Evaluation, management, and long-term follow up of vein of Galen malformations

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  • 1 Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute of Medical Sciences and Technology, Trivandrum, India
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Object

Vein of Galen malformations (VGMs) are extremely rare intracranial lesions. Clinical presentation and management strategies vary significantly in different areas of the world. The authors report their experience in evaluation, management, and long-term follow up of these lesions in India.

Methods

Between October 1983 and June 2003, 25 patients with VGMs were referred to the authors’ institution for evaluation and management. Ten children younger than 2 years of age presented with rapidly increasing head size as the chief complaint. Among 11 children 2 years of age or older, the most common presenting symptom was chronic headache. Four patients who presented during adulthood had chronic headache for many years before presentation. Angiographic evaluation of the lesion was performed in 21 patients. Fifteen patients were treated using endovascular techniques. Injection of the embolic material was performed after induction of systemic hypotension when the flow in the fistula was high.

Complete occlusion of the arteriovenous shunt could be achieved in two patients with vein of Galen aneurysmal dilation (100% of patients with this type of malformation) and in five of the six patients with the mural type of malformation (83%). Among patients with the choroidal type of malformation, complete obliteration of the shunt could be achieved in three patients. In three patients with high-flow choroidal malformations, embolization carried out in a single sitting resulted in shunt reduction of nearly 90%. These patients received clinical follow up.

Conclusions

The authors’ experience in evaluation and management of VGMs reveals that in areas of the world where access to dedicated specialist care is limited, the clinical presentation of VGMs can differ appreciably from the classic descriptions in the literature. Endovascular management of these lesions results in excellent angiographic and clinical results.

Abbreviations used in this paper:

CT = computed tomography; NBCA = N-butyl cyanoacrylate; VGAD = vein of Galen aneurysmal dilatation; VGM = vein of Galen malformation; VP = ventriculoperitoneal.

Object

Vein of Galen malformations (VGMs) are extremely rare intracranial lesions. Clinical presentation and management strategies vary significantly in different areas of the world. The authors report their experience in evaluation, management, and long-term follow up of these lesions in India.

Methods

Between October 1983 and June 2003, 25 patients with VGMs were referred to the authors’ institution for evaluation and management. Ten children younger than 2 years of age presented with rapidly increasing head size as the chief complaint. Among 11 children 2 years of age or older, the most common presenting symptom was chronic headache. Four patients who presented during adulthood had chronic headache for many years before presentation. Angiographic evaluation of the lesion was performed in 21 patients. Fifteen patients were treated using endovascular techniques. Injection of the embolic material was performed after induction of systemic hypotension when the flow in the fistula was high.

Complete occlusion of the arteriovenous shunt could be achieved in two patients with vein of Galen aneurysmal dilation (100% of patients with this type of malformation) and in five of the six patients with the mural type of malformation (83%). Among patients with the choroidal type of malformation, complete obliteration of the shunt could be achieved in three patients. In three patients with high-flow choroidal malformations, embolization carried out in a single sitting resulted in shunt reduction of nearly 90%. These patients received clinical follow up.

Conclusions

The authors’ experience in evaluation and management of VGMs reveals that in areas of the world where access to dedicated specialist care is limited, the clinical presentation of VGMs can differ appreciably from the classic descriptions in the literature. Endovascular management of these lesions results in excellent angiographic and clinical results.

Vein of Galen malformations are rare anomalies of the intracranial circulation that constitute approximately 1% of all intracranial vascular lesions.16 However, they represent 30% of vascular malformations in the pediatric age group.7,16,17 The malformation occupies the subarachnoid space of the velum interpositum and the quadrigeminal cistern, which extend anteriorly up to the foramen of Monro and posteriorly up to the confluence of falx cerebri and tentorium cerebelli. The lesion is characterized by the presence of an abnormal median vein of prosencephalon, an embryonic precursor of the vein of Galen, and abnormal shunt fed by normally developed but extremely dilated arteries.23 The principal feeders are branches that normally supply the tela choroidea and quadrigeminal plate, which are enlarged, dilated, and tortuous.23 These vessels can be divided into two groups: 1) an anterior or prosencephalic group (anterior and middle cerebral, anterior choroidal, and posterolateral choroidal arteries); and 2) a posterior or mesencephalic group (posteromedial choroidal, posterior thalamoperforating, quadrigeminal, and superior cerebellar arteries). Lasjaunias, et al.,2,12,14 have classified primary VGMs into two types, choroidal and mural, based on their angioarchitecture. Aneurysmal dilation of the vein of Galen can also occur in cases of arteriovenous malformation near this vein, in which the malformation drains through the deep venous system.

