treated AVMs with IAs were included. Patients were categorized into those treated with upfront embolization (E + SRS) vs stand-alone SRS (SRS). Primary end point was a favorable outcome (AVM obliteration + no permanent radiation-induced changes or post-SRS hemorrhage). Secondary outcomes included AVM obliteration, mortality, follow-up modified Rankin Scale, post-SRS hemorrhage, and radiation-induced changes. Forty four AVM patients with associated IAs were included, of which 23 (52.3%) underwent pre-SRS embolization and 21 (47.7%) SRS only. Significant differences between the E + SRS vs SRS groups were found for AVM maximum diameter (1.5 ± 0.5 vs 1.1 ± 0.4 cm3, P = .019) and SRS treatment volume (9.3 ± 8.3 vs 4.3 ± 3.3 cm3, P = .025). A favorable outcome was achieved in 45.4% of patients in the E + SRS group and 38.1% in the SRS group (P = .625). Obliteration rates were comparable (56.5% for E + SRS vs 47.6% for SRS, P = .555), whereas a higher mortality rate was found in the SRS group (19.1% vs 0%, P = .048). After adjusting for AVM maximum diameter, SRS treatment volume, and maximum radiation dose, the likelihood of achieving favorable outcome and AVM obliteration did not differ between groups (P = .475 and P = .820, respectively). The likelihood of a favorable outcome and AVM obliteration after SRS with neoadjuvant embolization in AVMs with concomitant IA seems to be comparable with stand-alone SRS, even after adjusting for AVM volume and SRS maximum dose. However, the increased mortality among the stand-alone SRS group and relatively low risk of embolization-related complications suggest that these patients may benefit from a combined treatment approach.

Stereotactic Radiosurgery Outcomes in Arteriovenous Malformations: A Pediatric-Adult Comparative Meta-Analysis

Stereotactic radiosurgery (SRS) is an established treatment for brain arteriovenous malformations (AVMs), but outcomes between pediatric and adult populations are not well compared. We conducted a systematic review and meta-analysis comparing SRS outcomes for pediatric versus adult AVMs. PubMed was searched for studies reporting SRS outcomes for pediatric or adult AVMs up to January 2024. Primary outcome was obliteration rate, with secondary outcomes including post-SRS hemorrhage, symptomatic radiation-induced changes (RICs), and permanent RICs. Pooled estimates were calculated using random effects models. Analysis included 22 studies with 3469 patients (1316 pediatric, 2153 adult). Pooled obliteration rate was 63% (95% confidence interval: 56%-70%) overall, with no significant difference between pediatric (61%) and adult (67%) cohorts (P= 0.38). Post-SRS hemorrhage rates were similar (5% pediatric, 6% adult, P= 0.60). Symptomatic RICs occurred in 9% (95% confidence interval: 6%-13%) overall, with 10% in both cohorts (P= 0.91). Permanent RIC rates were 4% in pediatric and 3% in adult cohorts (P= 0.43). Cyst formation (0.6%) and radiation-induced tumors (0.2%) were rare. All-cause mortality was significantly lower in the pediatric cohort (2.6% vs. 9.8%, P= 0.003). Hemorrhagic AVM presentation was inversely correlated with symptomatic RICs across both groups. SRS is a reasonable treatment option for appropriately selected AVM patients in both pediatric and adult populations, offering comparable obliteration rates and adverse event profiles. The lower mortality in pediatric patients underscores the importance of early intervention in this population given their high cumulative lifetime rupture risks.

Surgical Results with Low-Grade Arteriovenous Malformations : A Single Center 14-Year Experience.

Advancements in AVM surgical techniques for cerebral arteriovenous malformation (AVM) underscore its efficacy. Our research aims to showcase the positive outcomes of treating low-grade AVMs surgically, focusing on safety and effectiveness. We retrospectively reviewed 55 patients (36 males and 19 females; average age 37.4 years) with Spetzler-Martin (S-M) grade 1 and 2 AVMs who underwent surgical resection between January 2009 and December 2022. In our study, 55 patients with S-M grade 1 and 2 AVMs underwent surgical resection, evenly divided between grades 1 (50.9%) and 2 (49.1%). Intracranial hemorrhage was the primary symptom in 74.5% of cases. Pre-operative Glasgow coma scale (GCS) scores revealed 69.1% of patients scored above 13, with 18% below 8. Successful resection was achieved in 87.3%. Postoperatively, 95.5% of ruptured and 90.9% of unruptured AVM patients showed lower or same modified Rankin scale scores. Poorer outcomes were significantly linked to lower GCS scores and intranidal/flow-related aneurysms through multivariate logistic regression. Postoperative seizures noted in nine patients, were exclusive to the ruptured AVM group. Our findings indicate surgical resection as a beneficial treatment for low-grade AVMs, yielding high cure rates and positive functional outcomes in both ruptured and unruptured cases. Preoperative GCS scores and the presence of associated aneurysms are predictive of postoperative functional status. Additionally, managing postoperative seizures effectively is key to enhancing prognosis.

