The role of angiogenic factor bFGF in the development of dural AVFs

Carotid Cavernous Fistula

Carotid cavernous fistulae (CCFs) are arteriovenous shunts involving the cavernous sinus. CCFs are defined as direct or indirect. Direct CCFs are treated by deconstructive or reconstructive techniques depending on whether the affected internal carotid artery is required to perfuse the ipsilateral cerebral hemisphere, as determined by a balloon test occlusion. Indirect CCFs, or dural fistulae of the cavernous sinus wall, are most often treated with transvenous embolization. Stereotactic radiosurgery is reserved for cases of indirect CCFs that are not completely obliterated by embolization. Overall, cure rates are high with relatively low complication rates.

New insight into DAVF pathology—Clues from meningeal immunity

In recent years, with the current access in techniques, studies have significantly advanced the knowledge on meningeal immunity, revealing that the central nervous system (CNS) border acts as an immune landscape. The latest concept of meningeal immune system is a tertiary structure, which is a comprehensive overview of the meningeal immune system from macro to micro. We comprehensively reviewed recent advances in meningeal immunity, particularly the new understanding of the dural sinus and meningeal lymphatics. Moreover, based on the clues from the meningeal immunity, new insights were proposed into the dural arteriovenous fistula (DAVF) pathology, aiming to provide novel ideas for DAVF understanding.

De novo dural arteriovenous fistula after mechanical thrombectomy for cerebral venous thrombosis: A case report

Background:

Although the relationship between dural arteriovenous fistula (dAVF) and cerebral venous thrombosis (CVT) has been reported, the etiology has not been clarified. Here, we report a case of de novo dAVF after mechanical thrombectomy for CVT and discuss the underlying mechanism.

Case Description:

A 61-year-old woman presented with a gradually worsening headache and was diagnosed with severe CVT. Mechanical thrombectomy was performed for the CVT because of progressive neurological deterioration despite anticoagulation therapy. Two years after the initial treatment, angiography revealed a de novo dAVF with a direct shunt of the left convexity cortical vein. Transarterial embolization with Onyx was performed and the shunt was completely obliterated.

Conclusion:

In this report, we describe a case of de novo dAVF with CVT that was treated with mechanical thrombectomy. Even if CVT improves with mechanical thrombectomy, we must be aware of the occurrence of de novo dAVF.

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.

Coexistence of anterior cranial fossa dural arteriovenous fistula and arteriovenous malformation with the same drainage system: illustrative case

BACKGROUND

The authors report a rare case of coexistence of dural arteriovenous fistula (DAVF) and arteriovenous malformation (AVM), with a common trunk drainer from both DAVF and AVM in the left anterior cranial fossa (ACF) with simple DAVF in the right ACF.

OBSERVATIONS

A 63-year-old female presented with seizure. Cerebral angiography showed bilateral DAVFs in the ACF and AVM in the left frontal lobe. A dilated frontal vein acted as a simple drainer of the right DAVF. In contrast, a dilated vein with large varix was the common drainer of both the left DAVF and the AVM. During surgery, indocyanine green videoangiography was performed with direct observation. In the left ACF, the drainer occlusion of the DAVF resulted in partial shrinkage of the varix and decreased distal blood flow. Additional main feeder occlusion of the AVM could decrease the blood flow further, but not completely because of the residual pial supplies for the AVM. Finally, the nidus of the AVM with varix was removed by en bloc resection.

LESSONS

Neurosurgeons should be aware of the coexistence of DAVF and AVM with a common trunk drainer. Only simple occlusion of the drainer from DAVF is not sufficient, so removal of the AVM is essential.

Dural arteriovenous fistulas in cerebral venous thrombosis: Data from the International Cerebral Venous Thrombosis Consortium

BACKGROUND AND PURPOSE

To explore the prevalence, risk factors, time correlation, characteristics and clinical outcome of dural arteriovenous fistulas (dAVFs) in a cerebral venous thrombosis (CVT) population.

METHODS

We included patients from the International CVT Consortium registries. Diagnosis of dAVF was confirmed centrally. We assessed the prevalence and risk factors for dAVF among consecutive CVT patients and investigated its impact on clinical outcome using logistic regression analysis. We defined poor outcome as modified Rankin Scale score 3-6 at last follow-up.

