41 Endovascular Thrombectomy for Pediatric Acute Ischemic Stroke
41.1 Case Description
41.1.1 Clinical Presentation
A 14-year-old female patient presented to the pediatric emergency department with quadriparesis, obtundation, and dysconjugate eye movements.
41.1.2 Imaging Workup and Investigations
Noncontrast CT (NCCT) of the head (Fig. 41.1a) demonstrated a “hyperdense” basilar artery sign, representing an acute thromboembolic occlusion of the basilar artery. Low-attenuation changes, representing evolving perforator infarcts, were seen in the pons (Fig. 41.1b), with no abnormalities in the remaining posterior fossa parenchyma, thalami, or the occipital lobes bilaterally.
CT angiography arch to vertex demonstrated a right cervical rib and associated thrombosed pseudoaneurysm of the right subclavian artery (Fig. 41.2a), with digital subtraction angiography confirming the basilar artery thrombosis, as predicted by unenhanced CT (Fig. 41.2b).
Fig. 41.1 Noncontrast CT of the head (a) demonstrated a “hyperdense” basilar artery sign, representing an acute thromboembolic occlusion of the basilar artery. Low-attenuation changes, representing evolving perforator infarcts, were seen in the pons (b), with no abnormalities in the remaining posterior fossa parenchyma, thalami, or the occipital lobes bilaterally. 
Fig. 41.2 CT angiography arch to vertex demonstrated a right cervical rib and associated thrombosed pseudoaneurysm of the right subclavian artery (a), with digital subtraction angiography confirming the basilar artery thrombosis, as predicted by unenhanced CT (b).
41.2 Diagnosis
Acute basilar artery thromboembolic occlusion due to a right subclavian thrombosed pseudoaneurysm that was believed to be a result of repetitive traumatic injuries due to an adjacent right cervical rib.
41.2.1 Treatment
As the pediatric hospital had no expertise in pediatric stroke intervention, the patient was transferred to an adult tertiary care hospital where emergency mechanical thrombectomy was performed by the adult interventional neuroradiology service.
Materials
5-Fr Micropuncture kit.
6-Fr 90-cm Neuron Max 0.088-in guide sheath (Penumbra, Alameda, CA).
Berenstein Select catheter (Penumbra).
Rotating Tuohy Borst Hemostatic valve (Merit Medical, South Jordan, UT).
ACE 60 aspiration catheter (Penumbra).
Velocity microcatheter (Penumbra).
Fathom 16 microwire (Boston Scientific, Fremont, CA).
Vascular closure device (6-Fr Angio-Seal, Terumo Medical, Somerset, NJ).
Technique
Endotracheal intubation and general anesthesia support of the patient was provided on an emergent basis by the adult anesthesia department due to the impaired level of consciousness of the patient.
Percutaneous ultrasound (US)-guided access to the right common femoral artery (CFA) was achieved using a 5-Fr micropuncture kit, with placement of a 5-Fr vascular sheath.
After placement of an Amplatz Extra Stiff guidewire in the abdominal aorta, the 5-Fr sheath was removed, with subsequent advancement of a 6-Fr Neuro Max guide sheath (over its dilator), with the guide sheath serving as the primary access sheath.
As the right vertebral artery was the dominant vessel of the posterior circulation, using a Berenstein Select catheter and Terumo guidewire, the Neuron Max guide sheath was positioned in the right subclavian artery, proximal to the right vertebral artery origin.
With the Select catheter removed, the detachable sheath valve was replaced with a Tuohy Borst rotating hemostatic valve, with the guide sheath placed on continuous flush, and side-arm access provided for performing angiography.
Control angiography confirmed the proximal basilar artery occlusion (Fig. 41.3a). A coaxial system of an ACE 60 aspiration catheter and a Velocity microcatheter was advanced over a Fathom 16 guidewire to the level of the basilar artery occlusion.
After one pass of aspiration, there was complete recanalization of the basilar artery (thrombolysis in cerebral artery 3) with no distal emboli (Fig. 41.3b).
Fig. 41.3 Control angiography confirmed the proximal basilar artery occlusion (a). After one passage of aspiration, there was complete recanalization of the basilar artery (TICI 3) with no distal emboli (b).
41.2.2 Postprocedure Care
A 6-Fr vascular closure device (Angio-Seal, Terumo Medical) was deployed for hemostasis.
CT of the head was performed immediately following the intervention, as well as 24 hours later.
41.2.3 Outcome
The patient was extubated shortly after completion of the procedure, with her being able to move all extremities better than the preprocedural phase. She was significantly better 24 hours postprocedure, with marked improvement in her strength, wakefulness, alertness, and orientation. At 3 months, she had no residual deficits (modified Rankin scale [mRS] score of 0).
