Cerebral arteriovenous fistulas induced by dural arteriovenous shunts

Dural arteriovenous shunts and pial arteriovenous fistulas are uncommonly associated. Their etiology, pathogenesis, and natural history are still unclear and are likely different. We present three cases of high-flow dural arteriovenous shunts associated with pial arteriovenous fistulas and discuss their pathogenesis, anatomic association, and angioarchitecture. We propose that venous steal effect in the dural sinus secondary to the high-flow dural arteriovenous shunt induced the pial arteriovenous fistulas. Treatment of the high-flow dural arteriovenous shunts and the induced pial arteriovenous fistulas are discussed.     

Transcatheter venous embolization of a massive hepatic arteriovenous shunt complicating hepatocellular carcinoma using an Amplatzer Vascular Plug

Arteriovenous (AV) shunts are relatively uncommon in the liver and usually associated with advanced hepatocellular carcinoma (HCC). In patients with massive AV shunts complicating advanced HCC, transarterial chemoinfusion therapy is not effective because chemotherapeutic agents go through the shunts and may cause systemic toxicity as well as decrease the chemotherapeutic effects against the tumor. We report two cases of successful transcatheter venous embolization of massive AV shunts complicating advanced HCC using the Amplatzer Vascular Plug for transarterial chemoinfusion therapy.     

Angiographic classification of hepatic hemangiomas in infants

PURPOSE: To review the angiograms in patients with hepatic hemangiomas referred to two North American children's hospitals to determine the variability in angiographic findings and to propose a classification system that is based on these findings. MATERIALS AND METHODS: Angiograms obtained in 15 infants with a diagnosis of hepatic hemangioma who were examined at or referred to two tertiary pediatric hospitals in North America from 1981 through 2000 were reviewed. The angiographic findings were then used to classify hemangiomas into types on the basis of a number of features, including high-flow nodules, early filling of veins, and the type of direct shunt present. Clinical data, including age at presentation, presence of cardiac insufficiency, and treatment, were also recorded. RESULTS: Lesions were classified into five types on the basis of angiographic findings. In three of 15 patients, angiograms demonstrated the classic appearance of hepatic hemangiomas, with early filling of abnormal vascular channels, stagnation of contrast material, and no evidence of a direct shunt (type 1). In four patients, images showed high-flow nodules without direct shunts (type 2). In eight patients, direct shunts were demonstrated: arteriovenous shunts (type 3) in one, portovenous shunts (type 4) in three, and both arteriovenous and portovenous shunts (type 5) in four. CONCLUSION: Hepatic hemangioma in infants is a heterogeneous lesion with variable angioarchitecture and a spectrum of angiographic findings.     

Double-Balloon-Assisted N-Butyl-2-Cyanoacrylate Embolization of Nontumorous Intrahepatic Arterioportal Shunts

This report describes the safety and efficacy of double-balloon-assisted N-butyl-2-cyanoacrylate embolization of nontumorous intrahepatic arterioportal shunts in 5 consecutive, previously untreated patients. A proximal balloon was used for flow control and a coaxial microballoon was used to control the delivery of N-butyl-2-cyanoacrylate. Complete occlusion was achieved in 3 patients and shunt flow decreased in 2 patients, without complications. In the latter 2 patients, pre-embolization shunt flow was lower than that in patients with complete occlusion. Our results suggest that this coaxial double-balloon-assisted technique may be safe and effective for the embolization of nontumorous intrahepatic arterioportal shunts, especially in high-flow shunts.     

Endovascular trapping of traumatic carotid-cavernous fistulae

We describe an unconventional endovascular approach to the treatment of traumatic carotid-cavernous fistulas. Four patients with large high-flow shunts have been successfully treated by trapping of the fistula by using a combination of proximal balloon occlusion and distal coil embolization. The latter was achieved following retrograde catheterization of the distal parent vessel via the contralateral carotid or ipsilateral vertebral artery.     

