Multimodal treatment strategies for complex pediatric cerebral arteriovenous fistulas: contemporary case series at Barrow Neurological Institute

Paediatric intracranial dural arteriovenous fistulas: clinical characteristics, treatment outcomes and prognosis

BACKGROUND

Compared with dural arteriovenous fistulas (DAVFs) in adult, paediatric DAVFs are notable for distinct clinical manifestations, low cure rate and poor prognosis. However, due to the limitations of small sample sizes, the long-term prognosis and follow-up data have not been described.

METHODS

Clinical data from 43 consecutive paediatric DAVFs were documented and analysed between 2002 and 2022 at the author's institution. They were divided into infantile (Lasjaunias classification) and non-infantile (adult type and dural sinus malformation (DSM)) type DAVFs based on prognosis differences.

RESULTS

Their mean age at first symptoms was 8.4±6.0 years. 29 boys and 14 girls presented between at birth and 18 years of age. 5 of 10 patients ≤1 year of age presented with asymptomatic cardiomegaly compared with 5/33 patients >1 year of age (p=0.022). 42 (88.4%) patients received endovascular treatment alone, while 9.3% underwent radiosurgery, burr hole embolisation or surgery. 28 (65.1%) patients experienced DAVF obliteration by the end of treatment. Among them, 26 cases underwent embolisation alone, one case had embolisation in conjunction with surgery, and one case underwent burr hole embolisation. The overall complication rate among patients was 9.3%, all resulting from endovascular treatment. According to the Lasjaunias Classification, there were 18 cases of adult type, 17 cases of infantile type and 8 cases of DSM. Compared with non-infantile-type DAVFs, infantile-type DAVFs showed more times of treatment, lower cure rate and worse prognosis (p<0.001, 0.003 and 0.021, respectively). The average follow-up duration was 41.4±36.2 months (3-228 months). 8 (22.9%) patients died.

CONCLUSIONS

Most adult-type DAVFs and DSMs can now be effectively treated with embolisation, resulting in good outcomes and prognosis. However, there are still challenges in treating infantile-type DAVFs, and the prognosis is frequently poor.

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.

Characteristics and outcomes of pediatric dural arteriovenous fistulas: a systematic review

BACKGROUND

Dural arteriovenous fistulas (dAVF) are arteriovenous shunts in communication with the dural vasculature in the brain or spine. Apart from single-center series, risk factors and treatment outcomes for pediatric dAVFs are largely undescribed.

METHODS

We performed a systematic literature review of pediatric (< 18 years at diagnosis) intracranial and spinal dAVF according to PRISMA guidelines. We queried PubMed, CINAHL, SCOPUS, and Embase databases without time/date restriction. Search strings included a variety of MeSH keywords relating to dural AV fistulas in combination with MeSH keywords related to pediatric cases (see Appendix). Manuscripts describing patients diagnosed with dural sinus malformations or pial AVF were excluded.

RESULTS

We identified 61 studies describing 69 individual patients. Overall, dAVF were more common in males (55.1%) with a mean age of diagnosis (5.17 ± 4.42 years). Approximately 20.2% of patients presented with cardiovascular disease (CVD), and 31.9% were discovered incidentally on neuroimaging studies. Transverse-sigmoid junction was the most common location (17.3%). Ninety-three percent (64 patients) were treated, most commonly using endovascular embolization (68.1%) followed by surgery (8.7%) and radiosurgery (2.9%). Almost half (43.8%) of dAVFs were completely obliterated. Of the 64 procedures, there were 19 neurological complications (29.7%) of varying severity where 12.5% were considered transient (i.e., pseudomeningocele) and 17.2% permanent (i.e., mortality secondary to acute sinus thrombosis, etc.).

CONCLUSION

There is a paucity of information on pediatric dAVFs. This systematic review summarizes the published cases of dAVFs in the pediatric population. While the rate of missing data is high, there is publication bias, and precise details regarding complications are difficult to ascertain, this review serves as a descriptive summary of pediatric dAVFs.

Angioarchitecture and prognosis of pediatric intracranial pial arteriovenous fistula

OBJECTIVE

Pial arteriovenous fistulas (PAVFs) are rare and mostly observed in children. However, the overall angioarchitecture, clinical features, treatments and long-term prognosis for pediatric patients remain unclear.