Comparative analysis of peri-nidal cerebral blood flow and metabolism using a novel quantitative 15O-PET method in patients with arteriovenous malformations.

To effectively treat cerebral arteriovenous malformations (AVMs), peri-nidal flow regulation and metabolic status must be understood. In this study, we used 15O-oxygen positron emission tomography (PET) post-processing analysis to investigate vascular radioactivity in the nidal region of AVMs. Single-dynamic PET imaging was performed on seven unruptured AVM patients during the sequential inhalation of 15O2 and C15O2. A previously validated dual-tracer basis function method (DBFM) was employed to calculate parametric images. The results of our study were as follows. First, in remote and contralateral AVM regions, DBFM and a previous approach of dual-tracer autoradiography (DARG) showed strong positive correlations in cerebral blood flow (CBF), cerebral oxygen metabolism rate (CMRO2), and oxygen extraction fraction. Second, peri-nidal CBF and CMRO2 correlation was lower, and overestimation occurred with DARG compared to with DBFM. Third, on comparing DBFM to quantitative 123I-iodoamphetamine single-photon emission computed tomography (SPECT), CBF correlated significantly. In contrast, the correlation between DARG and quantitative 123I-iodoamphetamine-SPECT was weaker in the peri-nidal regions. Fourth, analysis of tissue time-activity curves demonstrated good reproducibility using the novel formulation in the control, peri-nidus, and core nidal regions, indicating the adequacy of this approach. Overall, the DBFM approach holds promise for assessing haemodynamic alterations in patients with AVMs.

Arterial Spin-Labeling MR Imaging in the Detection of Intracranial Arteriovenous Malformations in Patients with Hereditary Hemorrhagic Telangiectasia.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease that causes vascular malformations in a variety of organs and tissues, including brain AVMs. Because brain AVMs have the potential to cause disabling or fatal intracranial hemorrhage, detection of these lesions before rupture is the goal of screening MR imaging/MRA examinations in patients with HHT. Prior studies have demonstrated superior sensitivity for HHT-related brain AVMs by using postcontrast MR imaging sequences as compared with MRA alone. We now present data regarding the incremental benefit of including arterial spin-labeling (ASL) perfusion sequences as part of MR imaging/MRA screening in patients with this condition. We retrospectively analyzed 831 patients at the UCSF Hereditary Hemorrhagic Telangiectasia Center of Excellence. Of these, 42 patients had complete MR imaging/MRA, ASL perfusion scans, and criterion-standard DSA data. Two neuroradiologists reviewed imaging studies and a third provided adjudication when needed. Eight patients had no brain AVMs detected on DSA. The remaining 34 patients had 57 brain AVMs on DSA. Of the 57 identified AVMs, 51 (89.5%) were detected on ASL and 43 (75.4%) were detected on conventional MR imaging/MRA sequences (P = .049), with 8 lesions detected on ASL perfusion but not on conventional MR imaging. ASL provides increased sensitivity for brain AVMs in patients with HHT. Inclusion of ASL should be considered as part of comprehensive MR imaging/MRA screening protocols for institutions taking care of patients with HHT.