41.2.4 Background
Although the role of intravenous thrombolysis (IVT) and endovascular therapy (EVT) is now well established in adults presenting with acute ischemic stroke (AIS) due to a large cerebral artery occlusion, randomized controlled trials demonstrating the same benefit in pediatric AIS patients is lacking. Despite this paucity of data, there are increasing reports in the literature of EVT in the setting of pediatric AIS, with techniques used being similar to adult therapy for certain AIS pathologies.
41.3 Discussion
Many publications on pediatric AIS exist in the literature, describing its incidence, prevalence, as well as mechanisms and etiologies, including the differences in comparison to adults presenting with the same syndromes. 1 , 2 Advances in medicine, including genetics, have been able to provide a better understanding of the many different factors playing a role in pediatric AIS. However, in most instances, rapid diagnosis and initiation of therapy able to improve patient outcome remain challenging due to the relative rarity of AIS in children compared to adults, its variable presentation, and the resultant lack of development of clinical and imaging protocols meant to recognize those able to receive IVT/EVT.
Despite the commonly held belief that pediatric patients suffering from AIS have better outcomes than adults with the same strokes, more recent literature shows that the long-term impact of stroke in children cannot simply be assessed through motor, sensory, or language deficits. Even though stroke-specific mortality is roughly 5%, persisting neurological deficits can be seen in up to 70% of older children. 1 Deotto et al have demonstrated an association with a reduction in intellectual functioning. 3 Children with AIS demonstrated poorer functioning in math, spelling, metacognition, and behavioral regulation. Williams et al not only confirmed these learning and intellectual disabilities but also demonstrated the psychological impact of AIS, especially the development of attention-deficit hyperactivity disorder. 4 Westmacott et al examined the impact of AIS on children with respect to intellectual ability, academics, attention, executive function, and psychological disorders, and reached many of the same conclusions already described. However, they demonstrated the impact of lesion location, size, and age at time of AIS with respect to the intellectual and psychological challenges these children faced afterward. 5
As in adult AIS, imaging plays a vital role in determining the type, location, and possibly the etiology of pediatric AIS. 6 Given the different etiologies that exist for pediatric AIS (compared to adult AIS), the decision to offer medical or EVT rests on correct identification of the pathology causing flow impairment to brain tissue. While adult AIS amenable to EVT is most commonly a result of cardioembolic or artery-to-artery embolism, these diagnoses are rare in children. However, congenital heart disease and other cardiac disorders, arteriopathies, infections, traumatic head and neck disorders, as well as acute and chronic systemic conditions and prothrombotic states may give rise to large vessel occlusion in the pediatric setting. 1 , 2 Imaging paradigms should focus on rapid diagnosis of those AIS that are related to mechanisms amenable to emergency therapy, especially in extended time windows validated in adult EVT through DAWN) and DEFUSE 3 trials.
Several authors have published case reports, case series, as well as meta-analyses on EVT in pediatric AIS. 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 All have demonstrated high rates of revascularization, with excellent clinical outcomes. Although long-term outcomes, as well as prospective randomized controlled data, are lacking, techniques currently applied for adult EVT can be adapted to the pediatric setting, with the time taken to reach the target vessel occlusion likely faster in children due to the lack of arterial tortuosity. The specific technique used (stent retrievers, aspiration systems, or both) is dependent on patient-specific factors, including size and weight of the child, location of the thromboembolic occlusion, and considerations such as arterial access and target vessel diameter. Savastano et al have reported successful endovascular management of a basilar artery thrombosis in a 22-month-old patient. 19 Although significant work remains to be done in finding the true place of EVT in pediatric AIS, the ultimate goal remains the same as in adults: rapid clinical and imaging diagnosis of AIS amenable to EVT, with emergency mobilization of appropriately trained teams to perform this procedure in as short a time as possible.
41.3.1 Pearls and Pitfalls
Pediatric AIS has many far-reaching negative impacts on the affected child, including learning and intellectual difficulties, as well as a range of psychological disorders. These can occur (and persist) despite potential rapid improvements in initial motor, sensory, and speech deficits.
Pediatric AIS amenable to EVT is much less common than that seen in adults.
Rapid clinical and imaging evaluation is necessary to identify those children in whom EVT may be appropriate.
Current techniques used for performing adult EVT can be used in the pediatric setting, and may, in fact, be easier, given the relative lack of arterial tortuosity seen in children.
The procedure likely requires general anesthetic with endotracheal intubation to ensure patient cooperation.
Specific techniques (i.e., choice of stent retriever and/or aspiration catheter) will depend on various factors, including the weight, age, and size of the child; location of the culprit lesion; groin sheath considerations; and other medically relevant issues.
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