The clinical presentation of VGMs can take three forms. In the newborn period, they may manifest with cyanosis or high-output cardiac failure; in infants, with hydrocephalus with or without heart failure; in older children and adults, with macrocephaly and headache.1,7,9,19 They may also present with intracerebral hemorrhage and subarachnoid hemorrhage. Surgical treatment of these lesions carries a risk of death of between 33.3 and 91.4%, depending on the age of the patient.10,11 Endovascular therapy has proved safe and effective in these patients. Because of both poor surgical results and advances in neurointerventional techniques, endovascular intervention has established itself as the primary therapeutic modality in these patients.

We report our experience in evaluation and management of VGMs with long-term follow up at a single medical center in India.

Clinical Material and Methods

Between October 1983 and June 2003, 25 patients with VGMs were referred to our institute for evaluation and management. The clinical details and imaging findings in these patients are summarized in Table 1.

TABLE 1

Clinical history and imaging study findings in 25 patients with VGMs

VariableNo. of Patients
clinical presentation
 increasing head circumference13
 headache10
 delayed milestones7
 prominent scalp veins5
 neurological deficits4
 subarachnoid or intraventricular hemorrhage3
 poor scholastic performance2
 Seizures2
 antenatal detection2
imaging study findings
 ventricular dilation16
 diffuse cerebral atrophy6
 wall calcifications5
 parenchymal calcifications4
 thrombosis3

Clinical Presentation

All 10 children who were younger than 2 years of age presented with rapidly increasing head size as the chief complaint. Four children in this group also had delay in achieving developmental milestones. Presentation with neurological deficits and seizures was uncommon in this age group. Although six children had a history of respiratory distress at birth, only one child had clinically significant congestive heart failure at the time of presentation. Associated cardiac anomalies in the form of atrial septal defect and patent ductus arteriosus were found in three children, and asymptomatic cardiomegaly was seen in three other children. The lesion was diagnosed antenatally in two patients. Both of these children presented at birth with congestive heart failure, which responded to medical management.

Among 11 children who were 2 years of age or older, the most common presenting symptom was chronic headache. Two children in this subgroup had increased head circumference. Delay in achieving neurological developmental milestones and poor scholastic performance were seen in four children. Presentation with seizures, with proptosis, and with subarachnoid hemorrhage was seen in one patient each.

All four patients who presented during adulthood had experienced chronic headache from many years before presentation. Among these, two patients presented to the hospital with intraventricular hemorrhage and subarachnoid hemorrhage. In two others, the presence of the malformation was detected during investigations for the cause of chronic headache.

Imaging Features

Hydrocephalus was the most common imaging finding associated with the lesion and was seen in 16 patients. Cerebral parenchymal changes in the form of diffuse cerebral atrophy and parenchymal calcifications were seen in six patients and four patients, respectively. Thrombosis of the venous sac was demonstrable in three patients. In two of these patients, complete thrombosis of the sac was seen. Calcification of the wall of the aneurysmal venous sac was noted in five patients.

Angiographic Findings

Angiographic evaluation of the lesion was performed in 21 patients. One patient with imaging evidence of complete thrombosis of the venous sac did not undergo angiography. This patient was managed conservatively after placement of a VP shunt. Three other patients who had imaging evidence of a VGM could not undergo angiographic evaluation. Among the 21 patients who underwent angiographic studies, the lesions were classified as choroidal type (10 patients), mural type (seven patients), and VGAD (three patients) using the classification system proposed by Berenstein and Lasjaunias.2 Complete thrombosis of the venous sac did not permit characterization of the lesion in one of the 21 patients.

Angiography revealed a variety of arterial and venous anomalies. Persistence of proatlantal arteries was seen in three patients, including one patient who had bilateral persistence of proatlantal arteries. Only a handful of cases of this extremely uncommon anomaly have been reported in the literature. Similarly, association of VGM with any sort of carotid-basilar anastomosis has not been described in the literature. Other associated arterial anomalies included the presence of a limbic arterial ring, a right-sided aortic arch, and Kommerell’s diverticulum (one patient each). Venous anomalies included atresia of the straight sinus (four patients) and other deep venous sinuses (three patients) and persistence of falcine sinus (six patients) and occipital sinus (five patients). One case showed the presence of large venous sacs at the torcular herophili.

Therapeutic Management

Since the first procedure in 1983, embolization has been the mainstay of therapy for these lesions at our institution. Only 15 patients were treated using endovascular techniques. Six other patients awaiting embolization were lost to follow up. All procedures were carried out after induction of anesthesia. A detailed analysis of the angioarchitecture was performed before interventional procedures. This analysis revealed that seven of the 15 patients had the choroidal type of malformation, six had the mural type of malformation, and two had VGAD. Transfemoral transarterial embolization using a surgical tissue adhesive containing NBCA (Histoacryl; B. Braun, Melsungen, Germany) and an iodinized oil (Lipiodol)/tantalum powder mixture at various concentrations was the most common technique employed to treat these lesions (Table 2). The embolic agents included cyanoacrylate glue (seven patients) and combination of coils and cyanoacrylate glue (six patients). Free-flow embolization with muscle pieces and embolization with detachable balloons were performed in two early cases in 1983 and 1987, respectively. Injection of the embolic material was performed after induction of systemic hypotension when the flow in the fistula was high. In five patients with the choroidal type and in one with the mural type of malformation, a combination of platinum coils and cyanoacrylate glue was used. In five of these patients, coils were placed within the venous sac using a transfemoral transvenous approach, and in one patient the coils were negotiated into the venous sac through an arterial feeder (Fig. 1). In one patient, the occipital sinus was used to access the venous sac. Therapeutic intervention was carried out in a single sitting in all patients except in one child with a choroidal type of malformation, in whom the embolization was carried out in two sittings.