RESULTS

dAVF was confirmed in 29/1218 (2.4%) consecutive CVT patients. The median (interquartile range [IQR]) follow-up time was 8 (5-23) months. Patients with dAVF were older (median [IQR] 53 [44-61] vs. 41 [29-53] years; p < 0.001), more frequently male (69% vs. 33%; p < 0.001), more often had chronic clinical CVT onset (>30 days: 39% vs. 7%; p < 0.001) and sigmoid sinus thrombosis (86% vs. 51%; p < 0.001), and less frequently had parenchymal lesions (31% vs. 55%; p = 0.013) at baseline imaging. Clinical outcome at last follow-up did not differ between patients with and without dAVF. Additionally, five patients were confirmed with dAVF from non-consecutive CVT cohorts. Among all patients with CVT and dAVF, 17/34 (50%) had multiple fistulas and 23/34 (68%) had cortical venous drainage. Of 34 patients with dAVF with 36 separate CVT events, 3/36 fistulas (8%) were diagnosed prior to, 20/36 (56%) simultaneously and 13/36 after (36%, median 115 [IQR 38-337] days) diagnosis of CVT.

CONCLUSIONS

Dural arteriovenous fistulas occur in at least 2% of CVT patients and are associated with chronic CVT onset, older age and male sex. Most CVT-related dAVFs are detected simultaneously or subsequently to diagnosis of CVT.

Variations and management for patients with craniocervical junction arteriovenous fistulas: Comparison of dural, radicular, and epidural arteriovenous fistulas

Background:

Craniocervical junction arteriovenous fistulas (CCJAVFs) are known to be rare, but variations and clinical behaviors remain controversial.

Methods:

A total of 11 CCJAVF patients (M: F=9:2, age 54–77 years) were investigated. Based on the radiological and intraoperative findings, they were categorized into three types: dural AVF (DAVF), radicular AVF (RAVF), and epidural AVF (EDAVF).

Results:

There were four symptomatic patients (subarachnoid hemorrhage in two, myelopathy in one, and tinnitus in one) and seven asymptomatic patients in whom coincidental CCJAVFs were discovered on imaging studies for other vascular diseases (arteriovenous malformation in one, intracranial DAVF in two, ruptured cerebral aneurysm in two, and carotid artery stenosis in two). Of these 11 patients, 2 (18.2%) had multiple CCJAVFs. Of 14 lesions, the diagnoses were DAVF in 5, RAVF in 3, and EDAVF in 6 (C1–C2 level ratio =5:0, 2:1, 3:3). Patients with DAVF/RAVF in four lesions with intradural venous reflux underwent surgery, although an RAVF remained in one lesion after embolization/radiation. Since all six EDAVFs, two DAVFs, and one RAVF had neither feeder aneurysms nor significant symptoms, no treatment was provided; of these nine lesions, one DAVF and one RAVF remained unchanged, whereas six EDAVFs showed spontaneous obliteration within a year. Unfortunately, however, one DAVF bled before elective surgery.

Conclusion:

CCJAVFs have many variations of shunting site, angioarchitecture, and multiplicity, and they were frequently associated with coincidental vascular lesions. For symptomatic DAVF/RAVF lesions with intradural drainage, surgery is preferred, whereas asymptomatic EDAVFs without dangerous drainage may obliterate during their natural course.

De Novo Pial Arteriovenous Fistula Associated With Cerebral Infarction and Venous Hypertension: Report of 2 Cases Suggesting a “Second Hit Theory”

BACKGROUND AND IMPORTANCE

The etiology of de novo pial arteriovenous fistula (AVF) is unknown. We found 2 cases of de novo pial AVF, which appeared after cerebral infarction and which was associated with venous hypertension secondary to venous sinus thrombosis with a dural AVF (dAVF). Additional angiogenic stimuli (second hit) were considered as one of the mechanisms of de novo pial AVF.

CLINICAL PRESENTATION

A 63-yr-old male was admitted to our hospital due to an intraventricular hemorrhage. He had a history of cerebral infarction 2 yr before. Angiography demonstrated multiple dAVFs with bilateral occlusion of the distal transverse sinus associated with prominent retrograde cortical venous drainage. A pial AVF was found at the border of his previous cerebral infarction. Both lesions were successfully treated using endovascular technique.

A second case involved a 47-yr-old female who was admitted to our hospital due to venous infarction also associated with sinus thrombosis. De novo pial AVF at the border of the venous infarction and dAVF at the transverse sigmoid junction were demonstrated on angiography 6 mo later.

CONCLUSION

We speculate that venous hypertension associated with additional angiogenic stimuli (second hit) due to brain ischemia and/or brain injury related to infarction caused de novo pial AVF in these 2 cases.

Brain vascular biology

The complex development of the brain vascular system can be broken down by embryonic stages and anatomic locations, which are tightly regulated by different factors and pathways in time and spatially. The adult brain is relatively quiescent in angiogenesis. However, under disease conditions, such as trauma, stroke, or tumor, angiogenesis can be activated in the adult brain. Disruption of any of the factors or pathways may lead to malformed vessel development. In this chapter, we will discuss factors and pathways involved in normal brain vasculogenesis and vascular maturation, and the pathogenesis of several brain vascular malformations.

