Case Report
Heji Ala’a, Alajlan Fahad, Alokaly Riyadh1; Almubark Suliman1; Professor Shuaib, Ashfaq2
AUTHOR AFFILIATIONS
1 King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia
2 University of Alberta, Edmonton, Alberta Canada
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Introduction
Childhood arterial ischemic stroke is a rare clinical event that occurs 2 to 8 times per 100,000 children per year (1). The outcome is potentially severe, resulting in disabilities and long-term economic and social consequences (2). Pediatric stroke patients often present late, leading to delays in treatment. The mortality rates are approximately 5% but neurological deficits maybe seen in 60% of neonates and 70% of older children (3)
The efficacy and safety of endovascular recanalization in adults for large vessel occlusions is now well established (1). There is also considerable evidence that thrombectomy can lead to successful outcomes with treatment up to 24 hours in carefully selected patients (4). CT-perfusion (CTP) studies help identify patients who may benefit in the late time window, following the onset of symptoms (1,4).
There are no randomized trials of thrombectomy in the pediatric population. It is, however, recommended that thrombectomy be considered in selected pediatric patients with LVO with acute stroke (5). Two recent series of thrombectomy in this population reveal effectiveness in the pediatric population (8,9). Despite guidelines recommendations, thrombectomy may not be offered to pediatric stroke patients, especially in patients younger than 2 years of age, especially when they present late to the hospital (5).
We report a two-year-old patient with LVO in whom CTP was helpful in a successful thrombectomy 16 hours following onset of neurological symptoms.
Case Presentation
A two-year-old Saudi male presented to our pediatric emergency department with acute right hemiplegia and aphasia 16 hours from last seen normal. His history was significant for chronic hydrocephalus and multiple apical ventricular septal defect (VSD), requiring multiple surgeries, including patch closure of apical VSD. He also suffered from non-sustained supraventricular tachycardia. Whole exome sequence (WES) showed a positive gene for arrhythmogenic cardiomyopathy (ARVC/ACM). His developmental milestones were however normal and were verified by the parents.
Upon arrival at the hospital, the stroke code was activated immediately. His National Institutes of Health Stroke Scale (Pediatric NIHSS) was 10, with decrease in level of consciences (not alert but arousable to minor stimulation), he did not answer simple questions and commands appropriately. He also had partial facial palsy, right arm and leg weakness. He was able to lift his right arm and leg with some effort against gravity. He had no verbal output and could not understand simple verbal command. His modified Rankin scale (Pediatric mRS) was 1 at baseline with no significant disabilities. His behavior was appropriate for age and had normal developmental milestones appropriate for his age.
On examination in the Emergency Department in our hospital he was hemodynamically stable. A CT scan of the head demonstrated an area of hypodensity within the left parietotemporal and left subcortical basal ganglia suggestive of a recent evolving infarction. (Figure 1a). CT angiogram (CTA) revealed occlusion of the proximal left internal carotid artery just distal to the bifurcation extending to and involving the left middle cerebral artery (L MCA) (Figure 1b). CT perfusion imaging (CTP) showed a small infarct core (CBF<30% estimated volume 4ml) with a mismatch ratio of 7.5 with a hypoperfusion index (HI) of 0.1suggesting the patient to be a slow progressor (Figure 1c). There was a larger region of low blood flow as measured with “Tmax-4” on the CTP (T max>4s: 54 ml). The patient was not a candidate for intravenous tissue-type plasminogen activator (tPA) due to the late arrival at the hospital.
Due to the ongoing focal deficits and the CTP showing a reasonable mismatch, he was considered a good candidate for mechanical thrombectomy. The patient was electively intubated and shifted to the endovascular suite for emergency intervention after informed consent was obtained from his father. A single pass (3.5*15mm catch stent) with aspiration resulted in the extraction of the clot down to the proximal internal carotid artery. This was followed by treatment with 2 mg of intra-arterial (tPA), which led to the final run being consistent with the TICI III flow (Figure 2 a-c). The patient was shifted to pediatric neurocritical care for close neurological observation and multidisciplinary team care. An emergent MRI/MRA obtained following the procedure showed left MCA territory diffusion restriction, right acute watershed infarctions, and absent flow within the left petrous and cavernous segments of the left internal carotid artery (Figure 3 a-c). Reassessment on the following day showed significant improvement in his level of consciousness, language, and right-sided weakness. He started to withdraw and elevate his right arm minimally against gravity with NIHSS of 6. He was started on ASA (4 mg/kg) on the day following hospitalization. At 12 months follow-up, the patient has shown significant improvement. There is mild right hemiparesis but he is able to walk without assistance. The Pediatric NIH Stroke Scale (NIHSS) is 1, and accounts for right upper limb drift.
