Pial arteriovenous fistulas: dilemmas in prenatal diagnosis, counseling and postnatal treatment. Report of three cases

Pediatric non-galenic pial arteriovenous fistula's characteristics and outcomes: a systematic review

INTRODUCTION

Pediatric non-galenic pial arteriovenous fistulas (pAVFs) are rare vascular malformations that are characterized by a pial arterial-venous connection without an intervening capillary bed. Outcomes and treatment strategies for pAVFs are highly individualized, owing to the rarity of the disease and lack of large-scale data guiding optimal treatment approaches.

METHODS

We performed a systematic review of pediatric patients (< 18 years at diagnosis) diagnosed with a pAVF by digital subtraction angiogram (DSA). The demographics, treatment modalities, and outcomes were documented for each patient and clinical outcome data was collected. Descriptive information stratified by outcome scores were classified as follows: 1 = excellent (no deficit and full premorbid activity), 2 = good (mild deficit and full premorbid activity), 3 = fair (moderate deficit and impaired activity), 4 = poor (severe deficit and dependent on others), 5 = death.

RESULTS

A total of 87 studies involving 231 patients were identified. Median age at diagnosis was 3 years (neonates to 18 years). There was slight male preponderance (55.4%), and 150 subjects (81.1%*) experienced excellent outcomes after treatment. Of the 189 patients treated using endovascular approaches, 80.3% experienced excellent outcomes and of the 15 patients surgically treated subjects 75% had an excellent outcome. The highest rate of excellent outcomes was achieved in patients treated with Onyx (95.2%) and other forms of EvOH (100%). High output heart failure and comorbid vascular lesions tended to result in worse outcomes, with only 54.2% and 68% of subjects experiencing an excellent outcome, respectively. *Outcomes were reported in only 185 patients.

CONCLUSION

pAVFs are rare lesions, necessitating aggregation of patient data to inform natural history and optimal treatment strategies. This review summarizes the current literature on pAVF in children, where children presenting with heart failure as a result of high flow through the lesion were less likely to experience an excellent outcome. Prospective, large-scale studies would further characterize pediatric pAVFs and enable quantitative analysis of outcomes to inform best treatment practices.

Use of greyscale and Doppler ultrasound in initial evaluation and follow-up of neurovascular malformations in children

Pediatric intracranial arteriovenous shunts are rare vascular malformations that can be diagnosed prenatally or postnatally, as an incidental finding or due to complications. We propose a review of cerebral vascular malformations in newborns and infants with special emphasis on neurosonography and Doppler ultrasound as the first diagnostic method. Sonography can thus contribute in the planning of further studies that are always necessary, and in post-therapy follow-up.

Fetal brain MR angiography at 1.5 T: a feasible study

PURPOSE

The use of magnetic resonance angiography (MRA) for assessing CNS fetal vasculature has been limited. The aim of this study was to determine the feasibility and added value of 2D time-of-flight (TOF) MRA of the fetal brain vasculature with a 1.5 T scanner.

METHODS

We conducted a prospective study (September 2018 to October 2022) by consecutively selecting pregnant women (≥ 18 years) with clinical indication to fetal brain MRI. On a 1.5 T scanner, a 2D TOF MRA acquisition was obtained at the end of the clinical protocol. Two neuroradiologists independently reviewed all MRIs; a qualitative scale of motion artifacts was applied to MRA images; represented vessels in MRA and T2 images were registered.

RESULTS

Thirty-five fetal brain MRIs. Mean maternal age: 32 years; mean fetal gestational age (GA): 31 weeks. Artifacts were found in 74% of MRA. The number of MRAs performed without artifacts increased with GA. On MRA, the identification of the majority of vessels increased with GA; statistical significance was reached in the identification of torcular Herophili (p = 0.026), vein of Galen (p < 0.001), internal cerebral veins (p = 0.002), basilar artery (p = 0.027), vertebral arteries (p = 0.025), and middle cerebral arteries (p = 0.044). Significantly, MRA depicted the sigmoid sinuses and internal jugular veins more frequently. Vascular pathology was found in 3/35 fetal brain MRIs.