Cavernous Sinus Dural Arteriovenous Fistulas: General Aspects

Cavernous sinus (CS) dural arteriovenous fistulas (AVF), which are most common in middle-aged females, present with benign symptoms such as exophthalmos, chemosis, and orbital bruit. Benign CS dural AVF without cortical venous drainage (CVD) have the rare potential for development of CVD with neurological symptoms, even without treatment. On the other hand, aggressive type AVF with CVD can cause more aggressive symptoms such as cerebral hemorrhage. As symptoms are highly related to the drainage pattern, it is important to understand the anatomy of the CS itself, shunt point, and draining vein when treating the lesion. In general, the drainage route is gradually diminished by thrombosis and compartmentalization within the CS according to progression of the angiographical stage. At the restrictive stage, the disease is usually treated by endovascular treatment, particularly transvenous embolization.

Epidemiology, clinical presentation, diagnostic evaluation, and prognosis of cerebral dural arteriovenous fistulas

Dural arteriovenous fistulas are abnormal communications, within the dural leaflets, between meningeal arteries and dural venous sinuses and/or subarachnoid veins. Although many fistulas remain clinically silent and do not require treatment, presence of cortical venous reflux, intracranial bleed, and intolerable symptoms are the main indications for treatment. A thorough understanding of the natural history is of prime importance in the decision making and management of these lesions. In this chapter we discuss the epidemiology and natural history of intracranial dural arteriovenous fistulae.

Posterior Fossa Arteriovenous Pial Fistula: Diagnostic and Endovascular Therapeutic Features

Intracranial arteriovenous fistulas (AVFs) are rare vascular cerebral lesions composed of one or more corticalpial arterial feeders directly connected with a single draining vein. They differ from the other AV malformations in that they lack a nidus and are located outside the dural leaflets. Because of high flow and pressure AVFs have a high risk of hemorrhage and if untreated cause death in up to 63% of cases. Treatment can be endovascular or microneurosurgical. We describe an infant with hydrocephalus and raised intracranial pressure and MRI findings of a single dilated venous vessel with a proximal varix in the perimedullary spaces confirmed by CT angiography and DSA that found a single artery-single vein fistula we successfully occluded with GDC coils.

Acquired pial and dural arteriovenous fistulae following superior sagittal sinus thrombosis in patients with protein S deficiency: a report of two cases

Two patients with protein S deficiency with acquired multiple pial and dural arteriovenous fistulae (AVFs) following superior sagittal sinus (SSS) thrombosis are reported. Case 1 is a 38-year-old male with protein S deficiency who developed generalized seizure due to SSS thrombosis. Local fibrinolysis was achieved in the acute stage. His 10-month follow-up angiogram revealed an asymptomatic acquired dural AVF arising from the middle meningeal artery and the anterior cerebral artery with drainage to the thrombosed cortical vein in the right frontal lobe. Furthermore, his 2-year follow-up angiogram revealed a de novo pial AVF from the middle cerebral artery in the Sylvian fissure with drainage to the cortical vein initially thrombosed. However, this asymptomatic pial AVF caused bleeding in the ipsilateral cerebral hemisphere 12 years after onset, whereas the dural AVF spontaneously disappeared. Surgical disconnection was successfully performed to eliminate the source of hemorrhage. Case 2 is a 50-year-old male with a past history of SSS thrombosis with protein S deficiency who developed pulsatile tinnitus and generalized seizure. His angiogram showed a cortical dural AVF in the left parietal lobe and a sporadic dural AVF involving the right sigmoid sinus. The parietal lesion was eliminated by transarterial embolization followed by craniotomy. However, a de novo pial AVF emerged from the middle cerebral artery adjacent to the previously treated lesion. Of four cortical AVFs in two patients, thrombosis of cortical veins caused by protein S deficiency might play an important role in their formation. Long-term follow-up is required because this peculiar disorder has an unusual clinical course.

Relationship between diabetes mellitus with dural arteriovenous fistula

INTRODUCTION

The aetiology of dural arteriovenous fistula (DAVF) is not well known, but it has been suggested that abnormality in angiogenesis plays a pathological role. Abnormality in angiogenesis is also involved in diabetes mellitus (DM). The purpose of this study was to quantify the relation between DAVF and DM in a Korean population.

