Peak blood pressure and prediction of posterior reversible encephalopathy syndrome in children.

backgroundHypertension is a risk factor for posterior reversible encephalopathy syndrome (PRES), but the timing and severity of hypertension relative to PRES are unknown. The objective was to identify a clinically meaningful blood pressure (BP) threshold that predicts PRES development in high-risk children.

methodsWe recorded peak systolic BP, diastolic BP, BP z-scores, and mean arterial pressure over the 14 days preceding clinical concern for PRES in 35 subjects who developed PRES, compared to 14 controls who had normal brain magnetic resonance imaging and similar underlying disease, renal function, and medications. We used multivariable logistic regression models adjusted for fluid overload and obesity to estimate the association of peak BP with PRES. We used receiver operating characteristic curves to determine which peak BP thresholds best predicted PRES and calculated the corresponding sensitivity, specificity, and positive and negative predictive values.

resultsPeak systolic BP z-score was most strongly associated with PRES (OR 3.97, 95% CI 1.62-9.74), and peak systolic BP z-score ≥ 3.0 predicted PRES (area under the curve 0.95, 95% CI 0.88-1.0) with 91% sensitivity and 85% specificity, indicating 94% positive predictive value and 79% negative predictive value.

conclusionsWe demonstrated that peak systolic BP z-score ≥ 3.0 in the preceding 14 days predicted PRES development in cases compared with controls in children at high risk. Our study suggests that stage 2 hypertension, corresponding to a z-score ≥ 3.0, could help define hypertensive emergency in high-risk children and indicate when more aggressive treatment is warranted to prevent neurologic injury.