Follow-up results after stent placement in failing arteriovenous shunts: A three-year experience

Self-expandable endoprostheses were used in 18 failing arteriovenous shunts after unsuccessful balloon dilatation. Technical success was satisfactory with an early patency in 17 of 18 shunts. Thrombosis right after stenting occurred in three shunts but was successfully treated in two. Followup history revealed recurrent events of reobstruction due either to stent or shunt stenoses or thrombosis. Restenosis within the stented segment was responsible for reobstruction in about half the cases. Although patency was low with 27% at 18-month follow-up, repeated intervention established a shunt survival rate of 77% at 18-month follow-up. Stent placement in AV shunts is useful for overcoming acute problems of balloon dilatation but does not prevent restenosis.     

Priapism

Priapism is a relatively uncommon condition that may present as a medical emergency associated with significant pain and anxiety in the veno-occlusive or low-flow variant. Pharmacologic advances and, specifically, the availability of intracavemosal alpha-agonist therapy have dramatically improved the prospects of resolution for patients with low-flow priapism presenting within the first few hours of the acute episode. High-flow priapism is not considered an emergency and treatment measures are typically conservative aimed at preservation of potency. Urologists, radiologists, and other health care personnel caring for the patient with priapism must be familiar with various etiologic factors implicated in low-flow and high-flow priapism to formulate a logical step-care approach. Differentiation of the low-flow from the high-flow state is perhaps the most critical initial diagnostic challenge that determines the sequence of further interventions including surgical shunts in low-flow priapism refractory to medical therapy.     

伴有动静脉瘘的静脉狭窄模型的建立

目的　评价一种新的静脉狭窄模型的建立方法。方法　用手术方法在 6只成年实验猪的两侧颈动静脉之间建立了 12个动静脉瘘。然后在距吻合口上下 1～ 2cm处的颈静脉上用手指或镊子挤压造成局部损伤。分别在术后 3周、6周做血管造影随访 ,并处死动物 ,获取动静脉吻合、受损颈静脉的组织作病理学检查。狭窄程度用血管造影评价。结果　造影片上 ,12个动静脉吻合口有 6个保持通畅 ,无明显狭窄 ,5个通畅但有明显狭窄 ,1个完全闭塞。 2 4处被损伤的静脉点有 17处可见直径大于5 0 %的狭窄。组织学检查显示狭窄由局部组织增生所致。结论　动静脉瘘加局部静脉损伤可建成高血流量、增生性静脉狭窄。这一模型可能特别适用于研究发生在无肾功能、长期血透患者身上的血透管静脉狭窄。     

Digital angiography in evaluation of orthopedic tumors

Preoperative evaluation of orthopedic tumors using digital subtraction angiography (DSA) proved useful to ascertain the nature of the lesion, its extension to soft tissues and joints, and the presence of arteriovenous (AV) shunts. We report that overall accuracy varied from 89% to 92%, depending on the feature evaluated. The importance of angiographic examination of this entity is discussed as well as the advantages of DSA over conventional angiography.     

Interlocking detachable platinum coils,a controlled embolization device: Early clinical experience

Purpose: To present the early clinical experience of a new mechanically controlled-release embolization device<+>—<+>the interlocking detachable coil (IDC)—in complex embolization outside the head. Methods: IDCs were used only when conventional embolization techniques were considered too risky or unsafe. The coils consist of unfibered coiled platinum (0.012 inch), mechanically connected to a pusher wire and deployed through a Tracker 18 catheter. IDCs come in a range of diameters (2<+>–<+>8 mm) and lengths (1<+>–<+>30 cm). Results: A total of 87 IDCs were used for 27 procedures in 25 patients (mean 14.5 years) to occlude 31 arteries or vascular lesions. Control of the coil and its release were satisfactory and all coils were fully retrievable up to the point of deployment. Two IDC coils embolized inadvertently but were retrieved; there were no other complications. The IDC coils could not be satisfactorily placed in one high-flow arteriovenous (AV) fistula, and in another case there was a small residual fistula. Occlusion was produced in 29 of 31 lesions. Ancillary techniques were needed in 5 patients: temporary balloon occlusion in 2 and 0.038-inch coils in 3. Conclusion: The IDC coil is an effective device that allows controlled embolization to be performed, especially in aneurysms and in high-flow AV fistulas in children.     

Porous and nonporous polycarbonate urethane stent-grafts for TIPS formation: biologic responses.

