Leptomeningeal Venous Drainage Research Articles

Treatment outcomes and the role of the DES scheme in the appropriate treatment selection for high-grade dural arteriovenous fistulas.

Endovascular and microsurgical treatment are viable options for the majority of Borden type III dural arteriovenous fistulas (dAVFs). The aim of this study was to examine treatment outcomes in a comparative analysis of endovascular and surgical treatment modalities for Borden type III fistulas and explore clinical implications of the DES scheme in selecting ideal candidates for surgical therapy. Patients diagnosed with dAVFs with leptomeningeal venous drainage admitted to the Departments of Neurosurgery or Neuroradiology of the University Hospital Zurich between January 2014 and October 2021 were included in this study. Comprehensive patient data including demographics, clinical presentation, and dAVF characteristics, including established classifications, were collected. Treatment outcomes were assessed based on postinterventional angiography findings. In addition, treatment-related complications were assessed based on the Clavien-Dindo classification. Among all Borden type III dAVFs, 15 were initially treated endovascularly (60% complete occlusion rate) and 10 with microsurgical disconnection (90% complete occlusion rate) (p = 0.18). Subgroup analysis of dAVFs meeting the criteria for directness and exclusivity based on the DES scheme showed a 100% complete occlusion rate after microsurgical disconnection, whereas embolization achieved a complete occlusion rate of 60% (p = 0.06). There was no significant difference in the rate or severity of treatment-related complications between treatment modalities. This study suggests that microsurgical disconnection is a viable primary treatment modality for Borden type III dAVFs, particularly for dAVFs that meet the criteria of directness and exclusivity according to the DES scheme. The DES scheme demonstrates its relevance in selecting the most appropriate treatment strategy for affected patients.

Neuronal dysfunction and hemodynamic disturbance due to venous congestion in dural arteriovenous fistula revealed by 123I-iomazenil SPECT.

Retrograde leptomeningeal venous drainage (RLVD) of a dural arteriovenous fistula (dAVF) is associated with neurological morbidity and unfavorable outcomes. However, the direct damage to cortical neurons by dAVF with RLVD has not been elucidated. 123I-iomazenil (123I-IMZ) SPECT can reveal cerebral blood flow and cortical neuronal damage in early and late images, respectively. This study aimed to assess the cerebral venous congestive encephalopathy caused by dAVF using 123I-IMZ SPECT. Based on the pre- and posttreatment MRI findings, patients were divided into three groups: a normal group, an edema group, and an infarction group. Radioactive counts in the early and late images of 123I-IMZ SPECT were investigated using the affected-to-contralateral side asymmetry ratio (ACR). None of the patients in the normal group showed any symptoms related to venous congestion. In contrast, all the patients in the edema and infarction groups developed neurological symptoms. The ACR in early images in the edema group was significantly lower than that in the normal group and significantly higher than that in the infarction group. The ACR in the late images of the infarction group was significantly lower than those of the normal and edema groups. After treatment, the neurological signs disappeared in the edema group, but only partial improvement was observed in the infarction group. The ACR in early images significantly improved after treatment in the edema group, but the ACR in late images did not change in any groups. 123I-IMZ SPECT is useful for evaluating hemodynamic disturbances and neuronal damage in dAVFs. The reduction in early images was correlated with the severity of venous congestive encephalopathy, and the significant reduction in late images is a reliable indicator of irreversible venous infarction caused by RLVD.