METHODS

Medical records of 192 patients with DAVF between 2002 and 2011 were reviewed. Age, sex and the presence of DM, hypertension, hyperlipidaemia, stroke, coronary artery disease and cancers were compared between DAVF and control subjects. Data for control were obtained from the Korean National Health and Nutrition Examination Survey. The relationship of DM and DAVF location, presenting symptoms (benign vs. aggressive) and classification (Borden and Geibprasert) were assessed using the Pearson's chi-square test.

RESULTS

Prevalence of DM was higher in DAVF patients (19.8 %) than in controls (9.5 %; p = 0.004). Univariate analysis showed that DM (odds ratio (OR), 2.356; 95 % confidence interval (CI), 1.634-3.399; p < 0.001) and age (OR, 1.022; 95 % CI, 1.012-1.032; p < 0.001) increased the odds of DAVF. This was supported by multivariate analysis (DM: OR, 2.092; 95 % CI, 1.391-3.145; p = 0.0004 and Age: OR, 1.021; 95 % CI, 1.009-1.033; p = 0.001). When these analyses were repeated after stratification by sex, there was no relation between age and DAVF in men. Borden II and III (p = 0.038) and aggressive symptoms (p = 0.023) were related to DM.

CONCLUSION

There was a positive relation between DM and DAVF in a Korean population. DAVFs with aggressive symptoms and behaviour were more commonly related to DM.

Mixed pial-dural arteriovenous malformation in the anterior cranial fossa--two case reports

Most arteriovenous malformations (AVMs) associated with the meningeal artery in the anterior cranial fossa are the pure dural type, and mixed pial-dural AVMs are rare. Two types of mixed pial-dural AVM occur in the anterior cranial fossa according to the shunting point: one with the nidus in the brain parenchyma of the frontal lobe, and the other with the shunting point in the dura mater. We describe two patients with AVMs fed by the anterior ethmoidal arteries and the persistent primitive olfactory artery, with the nidus located in the pure brain parenchyma of the inferior aspect of frontal lobe, and drained via an abnormal cortical vein into the cavernous and superior sagittal sinuses. The importance of occluding the venous outflow to obliterate intracranial dural arteriovenous fistula (AVF) is emphasized. However, removal of the nidus in the brain parenchyma is required. The presence of a pial feeder should be considered before diagnosis of dural AVF of the anterior cranial fossa, and preoperative detailed evaluation for the pial supply and shunting point is mandatory.

Mechanism of the formation of dural arteriovenous fistula: the role of the emissary vein

Dural arteriovenous fistula (DAVF) can be separated into two types: DAVF which drains through an affected sinus (sinus type) and DAVF with direct reflux to the cortical vein (non-sinus type). The present report attempted to clarify the mechanism of formation and development of DAVF focusing on the emissary vein (EV) hypothesis.First, inflammation occurs at the penetrating point of the EV on the dura due to idiopathic or secondary causes. Local inflammatory reactions induce vessel dilatation and neovascularization, and subsequently create arteriovenous (AV) connections on the arteriole level. Although EV communicating with dural arteries might play a role as draining routes at first, they start to degrade due to compression of enlarged emissary arteries or to a hemodynamic shift to the drainage pathway of least resistance. Following the occlusion of drainage pathway through EV into the sinus or cortical veins may form, resulting in clinically detectable DAVF. The AV shunt then expands to the surrounding dura associated with recruitment of feeders from distant sites induced by expression of angiogenetic factors and a shift in the hemodynamic balance. In sinus type DAVF, the sinus is progressively compartmentalized and finally occludes due to thrombogenesis with activated coagulopathy or to hemodynamic hypertrophy of the sinus wall. This progression results in the mature, aggressive DAVF with drainage impairments. Previous mechanistic hypotheses focusing on sinus hypertension and sinus thromboses cannot explain the pathogenesis of non-sinus type of DAVF. Although the etiology of DAVF may be concerned by the thrombo-occlusive change of sinus, the unique theory presented in this report may enable an understanding of the common etiology of both types of DAVF.

Development of indirect cavernous dural arteriovenous fistula after trapping for direct carotid cavernous fistula. A case report

SUMMARY

A 60-year-old man with direct carotid cavernous fistula (CCF) due to a motor vehicle accident underwent internal carotid artery trapping following high-flow external carotid to internal carotid artery bypass (EC-IC bypass). Follow-up angiography revealed ipsilateral complex indirect cavernous arteriovenous fistula. Although the traumatic indirect CCF angioarchitecture differs from cavernous-sinus dural arteriovenous fistula (CS-DAVF), the present indirect fistula was similar to the latter. Complex indirect CCF can occur after treatment of direct CCF caused by severe head injury.