CONCLUSION

Although artifacts were found in 74% of cases, MRA acquisitions were informative and of sufficient diagnostic quality in most studies. This technique may represent a valuable complimentary tool in CNS prenatal vascular studies.

Endovascular treatment of dural arteriovenous fistulas involving the vein of Galen: a single-center cohort and meta-analysis

BACKGROUND

Dural arteriovenous fistulas (dAVFs) draining into the vein of Galen (VoG) are complex lesions that often necessitate treatment to minimize the risk of rupture and relieve symptoms. These lesions can be treated with open surgical resection, radiosurgery, or endovascular embolization. Unfortunately, endovascular treatment of dAVFs involving the VoG has not been robustly assessed across large patient cohorts. To meet this need, we performed a retrospective review of dAVFs involving the VoG at our center, and included these in a meta-analysis to identify the safety and efficacy of endovascular embolization, as well as describing current treatment trends for this disease.

METHODS

Consecutive patients with dAVFs involving the VoG treated at a single center were identified from a prospective database and retrospectively reviewed. A literature search was conducted with defined search criteria, and eligible studies were included alongside our cohort in a meta-analysis. Rates of complete dAVF treatment and clinical complications were pooled across studies with a random effects model and reported with a 95% CI.

RESULTS

Five dAVFs involving the VoG were treated endovascularly at our center during the study period. In this series, 80% of treatments led to complete occlusion of the fistula while no patients had clinical complications. Onyx was used for all treatments. In our meta-analysis, the overall rate of complete occlusion was 72.0% (95% CI 59.8% to 84.1%) and the overall rate of clinical complications was 10.0% (95% CI 4.7% to 15.3%).

CONCLUSIONS

Endovascular approaches for dAVFs involving the VoG are technically feasible, but carry a risk of clinical complications. Future work should identify optimal endovascular embolic agents.

Neonatal bilateral cerebral high flow fistulae leading to detection of a HHT-family carrier

Cerebral and spinal cord high-flow arteriovenous fistulae (HFAVF) are part of the spectrum of lesions found in Hereditary Hemorrhagic Telangiectasia (HHT). HFAVF consist of communications between large arteries and veins without interposed nidi or capillary transitions. The association between HHT and cerebral or spinal HFAVF in children has been reported and suggested as a potential marker for HHT. We present a newborn with bilateral intracranial HFAVF tested positive for HHT1 and belonging to a family non known for carrying a HHT mutation. We also review reported cases of neonates and infants with cerebral and spinal HFAVF emphasizing their associations with genetic syndromes. Our aim is to add a new case to the pertinent literature and emphasize the need for molecular testing in children with spinal or brain HFAVF.

Neurovascular disease and syndromes: Diagnosis and therapy in children

The pediatric neurovascular disease runs the chronologic spectrum with dramatic changes in the presentation, evaluation, and treatment from the prenatal, perinatal, and infant periods through childhood and adolescence. These diseases are often dynamic throughout this period and the dynamic continues throughout life. There are four major categories: high-flow arteriovenous shunting lesions, arterial aneurysms, low-flow vascular lesions, and vascular occlusive disease. The high-flow lesions can be subdivided into a vein of Galen malformation, non-Galenic arteriovenous fistula, dural sinus malformations and fistula, and arteriovenous malformation. Low-flow vascular lesions include cerebral cavernous malformation, developmental venous anomaly, and capillary telangiectasia. The cerebrovascular occlusive disease can be divided between arterial occlusive disease and cerebral venous sinus thrombosis. The presentation of each of these entities can be very similar, especially in younger children; however, imaging and laboratory analysis can establish the diagnosis leading to the most appropriate therapy. A multidisciplinary team, dedicated to treating pediatric cerebrovascular disease, is important in delivering the best outcomes in these complex diseases. Given the relative rarity of pediatric presentation of cerebrovascular disease, many apply adult concepts to children. A better understanding of the diseases and their difference from adults makes a critical difference in selecting the correct approach.