Abstract TP103: Neuronal Dysfunction And Hemodynamic Disturbance Due To Venous Congestion In Dural Arteriovenous Fistula Revealed By 123 I-iomazenil Single-photon Emission Computed Tomography

Objective: Retrograde leptomeningeal venous drainage (RLVD) of a dural arteriovenous fistula (dAVF) is related to neurological morbidity and unfavorable outcomes. However, the direct damage to cortical neurons by dAVF with RLVD has not been elucidated. 123 I-iomazenil ( 123 I-IMZ) single-photon emission computed tomography (SPECT) can reveal cerebral blood flow and cortical neuronal damage in early and late images, respectively. This study aimed to assess the relationship association between cerebral venous congestive encephalopathy caused by dAVF using 123 I-IMZ SPECT. Methods: Based on the pre- and post-treatment magnetic resonance imaging findings, patients were divided into three groups: normal, edema, and infarction groups. Radioactivities in the early and late images of 123 I-IMZ SPECT were investigated using the affected-to-contralateral side asymmetry ratio (ACR). Results: None of the patients in the normal group showed any symptoms related to venous congestion. In contrast, all the patients in the edema and infarction groups developed neurological symptoms. The ACR in early images in the edema group was significantly lower than that in the normal group and significantly higher than that in the infarction group. The ACR in the late images of the infarction group was significantly lower than those of the normal and edema groups. After treatment, the neurological signs disappeared in the edema group, but only partial improvement was observed in the infarction group. The ACR in early images significantly improved after treatment in the edema group; however, that in late images did not change in any groups. Conclusions: 123 I-IMZ SPECT is useful for evaluating hemodynamic disturbances and neuronal damage in dAVFs. The reduction in early images was correlated with the severity of venous congestive encephalopathy, and the significant reduction in late images is a reliable indicator of irreversible venous infarction caused by RLVD.

Pathophysiology and classification of intracranial and spinal dural AVF.

Dural arteriovenous fistulas (DAVFs) are pathologic shunts between pachymeningeal arteries and dural venous channel. DAVFs are relatively rare, however, DAVFs can lead to significant morbidity and mortality due to intracranial hemorrhage and non-hemorrhagic neurologic deterioration related to leptomeningeal venous drainage. The etiology and pathophysiology of DAVFs is not fully understood. Several hypotheses for development of DAVF and classifications for predicting risk of hemorrhage and neurological deficit have been proposed to help clinical decision making according to its natural history. Herein, incidence, etiology, pathophysiology of development of intracranial and spinal DAVF including their classifications are briefly described with short historical review.

Risk Factors of Aggressive Clinical Presentation in Patients with Angiographically Aggressive Cranial Dural Arteriovenous Fistulas.

Compared to nonaggressive cranial dural arteriovenous fistulae (cDAVF), aggressive cDAVF carries leptomeningeal venous drainage (LVD) and has approximately 15% annual risk of hemorrhagic and non-hemorrhagic aggressive neurological presentations. In terms of aggressive clinical presentations, the previous classification does not adequately differentiate the higher risk group from the lower risk group. Herein, we retrospectively collected a series of patients with aggressive cDAVF and explored the risk factors for differentiating the higher-risk group from the lower-risk group with aggressive clinical presentations. We retrospectively collected patients with aggressive cDAVF from March 2011 to March 2019. The risk of aggressive clinical presentation was recorded. Risk factors were included in the analysis for aggressive clinical presentations. From March 2011 to March 2019, 37 patients had aggressive cDAVF. Among them, 24 presented with aggressive clinical presentation (20, hemorrhagic presentation; four, non-hemorrhagic presentation). In patients presenting with hemorrhage, four patients experienced early rebleeding after diagnosis. In the univariate analysis, risk location, directness of LVD, exclusiveness of LVD, and venous strain were significantly different in patients with aggressive clinical presentation. In the multivariate analysis, exclusiveness of LVD and venous strain were observed, with a significant difference between patients with aggressive clinical presentation and those with benign clinical presentation. Among patients with angiographically aggressive cDAVFs, approximately 65% presented with aggressive clinical presentations in our series. Among all potential risk factors, patients with exclusiveness of LVD and venous strain have even higher risk and should be treated aggressively and urgently.

