Histopathological study of venous aneurysms in patients with dural arteriovenous fistulas

Dural Arteriovenous Fistula within Superior Sagittal Sinus Wall with Direct Cortical Venous Drainage: A Systematic Literature Review

Dural arteriovenous fistulas (DAVFs) located within superior sagittal sinus (SSS) wall with direct cortical venous drainage are rare. They are also known as variant DAVF (vDAVF) and form a special subgroup of DAVFs. Their chance of presenting with aggressive features is high compared with transverse sigmoid sinus fistula. They drain directly into cortical veins (Borden type 3, Cognard type III and IV). A systematic English literature review of SSS vDAVF was made. Systematic literature review revealed a total of 31 published cases. These were commonly seen in male population, (24 males, 77.41%, 24/31). Average age of patients was 54 years. A total of 24 patients (77.41%, 24/31) had aggressive clinical presentations with 13 patients (41.93%, 13/31) having intracranial hemorrhages (ICH). Two patients had rebleeding (15.38%, 2/13). Middle portion of SSS was commonly involved (15 cases, 75%). A total of 25 (96.15%, 25/26) cases had patent SSS. Most of the fistulas were idiopathic (65.38%, 17/26), with trauma being a frequent etiological factor (26.92%, 7/26). Venous ectasia was seen in 19 patients (59.37%, 19/32). Middle meningeal arterial (MMA) supply was seen in all patients (100%, 26/26), with bilateral MMA supply in 21 cases (80.76%), and unilateral in 5 cases (19.23%). Twenty patients (62.50%, 20/32) received only endovascular treatment (EVT), while four patients had EVT followed by surgery (12.5%, 4/32). Transarterial route via MMA was the preferred treatment option (79.16%). Complete obliteration of fistulas was noted in all cases (100%, 30/30). No immediate complication was noted after EVT. As much as 92.30% patients showed good recovery. Thus, SSS vDAVF forms a special subgroup of DAVF, with aggressive presentation, and warrants urgent treatment. EVT is effective treatment option and can produce complete obliteration.

miR-34a regulates phenotypic modulation of vascular smooth muscle cells in intracranial aneurysm by targeting CXCR3 and MMP-2

MicroRNAs (miRNAs) dysregulation is tightly related to diseases including tumor, neuro disease and cardiovascular disease. In this study, we investigated the potential biological effects of miR-34a and its target CXCR3 in phenotypic modulation of vascular smooth muscle cells (VSMCs) of intracranial aneurysms (IAs). MiR-34a was found to be down-regulated in IAs patients tested by Real-time PCR and decreased in GEO data. Meanwhile, our study also showed miR-34a inhibited matrix metalloproteinases (MMPs) and migration of VSMCs. Besides, CXCR3 is a direct target of miR-34a identified via luciferase assay. CXCR3 showed inhibitory effect on SM-MHC, SM22 while promoted MMPs expression, cell proliferation and migration in VSMCs. MiR-34a reversed the effect of CXCR3 in VSMCs. In addition, MMP-2 is a competitive endogenous RNA (ceRNA) of CXCR3 sharing common miR-34a target. CXCR3 increased MMP-2 level through competitive endogenous RNA regulation by sponging endogenous miR-34a. In conclusion, miR-34a is down-regulated in IAs while CXCR3 is the direct target of miR-34a that regulates phenotypic modulation of VSMCs. CXCR3 increased MMP-2 level through competitive endogenous RNA regulation by sharing common miR-34a targets.

Thrombosis of venous outflows of the cavernous sinus: possible aetiology of the cortical venous reflux in case of indirect carotid-cavernous fistulas

BACKGROUND

The presence of a cortical venous reflux (CVR) in a carotid-cavernous fistula (CCF) is well described and is considered to be a criterion for urgent treatment. This reflux is often associated with direct/traumatic CCF and the high-flow of the fistula alone explains the reflux. For indirect CCF, the pathophysiology of a CVR is unclear.

METHODS

All patients treated endovascularly for an indirect CCF with a cortical venous reflux between 2003 and 2015 were included. We retrospectively analysed data focusing on whether venous outflows of the cavernous sinus would opacify or not with the local injection of contrast, in order to locate those that could explain the venous reflux.