Management of dural arteriovenous fistulas - Helsinki and Kuopio experience

Dural arteriovenous fistulas (DAVFs) are complex disorders, some of them with aggressive clinical behaviour. During past decades their treatment strategy has changed due to increased knowledge of their pathophysiology and natural history, and advances in treatment modalities. In asymptomatic cases or cases with mild symptoms in the absence of cortical venous drainage (CVD) no treatment is necessarily required, whereas aggressive DAVFs should be treated promptly by endovascular or microsurgical means.In our series of 323 patients with 333 fistulas, treated in two neurosurgical units in Finland since 1944, there were 265 true DAVFs and 68 Barrow type A caroticocavernous fistulas. Among the DAVFs there was a slight female predominance, 140 women (55%) and 115 men (45%), and the majority of the cases were located in the area of transverse and sigmoid sinuses. Mode of treatment in the early series was proximal ligation of feeding artery, and later craniotomy, endovascular treatment and radiosurgery, or combination of these treatments, with total occlusion rate being 53%.

Possible role of local hypoxia in the de novo formation of dural and osteodural arteriovenous fistulas after encephalitis. A case report

A rare case of de novo formation of dural and osteodural arteriovenous fistulas after encephalitis is presented. We review and discuss the etiological angiogenetic factors and processes in intracranial dural arteriovenous fistulas formation. Local tissue hypoxia may have played a role in the initial step causing sprouting angiogenesis as the main pathogenesis of DAVFs formation.

The relationship between venous hypertension and expression of vascular endothelial growth factor: hemodynamic and immunohistochemical examinations in a rat venous hypertension model

BACKGROUND

Venous hypertension is regarded as an important factor in the pathogenesis of dural arteriovenous fistula (DAVF). We investigate histologic reaction of dural sinus under the condition of venous hypertension using a rat venous hypertension model to present hemodynamic and immunohistochemical effect in the development of DAVF.

METHODS

Twenty-four Sprague-Dawley male rats were divided into venous hypertension and control groups. Venous hypertension was induced with a left common carotid artery-external jugular vein anastomosis and an occlusion of a right posterior facial vein. Measurements of systemic mean arterial pressure, draining vein pressure (DVP), and cerebral perfusion pressure (CPP) were conducted on the next day, at 7 days, and at 28 days after surgery, and the rats were killed for histologic examinations.

RESULTS

Postoperative DVP increased significantly in venous hypertension group compared to control group (35 +/- 5 vs 13 +/- 2 mm Hg, P < .05). Increased DVP remained above 30 mm Hg throughout the observation period. Postoperative CPP decreased significantly in venous hypertension group compared to control group (49 +/- 8 vs 86 +/- 9 mm Hg, P < .05). In venous hypertension group, there was a significant difference between days 1 and 28 (49 +/- 8 vs 64 +/- 8 mm Hg, P < .05). Histologic examination revealed thickening of connective tissues, proliferation of fibroblasts, and strong expression of vascular endothelial growth factor (VEGF) in endothelium under venous hypertension condition. Immunostained VEGF cells decreased significantly from day 7 to day 28 (100 +/- 16 vs 72 +/- 19 cells, P < .05). A positive correlation was observed between DVP and VEGF expression (Pearson correlation coefficient; r = 0.671, P = .0017). There was a negative correlation between CPP and immunostained VEGF cells (r = -0.702, P = .0089).

CONCLUSIONS

These results suggest that venous hypertension is associated with increased expression of VEGF, and a decreased CPP may have a potential effect in VEGF expression under venous hypertension condition. These factors are speculated to play an important role in progression of DAVF.

Surgical management of dural arteriovenous fistulas with transosseous arterial feeders involving the jugular bulb

Dural arteriovenous fistulas located in the vicinity of the jugular foramen are complex vascular malformations and belong to the most challenging skull base lesions to treat. The authors comprehensively analyze multiple features in a series of dural arteriovenous fistulas with transosseous arterial feeders involving the jugular bulb. Four patients who underwent surgery via the transcondylar approach to treat dural arteriovenous fistulas around the jugular foramen were retrospectively reviewed. Previously, endovascular treatment was attempted in all patients. The success of the surgical treatment was examined with postoperative angiography. Complete obliteration of the dural arteriovenous fistulas (DAVFs) was achieved in three patients, and significant flow reduction in one individual. All patients had a good postoperative outcome, and only one experienced mild hypoglossal nerve palsy. Despite extensive bone drilling, an occipitocervical fusion was necessary in only one patient with bilateral lesions. The use of an individually tailored transcondylar approach to treat dural arteriovenous fistulas at the region of the jugular foramen is most effective. This approach allows for complete obliteration of the connecting arterial feeders, and removal of bony structures containing pathological vessels.