A multicenter prospective registry of Borden type I dural arteriovenous fistula: results of a 3-year follow-up study

PurposeAlthough intracranial dural arteriovenous fistula (DAVF) without retrograde leptomeningeal venous drainage (Borden type I) is reported to have a benign nature, no study has prospectively determined its clinical course. Here, we report a 3-year prospective observational study of Borden type I DAVF.MethodsFrom April 2013 to March 2016, consecutive patients with DAVF were screened at 13 study institutions. We collected data on baseline characteristics, clinical symptoms, angiography, and neuroimaging. Patients with Borden type I DAVF received conservative care while palliative intervention was considered when the neurological symptoms were intolerable, and were followed at 6, 12, 24, and 36 months after inclusion.ResultsDuring the study period, 110 patients with intracranial DAVF were screened and 28 patients with Borden type I DAVF were prospectively followed. None of the patients had conversion to higher type of Borden classification or intracranial hemorrhage during follow-up. Five patients showed spontaneous improvement or disappearance of neurological symptoms (5/28, 17.9%), and 5 patients showed a spontaneous decrease or disappearance of shunt flow on imaging during follow-up (5/28, 17.9%). Stenosis or occlusion of the draining sinuses on initial angiography was significantly associated with shunt flow reduction during follow-up (80.0% vs 21.7%, p = 0.02).ConclusionIn this 3-year prospective study, patients with Borden type I DAVF showed benign clinical course; none of these patients experienced conversion to higher type of Borden classification or intracranial hemorrhage. The restrictive changes of the draining sinuses at initial diagnosis might be an imaging biomarker for future shunt flow reduction.

Outcome of Endovascular Therapy Aiming for Single-session Obliteration of Intracranial Dural Arteriovenous Fistulas.

The goal of dural arteriovenous fistula (dAVF) treatment is obliteration of the arteriovenous shunt and/or retrograde leptomeningeal venous drainage (RLVD). Single-session obliteration could improve symptoms early and reduce risk of neurological sequelae. This study investigated the efficacy and adverse events of endovascular therapy (EVT) aiming for single-session obliteration in dAVF treatment. We retrospectively examined post-treatment arteriovenous shunt status, number of treatments per case, treatment-related complications, and long-term outcome in 92 dAVF patients who underwent initial EVT at our institution. Single-session obliteration was intended in all cases, but a second session was performed in cases of partial shunt occlusion or remaining RLVD. Complete occlusion was achieved in 85 cases (92.4%) after the single session; RLVD was obliterated in 66 of the 67 Borden type II and III cases combined (98.5%). A second session was necessary in seven cases (7.6%). Complete shunt obliteration was eventually achieved in all cases. The average number of treatments was 1.08 per case. dAVF-related stroke and mortality did not occur after the treatment. On the other hand, radiation-induced skin erythema and alopecia, although all symptoms were transient, occurred in 26 cases (28.3%). Over an average 60.2-month follow-up period, recurrence was observed in seven cases (7.6%). Single-session obliteration was successful in 92% of cases. Especially, single-session obliteration of RLVD may contribute to early prevent of future stroke events. However, reducing total radiation dose during each session is an issue of further study.

Transarterial Treatment of Cranial Dural Arteriovenous Fistulas: The Role of Transarterial and Transvenous Balloon-Assisted Embolization.

Treatment of dural arteriovenous fistulas can be performed by transarterial or transvenous accesses. For those fistulas located at a dural sinus wall, obliteration of the sinus might lead to a substantial risk of complications if the occluded sinus impairs normal venous drainage. For those fistulas with direct leptomeningeal venous drainage, navigation to reach the arteriovenous shunting point of a leptomeningeal vein is usually technically demanding. We report the outcomes of patients with dural AVFs treated by transarterial injection of liquid embolic agents assisted by transarterial double-lumen balloon catheters and/or transvenous balloon catheters. This was a retrospective, 3-center study including patients with dural AVFs treated with a balloon-assisted technique in at least 1 treatment session. Angiographic follow-up was performed at 6 months. Clinical assessment was performed at admission and discharge and was reassessed at 30-day and 6-month follow-ups. Forty-one patients with 43 dural AVFs were treated. Thirty-four fistulas were located at a dural sinus wall. Treatment was performed using only a transarterial approach in 42 fistulas. Only 1 session was needed for complete obliteration of the fistula in 86% of the patients. Immediate complete angiographic occlusion was achieved in 39 fistulas. Of the 41 controlled fistulas, 40 (97.6%) were completely occluded at 6 months. Thirty-nine fistulas (95.1%) were cured without any report of major neurologic events or death during follow-up. Transarterial balloon-assisted treatment of dural AVFs with or without transvenous balloon protection was shown to be safe and effective.