RESULTS

Twenty consecutive patients (male/female ratio, 2/3) were included in this series with a mean age of 63 years. All patients presented ocular signs and no patients showed any neurological sign secondary to the CVR. We distinguished four patterns of CVR: in the superficial middle cerebral vein (75%), in the uncal vein (15%), in the superior petrosal vein (5%) and in the inferior petrosal vein (5%). Seventy percent of the cases presented a lack of opacification in more than three venous outflows of the CS involved. Each patient received an endovascular therapy by venous approach with a success rate of 76.9% per embolisation session. Two patients (10%) presented a permanent ocular paresis and two others a transient deficit.

CONCLUSIONS

CVR is directly correlated with the thrombosis of multiple venous outflows of the CS. The "non-opacification" of at least three of the CS venous outflows is necessary for the development of CVR. Such thrombosis may be explained by the combination of haemodynamic and inflammatory changes of the venous wall.

The myodural bridge existing in the Nephocaena phocaenoides

Recent studies have identified that the myodural bridge (MDB) between the rectus capitis posterior minor (RCPmi) and the cervical spinal dura mater in the posterior atlanto-occipital interspace in humans. And it was supposed that the MDB may play essential physiological roles. As a result, the MDB is possibly a highly conserved structure in the evolution of mammals. However, there is little confirmative description about the existence of the MDB in marine mammals. The objective of this study was to explore the existence and the fiber property of the MDB in the Neophocaena phocaenoides. Six cadavers of the Neophocaena phocaenoides with formalin fixation were used in this study. One was used for head and neck CT scanning and three-dimensional (3D) reconstruction and suboccipital region dissection, two were for sectional observation by P45 plastinated sheets of head and neck, and three were for histological analysis of suboccipial structures. This is the first study to demonstrate the existence of the MDB in the aquatic mammals. The rectus capitis dorsal minor (RCDmi) originated from the inferior border of the occiput and inserted into the cervical spinal dura mater. At the ventral aspect of the RCDmi, the MDB directly extended through the posterior atlanto-occipital interspace and connected with the cervical spinal dura mater which was consisted of type Ⅰ collagen. In addition, the dorsal atlanto-occipital membrane was not found in the Neophocaena phocaenoides. The tendinous myodural bridge extended from the RCDmi to the spinal dura mater through the posterior atlanto-occipital interspace in the Neophocaena phocaenoides.

Isolated giant cerebral varix - A diagnostic and therapeutic challenge: A case report

Background:

Isolated giant cerebral varix (IGV) is an uncommon vascular lesion that represents a diagnostic challenge and requires dynamic vascular studies for its characterization. The IGV is considered a benign, low-flow venous lesion with very low risk of bleeding that might cause secondary symptoms mainly due to compression of the adjacent parenchyma.

Case Description:

A 12-year-old female patient with non-contributory medical history presented with headache for the last 2 months. Upon admission, her neurological examination was unremarkable. Magnetic resonance imaging (MRI) and computed tomography angiography (CTA) images demonstrated a large varicose dilation of the superficial Sylvian vein, located anterior to the left temporal pole, with no evidence of abnormal arteriovenous connections or tumoral lesions. This finding was considered incidental and unrelated to her symptoms. In this case, we considered that the combination of CTA and MRIs was enough to establish an accurate diagnosis, excluding the need to perform invasive imaging studies. Taking into account these considerations, the patient was managed with conservative treatment and has been followed up for 1 year, remaining asymptomatic.

Conclusion:

Cerebral IGVs are rare vascular lesions that are treated conservatively when asymptomatic and surgically in the case of rupture or compression of adjacent structures. Given our observation of a high unlikelihood of vascular connections to arteries, and the information obtained with non-invasive imaging techniques such as CTA and MRI was enough to make a clinical decision and avoid the evaluation with invasive procedures.