Microsurgery of Cerebral Arteriovenous Malformations in a Resource-Limited Setting: The First Case-Series from Iraq

Cerebral arteriovenous malformations (AVMs) can lead to significant morbidity and are particularly challenging to manage in resource-limited settings where endovascular treatment modalities are unaffordable for most patients. To describe the first case series of AVM from Iraq with an analysis of the related clinicoradiologic characteristics, operative features, and outcomes. A single-center database from October 2018 to December 2022 was reviewed to analyze the characteristics of cerebral AVMs who underwent surgical treatment in Baghdad, Iraq. We collected patient demographics, clinical, radiologic, operative, and the follow-up combined outcome results (modified Rankin Scale score and the presence of AVM remnants). Of the 54 AVM patients treated with microsurgery, the majority of lesions have Spetzler-Martin grade of 3 (31.5%), followed by grade 1 (29.6%). The parietal lobe was the most common location of AVM in 25.9% of the cases, and the temporal location had better outcomes. The mean duration of surgery was 8.5 hours, ranging from 3 to 14 hours, with 20.3% of cases having undergone preoperative stereotactic radiosurgery, and just one patient received preoperative embolization. Good combined outcome (modified Rankin Scale 0-2 and no AVM remnant) was associated with lower SM grades (P=0.003); location in the nondominant hemisphere (P=0.036), and noneloquent regions (P=0.006); absence of deep venous drainage (P=0.042) and no intraoperative brain swelling (P=0.004). The mortality rate in our series was 5.5%. Good clinicoradiologic outcomes can be achieved through microsurgery in a setting where endovascular treatment is inaccessible to patients due to limited resources.

Timing of Embolization, Radiosurgery, and Resection of Arteriovenous Malformations in Pediatric Patients: A Retrospective, Descriptive Study

ObjectiveCerebral arteriovenous malformations (AVMs) are a challenging pathology in pediatric patients, carrying a high risk of morbidity and mortality. Treatment modalities include resection, endovascular embolization and stereotactic radiosurgery (SRS). There is currently no consensus favoring one modality over another. Timing of multimodal therapy with embolization/SRS and resection is not well explored in the literature. Here we present a series of pediatric AVM patients, with special attention paid to the timing of treatment. MethodsElectronic medical records of all pediatric patients (<18 years at treatment) with AVMs treated at our institution were retrospectively reviewed after IRB approval. Demographic information, AVM characteristics, treatment variables and outcomes were recorded. Results27 total patients were included. 21 (77.8%) presented with a ruptured AVM. 6 patients (28.6%) had an GCS of 3 to 10, and underwent treatment within 24 hours of presentation. 10 patients (47.6 %) with a GCS of 12 to 15 were treated between 24 to 120 hours. 5 patients (23.8%) were treated 3 weeks to 14 months after AVM rupture. 96% of our cohort, regardless of rupture status, had mRS of 1-2 at most recent follow-up. ConclusionsWe present our institution’s experience with pediatric AVM’s, focusing on the timing of treatment. Based on our experience, early treatment of AVMs seems to be safe and effective regardless of rupture status.

Intraventricular hemorrhage secondary to ruptured arteriovenous malformation: A case report

Introduction: An arteriovenous malformation (AVM) is a lesion in which the feeding artery and the draining vein are connected by a coiled, tortuous vascular link. This nidus is where arteriovenous shunting occurs. While pediatric AVM is uncommon, there has been evidence of possible impairments and an increased risk of hemorrhage. This study aimed to elaborate on a rare case of pediatric arteriovenous malformation with intraventricular hemorrhage. Case report: A male patient, fifteen years of age, was referred from P hospital due to a severe headache that was accompanied by nausea and vomiting two days prior to hospital admission. Chief Computed Tomography Digitizing and Angiographic Images In the left lateral ventricle, the posterior horn of the right lateral ventricle, the third ventricle, and the left pericallosal area AVM (Spletzer Martin grading: 2), intraventricular hemorrhage (IVH), and moderate cerebral edema were all seen during an angiography. AVM was managed conservatively with head positioning 30o, analgesics, and ranitidine. Phenytoin was given as a precaution for seizure in intracerebral hemorrhage. The headache improved gradually during the hospital stay. Upon follow-up at the outpatient clinic, headache and other neurological symptoms were absent, and the patient had typical vital signs. Conclusion: AVM rupture can cause IVH that occurs more often in young patients. Management of pediatric AVM requires discussion among pediatric neurologists, neurosurgeons, and interventional radiologists to decide the best care for the patient. AVM patients who received conservative treatment had a higher risk of bleeding and, therefore, required routine monitoring.