Vagal Nerve Palsy After Transarterial Embolization of Transverse-Sigmoid Dural Arteriovenous Fistula Using Onyx

ObjectiveWe report a case of a 70-year-old man who developed a transverse-sigmoid dural arteriovenous fistula (TS-DAVF) that was successfully treated by transarterial embolization (TAE) with Onyx. Case PresentationThe patient presented with sudden and progressive disturbance of consciousness and left hemiparesis. Magnetic resonance imaging (MRI) revealed venous infarction and hemorrhagic changes with brain swelling in the right parietal lobe. Angiography revealed a right TS-DAVF and multiple occlusions with retrograde leptomeningeal venous drainage into the cortical veins. The TS-DAVF was graded as Borden type III and Cognard type IIa+b. Because of its progressive clinical nature and wide distribution of DAVF in the occluded sinus wall, he underwent emergent TAE with liquid embolic materials including n-butyl cyanoacrylate and Onyx under informed consent by his family. Complete obliteration of the TS-DAVF was achieved, leading to a marked amelioration of symptoms, and MRI after treatment confirmed a decrease in the brain swelling. However, he suffered transient dysphagia due to right vagal nerve palsy caused by occlusion of vasa nervorum of ascending pharyngeal artery. He returned home 5 months later with a modified Rankin Scale of 1. ConclusionsTAE with Onyx appears to be effective for aggressive TS-DAVF with a widely distributed shunt. However, the blood supply to the cranial nerves and potentially dangerous anastomoses between the external-internal carotid artery and vertebral artery should be taken into account to avoid serious complications.

Dural arteriovenous shunts in children

Dural arteriovenous shunts (dAVF) in children can be classified as dural sinus malformations, infantile dural arteriovenous shunts, and adult-type dural arteriovenous shunts. All subtypes can result in neurologic morbidity as a result of venous or intracranial hypertension and its sequelae. Prognostication and appropriate management is incumbent depends upon understanding both the subtype of dural arteriovenous shunt and its relevant anatomy. When treatment is indicated, endovascular embolization is the mainstay. Surgical treatment may be used adjunctively, though its primary indication is for adult-type dAVF with direct leptomeningeal venous drainage, which cannot be easily accessed by endovascular means. Although radiosurgery has been used successfully in adults with dAVF, its utility for pediatric patients remains largely unexplored.

Abstract W P420: Impact of Embolization Therapy on Venous Congestion in Patients with Transverse-sigmoid Sinus Dural Arteriovenous Fistulas - A Semi-quantitative Susceptibility-weighted MRI study

