INTRODUCTION
Traditionally, the femoral artery approach is the primary option for neuroendovascular procedures in pediatric patients. However, certain pathologies require multiple sessions of endovascular intervention [1,2].
In such cases, alternative access sites are essential, including catheterization of the umbilical artery during or transitioning from venous to arterial territory via a patent foramen ovale [2,3]. Additionally, more cranial puncture sites, such as direct carotid artery and transverse sinus puncture, have been described [4,5]. It is important to note that each access site presents specific complications and challenges [6].
To the best of our knowledge, this is the first report on using axillary arterial access for neuroendovascular intervention in an infant. Additionally, we conducted a literature review on vascular access routes for pediatric patients.
CASE REPORT
A male neonate was born at 36 weeks and 3 days gestational age, 3,145 grams, via vaginal delivery (Apgar 8 and 9). The pregnancy was complicated by maternal pre-eclampsia and an eclamptic seizure on the day of delivery. The patient developed heart failure, and an echocardiogram revealed holodiastolic flow reversal in the distal aortic arch. A head ultrasound showed a mass-like structure, raising concern for a vein of Galen malformation (VGM), with MRI confirming the diagnosis (Fig. 1). The Bicêtre Score was 14.
Digital subtraction angiography confirmed a mural VGM with feeders originating from the bilateral posterior cerebral and pericallosal arteries. The straight sinus was absent, and a residual prosencephalic vein was observed.
The first endovascular treatment was prompted by worsening heart failure. Under general anesthesia, embolization was performed via ultrasound-guided right femoral artery access using a 4F sheath (Terumo). A 4F glide catheter (Terumo) and Aristotle 14G guidewire (Scientia Vascular) were used to reach the left internal carotid, and a Duo microcatheter (Terumo Neuro) over a Synchro microwire (Stryker Neurovascular) catheterized the anterior choroidal artery feeders. Onyx 18 and coils were delivered to embolize the VGM. Stasis was achieved in the prosencephalic vein, though posterior choroidal feeders remained. Post-procedure CT showed no acute issues, and the patient’s neuro exam was stable. Femoral access was closed with manual compression, and the patient was extubated and moved to the Intensive Care Unit (ICU).
Follow-up imaging showed VGM enlargement. A second embolization was attempted but aborted due to failed femoral access, despite ultrasound guidance; Doppler confirmed intact femoral pulses afterward. The infant’s condition stabilized, VGM size remained stable, and he was discharged with plans for elective embolization at 6 months. Later outpatient visits revealed worsening ventriculomegaly and a new Chiari malformation.
At readmission, a new embolization attempt was unsuccessful due to failure of ultrasonography-guided femoral artery access. Cerebral imaging was performed via venous access, but no intervention was carried out. In the Pediatric ICU (PICU), we placed an axillary arterial line under ultrasound guidance for future endovascular procedure.
Operative Technique
The patient was intubated, sedated, and positioned supine. The procedure began with prepping and draping the right axillary artery access in a sterile manner, followed by the placement of a 4F sheath directly through the axillary artery access, which had been established in the PICU. A Duo microcatheter was then navigated over a Synchro microwire, advancing from the subclavian artery into the right vertebral artery, basilar artery, and the left posterior cerebral artery pedicle, targeting the VGM. Onyx 18 was used to occlude the arterial feeders and the nidus of the VGM (Supplementary Video 1). Post-embolization angiography and Dyna CT imaging were conducted to assess residual filling and potential intracranial hemorrhage. These confirmed successful occlusion with minimal residual VGM filling and no evidence of hemorrhage (Fig. 1). Following the procedure, manual pressure was held on the right axillary artery, and the skin was sutured. Neurological exam and vital signs remained stable throughout the procedure.
Outcome and Follow-Up
In Neurocritical Care Unit, the patient had ventriculomegaly worsening and underwent endoscopic third ventriculostomy. He did not have axillary artery puncture-related complications. He had cardiovascular improvement and was discharged. At his 4-month post-second embolization follow-up visit, he was recovering well, with good limb perfusion and no puncture-related complications. We planned to have monthly outpatient visits.