Brainstem Congestion due to Dural Ateriovenous Fistula at the Craniocervical Junction

Dural ateriovenous fistula (DAVF) at the craniocervical junction is rare. We report a patient presenting with brainstem dysfunction as an uncommon onset. Brainstem lesion was suggested by magnetic resonance image study. Angiogram revealed a DAVF at a high cervical segment supplied by the meningeal branch of the right vertebral artery, with ascending and descending venous drainage. Complete obliteration of the fistula was achieved via transarterial Onyx embolization. Clinical cure was achieved in the follow-up period; meanwhile, imaging abnormalities of this case disappeared. Accordingly, we hypothesize that a brainstem lesion of this case was caused by craniocervical DAVF, which induced venous hypertension. Thus, venous drainage patterns should be paid attention to because they are important for diagnosis and theraputic strategy.

Transarterial embolization of dural arteriovenous fistulas of the anterior cranial fossa with Onyx

Dural arteriovenous fistulas (DAVF) of the anterior cranial fossa are often associated with hemorrhage and are usually treated surgically. This clinical study summarizes our preliminary experience in the transarterial embolization of these lesions. We retrospectively reviewed the data for 11 patients with anterior cranial fossa DAVF who underwent transarterial embolization with the Onyx Liquid Embolic System (eV3 Endovascular, Plymouth, MN, USA) at our institute between 2007 and 2011. In four patients, a balloon-assisted technique was used to facilitate superselective catheterization. According to the Cognard classification of DAVF, three fistulas were type III, and the other eight were type IV. DAVF were completely obliterated in 10 patients after treatment via a single ethmoidal artery, but the other patient was not completely cured. No signs of rebleeding or symptom progression were observed at a mean follow-up of 18.5 months (range: 2-49 months). Transarterial embolization using Onyx is therefore feasible and effective for the management of DAVF of the anterior cranial fossa.

Pathogenic mechanisms in varicose vein disease: the role of hypoxia and inflammation

AIMS

Although the aetiology of varicose veins remains unknown, recent studies have focused on endothelial cell integrity and function. Among the regulatory factors of vessel tone, synthesises, pro- and anti-inflammatory, adhesion molecules and the transcription factor hypoxia inducible factor-1 alpha (HIF-1alpha), which are responsible for recruiting leukocytes, are very important.

METHODS

Investigation in this study focused on the expression of ICAM-1, E-selectin and HIF-1alpha on endothelial cells using immunostaining and RT-PCR in varicose vein specimens compared with controls.

RESULTS

Findings of this study showed alterations of the intima, such as focal intimal discontinuity and denudation of endothelium in varicose veins. Based on data derived from immunostaining and RT-PCR, no major differences were identified between ICAM-1 and E-selectin expression in varicose vein specimens compared with controls. In contrast, immunostaining results identified HIF-1alpha expression in five (5/20) varicose vein specimens, whereas no control saphenous vein specimens expressed HIF-1alpha.

CONCLUSIONS

These findings could explain other evidence of hypoxia in varicose veins. Finally, results already obtained in this investigation suggest that the process of pathogenesis of varicose veins is not restricted to the role of adhesion molecules.

Anterior cranial fossa dural arteriovenous fistula with bilateral cortical drainers--case report

A 58-year-old man presented with sudden onset of severe headache. Computed tomography demonstrated subarachnoid hemorrhage and right acute subdural hematoma. He had no neurological deficits. Cerebral angiography showed an anterior cranial fossa dural arteriovenous fistula (AVF) supplied by the bilateral ethmoidal arteries. A fistula was suggested on the right side, and the dural AVF drained into the superior sagittal sinus via the bilateral frontal cortical veins. Venous varix was observed at both drainage sites. Bifrontal craniotomy with right-side dural incision was performed and the fistula was interrupted. Postoperative angiography demonstrated a persistent fistula draining into the left cortical vein. Nineteen days later, bifrontal craniotomy with left-side dural incision was performed and the draining vein was completely coagulated with the aid of intraoperative angiography. Postoperatively, there was no detectable residual fistula. He was discharged without neurological deficits 2 weeks after surgery. The present case of anterior cranial fossa dural AVF with bilateral cortical drainers shows that drainer occlusion at two points may be needed for complete obliteration of the drainers because the fistulous connection may not be simple.