Background and Purpose: Dural arteriovenous fistulas (DAVFs) often provoke intracerebral hemorrhage (ICH) and progressive neurological deficits due to chronic venous congestion. Trans-arterial and/or trans-venous embolization (TAE/TVE) is known useful to dramatically improve cerebral hemodynamics. However, the methodology to non-invasively visualize venous congestion due to dAVFs has not been established yet. In this study, therefore, the authors evaluated the usefulness of susceptibility-weighted imaging (SWI) to evaluate the degree of venous congestion due to transverse-sigmoid sinus DAVF before and after TAE/TVE. Methods: This prospective study included totally 13 patients with transverse-sigmoid sinus DAVFs who underwent TAE/TVE in our hospital. SWI images were binarized and the number of pixels with the low intensity was automatically counted on each slice. Finally, the ratio of low-intensity pixels to total pixels on each slice was defined as the low intensity ratio (LIR). Results: Of 13 patients, 3 presented with ICH and two developed venous infarction. Cerebral angiography showed diffuse RLVD (retrograde leptomeningeal venous drainage) in four patients and PPP (pseudo-phlebitic pattern) in five. Before embolization, the mean LIR was 10.2±5.6%, ranging from 4.6 to 24%, being significantly higher than the control value (2.7±1.2%, n=5). Angiographical signs of venous congestion were closely related to high LIR values. Endovascular embolization markedly improved the sign of venous congestion on cerebral angiography in all patients. The LIR significantly decreased from 10.2±5.6% to 7.0±3.8% after TAE/TVE (P<0.05). None of them recurred cerebrovascular events due to DAVFs during a mean follow-up period of 20 months. Conclusions: The findings strongly suggest that SWI can non-invasively quantify venous congestion due to DAVFs with high sensitivity and provide reliable information on the efficacy of endovascular treatments.

Cranial dural arteriovenous shunts. Part 3. Classification based on the leptomeningeal venous drainage.

The commonly used Borden and Cognard classification systems for the prediction of clinical behavior of cranial dural arteriovenous shunts focus on the venous drainage, particularly the presence of leptomeningeal venous drainage, and on the direction of flow, particularly the presence of retrograde flow. In addition, the latter includes ectasia and spinal drainage as criteria of two distinct grades. However, none of the above classifications (a) differentiates direct from exclusive leptomeningeal venous drainage, (b) considers cortical venous congestion as a factor potentially associated with an aggressive clinical course, and (c) anticipates ectasia in shunts with a mixed dural-cortical venous drainage (type 2). In this study, we analyzed the angiographic images of 107 consecutive patients having a cranial dural arteriovenous fistula with leptomeningeal venous drainage, based on a newly developed scheme. This scheme, symbolized with the acronym "DES," groups the dural shunts according to three factors: directness and exclusivity of leptomeningeal venous drainage and signs of venous strain. According to the combination of the three factors, eight different groups were distinguished. All analyzed cases could be assigned to one of these groups. Directness of leptomeningeal venous drainage expresses the exact site of the shunt (bridging vein vs sinus wall), whereas exclusivity expresses venous outlet restrictions. All bridging vein shunts had a direct leptomeningeal venous drainage. Almost all bridging vein shunts and all "isolated" sinus shunts had an exclusive leptomeningeal venous drainage. Venous strain, manifested as ectasia and/or congestion, denotes the decompensation of the cerebral venous system due to the shunt reflux. The comparison of the presented concept with the currently used classifications highlighted the advantages of the former and the weaknesses of the latter.

Cranial dural arteriovenous shunts. Part 4. Clinical presentation of the shunts with leptomeningeal venous drainage.

Cranial dural arteriovenous fistulae have been classified into high- and low-risk lesions mainly based on the pattern of venous drainage. Those with leptomeningeal venous drainage carry a higher risk of an aggressive clinical presentation. Recently, it has been proposed that the clinical presentation should be considered as an additional independent factor determining the clinical course of these lesions. However, dural shunts with leptomeningeal venous drainage include a very wide spectrum of inhomogeneous lesions. In the current study, we correlated the clinical presentation of 107 consecutive patients harboring cranial dural arteriovenous shunts with leptomeningeal venous drainage, with their distinct anatomic and angiographic features categorized into eight groups based on the "DES" (Directness and Exclusivity of leptomeningeal venous drainage and features of venous Strain) concept. We found that among these groups, there are significant angioarchitectural differences, which are reflected by considerable differences in clinical presentation. Leptomeningeal venous drainage of dural sinus shunts that is neither direct nor exclusive and without venous strain manifested only benign symptoms (aggressive presentation 0%). On the other end of the spectrum, the bridging vein shunts with direct and exclusive leptomeningeal venous drainage and venous strain are expected to present aggressive symptoms almost always and most likely with bleeding (aggressive presentation 91.5%). Important aspects of the above correlations are discussed. Therefore, the consideration of leptomeningeal venous drainage alone, for prediction of the clinical presentation of these shunts appears insufficient. Angiographic analysis based on the above concept, offers the possibility to distinguish the higher- from the lower-risk types of leptomeningeal venous drainage. In this context, consideration of the clinical presentation as an additional independent factor for the prediction of their clinical course seems superfluous and possibly misleading. Topography is connected to the clinical presentation of the dural shunts inasmuch as the former determines the venous anatomy and the angioarchitectural features of the lesions.