Hemorrhagic Cerebrovascular Pathology in the Pediatric Population

Hemorrhagic cerebrovascular disease in the pediatric population can have devastating and long-term effects. Progress in the fields of genetics, neuroimaging, pharmacology, and surgical techniques has led to improved diagnosis and management of pediatric cerebrovascular diseases. In this review we discuss the current etiologies and medical and surgical treatments of hemorrhagic cerebrovascular pathology affecting infants and children. A special emphasis is placed on neuroendovascular treatment options. Increased knowledge about this unique pathology and the medical and therapeutic options will empower practitioners to more quickly and accurately identify and accurately treat hemorrhagic diseases in the pediatric population.

Long-term outcome of vein of Galen malformation

AIM

To describe the long-term outcomes of children by the time they reached school age with vein of Galen aneurysmal malformation (VGAM).

METHOD

This was a retrospective observational study on a consecutive cohort of patients with VGAM. We included patients with at least one Francophone parent, aged between 6 and 11 years at the time of long-term evaluation. The neurological outcome was assessed with the King's Outcome Scale for Childhood Injury score and eight neurological and behavioural items from the Rivermead Postconcussion Symptoms questionnaire.

RESULTS

All 52 patients (17 females, 32 males [data missing for n=3]) with at least one Francophone parent (5 fetuses and 47 children) were included. At the long-term evaluation time-point, 33 patients were alive and 19 patients had died. Risk of postnatal death was associated with severe neonatal cardiac failure (p=0.007) or isosystemic or suprasystemic pulmonary hypertension (p=0.014). Among survivors, 19 had a good outcome with normal schooling and 14 had a poor outcome. Moreover, among the good outcome patients, a large proportion had neurodevelopmental alterations.

INTERPRETATION

Long-term outcome of patients with VGAM appears to be less favourable than outcome described at the short- and medium-term, even in the absence of encephalomalacia at birth. Even patients with good outcome often have neuropsychological disorders that may have repercussions on learning and requiring appropriate rehabilitation or medical management.

WHAT THIS PAPER ADDS

Long-term outcome appears to be less favourable than described at short- and medium-term follow-up. Even patients with good outcome at these time-points often have minor neuropsychological disorders.

Endovascular Management of Intracranial Pial Arteriovenous Fistulas: Experience of Largest Series at a Single Center Over Six Years

Introduction:

Intracranial pial fistulas are an extremely uncommon type of vascular pathology consisting of one or multiple arterial connections to a single venous drainage channel without the presence of an intervening nidus. Due to its typical location and high-flow dynamics, its management is difficult and options include endovascular treatment and open surgical treatment. The arterial supply of these lesions is usually derived from pial or cortical vessels, and commonly such lesions are not localized in the dura mater.

Materials and Methods:

Authors report the experience of consecutive ten cases managed at the Instituto Nacional de Neurología y Neurocirugía “Manuel Velasco Suárez” of México extending from 2007 to 2012 with endovascular technique, constituting one of the largest series in the Western literature.

Discussion:

Pial fistulas are associated with a poor natural history, and the selection of individualized therapeutic strategies can provide good outcomes.

Conclusion:

The neuroendovascular intervention is currently considered as safe, low cost, and effective management modality for such lesions.