Serum Vascular Endothelial Growth Factor and Endostatin as an Adjunct to Clinical Decision Making in Managing Radiation-induced Changes Post Gamma Knife Radiosurgery in Spetzler Martin Grade 3 Arteriovenous Malformations Patients: A Pilot Study

BackgroundRadiation induced changes (RIC) are the most common complications observed post GKRS and may be observed within 6-18months post procedure. It has been observed that almost one third of RICs are symptomatic and half of them are persistent. There is no way to predict which patients will develop these changes and to what extent.This was a prospective analytical pilot study with the aim of understanding the role of Serum Vascular Endothelial Growth Factor and Endostatin as a predictive factor for clinically symptomatic RIC in intracranial AVMs Spetzler Martin (SM) grade 3 being managed with primary Gamma Knife radiosurgery.Total of 15 patients were analysed. 60% of them had a history of bleed. The median volume of AVM Nidus was 4.36 cc. One third of the patients had no imaging changes suggestive of RIC at 1 year follow up and 2 of the patients had symptomatic RIC needing intervention. Before Gamma Knife, the median values of serum concentration of Endostatin and VEGF are 34.98 ng/mL and 168.37 pg/mL respectively . The serum values of VEGF at 1 month post GKRS was much less than the pre GKRS values but not found to be predictive of RIC. No correlation could be observed with the levels of serum endostatin and RIC.Some patients may develop resistant oedema and necrosis post GKRS for intracranial AVMs which may warrant medical and surgical intervention. Serum biomarkers like VEGF and Endostatin may vary in post GKRS period fpo can be used to identify at risk cases, however more studies are needed to decide on appropriate time of sampling and identify clinically relevant predictive factors.

Somatic RIT1 delins in arteriovenous malformations hyperactivate RAS-MAPK signaling amenable to MEK inhibition.

Arteriovenous malformations (AVM) are benign vascular anomalies prone to pain, bleeding, and progressive growth. AVM are mainly caused by mosaic pathogenic variants of the RAS-MAPK pathway. However, a causative variant is not identified in all patients. Using ultra-deep sequencing, we identified novel somatic RIT1 delins variants in lesional tissue of three AVM patients. RIT1 encodes a RAS-like protein that can modulate RAS-MAPK signaling. We expressed RIT1 variants in HEK293T cells, which led to a strong increase in ERK1/2 phosphorylation. Endothelial-specific mosaic overexpression of RIT1 delins in zebrafish embryos induced AVM formation, highlighting their functional importance in vascular development. Both ERK1/2 hyperactivation in vitro and AVM formation in vivo could be suppressed by pharmacological MEK inhibition. Treatment with the MEK inhibitor trametinib led to a significant decrease in bleeding episodes and AVM size in one patient. Our findings implicate RIT1 in AVM formation and provide a rationale for clinical trials with targeted treatments.

Sustaining consistent cobalt-60 dose rate enhances radiosurgical outcomes in brain arteriovenous malformation management

Background and purposeThe impact of cobalt-60 dose rate (Co-60 DR) on outcomes of stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVMs) remains fully elucidated. This study explored the association between Co-60 DR and SRS outcomes in AVM treatment. Materials and methods772 AVM patients from 1990 to 2020 were included. High DR was defined as ≥ 2.4 Gy/min. AVM patients were categorized into 3 cohorts based on the nidus volume: small (<5 mL), medium (≥5 mL and < 10 mL), and large (≥10 mL). The primary endpoint was AVM obliteration; secondary endpoints included post-SRS hemorrhage. ResultsCumulative obliteration rates of the large AVM were significantly increased in the high DR group than those in the low DR group (84 % vs. 45 % at 5 years, log-rank test; p = 0.011). Multivariable analysis showed that the obliteration rate was significantly elevated for the high DR group in the large AVM cohort with an adjusted hazard ratio (HR) of 1.78 (95 % confidence interval [CI]: 1.00–3.17, p = 0.049). Post-SRS hemorrhage rates of the entire cohort were significantly decreased in the high DR group than in the low DR group (2.5 % vs. 5.3 % at 5 years, log-rank test; p = 0.035). Multivariable analysis revealed post–SRS hemorrhage was reduced in the high DR group with an adjusted HR of 0.47 (95 % CI: 0.24–0.92, p = 0.026). ConclusionHigh DR may lead to increased efficiency for large AVMs and decreased post-SRS hemorrhage in all AVM cases. Sustaining a higher Co-60 DR could potentially yield favorable outcomes for SRS for AVMs.