PURPOSE: To evaluate the biologic response to transjugular intrahepatic portosystemic shunts (TIPS) lined with polycarbonate urethane endografts and the effects of different porosity formulations. MATERIALS AND METHODS: Seventeen TIPS were created in non-modified portal hypertensive miniswine with use of porous (n = 6), nonporous (n = 7) polycarbonate urethane stent-grafts, and control Wallstents TIPS (n = 4). Eight-week venography, histology, scanning electron microscopy, and immunohistochemical analyses were performed. RESULTS: The mean 8-week percent parenchymal tract shunt stenosis was 75%, 46%, and 26% in the control, porous, and nonporous groups, respectively. Occlusions developed in one control, one porous, and two nonporous shunts. The biologic response to porous grafts included marked inflammation and encapsulation and permeation of the grafts by a thick fibrous pseudointima. Nonporous grafts evoked little inflammation or pseudointima. Mature thrombus lined the occluded shunts (under which little luminal pseudointima or endothelium was present). The control group showed typical pseudointimal hyperplasia enveloping the intraparenchymal portions of the stents. CONCLUSIONS: The healing response of the porous and nonporous grafts markedly differed. Unlike the porous grafts and control stents, the nonporous endografts elicited little inflammation or luminal pseudointimal hyperplasia, although sporadic thrombosis was problematic in this normotensive model. Graft use in high-flow situations (ie, human TIPS, possibly in concert with antiplatelet agents) may allow desired shunt patency prolongation.     

Follow-up MRI in dural arteriovenous malformations involving the cavernous sinus: emphasis on detection of venous thrombosis

Summary Six patients with a dural arteriovenous malformation (dural AVM) involving the cavernous sinus were followed up with magnetic resonance imaging in order to assess change in the lesions. Spin-echo (SE) imaging of three patients in whom the AVM appeared to have closed at least 1 month earlier (two of them spontaneously, and one after external carotid artery embolization) showed neither apparent flow void in the involved cavernous sinus nor evidence of venous thrombosis. SE images of the other three patients who had not been cured by external carotid artery embolization (two of whom were examined within a week of treatment), detected persisting arteriovenous shunts, including high-flow cortical venous drainage, seen as flow void. Two-dimensional time-of-flight MR angiography (2D TOF MRA) was performed simultaneously in three patients. Whereas shunting blood and the normal cavernous sinus were of high intensity, presumed thrombosed cavernous sinuses were isointense with stationary brain tissue. SE imaging can confirm the resolution of arteriovenous shunts, but poorly delineates ver acute and chronic thrombosis of the draining veins. In contrast, 2D TOF MRA directly demonstrates flowing blood, permitting the diagnosis of venous thrombosis; it should be included in follow-up of a dural AVM involving the cavernous sinus when venous thrombosis is suspected.     

Diagnostic imaging in the study of visceral involvement of hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber disease, is an autosomal-dominant vascular disease characterised by mucocutaneous or visceral angiodysplastic lesions. Its diagnosis is exclusively based on clinical criteria. The brain, lungs and liver, in growing order of prevalence, are the most frequently involved organs. Diagnostic imaging based on ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI) and digital subtraction angiography (DSA) has a fundamental role in detecting visceral involvement in HHT patients and is therefore crucial for the prognostic assessment and therapeutic approach. Arteriovenous shunts are the most common cerebrovascular malformations (CVMs). MRI and CT angiography are the methods of choice for diagnosing cerebral involvement, and it is debated whether MRI could be considered as a screening examination on account of its noninvasiveness. Pulmonary arteriovenous malformations, diffuse telangiectases or high-flow, low-pressure shunts between pulmonary arteries and veins can be studied with contrast-enhanced US, but multidetector CT seems to provide the most comprehensive evaluation of their angioarchitecture, whereas angiography has a predominant role in treatment. Liver involvement is frequent and characterised by the presence of intrahepatic shunts, disseminated intraparenchymal telangiectases and other vascular lesions. US is useful for detecting hepatic lesions but should be completed by more accurate imaging methods such as multidetector CT and MRI.     