Congenital pial AVF along the falx cerebri with complete agenesis of the corpus callosum and bilateral parasagittal pachygyria-polymicrogyria secondary to chronic ischemia

OBJECTIVE

Pial arteriovenous fistula (AVF) is an extremely rare entity due to direct arterial connection with the venous plexus without an intervening capillary network. The objective of this article is to describe a unique case of congenital pial AVF along the interhemispheric falx with complete callosal agenesis and malformation of cortical development within the bilateral anterior cerebral artery territories. We also demonstrated the distinctive feature of temporal stability of the extensive intracranial abnormalities without active intervention. Less than 100 cases have been reported thus far, most of which involve the adult rather than pediatric age group. A comprehensive literature review of congenital pial AVF will also be included.

CASE DESCRIPTION

A 5-year-old child presented with headache and complex partial seizures. Imaging of the brain revealed the presence of polymicrogyria-pachygyria in the parasagittal frontoparietal lobes with associated underlying white matter hypodensities. Complete agenesis of the corpus callosum was also seen. In addition, enlarged and tortuous vessels were noted along the interhemispheric falx with no appreciable nidus. Bilateral dilated and tortuous ACAs were seen supplying the network of abnormal vessels along the falx. The radiological findings were stable on a follow-up MRI 12 years later.

CONCLUSION

Our reported case adds to current limited knowledge of this rare entity in the pediatric age group, which is traditionally treated aggressively and urgently. Our case demonstrated temporal stability of this lesion with no detrimental complications observed. This suggests that the outcome of pial AVFs with conservative treatment may not be as grim as previously thought.

Nongalenic pial arteriovenous fistula: Prenatal diagnosis

Pial arteriovenous (AV) fistulae have rarely been diagnosed in utero. They are characterized by one or more pial arteries flowing directly into a cortical vein without any shunt or interposed capillary bed. In the fetus and the newborn up to 2 years of age, the most common clinical manifestation is heart failure resulting from fistula overload. Later on, hydrocephalus, focal neurologic deficits, headaches, seizures, and cerebral hemorrhage are the most common manifestations. We present a case of nongalenic pial AV fistula diagnosed in the 25th week of pregnancy, which resulted in intrauterine fetal death due to congestive heart failure. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:621-625, 2017.

Prenatal Diagnosis and Multimodal Neonatal Treatment of a Rare Pial Arteriovenous Fistula: Case Report and Review of the Literature

BACKGROUND

Intracranial pial arteriovenous fistulas (PAVFs) are direct communications between the arterial and venous system of the brain, with the characteristic absence of a plexiform nidus, as seen in the classic cerebral arteriovenous malformations. These vascular malformations, usually occurring in the pediatric population, very rarely are diagnosed in utero, because of a lack of understanding of the condition and because they may be hard to visualize.

CASE DESCRIPTION

We report a rare case of a mass-effect PAVF diagnosed with fetal magnetic resonance imaging, involving the right cerebral hemisphere, fed by a pericallosal artery and associated with a giant venous dilatation. The PAVF initially was managed by the endovascular embolization. The recruitment of a middle cerebral artery feeder and the rapidly enlarging size of the venous pouch with mass effect required subsequent surgery.

CONCLUSIONS

The 2-stage multimodal treatment resulted in complete disappearance of the PAVF without complications.

Intracranial non-galenic pial arteriovenous fistula: A review of the literature

An intracranial non-galenic pial arteriovenous fistula (NGPAVF) is a direct connection between the intracranial artery and vein without a nidus. NGPAVFs are clinically rare, and the current understanding of NGPAVFs is limited. This study searched PubMed for the currently available literature, and a review of the relevant publications revealed that NGPAVFs require aggressive treatment, spontaneous occlusion is uncommon, and the prognosis following conservative treatment is poor. NGPAVFs can be divided into congenital and traumatic (including iatrogenic) types. Clinically, NGPAVFs are characterized by congestive heart failure, epilepsy, hemorrhage, mass effects, and nerve function deficits. For the imaging examination of NGPAVFs, digital subtraction angiography (DSA) is still the gold standard for diagnosis, although magnetic resonance DSA (MRDSA) and 4D computed tomography angiography (CTA) can also provide hemodynamic data in a non-invasive manner. Current treatments for NGPAVFs include surgical resection and endovascular embolization, both of which can yield clinical improvements. However, potential postoperative complications should be addressed, such as fatal bleeding due to rupture and deep vein thrombosis. Some studies recommend postoperative anticoagulation to reduce postoperative thrombotic complications.