METHODS

Clinical data of consecutive 42 pediatric PAVFs were documented and analysed. According to the differences of age distribution and clinical features, they were split into a younger group (≤3 years old; 20 cases) and an older group (3-14 years old; 22 cases).

RESULTS

Their mean age was 4.9±3.9 years, and the mean preoperative modified Rankin Scale (mRS) score was 1.64±1.57. Fourteen patients (33.3%) were asymptomatic, followed by epilepsy (21.4%), intracranial haemorrhage (16.7%), hydrocephalus (9.5%), developmental delay (7.1%), intermittent headache (7.1%) and congestive heart failure (4.8%). Annual bleeding rate and rebleeding rate before treatment reached 3.86% and 3.17%. Poor venous drainage including sinus dynamic obstruction (21 cases, 50.0%) and sinus occlusion (17 cases, 40.48%) were found with high frequency among these patients. Finally, 33 cases were cured (78.57%), and 4 cases faced surgery-related complications (9.52%). During 24-140 months' follow-up, the mean mRS score reduced to 0.57±0.40. However, only 22 cases (52.38%) recovered to absolutely normal, and poor venous drainage was the risk factor for patients' incomplete recovery (p=0.028, Exp(B)=14.692, 95% CI 1.346 to 160.392). Compared with the older group, younger group showed more chronic symptoms, more secondary pathological changes, more times treatment and worse prognosis (p=0.013, 0.002, 0.000 and 0.032, respectively).

CONCLUSIONS

Pediatric PAVF has different angioarchitectures, clinical features and prognoses in different age groups. Poor venous drainage is an important factor leading to poor prognosis, and it accounts for incomplete recovery in nearly half of patients.

Galenic Pial Arteriovenous Fistulas in Adults

BACKGROUND

Vein of Galen aneurysmal malformations (VOGMs) are pial arteriovenous fistulas possessing Galenic venous drainage most commonly presenting during the neonatal period and infancy, with initial discovery during adulthood quite rare.

OBJECTIVES AND METHODS

We conducted a literature survey of the PubMed database in order to identify Galenic pial arteriovenous fistulas (GPAVFs) with major manifestation or initial presentation during adulthood. Inclusionary criteria included pial AVFs with Galenic drainage with major manifestation or initial presentation at, or older than, 18 years. Exclusionary criteria included exclusive pediatric onset of symptomatology attributable to GPAVFs without a new onset major presentation during adulthood, exclusive or major dural arterial supply, arteriovenous malformations with Galenic drainage, developmental venous anomalies with Galenic drainage, isolated varices or anomalies of the vein of Galen, and any lesions with uncertainty regarding true GPAVF nature.

RESULTS

Our search generated 1589 articles. Excluding duplicates, 26 cases met criteria for evaluation. Mean age was 34.1 +/- 2.53 years. Clinical presentations of GPAVFs among adults included headache, intracranial hemorrhage, seizures, and focal neurologic deficits. Management strategies included observation (n = 5), emergent ventriculostomy or Torkildsen shunt (n = 3), cerebrospinal fluid diversion via ventriculoperitoneal shunting (n = 4), microsurgical obliteration or thrombectomy (n = 4), transarterial and/or transvenous embolotherapeutic obliteration (n = 7), and concurrent embolotherapy and radiosurgical irradiation (n = 1).

CONCLUSIONS

GPAVFs in adults often present with symptomatology of mild severity and may be effectively managed conservatively, though occasionally present catastrophically or may be treated via cerebrospinal fluid diversion, microsurgical obliteration, or endovascular embolization. Severity sufficient to require emergent intervention portended a poor outcome.

Endovascular embolization of dural arteriovenous fistula in a child presented with slight conjunctival hyperemia

BACKGROUND

Dural arteriovenous fistulas (DAVFs) are rare in pediatrics. A case of DAVF diagnosed because of a slight conjunctival hyperemia and endovascular coil embolization at 2 years old is reported.

CASE DESCRIPTION

The 2-year-old boy presented with a slight conjunctival hyperemia of the left eye for 1 month. Magnetic resonance imaging (MRI) examination of the head showed abnormal blood flow in the left middle cranial fossa. On digital subtraction angiography, a DAVF with a dural feeder shunt and a venous varix at the middle cranial fossa was confirmed. After transarterial coil embolization, shunt blood flow disappeared.