TABLE 2

Summary of clinical data in 15 patients who underwent embolization for VGMs*

Case No.Age at PresentationAge at Last Follow UpType of MalformationEmbolization Route and AgentDegree of OcclusionProcedure-Related ComplicationsClinical Follow Up
12140muralTAA w/ muscle piecestotaltransient gaze paresis, recovered in 3 days19
3722VGADTAA w/ balloonstotalNone15
5111muralTAA w/ gluetotaliliac artery spasm9.5
71122choroidalTAA w/ gluetotalNone11
83 moschoroidalTAA w/ glue in two sittingstotalhemiparesis due to para- ventricular infarct, resolved in 6 daysdeath due to meningitis
910 mos8muralTAA w/ gluenear totalNone7
12913muralTAA w/ gluetotalNone4.5
1447choroidalTVA w/ coils followed by TAA w/ gluenear totalNone3
15912VGADTAA w/ gluenear totalpulmonary microembolism w/ glue2.5
166 mos3choroidalTAA w/ glue followed by TVA w/ coils90%None2.5
181 yr 11 mos3choroidalTAA w/ coils & gluetotalNone1
2028choroidalTVA w/ coils followed by TAA w/ glueincompleteintraventricular bleeding during embolization
233 mos9 moschoroidalTVA w/ coils followed by TAA w/ glue90%None6 mos
243muralTAA w/ liquid coil, TVA w/ coils followed by TAA w/ glue80%intraventricular bleeding in postprocedural period
252 yr 6 mos2 yr 9 mosmuralTAA w/ glue100%None3 mos

* TAA = transarterial access; TVA = transvenous access.

† Unless indicated otherwise, age is expressed in years.

‡ At follow up all patients (except the patient in Case 8) remained neurologically stable and had no new symptom related to the malformation. Unless otherwise indicated, duration of follow up is expressed in years.

Fig. 1.
Fig. 1.

Preembolization and postembolization angiograms obtained in a patient with a VGM. A and B: Vertebral angiograms revealing a lobulated venous sac. C: The venous sac was approached from the arterial side, and coiling was performed. Subsequently, cyanoacrylate glue was injected (D) to achieve complete obliteration of the shunt (E and F).

Two children had imaging evidence of complete thrombosis of the venous sac. One child underwent surgery to relieve the mass effect on the ventricular system and is doing well on follow up. The other child’s condition was managed with follow up after placement of a VP shunt. Only one child with a patent VGM underwent surgery (in 1988).

After embolization, all patients were shifted to the intensive care unit and underwent close monitoring of hemodynamic and neurological status for 24 to 48 hours after the procedure. Systemic blood pressure was kept at or slightly lower than the baseline blood pressure of the patient by using short-acting vasodilators. Corticosteroids were used in the early postprocedure period for their cerebroprotective effects, and a hyperosmolar agent (mannitol) was used for reducing cerebral edema. After discharge, the patients were called back for follow up at 1 month, 3 months, 1 year, and then annually. Decisions regarding repetition of neuroimaging and angiographic studies were made on the basis of the clinical status of the patient.

Results

Treatment options and results of therapy in the patients who underwent embolization of VGMs are summarized in Table 2.

Angiographic Results

Ten of the 15 patients treated by embolization had complete obliteration of the fistula, as demonstrated by angiographic studies immediately after the procedure. Five patients underwent subtotal embolization (four patients with choroidal malformations and one patient with a mural malformation). Complete occlusion of the arteriovenous shunt could be achieved in both (100%) patients with VGAD and in five (83%) of the six patients with mural malformation. In three of seven patients with choroidal malformations, complete obliteration of the shunt was achieved. In three patients with high-flow choroidal malformations, embolization carried out in a single sitting resulted in shunt reduction of nearly 90%. These patients received clinical follow up. Because the procedure resulted in complete resolution of symptoms, further embolization has not been performed.

Major Complications

In two patients, intraventricular hemorrhage occurred during the periprocedural period. The first patient was a 28-year-old man (Case 20) who had a history of recurrent headaches since childhood and presented with intraventricular hemorrhage. Angiographic evaluation revealed a choroidal type of malformation (Fig. 2). The venous sac was partially coiled using a detachable platinum coil (Guglielmi Detachable Coil; Boston Scientific/Target Therapeutics, Inc., Fremont, CA) to achieve flow reduction. Subsequently, as the arterial feeders were being catheterized for embolization using cyanoacrylate, extravasation of contrast from one of the feeders was detected. This feeder was embolized immediately proximal to the leak site to prevent progression of hemorrhage. A postprocedure CT scan was performed, which revealed intraventricular and subarachnoid hemorrhage. External ventricular drainage was performed immediately, but the patient died of bleeding 3 days later.