Surgical treatment of brain arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia: a single-center experience

OBJECTIVE Hereditary hemorrhagic telangiectasia (HHT) is an autosomal-dominant disorder characterized by multiple vascular malformations. Brain arteriovenous malformations (bAVMs) are a significant manifestation of HHT. The surgical management of these lesions in patients with HHT remains debated, with limited literature on postoperative outcomes. The goal of this study was to evaluate the safety and efficacy of surgical treatment for bAVMs in patients with HHT and propose a treatment rationale based on a single-center experience. METHODS This retrospective review included 20 patients diagnosed with HHT who underwent resection of 23 bAVMs at the Stanford University Medical Center between January 2007 and September 2023. Data were also collected on bAVMs treated conservatively, with embolization, or with radiosurgery at the authors’ institution, for comparison. RESULTS There were 16 Spetzler-Martin (SM) grade I, 6 SM grade II, and 1 SM grade IV bAVM. Six of the bAVMs presented with neurological symptoms (3 with hemorrhage and 3 with focal neurological deficits), while the rest were detected on routine screening. Complete excision was angiographically confirmed in all patients, with a mean overall hospital stay of 2.1 days and a mean follow-up of 36 months. Postoperative complications were limited to transient mild weakness in 2 patients, 1 of whom also had transient speech deficits, and visual field deficits in 3 patients, 2 of whom improved on long-term follow-up. CONCLUSIONS In this most extensive surgical series published to date, resection of bAVMs in patients with HHT showed favorable outcomes with a low complication rate, suggesting that the benefits of surgery outweigh the risks, especially considering the potential cumulative lifetime risk of hemorrhage. MR arterial spin labeling was found to be the most sensitive noninvasive measure of detecting bAVMs in patients with HHT.

Pediatric Patients with Intracranial Arteriovenous Malformations: Trends in Emergency Room Presentation

Pediatric intracranial arteriovenous malformation (AVM) patients are commonly admitted to the emergency room (ER). Increasing patient utilization of the ER has been associated with healthcare disparities and a trend of decreased efficiency. The aim of this study was to evaluate the trends of pediatric AVM ER admissions over recent years and identify factors associated with health care resource utilization and outcomes. The 2016-2019 National Inpatient Sample was queried for patients under the age of 18 admitted with AVM. Cases of admission through the ER were identified. Demographic and severity factors associated with ER admission were explored using comparative and regression statistics. Of 3875 pediatric patients with AVM admitted between 2016 and 2019, 1280 (33.0%) were admitted via the ER. Patients admitted via the ER were more likely to be in the lowest median income category (P<0.001), on Medicaid insurance (P=0.008), or in the South (P<0.001) than patients admitted otherwise. There was increased severity and increased rates of intracranial hemorrhage (ICH) in patients admitted via the ER (P<0.001). Finally, there were increasing trends in ER admissions and ICH throughout the years. ER admission of pediatric AVM patients with ICH is increasing and is associated with a distinct socioeconomic profile and increased healthcare resource utilization. These findings may reflect decreased access to more advanced diagnostic modalities, primary care, and other important resources. Identifying populations with barriers to care is likely an important component of policy aimed at decreasing the risk of severe disease presentation.

Associations of Brain Arteriovenous Malformation-Related Factors with Epileptic Seizure Presentations.

Arteriovenous malformations (AVMs) are abnormal tangles of arteries and veins that connect directly without an intervening capillary bed. Epileptic seizures are the second most common symptom in patients with brain AVMs, occurring in 30 to 50% of cases. However, the exact mechanism of epileptic seizure development in AVMs remains unclear. In this study, we aimed to investigate the factors associated with epileptic seizures in patients with brain arteriovenous malformation (AVMs) in Kazakhstan. A case-control study was conducted, which included 163 patients diagnosed with brain AVMs. Demographic and clinical data were collected and analyzed, and multivariate logistic regression was built to assess the factors associated with seizures in brain AVMs. from this rupture of vessels OR = 0.36 95% CI (0.14-0.91, a medium-to-high Spetzler-Martin score (III-V) OR = 6.16 (2.14-17.69) and OR = 3.05 (1.08-8.68), respectively), location in brain cortex (frontal lobe OR = 6.16 (2.04-18.54), parietal lobe OR = 9.37 (3.26-26.91), temporal lobe OR = 4.57 (1.56-13.36), occipital lobe OR = 0.27 (0.08-0.91), and the presence of hemiparesis OR = 0.12 (0.02-0.66) in adverse outcomes were statistically significantly associated with the presence of epileptic seizures in brain arteriovenous malformations patients. To conclude, this contributed to model factors associated with brain arteriovenous malformations that are linked to epileptic seizures.