Cranial dural arteriovenous shunts. Part 2. The shunts of the bridging veins and leptomeningeal venous drainage.

Leptomeningeal venous drainage of cranial dural arteriovenous fistulae is the most important determinant of adverse clinical course. Factors that predispose to its occurrence have not been adequately addressed in the literature. In the present study, we investigated the relation of shunt location to the development of leptomeningeal venous drainage, with regard to the bridging veins. Angiographic data of 211 consecutive patients with cranial dural arteriovenous fistulae treated over 19 years were analyzed. Dural shunts with leptomeningeal venous drainage were found in 107 patients; of these, 71 patients had pure leptomeningeal venous drainage (Borden type 3). The angioarchitecture of the shunt, including pattern of arterial feeders, relation with the bridging veins, primary venous drainage, and venous outflow restrictions were recorded. After analysis of the 71 Borden type 3 shunts with exclusive leptomeningeal venous drainage, three patterns emerged. The commonest was the fistula engaging a bridging vein that had lost its connection to the parent sinus into which it previously drained; it was characterized by an arterial network of feeders converging onto the wall of a bridging vein, with leptomeningeal venous reflux. The other patterns were those of "isolated" sinus segment characterized by arterial feeders converging on to the wall of the dural sinus with leptomeningeal venous reflux following the opacification of the sinus and fistulae in the vicinity of the cribriform plate with two subtypes. The main angioarchitectural features of the 36 Borden type 2 shunts with mixed sinusal-cortical venous drainage were the presence of a diffuse arterial network of vessels converging onto a site in the wall of the dural sinus, with leptomeningeal venous reflux following the opacification of the sinus. In this group, four exceptions were noticed with arterial feeders converging onto a bridging vein and having a mixed venous drainage to the cortical venous system and the sinuses. We concluded that the exact location of the shunt with regard to the bridging veins is a key factor in the development of leptomeningeal venous drainage. Cranial dural arteriovenous fistulae (CDAVFs) of either Borden type 2 or 3 do not constitute a homogeneous group. The great majority of these shunts present thrombotic phenomena.

Prognosis and treatment of intracranial dural arteriovenous fistulae: a systematic review and meta-analysis.