Fig. 2.
Fig. 2.

Postembolization brain images obtained in a 28-year-old man with a choroidal VGM. A and B: Angiograms revealing intraventricular hemorrhage after embolization of the VGM. C: Angiogram revealing extravasation of the contrast after coil embolization of the venous sac. D and E: Repeated angiograms after embolization of this feeder with cyanoacrylate glue demonstrating complete obliteration of the arteriovenous shunt. F: A CT scan revealing extensive intra-ventricular hemorrhage, which proved fatal.

The second patient was a 3-year-old boy (Case 24) who presented with hydrocephalus. He had undergone VP shunt placement at 1 year of age. Angiographic evaluation revealed a mural type of malformation fed by the posterior thalamoperforator and thalamogeniculate branches of the posterior cerebral artery. Initially, using transarterial access, one of the feeders was cannulated, and a liquid coil (Berenstein Liquid Coil; Boston Scientific/Target Therapeutics, Inc.) was released to reduce the flow through the fistula. Subsequently, through a femoral venous access, the venous sac was cannulated, and seven vein of Galen coils (Boston Scientific/Target Therapeutics, Inc.) were deployed. Then the thalamogeniculate branch feeding the fistula was cannulated and embolized using 15% NBCA (Histoacryl; B. Braun). The patient underwent elective ventilation after the procedure. About 3 hours after the procedure, the child developed pupillary asymmetry. A CT scan of the brain revealed intraventricular and subarachnoid bleeding and ventriculomegaly. Despite immediate placement of external ventricular drainage and institution of barbiturate coma, the patient died of bleeding 2 days later.

One infant with a choroidal VGM underwent endovascular therapy in two sessions, resulting in 70% reduction and total occlusion of the shunt, respectively. The infant had no symptoms immediately after the procedure. However, 7 days later the infant developed irritability with neck rigidity. The clinical diagnosis of meningitis was confirmed by subsequent imaging and laboratory investigations. Despite aggressive management with antibiotics, the infant had a prolonged downhill course characterized by ventriculitis and hydrocephalus and died 5 months later.

Minor Complications

Escape of cyanoacrylate glue into the venous circulation with microembolism of the pulmonary circulation occurred in one patient. This child had a corpus callosal arteriovenous malformation draining into an aneurysmally dilated vein of Galen. Despite the use of a high concentration of glue, high flow within the malformation resulted in escape of significant amounts of embolic agent, causing pulmonary microembolism. Clinically, the child showed symptoms, including dyspnea and low oxygen saturation levels in the blood, immediately after embolization. However, response to treatment with administration of oxygen was excellent, and the child showed no symptoms a few hours later. During subsequent follow up for 1.5 years, the child did not have any symptoms attributable to this complication.

Transient neurological deficits in the form of gaze paresis occurred in one patient immediately after embolization and spontaneously resolved within 3 days. After embolization one patient had transient hemiparesis, which resolved completely within 6 days. One other child had a procedure-related spasm of the iliac artery on the side that was used for arterial access. This complication was largely asymptomatic and resolved with conservative therapy. In one infant with a choroidal malformation, there was migration of the first detachable platinum coil that was placed within the sac. Although the size of the coil was appropriate, after detachment of the coil, the high flow of the shunt resulted in migration of the coil into the falcine sinus and proximal part of occipital sinus. The procedure was continued and subsequent coils stayed within the venous sac at the site of detachment. The patient did not have any new neurological deficits after the procedure.

Follow Up

All 13 patients who underwent successful embolization had improvement in clinical status after the procedure. Duration of clinical follow up ranged from 3 months to 19 years (mean 6.8 years). All patients remained neurologically stable at follow up and did not develop any new symptom related to the malformation. Ten patients who had normal cognitive functions before embolization continued to have normal functions, and two patients who presented with delayed milestones at the time of intervention had improvement after embolization. Follow-up angiograms demonstrated persistence of angiographic occlusion in all patients who had complete obliteration of the shunt.

Illustrative Cases

Case 1.

A 21-year-old woman presented in 1983 with sudden onset of severe headache and neck stiffness. Lumbar puncture revealed features of subarachnoid hemorrhage. She had a past history of occasional holocranial headache for many years before presentation. A plain radiograph of the skull revealed a rounded mass with curvilinear calcification located in the posterior third ventricular region. Angiographic examination (Fig. 3) revealed a mural type of malformation supplied by posterior choroidal feeders from the posterior cerebral artery. Venous anomalies in the form of absence of right sigmoid sinus and persistence of occipital sinus were noted. Embolization was performed through a transarterial route using muscle pieces as embolic material. The left vertebral artery was catheterized, and a free-flow embolization technique was used to completely occlude the fistula.