Angiographic tool to detect pulmonary arteriovenous malformations in single ventricle physiology.

Individuals with single ventricle physiology who are palliated with superior cavopulmonary anastomosis (Glenn surgery) may develop pulmonary arteriovenous malformations. The traditional tools for pulmonary arteriovenous malformation diagnosis are often of limited diagnostic utility in this patient population. We sought to measure the pulmonary capillary transit time to determine its value as a tool to identify pulmonary arteriovenous malformations in patients with single ventricle physiology. We defined the angiographic pulmonary capillary transit time as the number of cardiac cycles required for transit of contrast from the distal pulmonary arteries to the pulmonary veins. Patients were retrospectively recruited from a single quaternary North American paediatric centre, and angiographic and clinical data were reviewed. Pulmonary capillary transit time was calculated in 20 control patients and compared to 20 single ventricle patients at the pre-Glenn, Glenn, and Fontan surgical stages (which were compared with a linear-mixed model). Correlation (Pearson) between pulmonary capillary transit time and haemodynamic and injection parameters was assessed using angiograms from 84 Glenn patients. Five independent observers calculated pulmonary capillary transit time to measure reproducibility (intraclass correlation coefficient). Mean pulmonary capillary transit time was 3.3 cardiac cycles in the control population, and 3.5, 2.4, and 3.5 in the pre-Glenn, Glenn, and Fontan stages, respectively. Pulmonary capillary transit time in the Glenn population did not correlate with injection conditions. Intraclass correlation coefficient was 0.87. Pulmonary angiography can be used to calculate the pulmonary capillary transit time, which is reproducible between observers. Pulmonary capillary transit time accelerates in the Glenn stage, correlating with absence of direct hepatopulmonary venous flow.

691 Correlation of Cerebral Arteriovenous Malformation Flow Measured by Quantitative Magnetic Resonance Angiography and MR-detected Arteriovenous Malformation Microhemorrhage

INTRODUCTION: Intracranial hemorrhage (ICH) significantly contributes to morbidity and mortality in cerebral arteriovenous malformations (AVM) patients, with a history of prior hemorrhage being the most significant predictor of a future hemorrhage. Recently, silent microhemorrhage as detected on magnetic resonance imaging (MRI) has been proposed as a potential risk factor for future hemorrhage in AVM patients. Recent data suggests that silent microhemorrhage is associated with higher nidal velocity measured through color-coded DSA, raising the question of correlation between flow and microhemorrhage. METHODS: All unruptured AVM patients with a baseline QMRA with noninvasive optimal vessel analysis (NOVA) and gradient echo or susceptibility-weighted MRI were retrospectively reviewed (2004-2022). AVM flow was calculated from the aggregate flow within primary arterial feeders relative to their contralateral counterparts. A review of the MRI determined the presence of microhemorrhages. Descriptive statistics, the X2 test, and a binomial logistic regression were performed to test the association of demographics, clinical, and AVM features with microhemorrhage. RESULTS: The study consisted of ninety patients, with fifty microhemorrhage-positive and forty microhemorrhage-negative patients. The presence of venous anomaly (varix, ectasia, aneurysm) is independently predictive of microhemorrhage (OR = 2.444, p = 0.050), and a compact AVM nidus trended towards independent negative predictability of microhemorrhage (OR =.462, p = 0.081). Calculated AVM flow trends higher in the microhemorrhage-positive group with the median flow 407 mL/min vs. 238 mL/min, and a trend towards predicting presence of microhemorrhage (OR = 1.375, p = 0.106). CONCLUSIONS: Patients with AVM-associated venous anomalies have an increased likelihood of AVM microhemorrhage. Higher AVM flow and a diffuse AVM nidus trend towards a higher likelihood of AVM microhemorrhage. These findings demonstrate the possible relationship between higher AVM flow and risk of future bleeding.