Serial angiography of dynamic changes of traumatic middle meningeal arteriovenous fistula: case report

A 48-year-old woman suffered head trauma and presented with an acute epidural hematoma with a linear fracture of the right temporal bone across the middle meningeal groove. Initial angiography demonstrated no vascular abnormalities. Eight months later, she again suffered head trauma and computed tomography demonstrated traumatic subarachnoid hemorrhage. Right external carotid angiography revealed a middle meningeal arteriovenous fistula (AVF) which drained into the superficial sylvian veins via the sphenoparietal sinus. Serial angiography showed progressive dilation of the draining veins, but she refused surgical intervention and dropped out of our outpatient clinic. Fifteen years after the first head trauma, she presented with subarachnoid hemorrhage. Angiography demonstrated formation of venous aneurysms on the drainer of the AVF. The dilated superficial sylvian vein was removed together with the ruptured venous aneurysm. Histological examination of the drainer revealed an arterialized vein. The serial angiographic evaluations revealed dynamic changes of the traumatic middle meningeal AVF, including progressive dilation of the drainers, simplification of the drainage routes, and the formation of venous aneurysms, which presumably represents the entire natural course of traumatic middle meningeal AVF manifesting as hemorrhage. The present case of traumatic middle meningeal AVF with a deteriorating course suggests that surgical removal or embolization of the AVF is strongly indicated if follow-up angiography shows dilation of the drainers, which implies increased shunt flow.

Intracranial pial single-channel arteriovenous fistula presenting with significant brain edema

The authors report a rare case of pial single-channel arteriovenous fistula presenting with significant brain edema. A 51-year-old woman was admitted with a 5-day history of headache and nausea, followed by consciousness disturbance. Computed tomography showed cerebellar swelling with obstructive hydrocephalus. Magnetic resonance imaging revealed extensive vasogenic edema in the cerebellum bilaterally. Angiography demonstrated 2 different arteriovenous shunts (AVSs) at peripheral branches of the right anterior inferior cerebellar artery. One was located on the suboccipital surface. It drained through a dilated inferior vermian vein and emptied retrogradely into the contralateral cerebellar veins with marked stagnation. Focal stenosis of the dilated draining vein was present. The other AVS was located on the petrosal surface, which had a slow flow with no angiographic evidence of venous congestion. Given that the latter was believed to be asymptomatic, the former AVS was excised, and histological examination revealed that the lesion consisted of a direct communication of multiple arterial feeding vessels with a single vein, consistent with a diagnosis of pial single-channel arteriovenous fistula. The restriction of venous drainage presumably caused venous hypertension, leading to the brain edema and neurological symptoms.

Cortical venous aneurysm isolated cerebral varix

SUMMARY

Venous aneurysms so-called isolated cerebral varix, are known as a related pathology in arteriovenous malformations (AVM) due to the arterial pressure on venous drainage (16). They are also observed in combination with developmental venous anomalies (DVA) (2,4,8,15). However, isolated varix is a rare entity (1,7,11,13). They appear in most cases without neurological deficits. Some of the cases mimic a meningioma due to their manifestation in CT and MR imaging and their axial cortical localization. The case presented here is a isolated varix of a cortical vein located rostral to the motor strip. The patient was operated on successfully. The MRI and the histology of the case are presented.

Vein of Galen aneurysm: Anatomical study of an adult autopsy case

We present a case of vein of Galen aneurysmal malformation in an adult, the rupture of which caused a fatal hemorrhage. Macroscopic examination, together with plastination of specimen with S10, and microscopic examination showed connection of the aneurysm with the right thalamoperforating artery and, bilaterally, with the posterior choroidal and mesencephalic arteries. Histology also showed thinning of the aneurysmal wall, due to marked reduction of the muscular media at the point of rupture, and its connection with an arteriovenous malformation of the left thalamus. A review of the anatomy of the Galenic system shows that the medullary veins curve at an acute angle to form the paired internal cerebral veins, with a sudden change in flow and that, from late fetal life, the vein of Galen curves around the splenium to enter the straight sinus at an angle opposing its flow. Based on anatomical study and a review of the literature, we suggest that aneurysmatic dilatation of the vein of Galen may result from a combination of pathological and predisposing anatomical factors. The anatomical characteristics of the origin of the internal cerebral veins and of the entry of the vein of Galen into the straight sinus make particularly susceptible to the hemodynamic effects of arteriovenous shunts the vein of Galen itself, which is situated in the cisterna ambiens, an anatomical space that does not impede its enlargement.