DISCUSSION
Our patient was diagnosed with a VGM, a congenital arteriovenous (AV) malformation involving the choroid plexus. Normally, the median prosencephalic vein (MPV) regresses during development, while its distal portion forms the vein of Galen. In VGM, abnormal fetal connections between choroidal arteries and the MPV persist, causing dilation and preventing normal regression. This can lead to symptoms ranging from none to severe, including high-output heart failure and “melting brain syndrome.” [7-9]
In pediatric neuroendovascular procedures, the transfemoral arterial approach is preferred; however, reduced aortic flow can limit the feasibility in neonates with large AV shunts. While possible in infants over 2.7 kg, the risk of arterial occlusion remains significant, and in those under 2.2 kg, femoral access is anatomically impractical [3,10]. When femoral access is not feasible, the transumbilical artery approach may be used, especially in neonates under 2.0 kg. Although viable up to 4 days after birth, early catheterization is recommended, and access beyond 10 days is discouraged due to infection risk [1,11]. Transradial cerebral angiography has shown feasibility in infants (median age 24 days; weight 4.2 kg), though limited by rare interventional use [1]. Direct carotid puncture offers another option, often preferred due to the larger caliber of the common carotid artery in infants with AV shunts [3,12]. Under general anesthesia, ultrasound-guided puncture with an 18G–21G needle is performed with fluoroscopic confirmation, but access provides only ipsilateral navigation [1,13]. Pure venous access routes are used for transvenous embolization (TVE), though not first-line due to hemorrhagic risk; TVE may be considered for persistent shunting after multiple transarterial embolization (TAE) attempts [14-16]. Venous pathways may also reach both sides of the shunt via fetal structures like the foramen ovale and ductus arteriosus [1,17]. The transcardiac approach accesses the left atrium via a patent foramen ovale, using balloon septal dilation and a 4F catheter to reach cerebral arteries [1,17]. The trans-ductus arteriosus route can access the descending aorta but carries risks of ductal closure and technical challenges from retrograde flow [1]. Neurosurgical techniques have included transtorcular puncture, first described in 1986, though complications such as bithalamic hemorrhages occurred with abrupt occlusion of high-flow VGMs [5,18]. More recently, Rangwala et al. [5] reported using direct transverse sinus puncture via a combined surgical-endovascular method when standard venous access failed, citing enhanced safety and control with stereotactic guidance and 3D coils (pediatric endovascular embolization accesses described in Table 1 [1,4,5,9,11,14,18,19]).
In our case, after multiple failed attempts to cannulate the femoral artery, we no longer had access to the umbilical artery [19], nor was there a patent foramen ovale. Therefore, identifying a new arterial access site was necessary to deliver treatment. The rationale for the axillary access was that this is a relatively superficial and large artery in children, which we could use to accommodate bigger catheters. Besides, we considered using a more distal approach before going for direct carotid puncture, because a new endovascular intervention could be required, and more proximal approaches could be explored if necessary. However, it is worth considering the potential drawbacks of this technique, such as the risk of brachial plexus injury, challenges with hemostasis due to arm mobility, or difficulties in compression.
This study presented a single case report of a new axillary arterial access for neuroendovascular intervention in a pediatric patient with VGM and challenging bilateral femoral access, which inherently limits the generalizability of the findings, such as where axillary access fits into the broader spectrum of pediatric neurointerventional strategies. However, this case provides insights into an alternative arterial access site for TAE in pediatric patients who need intervention, with the possibility of losing the puncture vessel sites. Besides, the precise site for puncture will depend on the anatomic aspects of the patient and how comfortable the team is with each approach. Further studies with larger sample sizes and long-term follow-up are needed to validate the safety and efficacy of the proposed arterial access site in different patient groups.
In this paper, we illustrated the axillary artery as a novel arterial site access for endovascular embolization of a VGM in a pediatric patient, which may be an alternative for similar challenging cases.
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