Gamma knife surgery for dural arteriovenous shunts: 25 years of experience

Object

The aim of this study was to assess the clinical efficacy of gamma knife surgery (GKS) in the treatment of dural arteriovenous shunts (DAVSs).

Methods

From a database of more than 1600 patients with intracranial arteriovenous shunts that had been treated with GKS, the authors retrospectively and prospectively identified 53 patients with 58 DAVSs from the period between 1978 and 2003. Four patients were lost to follow-up evaluation and were excluded from the series. Thus, this study is based on the remaining 49 patients with 52 DAVSs. Thirty-six of the shunts drained into the cortical venous system, either directly or indirectly, and 22 of these were associated with intracranial hemorrhage on patient presentation. The mean prescription radiation dose was 22 Gy (range 10–28 Gy).

All patients underwent a clinical follow-up examination. In 41 cases of DAVS a follow-up angiography study was performed. At the 2-year follow-up visit, 28 cases (68%) had angiographically proven obliteration of the shunt and in another 10 cases (24%) there was significant flow regression. Three shunts remained unchanged.

There was one immediate minor complication related to the administration of radiation. Furthermore, one patient had a radiation-induced complication 10 years after treatment, although she recovered completely. There was one posterior fossa bleed 2 months after radiosurgery; a hematoma, as well as a lesion, was evacuated, and the patient recovered uneventfully. A second patient had an asymptomatic occipital hemorrhage approximately 6 months postradiosurgery.

The clinical outcome after GKS was significantly better than that in patients with naturally progressing shunts (p < 0.01, chi-square test); figures on the latter have been reported previously.

Conclusions

Gamma knife surgery is an effective treatment for DAVSs, with a low risk of complications. Major disadvantages of this therapy include the time elapsed before obliteration and the possibility that not all shunts will be obliterated. Cortical venous drainage from a DAVS, a risk factor for intracranial hemorrhage, is therefore a relative contraindication. Consequently, GKS can be used in the treatment of both benign DAVSs with subjectively intolerable bruit and aggressive DAVSs not responsive to endovascular treatment or surgery.

Plasma vascular endothelial growth factor and serum soluble angiopoietin receptor sTIE-2 in patients with dural arteriovenous fistulas: a pilot study

Our aim was to correlate concentrations of circulating vascular endothelial growth factor (VEGF) and serum soluble angiopoietin receptor (sTIE-2) before and after endovascular treatment with the grading in human dural arteriovenous fistulas (DAVFs). In ten patients with DAVFs undergoing diagnostic cerebral angiography and endovascular intervention, pre-treatment and post-treatment levels of plasma VEGF and serum TIE-2 were examined in a prospective study design. A total of 32 plasma samples and 19 serum samples was collected from the cubital vein, the arterial sheath before and--if applicable--after intervention. Plasma VEGF and serum Tie-2 levels were measured by standardized ELISA protocols. In eight of ten patients with DAVF increased circulating VEGF levels (elevation of more than mean + 2 SD of published normal values) were found, whereas two patients showed increased sTIE-2 levels. Six of the seven patients treated by endovascular embolization displayed a post-interventional decrease of VEGF values. The serum TIE-2 levels decreased slightly after intervention. Pre-treatment vVEGF levels varied significantly between patients with grades I and II/III fistulas according to the Cognards classification system. Our pilot study suggests that assessment of angiogenesis parameters in patients with DAVFs might correlate with the DAVFs' grade. To support the hypothesis that a change in angiogenic indicators may serve as indicators for a response to therapy, a larger number of patients should be followed for a longer time period.

Immunohistochemical study in dural arteriovenous fistulas and possible role of local hypoxia for the de novo formation of dural arteriovenous fistulas

OBJECTIVE

Although previous clinical and experimental studies investigated the pathogenesis of dural arteriovenous fistulas (DAVFs), the biological process leading to intracranial DAVFs so far remains unknown. In this study, we investigated the expression of vascular growth factors in order to elucidate the possible role of these factors in the development of DAVFs.

METHODS

We examined the histological features, proliferative and angiogenic capacities of the tissue specimens obtained from eight patients who underwent surgery at our institution. Immunohistochemical staining for vascular endothelial growth factor (VEGF), its receptors Flk-1 and Flt-1, transforming growth factor alpha (TGFalpha), basic fibroblast growth factor (bFGF), hypoxia inducible factor 1alpha (Hif-1alpha), MIB-1 and proliferating cell nuclear antigen (PCNA) was performed using standard immunohistochemical techniques.