Are hemodynamics responsible for inflammatory changes in venous vessel walls? A quantitative study of wall-enhancing intracranial arteriovenous malformation draining veins.

Signal enhancement of vascular walls on vessel wall MRI might be a biomarker for inflammation. It has been theorized that contrast enhancement on vessel wall imaging (VWI) in draining veins of intracranial arteriovenous malformations (AVMs) may be associated with disease progression and development of venous stenosis. The aim of this study was to investigate the relationship between vessel wall enhancement and hemodynamic stressors along AVM draining veins. Eight AVM patients with 15 draining veins visualized on VWI were included. Based on MR venography data, patient-specific 3D surface models of the venous anatomy distal to the nidus were segmented. The enhanced vascular wall regions were manually extracted and mapped onto the venous surface models after registration of image data. Using image-based blood flow simulations applying patient-specific boundary conditions based on phase-contrast quantitative MR angiography, hemodynamics were investigated in the enhanced vasculature. For the shear-related parameters, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT) were calculated. Velocity, oscillatory velocity index (OVI), and vorticity were extracted for the intraluminal flow-related hemodynamics. Visual observations demonstrated overlap of enhancement with local lower shear stresses resulting from decreased velocities. Thus, higher RRT values were measured in the enhanced areas. Furthermore, nonenhancing draining veins showed on average slightly higher flow velocities and TAWSS. Significant decreases of 55% (p = 0.03) for TAWSS and of 24% (p = 0.03) for vorticity were identified in enhanced areas compared with near distal and proximal domains. Velocity magnitude in the enhanced region showed a nonsignificant decrease of 14% (p = 0.06). Furthermore, increases were present in the OSI (32%, p = 0.3), RRT (25%, p = 0.15), and OVI (26%, p = 0.3) in enhanced vessel sections, although the differences were not significant. This novel multimodal investigation of hemodynamics in AVM draining veins allows for precise prediction of occurring shear- and flow-related phenomena in enhanced vessel walls. These findings may suggest low shear to be a local predisposing factor for venous stenosis in AVMs.

Management outcomes of peripontine arteriovenous malformation patients presenting with trigeminal neuralgia.

Trigeminal neuralgia as the presenting symptom of brain arteriovenous malformation (bAVM) has been rarely reported. Treatment of reported cases has been skewed toward surgery for these scarce, deeply located bAVMs. Here, the authors report their management and outcomes of bAVM patients presenting with ipsilateral trigeminal neuralgia (TN) at their institution. This is a retrospective cohort study. The authors' institutional bAVM database was queried for non-hereditary hemorrhagic telangiectasia bAVMs in pontine, cistern, brainstem, trigeminal nerve, or tentorial locations. Patients with complete data were included in a search for trigeminal neuralgia or "facial pain" as the presenting symptom with TN being on the same side as the bAVM. Demographics, TN and bAVM characteristics, management strategies, and outcomes of bAVM and TN management were analyzed. Fifty-seven peripontine bAVMs were identified; 8 (14.0%) of these bAVMs were discovered because of ipsilateral TN, including 4 patients (50%) with facial pain in the V2 distribution. Five patients (62.5%) were treated with carbamazepine as the initial medical therapy, 2 (25%) underwent multiple rhizotomies, and 1 (12.5%) underwent microvascular decompression. None of the patients with TN-associated bAVMs presented with hemorrhage, compared with 25 patients (51%) with bAVMs that were not associated with TN (p < 0.01). TN-associated bAVMs were overall smaller than non-TN-associated bAVMs, but the difference was not statistically significant (1.71 cm vs 2.22 cm, p = 0.117), and the Spetzler-Martin grades were similar. Six patients (75%) underwent radiosurgery to the bAVM (mean dose 1800 cGy, mean target volume 0.563 cm3) and had complete resolution of TN symptoms (100%). The mean time from radiosurgery to TN resolution was 193 (range 21-360) days, and 83.3% of treated TN-associated bAVMs were obliterated via radiosurgery. Two patients (12.5%) were recommended for conservative management, with one undergoing subsequent rhizotomies and another patient died of hemorrhage during follow-up. TN-associated bAVM is a rare condition with limited evidence for management guidance. Radiosurgery can be safe and effective in achieving durable TN control in patients with TN-associated bAVMs. Despite their deep location and unruptured presentation, obliteration can reach 83.3% with radiosurgery.