Fig. 3.
Fig. 3.

Case 1. Preembolization and postembolization brain images obtained in an adult female patient with a VGM. A: Vertebral angiogram obtained in 1984, when the patient was 21 years of age, revealing a VGM (arrow). B: Free-flow embolization using muscle pieces resulted in total occlusion of the fistula (arrow). C and D: Follow-up angiograms obtained in 1992 showing no evidence of the malformation. E: Venous phase of left carotid angiogram demonstrating absence of straight sinus opacification. Comparison of a plain radiograph (F) obtained in 1983 and a CT scan (G) of the brain obtained in 1992 demonstrates a reduction of the size of the sac with an increase in mural calcification.

The postprocedural period was characterized by transient upward gaze paresis, which resolved completely before discharge. The patient has received regular follow up for the past 19 years and does not have any further neurological deficits. Angiographic evaluation performed 9 years after embolization revealed no evidence of a residual arteriovenous shunt.

Case 5.

A 1-year-old boy was brought in for evaluation in 1989 with progressively increasing head circumference. Clinical examination revealed an occipital bruit. An atrial septal defect was detected on cardiac evaluation. A CT scan of the brain (Fig. 4) revealed a densely enhancing venous sac with a smaller saccular diverticulum on its inferolateral aspect. An angiographic study revealed a single enlarged posterior medial choroidal artery terminating on the saccule. There was no evidence of opacification of the posterior cerebral artery distal to the feeder due to steal phenomenon. Venous stenosis at the junction of the venous sac and the straight sinus and aberrant venous channels in the form of falcine sinus and occipital sinus were also noted.

Fig. 4.
Fig. 4.

Case 5. Preembolization and postembolization brain images obtained in a boy with a VGM. A contrast-enhanced CT scan (A) of the brain and angiograms (B and C) obtained when the child was 1 year of age revealed a venous sac and a diverticulum-like saccule from its lateral wall. D and E: Postembolization angiograms revealing complete obliteration of the arteriovenous shunt and restoration of antegrade flow in the posterior cerebral arteries. F: An MR image obtained 8 years postembolization showing complete resolution of the malformation.

Embolization of the fistula was carried out in a single sitting through transarterial access. One milliliter of a mixture of undiluted NBCA and tantalum powder was injected after induction of systemic hypotension. A postembolization angiogram demonstrated complete obliteration of flow within the fistula, with establishment of good flow within the posterior cerebral and superior cerebellar arteries. The patient has received regular follow up since then and remains without symptoms, with normal intellectual and somatic development. Follow-up magnetic resonance imaging performed 8 years after embolization demonstrated normal cerebral parenchyma with complete regression of the venous sac.

Discussion

Untreated VGMs are associated with extremely high mortality and morbidity rates.10–12,24,25 The extraparenchymal location of the lesion allows for aggressive management by embolization. The superiority of endovascular techniques over surgery in the management of these lesions has been demonstrated in several studies.4,5,8,15,18,21,22 Apart from a few descriptions of clinical series, most reports of the interventional neuroradiological management of VGMs are limited to case reports. There have been only a handful of reports of more than 10 cases, and most of these have been from a couple of established centers that specialize in pediatric neurointerventional radiology.3,6,11,13,18,21 There have been no major series from the developing world.

The relative paucity of specialty referral centers that have facilities to manage such patients could play a major role in modifying the clinical presentation of these lesions. In nearly 45% of our cases, the patients were older than age 5 years at presentation. This proportion is in sharp contrast with the findings of Johnston, et al.,11 who found that, of 232 cases collected from literature, only 18% of the patients presented at an age older than 5 years. Similarly, Berenstein and Lasjaunias2 have reported that 22% of patients in their early series presented as adults.

In our experience, the clinical presentation had a poor correlation with the angioarchitecture. Berenstein and Lasjaunias2 have classified VGMs as choroidal (characterized by the presence of multiple arteriovenous fistulae and typically presenting in the neonatal period with heart failure) and mural (characterized by the presence of a single arteriovenous fistula over the wall of the venous sac and presenting in infancy with macrocephaly, cardiomegaly, or mild heart failure). In sharp contrast with their findings, in our experience, presentation with severe congestive cardiac failure was extremely rare and was seen in only one patient. All children who were younger than 5 years of age at presentation presented with features of hydrocephalus, whereas those older than 5 years of age presented with headache, delayed milestones, seizures, neurological deficits, and hemorrhage. Although a high proportion of the choroidal malformations was found in young children, several patients who presented in late childhood or as adults also had choroidal as well as mural malformations. A relatively lower volume of the arteriovenous shunt at the malformation may explain the later age of presentation and predominant neurological symptoms in our patients. This pattern is likely to be seen in other centers in the developing world, where lack of awareness regarding neurointerventional procedures and lack of access to centers performing these procedures result in very few sick neonates with high-flow shunts reaching such centers.

