Kevin O’Connor, MD
Although there are no evidence-based guidelines for the use of mechanical thrombectomy (MT) in children with acute ischemic stroke, trials in adult and limited pediatric studies currently guide decision making. Several unique aspects of the pediatric stroke population warrant attention when considering MT.
There is no randomized controlled trial (RCT) comparing intravenous tPA plus MT to MT alone in children. Additionally, dosing for IV tPA in children is based on adult data and the Thrombolysis in Pediatric Stroke (TIPS) study, which was stopped before the needed number of patients was enrolled due to slow recruitment. Various analyses of data from adults shows no significant difference between MT alone and IV tPA plus MT, although one meta-analysis found a tendency toward lower modified Rankin Scale scores (0-2) at 90 days with IV tPA plus MT. Administration of IV tPA to children prior to MT can be considered if they are otherwise candidates for a thrombolytic.
Variations in cardiac anatomy and function due to congenital heart disease may complicate technical aspects of MT and periprocedural hemodynamic stabilization. As with adults, initiation of antithrombotic or anticoagulant therapy following MT depends on the risk of recurrent stroke versus hemorrhage. Because data are limited, therapeutic decisions in most cases are individualized.
In children, extracorporeal membrane oxygenation (ECMO) can be lifesaving. When considering MT, however, ECMO may present logistical, as well as technical, challenges. Limited mobility and potentially limited vascular pathways may make the risks of MT untenable.
The window for MT in adults typically extends to 24-hours from the last known well time. Pediatric patients, however, may have longer windows due to reported successful MT in children 2-3 days from the last known well time. Because there is no consensus on a therapeutic window for pediatric MT, perfusion studies can help identify potential candidates.
Arteriopathies are a common cause of pediatric stroke and present increased risk for vascular injury during MT. Underlying vascular pathology can be aggravated during an endovascular procedure, resulting in further injury. Children with connective tissue disorders may be at particularly high risk of vascular injury during MT.
Due to the lack of evidence-based guidelines for the use of MT in children, further study is needed to direct the use of IV tPA prior to MT, employing MT in the setting of underlying congenital heart disease, arteriopathy, or connective tissue disorder, and the therapeutic window for the procedure. For now, considering MT in children with a stroke due to an emergent large vessel occlusion relies on the limited available observational data and extrapolation from adults.