CONCLUSIONS

This report describes a case of DAVF with a slight conjunctival hyperemia treated by coil embolization in a child.

Mixed pial and dural arteriovenous fistula after craniotomy: case report and literature review

Dural arteriovenous fistula (AVF) is known to occur after craniotomy, but mixed pial and dural AVF after craniotomy has not been reported. A 45-year-old man who had undergone surgical clipping of an unruptured aneurysm 2 years previously presented with small subcortical hemorrhage from mixed pial and dural AVF. Surgical disconnection could not be cured completely due to the granulomatous tissue around the aneurysm, and the presence of an undetected shunt. Postoperative digital subtraction angiography showed a new pial AVF supplied by the middle cerebral artery pial branches. Many branches were associated with the remnant aneurysm and pial AVF, so we did not try to embolize the fistula. Gamma knife surgery was performed as adjuvant radiotherapy, which achieved angiographically complete occlusion of the shunt points. Multimodal approaches including surgery, endovascular intervention, and radiotherapy are needed for radiological and clinical cure of mixed pial and dural AVF. Long-term follow up is essential.

Hybrid Operating Room Settings for Treatment of Complex Dural Arteriovenous Fistulas

OBJECTIVE

Dural arteriovenous fistulas (dAVFs) are abnormal direct shunts between the occipital or meningeal artery and a meningeal vein or dural venous sinus. Treatment strategies include endovascular, microsurgical, stereotactic radiosurgical, or combined interventions. With few previous reports focused on dAVF treatment in a hybrid operating room (hOR), the authors reviewed their 6-year experience in this unique setting for these complex fistulas.

METHODS

Patients with complex cerebral dAVFs underwent endovascular and microsurgical treatment in the hOR. In this retrospective review, 8 consecutive patients with cerebral dAVFs (Borden type 2 or higher) underwent endovascular and microsurgical treatment. Demographic characteristics, symptoms related to the dAVF, preoperative angiographic features, preinterventional therapies, intraoperative digital subtraction angiography (iDSA), and postoperative clinical and radiologic findings were reviewed.

RESULTS

Of these 8 patients, 5 patients underwent multiple embolizations (up to 3) and hybrid procedures, with no procedure-related complications. After microsurgical resection, iDSA revealed remnants of the fistula, which was then immediately re-resected, in 2 patients. At closing of the hybrid procedure, iDSA revealed no fistula remnants in 7 patients (88%). At mean follow-up examination (58 months), 5 patients (62%) had cure of the dAVF, confirmed by noninvasive angiography. Two patients (25%) experienced a recurrence of the dAVF within 5 months.

CONCLUSIONS

Our hybrid techniques achieved high rates of dAVF obliteration, with all 8 patients achieving good or excellent outcomes and symptom relief. Angiographic follow-up within 6 months after the hybrid procedure is recommended for all patients even when intraoperative findings do not show remnants.

Clipping of a Pediatric Pial Arteriovenous Fistula Located at Basilar Artery Tip Using a Hybrid Trapping-Evacuation Technique

BACKGROUND

Intracranial pial arteriovenous fistulas (PAVFs) are rare cerebrovascular lesions with high mortality rates. We report a rare case of pediatric PAVF at the basilar artery tip and its treatment with surgical clipping aided by a trapping-evacuation technique in a hybrid operating room.

CASE DESCRIPTION

An 18-month-old boy was admitted with hypoevolutism and 4-month history of weakness in the left extremities. Magnetic resonance imaging showed a giant aneurysm-like malformation in the area of midbrain and pons. Angiography showed a high-flow PAVF fed by the basilar artery and bilateral P1 segments of the posterior cerebral artery, with deep draining veins into the transverse sinus and straight sinus. Given the intrinsic characteristics of the lesion, such as deep location, giant fistula and varix, and multiple feeding arteries, clipping of PAVF was performed in a hybrid operating room aided by a trapping-evacuation technique to clearly identify and block the shunting point.

CONCLUSIONS

The successful obliteration of the lesion is reported. In addition, a brief review of literature comparing endovascular embolization, surgical disconnection, and hybrid technique for treatment of PAVF is included.

Pediatric neurointervention: collimation on radiation exposure-associated lifetime excess tumor risk

Background

Intracranial vascular malformations in children are being addressed through a variety of treatment modalities including open surgery, external beam radiation, and image-guided neuroendovascular procedures. These patients often receive multiple treatments and incur serial exposures to ionizing radiation which has been linked to tumor development in population-based data.