Surgical neuroangiography of the spine and spinal cord

The SCAVMs are high-flow lesions that present at a younger age, during the second or third decades of life. The most common presenting symptoms are subarachnoid hemorrhage and hematomyelia. Endovascular treatment of these lesions has become an important adjunct to surgical management. Complete occlusion is possible by superselective catheterizations and injection of a liquid embolic material. The SDAVFs are slow-flow AV shunting at the dura, which causes progressive neurologic deficit in older age--the fifth or sixth decades of life. Embolization is now the primary mode of treatment. Preoperative embolization of the hypervascular tumors of the spine and spinal cord has become a necessity to reduce bleeding during surgery, and it even reduces the size of the tumor and relieves spinal block. Thorough knowledge of vascular anatomy and better understanding of hemodynamics of these lesions are essential to perform proper and safe embolization.     

Improved distal distribution of n-butyl cyanoacrylate glue by simultaneous injection of dextrose 5% through the guiding catheter: technical note

Introduction The use of n-butyl cyanoacrylate (NBCA) as an adhesive agent for embolization of high-flow intracranial and extracranial vascular lesions is well established. To be successful, the embolization of arteriovenous malformations and fistulas must achieve obliteration of the arteriovenous shunts themselves rather than simply occlude the feeders proximal to the lesion. However, the feeders cannot always be negotiated over their entire length. This is often the case with dural arteriovenous fistulas (DAVF), which are usually vascularized by long and intricate meningeal networks. In such situations, NBCA may not be able to reach the lesion itself, rendering the embolization ineffective. We present a new technique that improves distal distribution of NBCA glue.Methods The technique described in this report consists of injecting dextrose 5% through the guiding catheter simultaneously with the superselective injection of NBCA glue into the targeted feeding branch. The technique is illustrated with three cases of posterior fossa DAVF.Results In the reported cases, flooding the territory of the targeted vessel with non-ionic dextrose 5% allowed deep progression of the glue by delaying contact with ionic substances. Excellent distribution of the NBCA glue reaching the site of the arteriovenous shunts was thus obtained despite suboptimal proximal microcatheter tip positions.Conclusion Simultaneous perfusion of dextrose 5% through the guiding catheter during NBCA injection dramatically improves the distal progression of glue through small, tortuous arterial feeders. This technique has the potential to increase the therapeutic value of transarterial embolization for DAVFs.     

Cerebral proliferative angiopathy depicted by four-dimensional computed tomographic angiography: A case report

Cerebral proliferative angiopathy is a rare cerebrovascular disorder characterized by diffuse abnormal vessels with intermingled brain parenchyma fed by many arteries and draining into many veins without high-flow arteriovenous shunts, which is usually confirmed by conventional digital subtraction angiography. However, dilution of the contrast medium due to the markedly increased blood flow and volume in cerebral proliferative angiopathy leads to low-contrast angiography. We report a 53-year-old man with cerebral proliferative angiopathy who underwent CT, MR imaging, MR angiography, digital subtraction angiography and 4D-CTA. The 4D-CTA exhibited abnormal vessels without early venous filling between the atrophic brain parenchyma in higher contrast than the angiography due to high spatial and time resolution, whereas the left external carotid angiography visualized the characteristic transdural supply more clearly than the 4D-CTA due to high vascular selectivity. Therefore, novel 4D-CTA and conventional angiography plays a complementary role in the accurate diagnosis of cerebral proliferative angiopathy. Taking invasiveness into account, 4D-CTA may be advantageous for the diagnosis of cerebral proliferative angiopathy based on the characteristic imaging findings.     

Value and limitations of contrast-enhanced MR angiography in spinal arteriovenous malformations and dural arteriovenous fistulas