A case of two pial arteriovenous fistulas with giant venous pouches treated by endovascular coil embolization: Therapy with and without anticoagulation

BACKGROUND

Endovascular coil embolization of pial arteriovenous fistulas (AVF) has been reported as an effective treatment. However, venous thrombosis and intracranial hemorrhage developing after endovascular occlusion of a pial AVF have not been adequately reported.

CASE DESCRIPTION

A 37-year-old man presented with left middle cerebral artery (MCA) AVF and right posterior cerebral artery (PCA) AVF with giant venous pouches. Staged endovascular coil embolization was performed. The MCA AVF was completely occluded by coils at the first stage. Intravenous heparin (3000 IU) was administered during the procedure, and then low molecular weight heparin (subcutaneous injection, 0.4 mL/12 hours) was administered for two days. The PCA AVF was near completely occluded by coils without anticoagulation therapy at the second stage. Rapid progressive venous thrombosis and intracranial hemorrhage were confirmed by computerized tomography brain scan postoperatively, and the patient was then transferred to the neurological intensive care unit for further treatment. Finally, the patient recovered well at the five-month follow-up.

CONCLUSIONS

Endovascular occlusion of a high-flow pial AVF with a giant venous pouch resulting in significant blood stasis could precipitate thrombosis in the venous system. Further studies are required to establish whether anticoagulation therapy is necessary.

Intracranial pial arteriovenous fistula in infancy: a case report and literature review

Intracranial pial arteriovenous fistulas (AVF) are rare vascular malformation especially in the first 2 years of life. The pathology in this age group is associated with greater morbidity and mortality. We report a rare case of 36-day-old male infant with a pial AVF associated with an arterial aneurysm, who presented with intraventricular hemorrhage and hydrocephalus. In addition, an online review of the literatures on pediatric pial AVF was performed using PubMed on published case reports and articles from 1980 to April 2013.

Aneurysm of the vein of galen diagnosed with MRI

We describe the case of a neonate with aneurysm of vein of Galen that was diagnosed prenatally in the 33rd gestational week by MRI. A 27-year-old woman, gravida 2, para 2, was admitted to our department at 33 weeks of gestation with suspected fetal hydrocephaly. Ultrasound examination after admission demonstrated an anechoic, supratentorial, and median mass with regular borders, raising the possible diagnosis of an aneurysm of the vein of Galen. MRI confirmed the presence of an aneurysm of the vein of Galen. An elective caesarean section was performed at 33 weeks of gestation. The newborn was admitted to the Neonatal Intensive Care Unit. Despite the full respiratory and medical support given, the sustainment of cardiac failure resulted in neonatal death just one day following its admission.

[Prenatal diagnosis of cerebral tumors and differential diagnosis]

Fetal brain tumors are rare and have different histologies. Although the definitive diagnosis relies on the histopathology of the tumor, it is useful to distinguish the tumors potentially curable from the tumors rapidly fatal after birth. Nevertheless, some intracranial masses are not tumors. We report four cases of intracerebral masses diagnosed prenatally corresponding to different histological lesions: teratoma, fetus-in-fetu, chraniopharyngioma, hemangioma. We discuss the elements of the differential diagnosis, which can be identified prenatally.