RESULTS

A positive immunostaining was found for all antibodies studied except MIB-1, whereas nuclear endothelial expression of PCNA was observed in only 3/8 cases. Hif-1alpha and VEGF stained positive in all of the available specimens (7/7). Flk-1 showed a positive immunoreaction in only 2/8 cases and Flt-1 in 5/7 cases. TGFalpha and bFGF were expressed in the majority (6/8) of cases.

CONCLUSION

These results indicate the possible role of local tissue hypoxia as the initial step causing neoangiogenesis and a low degree of endothelial proliferation in DAVFs. Such hypoxia might be caused by venous hypertension or venous thrombosis as it was previously suggested by other authors.

Transvenous treatment of carotid cavernous and dural arteriovenous fistulae: results for 31 patients and review of the literature

OBJECTIVE

To evaluate findings for patients with carotid cavernous fistulae or dural arteriovenous fistulae (AVFs) who underwent transvenous embolization via different transvenous approaches.

METHODS

Retrospective analysis of data for 31 patients (age range, 17-81 yr; mean age, 59.3 yr) with carotid cavernous fistulae (n = 6) or dural AVFs (cavernous sinus [CS], n = 11; transverse/sigmoid sinus, n = 14) was performed. The AVFs were treated with coils via different transvenous approaches, in 56 procedures. Doppler ultrasonography and time-resolved, two-dimensional, magnetic resonance projection angiography were performed to confirm the treatment. The mean clinical follow-up period was 32.5 months.

RESULTS

A total of 34 transvenous procedures were performed for 17 AVFs of the CS. Eleven patients with AVFs of the CS (63%) were cured with respect to clinical symptoms, and six patients experienced improvement (37%). The approach via the internal jugular vein and inferior petrosal sinus (n = 15) was possible in 60% of cases, with complete occlusion of the fistula in 78% of cases. With the approach via the facial vein (n = 8), there was a 50% success rate. The superior ophthalmic vein approach (n = 5) was associated with a high rate of technical success (100%), with a rate of complete fistula occlusion of 80%. We encountered complications, with transient morbidity, in four cases (23.5%). For 14 dural AVFs of the transverse/sigmoid sinus, 22 transvenous procedures were performed; 12 patients were cured (85.7%) and 2 experienced improvement (14.3%). The technical success rate was 86%, with complete occlusion in 42% of cases. Minor complications occurred in six cases (42.9%) but did not lead to permanent morbidity.

CONCLUSION

Transvenous treatment of CS and transverse/sigmoid sinus AVFs can be effective if all transvenous approaches, including combined surgical/endovascular approaches, are considered.

Combined transvenous and transarterial embolization of a tentorial-incisural dural arteriovenous malformation followed by primary stent placement in the associated stenotic straight sinus. Case report

Dural arteriovenous malformations (AVMs) involving the tentoria-incisura are associated with an aggressive clinical course characterized by subarachnoid and intracranial hemorrhage (ICH). In these lesions, venous outflow obstruction precipitates leptomeningeal venous drainage, resulting in the arterialization of pial veins and the formation of venous aneurysms, both of which are prone to hemorrhage. Stenotic lesions of the dural sinuses also contribute to the development of retrograde leptomeningeal drainage, which is responsible for the aggressive clinical course of the dural AVM. Endovascular approaches are successful in the treatment of these lesions and of any potential venous outflow obstruction caused by stenosis of a dural sinus. The authors report on a patient with a tentorial-incisural dural AVM and an accompanying stenotic venous sinus. A combined transvenous and transarterial embolization procedure was performed, resulting in complete obliteration of the dural AVM, followed by primary stent placement across a stenotic segment of the straight sinus and normalization of venous outflow. The authors conclude that dural AVMs can be treated safely by using a combined transarterial and transvenous approach and that an extensive search for venous outflow obstruction often reveals stenosis of a draining sinus. Consideration should be given to primary stent placement in the stenotic sinus to protect against ICH.

Multiple dural arteriovenous fistulas. Radiologic progression and endovascular cure. Case report

SUMMARY

Dural arteriovenous fistulas are most probably acquired lesions. However, they have been rarely encountered de novo.We present a unique case of a 71-year-old woman who initially presented with right-sided dural arteriovenous fistula (DAVF), which spontaneously resolved after diagnostic arteriography. She later developed asymptomatic occlusion of the left transverse sinus. Five years after her initial presentation she developed left-sided pulse-synchronous tinnitus. MRA and catheter angiography showed a complex type IV DAVF between the left transverse sinus and multiple dural branches arising from both left and right external carotid arteries. The left transverse sinus was isolated from the torcula herophili, with stenosis of the sigmoid sinus. Extensive cortical venous drainage was demonstrated. Endovascular cure was effected by polyvinyl alcohol particle and absolute alcohol occlusion of the dominant dural supply, and transvenous coil occlusion of the left transverse sinus. The patient's symptoms resolved almost immediately. This unique case demonstrates that dural sinus occlusion and DAVFs may co-exist, but there may not be a causal relationship. It is likely that both DAVFs and sinus occlusion are manifestations of the same disease process characterised by a pro-thrombotic state and secondary angiogenesis. It is important to recognise that changes in symptomatology, even long after apparent disappearance of a lesion may indicate recurrence, and careful follow up is advocated.

