Sishir Mannava, MD
International Stroke Conference 2021
March 17–19, 2021
Session: Treatment of Acute Stroke in Childhood and Young Adults (Debate) (179, On Demand)
This session began with Dr. Lisa Sun from Johns Hopkins School of Medicine presenting on brain attacks in teenagers, and that “we can best care for adolescents with stroke by organizing existing adult stroke centers to be able to treat teenagers.” Dr. Sun discussed how adult stroke centers and dedicated stroke units have better outcomes with organized stroke teams and stroke protocols. This leads to faster stroke recognition and treatment times. Dr. Sun presented data from time to imaging/diagnosis in major pediatric stroke centers after stroke protocol initiation, and, at best, the times appear to be between 1.3-1.6 hours, which is slower than the DTN times median of about 1 hour in adult stroke programs. Although primary pediatric stroke center development has been proven by the TIPS trial, Dr. Sun argued that it may not be feasible or resourceful to develop the needed amount of pediatric stroke centers to provide adequate coverage to all pediatric stroke populations.
“Endovascular therapy can be more safely and effectively administered to adolescents at an adult stroke center.” Dr. Sun discussed how thrombectomy in adolescents is technically like adult thrombectomy, and that by 5 years of age, head and neck arteries approach adult size. The common femoral artery (FA) sheaths used in adults can even be used in smaller adolescents as long as the ratio of FA size to catheter size is maintained, to avoid vasospasm. Adult stroke centers also have greater procedural experience, larger stock of devices, and higher volume of thrombectomies than pediatric thrombectomy centers. Data from the TRACK registry showed a significant difference in mRS ≥ 2 and final mTICI ≥2c-3 amongst higher volume centers as opposed to lower volume centers.
In conclusion, Dr. Sun argued that we can best develop pediatric stroke care pathways within existing adult stroke care infrastructure.
In Part 2 of the session, Dr. Melissa Chung from Nationwide Children’s Hospital argued the counterpoint, that “brain attacks in teenagers should be managed at a pediatric center.” Unlike adult stroke pathways where negative head CT rules out bleed to give alteplase, often the pediatric stroke pathway uses MRI to rule in stroke. Unlike adult studies which show up to 69% of adult stroke codes having a final diagnosis of stroke, between 7-40% of pediatric patients have final diagnoses of stroke in pediatric studies, as stroke mimics are much more common in children.
“Is time to intervention really better at adult centers?” Dr. Chung highlighted that in a review of the Get with the Guidelines Stroke Registry (a non-pediatric registry), younger patients were less likely to receive brain imaging within 25 minutes and less likely to be given thrombolytics within 60 minutes of hospital arrival. According to the Rambaud et al. study on this topic, stroke was only suspected in 64% of adolescents at first medical contact, and only 58% of adolescents presenting within 4.5 hours of symptoms were managed as presumed ischemic arterial stroke.
“Hyperacute therapy is not the most important factor in management.” Dr. Sun went on to argue, that the etiology of pediatric stroke is different than in adults, with many due to arteriopathy, dissections, vasculitis/autoimmune disease, moyamoya, etc. Treating the wrong etiology with hyperacute therapy may result in harm, and pediatric centers are more equipped to deal with common co-morbidities such as congenital heart disease, sickle cell disease, and vasculopathy.
“Everything matters at a pediatric center.” Pediatric centers are focused on a family centered care model, can provide multidisciplinary care to complex pediatric patients, and have better resources for emotional, neuropsychological, and school support for adolescents. In conclusion, Dr. Chung argued that thegoal should be elevation of stroke care at pediatric institutions rather than diversion to adult centers.
In part 3 of this session, Dr. Peter Sporns from University Hospital Basel presented the PRO argument for endovascular therapy in children. Dr. Sporns began by discussing how the 5 major endovascular trials excluded children, and that there were only small case studies and reviews that discussed thrombectomy in children. Many acute stroke trials in children typically suffer from difficulty in recruitment due to struggles with randomization.
Dr. Sporns then presented his group’s SaveChildS study focused on the feasibility, safety, and outcome of endovascular therapy in childhood stroke. They enrolled 73 patients with a median age of 11.3 years old, an even ratio of boys to girls, majority with cardioembolic stroke (43.8%), anterior circulation occlusion in 86.3%, with eTICI score ≥2b in 87.4% of cases. When comparing to the HERMES meta-analysis, pediatric NIHSS at admission, 24 hours, and 7 days were comparable or lower than the adult trials. Modified Rankin Score (mRS) was median 1.0 at discharge, 6 months, and 24 months and again comparable or lower than HERMES. On average, they also found a lower proportion of symptomatic ICH in SaveChildS compared to HERMES.
In a secondary analysis of the SaveChildS study focusing on device characteristics, there was no major difference in eTICI score ≥2b between ADAPT and no ADAPT devices, nor significant difference in vasospasm based on stent retriever dimensions. In another secondary analysis of the SaveChildS study for embolectomy in 6-24 hour window based on clinical diffusion mismatch, pediatric NIHSS decreased in all children, and the proportion of children with favorable outcome (mRS) was higher than the DAWN and DEFUSE 3 trials (with lower symptomatic ICH) and similar to the outcomes of children treated within 0-6 hour time window. In conclusion, Dr. Sporns argued that thrombectomy in children is safe even up to 24 hours if selected by a mismatch between clinical deficit and infarct. Eligible children should be treated regardless of technique or device.
In part 4 of this session, Dr. Catherine Amlie-Lefond from Seattle Children’s Hospital presented the CON argument against endovascular therapy for stroke in children. She argued that much of the data available for mechanical thrombectomy in children is based on case reports, which may overrepresent positive outcomes while underreporting negative outcomes. Dr. Amlie-Lefond discussed her group’s retrospective TIPSTER study on 43 children treated at former Thrombolysis in Pediatric Stroke (TIPS) sites with thrombectomy comparing data to available literature. Median time to recanalization was similar at 5.5 vs 6 hours when comparing to published reports. Most strokes were cardioembolic.. However, median NIHSS at 24 hours and at discharge showed higher NIHSS scores in their thrombectomy group. Using the Pediatric Stroke Outcome Measure (PSOM), they found that unlike the existing literature, which showed that approximately 90% of children had good outcome (mRS or PSOM), the TIPSTER group only had about 56% with a good outcome.
Dr. Amlie-Lefond went on to discuss how most childhood stroke outcomes are favorable at 2-year follow-up as reported from the International Pediatric Stroke Study in 2020, which had about 25% having moderate-severe impairment, in contrast to adult stroke where data shows a lower percentage of good long-term outcomes. She highlighted the importance of using a risk-benefit approach, clarifying that the benefit of thrombectomy in children is poorly characterized, especially as the natural history of stroke in childhood is unknown, and that children have better untreated outcomes than adults. In regard to risks, children also have delays to diagnosis, small vessel size in < 5 years of age, and a higher dependence on collaterals, which may translate to a higher tolerance to large vessel occlusions, and that congenital diseases and other co-morbidities may affect how a child tolerates thrombectomy and anesthesia. In conclusion, Dr. Amlie-Lefond stated that there is a critical need for early predictors of outcome in childhood stroke, and that complete and rigorous safety and outcome data must be collected from all children treated with thrombectomy.