BACKGROUND AND PURPOSE: The purpose of this work was to study the validity of MR angiography (MRA) for identification of spinal arteriovenous (AV) abnormalities. MATERIALS AND METHODS: Thirty-four consecutive patients with suspicion of spinal vascular abnormalities underwent digital subtraction angiography (DSA) after MRA. The level and side of the suspected spinal dural arteriovenous fistula (SDAVF) and the feeding arteries in spinal arteriovenous malformations (SAVMs) were determined from the MRA and compared with DSA. RESULTS: DSA revealed SDAVF in 20 abnormalities of which 19 were spinal and 1 was tentorial with spinal drainage, as well as SAVM in 11 patients. In 3 patients, MRA and DSA were both normal. For detection of spinal arteriovenous abnormalities, neither false-positive nor false-negative MRA results were obtained. The MRA-derived level of the feeding artery in SDAVF agreed with DSA in 14 of 19 cases. In 5 cases, a mismatch of 1 vertebral level (not side) was noted for the feeding artery. For the tentorial AVF, only the spinal drainage was depicted; the feeding artery was outside the MRA field of view. In intradural SAVM, the main feeding artery was identified by MRA in 10 of 11 patients. MRA could differentiate between glomerular and fistulous SAVM in 4 of 6 cases and between sacral SDAVF and filum terminale SAVM in 2 of 5 cases. CONCLUSIONS: MRA reliably detects or excludes various types of spinal AV abnormalities and localizes the (predominant) arterial feeder of most spinal AV shunts. Although classification of the subtype of SAVMs remains difficult, with MRA it greatly helps to focus subsequent DSA.     

Giant perimedullary arteriovenous fistulas of the spine: clinical and radiologic features and endovascular treatment.

PURPOSETo present the clinical and radiologic features of giant perimedullary arteriovenous fistulas (GAVFs) in 12 consecutive cases and to evaluate the results of endovascular treatment.METHODSWe retrospectively reviewed the clinical and radiologic data as well as the results of balloon endovascular treatment obtained from 1980 to 1989.RESULTSGAVFs, defined as large intradural perimedullary direct arteriovenous high-flow shunts, are revealed mainly in childhood either by subarachnoid hemorrhage or by progressive neurologic disorders. MR imaging and myelography show major vascular dilatations. The angioarchitecture of GAVFs can only be assessed by selective spinal angiography. Ten patients were treated by balloon occlusion resulting in eight anatomic cures and six good clinical results. One balloon migrated to the venous side, leading to clinical deterioration.CONCLUSIONGAVF is a special subgroup of intradural perimedullary arteriovenous fistula. The endovascular approach should be the first line of treatment, with surgery reserved for special circumstances. Nondetachable balloon occlusion is a safe and efficient method for treating GAVFs.     

Percutaneous Direct Puncture Embolization with <Emphasis Type="Italic">N</Emphasis>-butyl-cyanoacrylate for High-flow Priapism

There are many treatment options in high-flow priapism. Those mentioned most often are watchful waiting, Doppler-guided compression, endovascular highly selective embolization, and surgery. We present a case of high-flow priapism in a 57-year-old man treated by percutaneous direct puncture embolization of a post-traumatic left cavernosal arteriovenous fistula using N-butyl-cyanoacrylate. Erectile function was preserved during a 12-month follow-up. No patients with percutaneous direct puncture embolization for high-flow priapism have been reported previously. Percutaneous direct puncture embolization is a potentially useful and safe method for management of high-flow priapism.     

Uterine Artery Embolization for Retained Products of Conception with Marked Vascularity: A Safe and Efficient First-Line Treatment

To report our clinical practice regarding a case series of retained products of conception (RPOC) with marked vascularity (MV) managed with selective uterine artery embolization (UAE) as first-line treatment. This was a monocentric, retrospective study of 31 consecutive cases of RPOC with MV diagnosed by Doppler ultrasound in the context of postpartum/postabortal bleeding. The primary outcome was the absence of rebleeding following embolization. RPOC with MV occurred after abortion in 27 out of 31 patients (87%). The time elapsed between delivery/abortion and UAE ranged from 1 to 210 days (mean 55.7 ± 45 days). Primary clinical success was achieved in 23 women (74.2%) following a single embolization. In total, 27 out of 31 women (87%) had been exclusively managed by UAE with conservative success. Although procedural success was achieved in this number, six women had a further procedure to evacuate RPOC despite procedural success. Large uterine arteriovenous (AV) shunts associated with RPOC were observed in five cases (16.1%), among which two were successfully treated after a single UAE and one after two UAEs, while hysterectomy was performed in the last two cases despite two and three UAE procedures respectively. RPOC was histologically proven in ten cases (32.2%) including four out of five cases of uterine AV shunt. RPOC with MV can present with large uterine AV shunt, particularly in case of late management. Uterine artery embolization is an effective and safe first-line treatment, and should be evaluated for this indication in larger prospective trials.