The presence of a VGM was detected in the antenatal period on ultrasound in two patients. Both infants had a history of respiratory distress since birth, as well as congestive heart failure, which responded to conservative management. Both infants had features of hydrocephalus, and embolization was performed at 3 months and 6 months of age, respectively.

Except in one child with a choroidal malformation, all lesions were embolized in a single sitting. Three patients who underwent subtotal embolization had rapid improvement of their symptoms after therapy. Repeated angiographic studies in these patients demonstrated further reduction in shunt flow in one patient and complete occlusion of the shunt in two patients. These findings are highly important in the management of these lesions. Several authors have substantiated the efficacy of partial embolization to prevent congestive heart failure in neonates with high-flow lesions. This strategy may be extended to lesions presenting in other age groups. In centers with limited resources, partial embolization may be preferable to aggressive management of the whole lesion, especially in high-flow lesions such as choroidal malformations. Reduction of the arteriovenous shunt by partial embolization may promote further thrombosis and result in complete obliteration of the fistula without the need for a second procedure. Decisions regarding continuation of conservative management or timing of further embolization can be made on the basis of clinical follow up and periodic transcranial Doppler ultrasonography.

We routinely use vasodilator-induced hypotension during the injection of glue. This technique helps in the setting of glue at the site of the fistula. In the postprocedural period we maintain mean blood pressure 10 to 15% below baseline to avoid hemorrhagic complications. Maintenance of blood pressure below baseline also helps to reduce the flow within any residual shunts and aids in progressive thrombosis of the lesion, as we have seen in our cases. Postprocedural systemic hypotension also prevents normal perfusion pressure breakthrough, which can be associated with abrupt cessation of large arteriovenous shunts. However, induction of hypotension before closure of the fistula may be best avoided in children who have presented with congestive heart failure. The large shunt across the intracranial arteriovenous fistula significantly reduces the diastolic pressure within the aorta, causing reduced coronary artery flow. Induction of hypotension in these children may further reduce the subendocardial blood flow and result in myocardial infarction.20

Only two patients in our series had major procedure-related complications, which proved fatal. We could not determine the exact source and mechanism of bleeding in these patients, as the relatives of the patients did not give consent for autopsy. Partial coiling of the venous sac was performed initially to achieve reduction of the arteriovenous shunt in both patients. In the first patient (Case 20), extravasation of contrast medium was noted during catheterization of the arterial feeders after coil embolization of the venous sac. Venous hypertension induced by coiling of the venous sac could have been responsible for rupture of a subependymal vein, resulting in hemorrhage. The initial presentation of this patient with intraventricular hemorrhage may have played an important role in the occurrence of this complication. In such patients, aggressive coiling of the venous sac to achieve reduction of the arteriovenous shunt may be avoided. Instead, reduction of arterial inflow with transarterial glue embolization may be performed. In the other patient (Case 24) with major complications, massive sub-arachnoid hemorrhage occurred about 3 hours after the procedure. Review of the angiographic images revealed a bleb-like protrusion from the anterior aspect of the venous sac, at the point of entry of the feeders. This protrusion was likely the source of bleeding in this patient. Careful assessment of the angioarchitecture to identify such potentially weak spots may permit a less aggressive approach in the management of these lesions. Staged embolization may be carried out in such cases.

Conclusions

Our experience in evaluation and management of VGMs reveals that, in areas of the world where access to dedicated specialist care is limited, the clinical presentation of VGMs can significantly vary from the classic descriptions available in the literature. Both an older age at presentation and presentation with predominant neurological symptoms may be more common in such regions. Endovascular management of these lesions results in excellent angiographic and clinical results. Even when complete obliteration of the arteriovenous shunt cannot be achieved in high-flow malformations, subtotal embolization can result in improvement of neurological symptoms. Long-term follow up has revealed resolution of neurological deficits and improvement of cognitive status in all the patients in our series who underwent successful embolization.

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    • Export Citation
  • 15

    Lasjaunias P, , Rodesch G, , Terbrugge K, , Pruvost P, , Devictor D, & Comoy J, et al.: Vein of Galen aneurysmal malformations: report of 36 cases managed between 1982 and 1988. Acta Neurochir (Wien) 99:2637, 1989

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  • 16

    Lasjaunias P, , Terbrugge K, , Piske R, , Lopez Ibor L, & Manelfe C: Dilatation de la veine de Galien. Formes anatomo-cliniques et traitement endovasculaire à propos de 14 cas explorés et/ou traités entre 1983 et 1986. Neurochirurgie 33:315333, 1987

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  • 17

    Long DM, , Seljeskog EL, , Chou SN, & French LA: Giant arteriovenous malformations of infancy and childhood. J Neurosurg 40:304312, 1974