Vascular malformations of the brain

Pediatric neurovascular malformations are rare. However, proper diagnosis and management are mandatory to achieve a good neurocognitive outcome. Among them several types can be identified with specificities for each. In the newborn and infancy, the most frequent cerebral venous malformation is vein of Galen aneurysmal malformation. It can be discovered antenatally, in neonates (mainly in cases with hemodynamic impact), or in infants presenting with macrocrania and hydrocephalus. Treatment of choice is endovascular, by transarterial selective occlusion of pathological vessels. Interventions are staged with a first session at around 5 months, adjusted to neurological development. Late consequences, especially if left untreated or treated outside the therapeutic window, are delayed neurocognitive development and seizures. Pial arteriovenous malformation can also be diagnosed antenatally. Regional parenchymal destruction could occur in the first months of life, requiring early endovascular treatment. Dural sinus malformations are the third main type of neurovascular malformation, and are also diagnosed antenatally or in the first months of life. Cardiac tolerance is usually good. Adverse consequences are mainly neurocognitive delay due to chronic venous hyperpressure or acute hemorrhage due to thrombosis of the pathological sinuses. Nidal-type brain arteriovenous malformation and cavernous angioma are usually seen later in children, with hemorrhage often being the first presenting symptom.

High-output heart failure in a newborn

High-output cardiac failure is rare in newborns. Emergent diagnosis and management of this pathology is crucial. We report the case of a child, currently 12-months old; obstetric background is non-contributory. Clinic observation on D1 was normal except for the presence of a systolic cardiac murmur; cardiological evaluation revealed mild ventricular dysfunction of the right ventricle. On the third day of life, she developed cardiac failure with gallop rhythm, hepatomegaly and a murmur in the anterior fontanel; an echocardiogram confirmed clinic aggravation with biventricular dysfunction and right cavities and superior vena cava dilatation. The cranial MRI confirmed the presence of a pial arteriovenous malformation (AVM) involving the anterior and middle cerebral arteries with an associated fronto-parietal ischaemic lesion. The infant underwent embolisations of AVM with successful flow reduction and cardiac failure improvement. The multidisciplinary follow-up showed no cardiac dysfunction or permanent lesions but confirmed a severe psycho-motor delay and left hemiparesia.

Endovascular treatment of a pial arteriovenous fistula with occipital remodeling secondary to giant torcular dilation

Intracranial arteriovenous fistulas are vascular malformations in which clinical suspicion and prompt diagnosis, with a subsequent appropriate therapeutic approach, are crucial to avoid the development of irreversible neurological damage or even patient death because these lesions can be associated with heavy bleeding and high mortality rates. The authors present the case of a direct pial arteriovenous fistula in an infant and its unusual presentation as a large occipital protuberance with hard consistency and an audible murmur that produced bone remodeling. The patient was successfully treated by endovascular therapy, with complete regression of the occipital protuberance during follow-up.

Prenatal ultrasonographic diagnosis of vein of Galen aneurysms--report of two cases

Aneurysms of the vein of Galen (AVG) represent less than 1% of all intracranial arteriovenous malformations. Two cases of prenatal diagnosis made by color Doppler ultrasonography at 32 weeks of gestation are reported. Both cases presented with antenatal mild cardiomegaly and both developed severe cardiac failure in the neonatal period. Embolization was unsuccessful and both infants died. These cases highlight the need for a careful evaluation of the time and mode of delivery; embolization must be performed after a fully informed decision.

Prenatal MRI Diagnosis of Vein of Galen Malformation

This is a short comment on the article by Y. Iizuka et Al “Anatomical subcategorization for pediatric Vein of Galen aneurysmal dilatation” (The Neuroradiology Journal 2007, 20: 551–561).

Fetal MR Imaging

Ultrasonography is the primary prenatal screening modality used in the evaluation of the fetus and the maternal pelvis. However, fetal MR imaging plays a complementary role to prenatal ultrasound in the evaluation of the fetus with suspected abnormalities. MR imaging's role includes confirming or excluding possible lesions, defining their full extent, aiding in their characterization, and demonstrating other associated abnormalities. As newer techniques such as diffusion imaging, MR spectroscopy, and functional studies are used more widely, it is hoped that additional information will be made available by this modality to physicians evaluating and taking care of fetuses.