Left Atrial Size and Strain in Hypertensive Children Compared to Age-, Sex-, and Race/Ethnicity-Matched Controls.

Abstract

Left atrial (LA) volume and peak longitudinal strain (LA strain) are indicators of left ventricular (LV) diastolic function in adults, but little is known about LA volume and strain in pediatric patients with hypertension (HTN). We evaluated LA volume and strain in pediatric cases with HTN compared to age-, sex-, and race/ethnicity-matched controls. This was a retrospective matched case-control study of patients who presented to the HTN clinic at CHOP from 12/2011 to 9/2018. Coarctation of the aorta, cardiomyopathy or heart transplantation cases were excluded. HTN was defined by an abnormal ambulatory blood pressure result. LA volume was measured by biplane area-length method and indexed to body surface area (BSA). LA strain and strain rate were measured using TOMTEC® software. Left ventricular mass index (LVMI) was measured by M-mode and the 5/6 area-length method indexed to height^2.7. LV global longitudinal strain (LV GLS) was measured during the echocardiographic examination on the GE ultrasound machine for cases and offline using TOMTEC® software for controls. Measurements were compared using Chi-square, McNemar, or Wilcoxon signed rank tests. We included 47 cases and 47 controls. There was no difference in LA volume z-scores (- 1.9 vs. - 0.9, p = 0.068), LA strain (37.8% vs. 38.0%, p = 0.735) or LA strain rate (1.4 vs. 1.5, p = 0.852) in cases compared to controls. LVMI by M-mode and 5/6 area-length method was higher in cases compared to controls (40.0 vs. 33.7 g/m^2.7, p < 0.001 and 29.9 vs 24.4 g/m^2.7, p =  < 0.001, respectively). LV GLS was decreased (less negative) in cases compared to controls. In summary there was no difference in LA volume or LA strain in cases compared to controls. In cases, LVMI was significantly elevated and LV GLS was significantly decreased, which may be the first response to HTN, prior to affecting LA size.