  • 18

    Lylyk P, , Viñuela F, , Dion JE, , Duckwiler G, , Guglielmi G, & Peacock W, et al.: Therapeutic alternatives for vein of Galen vascular malformations. J Neurosurg 78:438445, 1993

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    • Export Citation
  • 19

    Maheut J, , Santini JJ, , Barthez MA, & Billard C: Symptomatologie cliniques de l’anevrysme de l’ampoule de Galien. Resultats d’une enquete nationale. Neurochirurgie 33:285290, 1987

    • Search Google Scholar
    • Export Citation
  • 20

    McLeod ME, , Creighton RE, & Humphreys RP: Anaesthetic management of arteriovenous malformations of the vein of Galen. Can Anaesth Soc J 29:307312, 1982

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    • Export Citation
  • 21

    Mickle AP, The transtorcular embolization of vein of Galen aneurysms and update on the use of this technique in twenty-four patients. Marlin AE: Concepts in Pediatric Neurosurgery Karger, Basel, 1991. Vol 11:6978

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    • Export Citation
  • 22

    Mitchell PJ, , Rosenfield JV, & Dargaville P: Endovascular management of vein of Galen aneurysmal malformations presenting in the neonatal period. AJNR Am J Neuroradiol 22:14031409, 2001

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    • Export Citation
  • 23

    Raybaud CA, , Strother CM, & Hald JK: Aneurysms of the vein of Galen: embryonic considerations and anatomical features relating to the pathogenesis of the malformation. Neuroradiology 31:109128, 1989

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    • Export Citation
  • 24

    Yas¸argil MG: Microneurosurgery Vol IIIB: AVM of the Brain, Clinical Considerations, General and Specific Operative Techniques, Surgical Results, Nonoperated Cases, Cavernous and Venous Angiomas, Neuroanesthesia New York, Thieme, 1994

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    • Export Citation
  • 25

    Yas¸argil MG, , Antic J, , Laciga R, , Jain KK, & Boone SC: Arteriovenous malformations of vein of Galen: microsurgical treatment. Surg Neurol 3:195200, 1976

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    Preembolization and postembolization angiograms obtained in a patient with a VGM. A and B: Vertebral angiograms revealing a lobulated venous sac. C: The venous sac was approached from the arterial side, and coiling was performed. Subsequently, cyanoacrylate glue was injected (D) to achieve complete obliteration of the shunt (E and F).

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    Postembolization brain images obtained in a 28-year-old man with a choroidal VGM. A and B: Angiograms revealing intraventricular hemorrhage after embolization of the VGM. C: Angiogram revealing extravasation of the contrast after coil embolization of the venous sac. D and E: Repeated angiograms after embolization of this feeder with cyanoacrylate glue demonstrating complete obliteration of the arteriovenous shunt. F: A CT scan revealing extensive intra-ventricular hemorrhage, which proved fatal.

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    Case 1. Preembolization and postembolization brain images obtained in an adult female patient with a VGM. A: Vertebral angiogram obtained in 1984, when the patient was 21 years of age, revealing a VGM (arrow). B: Free-flow embolization using muscle pieces resulted in total occlusion of the fistula (arrow). C and D: Follow-up angiograms obtained in 1992 showing no evidence of the malformation. E: Venous phase of left carotid angiogram demonstrating absence of straight sinus opacification. Comparison of a plain radiograph (F) obtained in 1983 and a CT scan (G) of the brain obtained in 1992 demonstrates a reduction of the size of the sac with an increase in mural calcification.

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    Case 5. Preembolization and postembolization brain images obtained in a boy with a VGM. A contrast-enhanced CT scan (A) of the brain and angiograms (B and C) obtained when the child was 1 year of age revealed a venous sac and a diverticulum-like saccule from its lateral wall. D and E: Postembolization angiograms revealing complete obliteration of the arteriovenous shunt and restoration of antegrade flow in the posterior cerebral arteries. F: An MR image obtained 8 years postembolization showing complete resolution of the malformation.

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    Amacher AL, & Schillito J Jr: The syndromes and surgical treatment of aneurysms of the great vein of Galen. J Neurosurg 39:8998, 1973

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    Berenstein A, & Lasjaunias P: Surgical Neuroangiography Berlin, Springer-Verlag, 1992. 267317

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  • 4

    Casasco A, , Lylyk P, , Hodes JE, , Kohan G, , Aymard A, & Merland JJ: Percutaneous transvenous catheterization and embolization of vein of Galen aneurysms. Neurosurgery 28:260266, 1991

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  • 5

    Dowd CF, , Halbach W, , Barnwell SL, , Higashida RT, , Edwards MS, & Hieshima GB: Transfemoral venous embolization of vein of Galen malformations. AJNR Am J Neuroradiol 11:643648, 1990

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    Friedman DM, , Madrid M, , Berenstein A, , Choi IS, & Wisoff JH: Neonatal vein of Galen malformations: experience in developing a multidisciplinary approach using an embolization treatment protocol. Clin Pediatr (Phila) 30:621629, 1991