Discussion
There are a few essential features that we want to highlight with our case. Our patient arrived late to the hospital. Late arrival following an acute stroke is not uncommon as is evident from previous reports (5,8,9). While the noncontrast head CT and CTA were helpful with establishing the diagnosis, the CTP was very helpful in determining that the patient had a large penumbra and a smaller core and, therefore, was a candidate for EVT. We prefer multimodal CT imaging to MRI in acute stroke evaluation because of rapid access to the CT suite. MRI is also used in many centers and may offer better resolution of the ischemic core and penumbral tissue (10). The multi-modal imaging showed a small core with sufficient penumbra, allowing for better selection for thrombectomy. Improvement in technology allows thrombectomy in the very young, even when the acute event occurred 16 hours earlier.
While there are no randomized trials of thrombectomy in stroke in children, case series have shown that it can be used successfully in patients with large arterial occlusion. In three recent retrospective, multicenter cohort study, most patients had good long-term outcomes (1,8,9). The excellent outcome was sustained at 6 and 24 months following the treatment(3) The results are in agreement with two smaller, single-center case series assessing recanalization treatments in pediatric populations for acute ischemic stroke (8).
Our patient presented to the hospital 16 hours following the onset of symptoms. Such delays are unfortunately not uncommon as the symptoms may be atypical and recognized secondary to a stroke (8,9). We reviewed the literature on thrombectomy in the delayed time window in the literature. Thirty-eight cases were found in 27 publications (15 case reports and 12 case series, Male: 60.5%). The median age was 10 years old. Before thrombectomy, the median NIHSS was 13, with a median time-to-treatment of 11 hours. In 50.0% of cases, the posterior circulation was involved. The majority of patients used stent retrievers, while 13.2% used aspiration. Angiographic outcome TICI ≥2B was achieved in 84.2% of cases (6,7)
The median time between the onset of symptoms and diagnosis in a recent study of 209 children with ischemic stroke was 22.7 hours (interquartile range, 7.1-57.4 hours) (5). As the time of onset to evaluation is often delayed, most pediatric stroke patients are unsuitable for intravenous thrombolysis. Such patients may however be candidates for endovascular therapy. In such patients multimodal CT or MRA imaging can identify salvageable tissue and help prioritize patients for recanalization therapies.
Most of the experience with delayed reperfusion treatments, especially thrombectomy comes from recent publications in the adult literature. The DEFUSE (enrollment window of 16 hours) and the DAWN trial (enrollment window of 24 hours) both utilized CT, CTA and CTP for patient selection (1,4). The combination of “small core-large penumbra” as evident on CTP were very helpful in selecting patients in whom the treatment was very effective. Rapid software detected the ischemic core in 19 patients. Three children imaged at 3.75, 11-, and 23.5-hours following stroke onset had favorable mismatch volumes (11). While MRI-perfusion imaging may be more sensitive to detect core and penumbra, multi-model CT is used in most hospitals in North America because CT is more widely available and can provide useful information in a very short time. Despite the lack of similar randomized trials in children, thrombectomy is now frequently offered to stroke patients in the pediatric population (8,9). However, when using catheters made for adults in children, patient size and thrombus location must also be considered. Even if mechanical thrombectomy is technically possible, decreased institutional readiness, potentially improvement despite intervention (since children frequently have excellent arterial collaterals), and increased plasticity of the immature brain for injury recovery are some of the reasons there is low appetite for the treatment in the pediatric population (5). As there is more experience with off-label reperfusion therapies increases in the pediatric population, we can expect increasing number of patients offered thrombectomy.
There are a few limitations including that this is only one case in a young infant. The emerging data from several case series with young patients affirm that very young patients with acute stroke can improve with thrombectomy following hours from onset provided the core is small and there is sufficient penumbra on perfusion imaging. While MR imaging may have provided more information, our hospital is better equipped with CT-perfusion imaging to manage acute stroke. Finally, the flow dynamics in children are different than adults and these require consideration when the CTP is being interpreted in children (12)
Conclusion
Pediatric acute ischemic stroke (AIS) is associated with poor neurological outcomes due to delayed diagnosis and treatment. Recent advances in imaging methods and technological improvement allow for mechanical thrombectomy beyond the 6-hour therapeutic window. We present a 2-year patient who presented 16 hours following the onset of symptoms with ICA/MCA occlusion, for whom CTP helped determine eligibility for treatment. Following successful treatment, there was a rapid improvement in symptoms.
References
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- Jauch EC, Saver JL, Adams HP, Bruno A, Connors JJB, Demaerschalk BM, et al. Guidelines for the early management of patients with acute ischemic stroke: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2013;44(3):870–947.
- Vázquez López M, de Castro de Castro P, Barredo Valderrama E, Miranda Herrero MC, Gil Villanueva N, Alcaraz Romero AJ, et al. Outcome of arterial ischemic stroke in children with heart disease. Eur J Paediatr Neurol [Internet]. 2017;21(5):730–7. Available from: http://dx.doi.org/10.1016/j.ejpn.2017.05.007
- Bhatia KD, Chowdhury S, Andrews I, Goetti R, Webster R, Troedson C, et al.
Figure Legends
Thrombectomy 16 Hours Following Onset Of Acute Stroke In A 2-year Old Child