Objective

This study quantifies the effect of collimation on exposures from single procedures and over patient lifetimes to estimate excess risk of lifetime tumor development.

Methods

215 patients aged 0–21 years from a single center took part in the study. Radiation exposure from neuroendovascular procedures was tabulated and converted to brain doses using modeled data and extrapolated to risk ratios using results of population-based estimates found in the literature.

Results

Lifetime and per procedure risk was highest in patients with brain arteriovenous malformations, brain arteriovenous fistulas, and vein of Galen malformations, a reflection of our institutional referral patterns. Across all pathologies the per procedure excess relative risk decreased from 13.4 to 2.3 when full collimation was employed. Lifetime excess relative risk decreased from 49.0 to 7.7 for full collimation.

Conclusions

This is the first study to quantify the effect of collimation on lifetime and per procedure risk of tumor development in a pediatric population. In addition to collimation, technical and operator-based aspects of the neurointerventional suite are discussed to further reduce patient exposure without sacrificing image quality.

Application of 4-Dimensional Digital Subtraction Angiography for Dural Arteriovenous Fistulas

BACKGROUND

Three-dimensional reconstruction of digital subtraction angiography (3D-DSA) is a useful imaging modality for assessing complex cerebrovascular lesions. However, due to the importance of flow over time in certain vascular lesions, 3D-DSA is of less value as it lacks the temporal resolution. Dural arteriovenous fistulas (AVFs) are complex lesions in which an arteriovenous shunt exists between meningeal arteries and a dural venous sinus or cortical vein. Traditional 2D-DSA, especially with superselective injections of feeding arteries, is currently the gold standard for assessment, but overlapping of opacified vessels can complicate interpretation. A novel imaging technique, 4D-DSA, merges 3D reconstructions of multiple temporal series. It offers a unique perspective on complex cerebrovascular lesions and may offer several advantages in the assessment of dural AVF.

METHODS

4D-DSA images were acquired in 5 patients who presented with dural AVFs. All relevant clinical data, imaging, and procedural/operative reports were reviewed retrospectively. 4D-DSA images were reconstructed on a separate 3D workstation and compared to 2D and 3D-DSA images in an offline fashion.

RESULTS

In all 5 cases, 4D-DSA proved to be useful in lesion assessment and treatment planning. This included observation (n = 2), microsurgery (n = 1), and endovascular embolization (n = 2).

CONCLUSIONS

In the small series of patients in which it has been evaluated, 4D-DSA offers several advantages in assessing dural AVFs. The ability to see and manipulate feeding arteries in 3D combined with temporal resolution was useful in assessment and treatment planning. Continued experience with this imaging technique will be needed to identify its optimal use.

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.

Rule of 5: angiographic diameters of cervicocerebral arteries in children and compatibility with adult neurointerventional devices

Background and purpose

The safety of using adult-sized neuroendovascular devices in the smaller pediatric vasculature is not known. In this study we measure vessel diameters in the cervical and cranial circulation in children to characterize when adult-approved devices might be compatible in children.

Methods

For 54 children without vasculopathy (mean age 9.5±4.9 years (range 0.02–17.8), 20F/34M) undergoing catheter angiography, the diameters of the large vessels in the cervical and cranial circulation (10 locations, 611 total measurements) were assessed by three radiologists. Mean±SD diameter was calculated for the following age groups: 0–6 months, 1, 2, 3, 4, 5–9, 10–14, and 15–18 years. To compare with adult sizes, each vessel measurement was normalized to the respective region mean diameter in the oldest age group (15–18 years). Normalized measurements were compared with age and fitted to a segmented regression.

Results

Vessel diameters increased rapidly from 0 to 5 years of age (slope=0.069/year) but changed minimally beyond that (slope=0.005/year) (R2=0.2). The regression model calculated that, at 5 years of age, vessels would be 94% of the diameter of the oldest age group (compared with 59% at birth). In addition, most vessels in children under 5, while smaller, were still potentially large enough to be compatible with many adult devices.

Conclusions

The growth curve of the cervicocerebral vasculature displays rapid growth until age 5, at which point most children's vessels are nearly adult size. By age 5, most neuroendovascular devices are size-compatible, including thrombectomy devices for stroke. Under 5 years of age, some devices might still be compatible.