Dural arteriovenous fistulae can cause intracranial hemorrhage, but influences on this are unclear. We searched Ovid MEDLINE (from 1966), Embase (from 1980), and the Cochrane Library in September 2013 for studies of ≥50 adults with dural arteriovenous fistulae describing death or intracranial hemorrhage. Of 16 studies of retrospective associations between dural arteriovenous fistulae vascular anatomy and prior mode of presentation, fistula location in the cavernous sinus was consistently associated with nonhemorrhagic modes of presentation; in five studies involving 855 patients, fistulae with retrograde leptomeningeal (cortical) venous drainage were associated with prior presentation with intracranial hemorrhage (pooled odds ratio 23·2, 95% CI 13·8 to 39·0; I(2) = 0%). Future intracranial hemorrhage during untreated clinical course was statistically significantly associated with the presence of venous varix in one study and with presentation with intracranial hemorrhage in patients with retrograde leptomeningeal venous drainage in another. In 19 observational studies of treatment of dural arteriovenous fistulae involving 2329 patients, the pooled risk of death was 1·2% (95% CI 0·6 to 1·8, I(2) = 35%), that of nonfatal intracranial haemorrhage was 0·5% (95%CI 0·2 to 0·8, I(2) = 9%), and that of nonfatal cerebral infarction was 0·7% (95% CI 0·3 to 1·4, I(2) = 52%), for a combined risk of 2·5% (95% CI 1·4 to 3·9, I(2) = 69%). Retrograde leptomeningeal venous drainage seems strongly associated with intracranial hemorrhage at presentation of dural arteriovenous fistula, but its association with subsequent intracranial hemorrhage is less clear. Short-term complications of dural arteriovenous fistula treatment affect 2-3% of patients in published reports.

Advances in Surgical Approaches to Dural Fistulas

Dural arteriovenous fistulas are abnormal connections of dural arteries to dural veins or venous sinuses originating from within the dural leaflets. They are usually located near or within the wall of a dural venous sinus that is frequently obstructed or stenosed. The dural fistula sac is contained within the dural leaflets, and drainage can be via a dural sinus or retrograde through cortical veins (leptomeningeal drainage). Dural arteriovenous fistulas can occur at any dural sinus but are found most frequently at the cavernous or transverse sinus. Leptomeningeal venous drainage can lead to venous hypertension and intracranial hemorrhage. The various treatment options include transarterial and transvenous embolization, stereotactic radiosurgery, and open surgery. Although many of the advances in dural arteriovenous fistula treatment have occurred in the endovascular arena, open microsurgical advances in the past decade have primarily been in the tools available to the surgeon. Improvements in microsurgical and skull base approaches have allowed surgeons to approach and obliterate fistulas with little or no retraction of the brain. Image-guided systems have also allowed better localization and more efficient approaches. A better understanding of the need to simply obliterate the venous drainage at the site of the fistula has eliminated the riskier resections of the past. Finally, the use of intraoperative angiography or indocyanine green videoangiography confirms the complete disconnection of fistula while the patient is still on the operating room table, preventing reoperation for residual fistulas.

Cerebral Perfusion Change of Venous Hypertension on Near-Infrared Spectroscopy Signals after Operation for Dural Arteriovenous Fistula

A dural arteriovenous fistula (AVF) is an arteriovenous shunt in the dura and is associated with a risk of intracranial hemorrhage and neurologic deficit. The morbidity of this disease depends on venous hypertension, and the classification of this disease is based on the pattern of venous drainage. The pattern of venous drainage relates to the clinical features of the disease, especially to the probability of intracranial hemorrhage. We report 1 case of dural AVF with retrograde leptomeningeal venous drainage. Cerebral hemodynamics were monitored using near-infrared spectroscopy imaging before, during, and after the 2-stage operative treatment. Preoperative functional near-infrared spectroscopy (fNIRS) showed an increase in deoxyhemoglobin (HbR) during a motor task. After partial coil embolization of the shunt points (stage 1), HbR increased during the first half of the task and decreased later, whereas oxyhemoglobin (HbO2) decreased in the first half of the task and increased later. After complete embolization (stage 2), fNIRS showed a pattern similar to that of a normal adult. The patient's symptoms improved gradually, and angiography showed a reduction of the retrograde venous drainage and venous congestion after this 2-stage operation. The reduction in venous hypertension may be the underlying mechanism behind the changes observed with fNIRS.

