The associations, while modest, were not strong enough to be accurately used as predictors of outcome, but the findings offer value for pediatric care.
Warren D. Lo, MD
Data from a recent study showed that that larger infarct volume and younger age at the time of arterial ischemic stroke (AIS) were associated with poorer outcomes. These associations were modest and the ability to use these characteristics as predictors of outcome is limited, but suggest that infarcts that disrupt critical networks have a disproportionate impact upon outcome after childhood AIS.
Infarcts that involved uncinate fasciculus, angular gyrus, insular cortex, or that extended from the cortex to the subcortical nuclei were significantly associated with poorer outcomes. Univariate analysis determined these associations to have odds ratios (ORs) ranging from 1.95 to 3.95. Infarct location was a significant predictor of poor outcome, but this significance disappeared when percentage infarct volume (PIV) was added to the model.
Senior author Warren D. Lo, MD, pediatric neurologist, Nationwide Children's Hospital, and clinical professor of pediatrics and neurology, The Ohio State University College of Medicine, and colleagues wrote that “this study adds new information that while infarct volumes and younger age at stroke onset are associated with poorer outcomes, the strength of these relationships is weak. As a consequence, it is difficult to use these 2 factors to predict the outcome of childhood AIS.”
Lo and colleagues analyzed outcome data from 288 patients that were enrolled in the Vascular Effects of Infection in Pediatric Stroke (VIPS) study. These patients had a median age of 7.77 years (interquartile range [IQR], 2.78–14.4; range, 0.08–18.9) at AIS and 56.3% were male. Definite arteriopathy (35%) was the most common stroke pathogenesis, followed by idiopathic (27%), and cardioembolic (22%). Pediatric stroke outcome measure (PSOM) was used to evaluate 1-year outcomes for 190 patients and recovery and recurrence questionnaire (RRQ) evaluated 84 patients.
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At 1-year, 84.4% (n = 243) of patients had normal/mild or moderate neurological impairment (PSOM, 0–1), 8.3% (n = 24) had moderate-to-severe impairment (PSOM, 3.5–6), and 7.3% (n = 21) had very severe impairments or died (PSOM, 6.5–10).
Lo and colleagues found that infarcts that involved the combination of cortex and white matter-subcortical nuclei structures were associated with worse outcome at 1 year according to univariate analysis. The odds of a worse outcome were 3.29 (95% CI, 1.84–5.87) when compared with patients whose infarcts did not involve this combination of structures.
The median PIV overall was 1.4% (IQR, 0.3–5.4). The median PIV was 0.9% for normal outcome groups, 3.1% for mild outcome groups, and 7.8% for moderate outcome groups, but dropped to 3.4% for severe outcomes. PIV was significantly associated with poorer outcome (OR, 1.08; 95% CI, 1.04–1.13; P <.001), but the specific infarct locations (cortex-subcortical white matter-nuclei, uncinate fasciculus, and angular gyrus) were no longer significant after adjusting for PIV in the logistic regression model.
Lo and colleagues found that patient age was inversely correlated with poorer outcome (OR, 0.96; 95% CI, 0.92–0.995; P = .03). No differences in total PSOM scores (P = .66, χ2 test) was found between children older and younger than 2 years of age. The association between age and outcomes for the whole group was slightly attenuated when analysis was limited to children above 2 years, but more strongly significant (OR, 0.92; 95% CI, 0.87–0.97; P = .003).
Hemorrhagic transformation (HT) was not associated with outcomes, and median outcome score was similar in children with HT (0.5; IQR, 0–2) and children without HT (1; IQR, 0–2) without significant differences (OR, 0.85; 95% CI, 0.36–2.01; P = .71)
“Our results support the findings of previous studies that larger infarct volume and younger age at stroke onset are associated with worse outcome. Our study adds new information by demonstrating that the strength of these associations, while significant, is modest. These new data help explain why it is difficult to predict outcome based solely upon infarct volume or patient age. In addition, we found that specific infarct locations are associated with worse outcome. This finding suggests the hypothesis that infarcts that damage structures that connect other regions and serve a network function have a disproportionate effect upon function. Future studies of pediatric AIS should examine the effect of network disruption upon outcomes,” Lo and colleagues concluded.