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  • 7

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    Halbach VV, , Dowd CF, , Higashida RT, , Balousek PA, , Ciricillo SF, & Edwards MS: Endovascular treatment of mural-type vein of Galen malformations. J Neurosurg 89:7480, 1998

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    Hirano A, & Solomon S: Arteriovenous aneurysm of the vein of Galen. Arch Neurol 3:589593, 1960

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    Hoffmann HJ, , Chuang S, , Hendrick EB, & Humphreys RP: Aneurysms of the vein of Galen. Experience at the Hospital for Sick Children, Toronto. J Neurosurg 57:316322, 1982

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  • 11

    Johnston IH, , Whittle IR, , Besser M, & Morgan MK: Vein of Galen malformation: diagnosis and management. Neurosurgery 20:747758, 1987

  • 12

    Lasjaunias P, , Garcia-Monaco R, , Rodesch G, , Ter Brugge K, , Zerah M, & Tardieu M, et al.: Vein of Galen malformation. Endovascular management of 43 cases. Childs Nerv Syst 7:360367, 1991

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  • 13

    Lasjaunias P, , Hui F, , Zerah M, , Garcia-Monaco R, , Malherbe V, & Rodesch G, et al.: Cerebral arteriovenous malformations in children. Management of 179 consecutive cases and review of the literature. Childs Nerv Syst 11:6679, 1995

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  • 14

    Lasjaunias P, , Rodesch G, , Pruvost P, , Laroche FG, & Landrieu P: Treatment of vein of Galen aneurysmal malformation. J Neurosurg 70:746750, 1989

    • Search Google Scholar
    • Export Citation
  • 15

    Lasjaunias P, , Rodesch G, , Terbrugge K, , Pruvost P, , Devictor D, & Comoy J, et al.: Vein of Galen aneurysmal malformations: report of 36 cases managed between 1982 and 1988. Acta Neurochir (Wien) 99:2637, 1989

    • Search Google Scholar
    • Export Citation
  • 16

    Lasjaunias P, , Terbrugge K, , Piske R, , Lopez Ibor L, & Manelfe C: Dilatation de la veine de Galien. Formes anatomo-cliniques et traitement endovasculaire à propos de 14 cas explorés et/ou traités entre 1983 et 1986. Neurochirurgie 33:315333, 1987

    • Search Google Scholar
    • Export Citation
  • 17

    Long DM, , Seljeskog EL, , Chou SN, & French LA: Giant arteriovenous malformations of infancy and childhood. J Neurosurg 40:304312, 1974

  • 18

    Lylyk P, , Viñuela F, , Dion JE, , Duckwiler G, , Guglielmi G, & Peacock W, et al.: Therapeutic alternatives for vein of Galen vascular malformations. J Neurosurg 78:438445, 1993

    • Search Google Scholar
    • Export Citation
  • 19

    Maheut J, , Santini JJ, , Barthez MA, & Billard C: Symptomatologie cliniques de l’anevrysme de l’ampoule de Galien. Resultats d’une enquete nationale. Neurochirurgie 33:285290, 1987

    • Search Google Scholar
    • Export Citation
  • 20

    McLeod ME, , Creighton RE, & Humphreys RP: Anaesthetic management of arteriovenous malformations of the vein of Galen. Can Anaesth Soc J 29:307312, 1982

    • Search Google Scholar
    • Export Citation
  • 21

    Mickle AP, The transtorcular embolization of vein of Galen aneurysms and update on the use of this technique in twenty-four patients. Marlin AE: Concepts in Pediatric Neurosurgery Karger, Basel, 1991. Vol 11:6978

    • Search Google Scholar
    • Export Citation
  • 22

    Mitchell PJ, , Rosenfield JV, & Dargaville P: Endovascular management of vein of Galen aneurysmal malformations presenting in the neonatal period. AJNR Am J Neuroradiol 22:14031409, 2001

    • Search Google Scholar
    • Export Citation
  • 23

    Raybaud CA, , Strother CM, & Hald JK: Aneurysms of the vein of Galen: embryonic considerations and anatomical features relating to the pathogenesis of the malformation. Neuroradiology 31:109128, 1989

    • Search Google Scholar
    • Export Citation
  • 24

    Yas¸argil MG: Microneurosurgery Vol IIIB: AVM of the Brain, Clinical Considerations, General and Specific Operative Techniques, Surgical Results, Nonoperated Cases, Cavernous and Venous Angiomas, Neuroanesthesia New York, Thieme, 1994

    • Search Google Scholar
    • Export Citation
  • 25

    Yas¸argil MG, , Antic J, , Laciga R, , Jain KK, & Boone SC: Arteriovenous malformations of vein of Galen: microsurgical treatment. Surg Neurol 3:195200, 1976

    • Search Google Scholar
    • Export Citation

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