Registries of children who receive endovascular therapy are being developed and are expected to provide further evidence of feasibility and safety in young patients.
Mechanical thrombectomy can safely and effectively be performed in cases of large-vessel occlusion (LVO) stroke that involve young children and even infants, according to two new studies. Due to gaps in knowledge, however, the authors of one of the studies say children should be included in clinical trials for stroke interventions.
The case series and the systematic review were both published online recently in the Journal of NeuroInterventional Surgery.
“There are many issues that hurdle treatment of pediatric patients,” Hazem Shoirah, MD (Icahn School of Medicine at Mount Sinai, New York, NY), lead author of the case series, told Neurovascular Exchange in an email.
“First and foremost is the recognition of stroke symptoms, which could be challenging, especially in very young patients,” he explained. “Even when stroke symptoms are recognized, there aren’t always clear algorithms of triaging and managing those patients, and the detection of LVOs may be delayed. Because of the rarity of this condition, many providers lack the familiarity or comfort with the treatment options available for pediatric patients with LVO.”
Lead author of the retrospective study, Lisa R. Sun, MD (Johns Hopkins University School of Medicine, Baltimore, MD), went on to explain to NXV why endovascular procedures can be tricky in this patient population.
“Young children have smaller cerebral blood vessels, so extra caution is needed when using devices designed for adults,” she explained. “Pediatric patients may be at higher risk for vasospasm, vessel rupture, or inability to perform the procedure given the small vessel size. Pediatric patients also have a lower blood volume, so when using aspiration techniques, the operator must be cognizant of the amount of blood lost during the procedure.”
Outcomes Comparable to Those of Adults
Shoirah et al looked at 19 pediatric stroke patients (mean age 10.9 years; 63.2% men) who underwent endovascular thrombectomy at one of nine US tertiary centers between 2008 and 2017. Patients weighed a mean of 30.8 kg, with a mean NIHSS score of 13.9 at presentation.
A CT-based assessment was obtained in 88.2% of patients, and a perfusion-based assessment was obtained in 58.8%. All procedures were performed via the transfemoral approach. The first-pass device was a stent retriever in 52.6% of patients and aspiration in 36.8%.
Successful revascularization was achieved in 89.5% of the patients after a mean of 2.2 passes, with a mean time from groin puncture to recanalization of 48.7 minutes (median 41.5 minutes).
The mean reduction in NIHSS score from admission to discharge was 10.2. A good neurological outcome was achieved in 89.5% of patients. One patient experienced a postrevascularization seizure, but no other procedural complications or mortality occurred.
According to the study authors, the technical and neurological outcomes in their pediatric patients were comparable to what has been seen in the adult literature.
“The data derived from such case reports should guide the discussion about standardizing algorithms of hyperacute stroke triage and management in pediatric patients,” Shoirah concluded about his findings. “Algorithms that prioritize detection of LVO in selected patients would lead to faster treatments and possibly better outcomes. However, in pediatric patients, the incidence of stroke mimics is high. Proper patient selection would spare a large proportion of patients from undergoing unnecessary radiographic tests. In this study we found that cardiac disease, hypercoagulability, and vessel dissection were the most common etiologies of LVO.”
‘Age Alone Should Not Exclude a Child’
The second study, by Sun et al, looked specifically at use of mechanical thrombectomy among acute stroke patients under 5 years of age. They conducted a review of the literature, identifying 11 reported cases of patients aged 9 months to 4 years.
“Young children, particularly those under 5 years of age, are a particularly controversial cohort due to small size of cerebral blood vessels and developmental differences in young brains,” Sun told NVX. “As a first step in studying the safety and efficacy of mechanical thrombectomy, it was important to review the existing literature to evaluate if the technique is even feasible in young children.”
Among these patients, the mean time from symptom onset to groin puncture was 12 hours (range 4-50 hours). Complete recanalization was achieved in seven of 12 vessels attempted, and partial recanalization was achieved in four of the remaining five vessels. Two procedure-related complications were reported, with small vessel size being a suspected contributor to basilar vasospasm in one case. Favorable neurological outcomes were reported in seven cases.
“Mechanical thrombectomy in young children with acute stroke is feasible in at least some circumstances,” Sun concluded. “Appropriate patient selection and sufficient experience of the treating team are probably important determinants of the success of the procedure. Based on these findings, age alone should not exclude a child from clinical treatment or research studies involving endovascular therapy.”
Sun pointed out to NXV that while her study and that by Shoirah et al differ with regard to mean patient age and data-collection methods, they came to similar conclusions. “Both support consideration of mechanical thrombectomy for treatment of acute stroke in children, even young children, in consultation with experienced pediatric stroke neurologists and interventionalists, and urge further research on this important topic,” she said.
Shoirah concurred. “This modality of treatment that is generally hailed as a breakthrough treatment in adult stroke patients should be seriously considered in pediatric patients suffering from this condition,” he concluded, adding that more data in the pediatric setting are needed.
“Registries of children who receive endovascular therapy are being developed,” said Sun, “and this will provide a higher level of evidence of the feasibility and safety of this procedure. Ultimately, randomized controlled trials of mechanical thrombectomy will be needed to truly evaluate the safety and efficacy of this procedure.” She and her colleagues urge the inclusion of children in future clinical trials of mechanical thrombectomy for stroke.
- Shoirah H, Shallwani H, Siddiqui AH, et al. . J NeuroInterv Surg. 2019;Epub ahead of print.
- Sun LR, Felling RJ, Pearl MS. . J NeuroInterv Surg. 2019;Epub ahead of print.
- Shoirah and Sun report no relevant conflicts of interest.