Angiotensin-converting enzyme-inhibitors, statins and the risk of hemorrhage from cerebral dural arteriovenous fistulae

Leptomeningeal venous drainage and symptomatic presentation are known risk factors for cerebral dural arteriovenous fistula (dAVF) hemorrhage. An evaluation of potentially modifiable risk factors such as hypertension and medication usage has not been undertaken to our knowledge. The authors thus reviewed a cohort of 45 consecutive patients with cerebral dAVF with leptomeningeal venous drainage and compared the rate of hemorrhagic presentation for patients with and without a history of hypertension, hyperlipidemia or the usage of certain medications. Logistic regression was performed to determine the statistical significance of associations of each factor with hemorrhagic presentation. On univariate analysis, angiotensin-converting enzyme (ACE)-inhibitors (odds ratio [OR] 0.100, 95% confidence interval [CI] 0–0.764, p=0.024) and statins (OR 0.142, 95% CI 0.025–0.825, p=0.030) were associated with a statistically significant lower rate of hemorrhagic presentation. A trend toward a lower rate of hemorrhagic presentation was seen for patients taking aspirin (OR 0.153, 95% CI 0.016–1.43, p=0.10). These trends continued on multivariate analysis; however they did not meet statistical significance (p>0.05). Beta-blockers, calcium channel blockers, warfarin and selective serotonin reuptake inhibitors did not have a statistically significant association with the rate of hemorrhagic presentation (p>0.05). Although limited by small sample size, these results may suggest a beneficial effect of statins and ACE-inhibitors on the rate of dAVF hemorrhagic presentation, potentially as a result of anti-inflammatory, anti-angiogenic or even venous antithrombotic mechanisms. Despite this study’s limitations, we hope it encourages further evaluation of potentially modifiable risk factors for vascular malformation hemorrhage.

The Use of Susceptibility-Weighted Imaging as an Indicator of Retrograde Leptomeningeal Venous Drainage and Venous Congestion With Dural Arteriovenous Fistula

Retrograde leptomeningeal venous drainage (RLVD) in dural arteriovenous fistulas (DAVFs) is associated with intracerebral hemorrhage and nonhemorrhagic neurological deficits or death. Angiographic evidence of RLVD is a definite indication for treatment, but less invasive methods of identifying RLVD are required. To evaluate the efficacy of susceptibility-weighted magnetic resonance imaging (SWI) in detecting RLVD in DAVFs. We retrospectively identified 17 DAVF patients who had angiographic evidence of RLVD and received treatment. Conventional angiography and SWI were assessed at pretreatment and posttreatment time points. The presence of RLVD on SWI was defined as cortical venous hyperintensity, and the presence of venous congestion on SWI venograms was defined as increased caliber of cortical or medullary veins. Cortical venous hyperintensity was identified in pretreatment SWI of 15 patients. Cortical venous hyperintensity was absent in early posttreatment SWI, consistent with the absence of RLVD in posttreatment angiography, in all but one of these patients. In 2 patients, cortical venous hyperintensity was identified during follow-up, indicating the recurrence of RLVD. Cortical venous hyperintensity was not identified in the pretreatment SWI of 2 patients despite angiographic evidence of RLVD. Venous congestion was identified in pretreatment SWI venograms of 11 patients and had an appearance similar to that identified from angiography. Venous congestive signs improved over the follow-up period. The presence of SWI hyperintensity within the venous structure could be a useful indicator of RLVD in DAVF patients. Thus, SWI offers a noninvasive alternative to angiography for the identification of RLVD in pretreated and posttreated DAVF patients.

Global Aphasia without Hemiparesis Caused by a Dural Arteriovenous Fistula

A 61-year-old Japanese woman with chronic renal failure suddenly became silent at the end of hemodialysis. On a neurological examination, she was unable to respond to one-step commands, state the names of objects, repeat single words, read words aloud or write her name. Because she exhibited no paralysis of the extremities, we diagnosed her as having global aphasia without hemiparesis (GAWH). Cerebral angiography showed a dural arteriovenous fistula (AVF) in the left isolated transverse sinus with leptomeningeal venous drainage (Borden type 3, Lalwani grade 4). This case highlights dural AVF as an etiology of GAWH.