Transarterial intravenous coil embolization of dural arteriovenous fistula involving the superior sagittal sinus

BACKGROUND

We report a rare case of traumatic dural arteriovenous fistula involving the superior sagittal sinus successfully treated by transarterial intravenous coil embolization.

CASE PRESENTATION

A 38-year-old woman presented with tension headache. She had a past history of severe head injury at the age of three. Computed tomography scanning showed a heterogenous low-density area in the right frontal lobe, and magnetic resonance imaging demonstrated abnormal vascular structures in the same area. Angiography revealed a dural arteriovenous fistula involving the lateral wall of the fully patent superior sagittal sinus. The fistula was fed by scalp, meningeal, and cortical arteries, and drained into a cortical vein leading to the superior sagittal sinus. Femoral transarterial intravenous embolization with microcoils completely occluded the dural arteriovenous fistula.

CONCLUSION

Severe head injury may lead to asymptomatic dural arteriovenous fistulas after a long time. Transarterial intravenous coil embolization can be effective in the treatment of dural arteriovenous fistulas involving the superior sagittal sinus.

Acquired pial arteriovenous fistula following cerebral vein thrombosis

BACKGROUND

We report a unique case of an acquired pial arteriovenous fistula occurring after an asymptomatic thrombosis of a superficial cerebral vein.

CASE DESCRIPTION

A cerebral angiogram performed in a 51-year-old man with subarachnoid hemorrhage revealed a 10-mm ruptured anterior communicating artery aneurysm and a thrombosed left superficial middle cerebral vein. Coil embolization of the anterior communicating aneurysm was performed. Follow-up angiography 18 months later revealed a new, asymptomatic, pial arteriovenous fistula between the previously thrombosed left superficial middle cerebral vein and a small sylvian branch of the left middle cerebral artery.

CONCLUSIONS

This case provides evidence that pial arteriovenous fistulas may develop as acquired lesions and furthermore may rarely follow cerebral vein thrombosis. Several cases of dural arteriovenous fistulas, as well as a single case of a mixed pial-dural arteriovenous fistula, occurring after dural sinus thrombosis have been reported previously. However, to our knowledge, this is the first report of an acquired pial arteriovenous fistula following a cerebral vein thrombosis.

Endovascular recanalization with balloon angioplasty and stenting of an occluded occipital sinus for treatment of intracranial venous hypertension: technical case report

OBJECTIVE AND IMPORTANCE

Dural sinus thrombosis can lead to intracranial venous hypertension and can be complicated by intracranial hemorrhage. We present a case report of a patient who underwent endovascular recanalization and stenting of a thrombosed occipital sinus.

CLINICAL PRESENTATION

A 13-year-old patient with a history of chronic sinus thrombosis refractory to anticoagulant therapy presented with acute onset of aphasia and hemiparesis. Computed tomography and magnetic resonance imaging revealed hydrocephalus and cerebral edema. Angiography delineated multiple dural arteriovenous fistulae and persistent occlusion of the posterior sagittal, occipital, and bilateral transverse dural sinuses with retrograde cortical venous drainage.

INTERVENTION

After embolization of the dural arteriovenous fistulae, a transvenous approach was used to recanalize and perform balloon angioplasty of the right internal jugular vein and the occipital and left transverse sinuses, resulting in subsequent clinical improvement. The patient's condition deteriorated 3 days later with reocclusion of both balloon-dilated sinuses. Repeat angioplasty and then deployment of an endovascular stent in the occipital sinus were performed, and reestablishment of venous outflow was achieved, resulting in a decrease of intracranial venous pressure from 41 to 14 mm Hg and neurological improvement. At the 3-month follow-up examination, the stented occipital sinus remained patent and served as the only conduit for extracranial venous outflow; the patient remained neurologically intact at the 12-month follow-up examination.

CONCLUSION

This is the first report of mechanical recanalization, balloon angioplasty, and stent deployment in the occipital sinus to provide sustained venous outflow for the treatment of venous hypertension with retrograde cortical venous drainage in a patient with dural pansinus thrombosis refractory to anticoagulant therapy.