Abstract 2763: A Novel Method of Expressing Left Ventricular Mass Relative to Body Size in Children

Abstract

The presence of left ventricular hypertrophy (LVH) is a common outcome measure in studies of cardiovascular health in children. A widely used definition of pediatric LVH is a LV mass index (LVMI, g/m 2.7 )> 95 th percentile for healthy children – determined to be 38.6 in a single pediatric reference population. However, LVMI increases with decreasing height in young children; it is therefore a suboptimal method of normalizing LV mass for body size and of defining LVH. The 95 th %ile LVMI in any reference population will depend heavily on the height and age distribution of the population. The objective of this study was to compare the performance of a novel method of expressing LV mass relative to body size (centile curves) to the LVMI method. LV mass was estimated using 2D-guided M-mode echocardiography in 440 healthy, non-obese (BMI< 95 th %ile) reference children (birth to 21 y) and 239 children at risk for LVH (hypertension, chronic kidney disease); the LVMI was calculated for all children. Three samples of 270 children, each with different age distributions, were drawn from the reference population, and a sample-specific 95 th %ile LVMI was determined for each sample and for the whole reference group. At risk children were classified as having LVH or not based on each sample-specific 95 th %ile. Then four sets of LV mass-for-height centile curves were constructed using Cole’s Lambda-Mu-Sigma method and data from each reference sample. At risk children were each assigned a LV mass-for-height %ile using these curves, and were re-classified as having LVH if the LV mass-for-height was >95 th %ile. Table 1 provides results. The centile method provided a stable estimate of the proportion of at risk children with LVH regardless of reference group, whereas proportion estimates varied widely, and significantly, depending on reference population when the LVMI method was used. LV mass-for-height centile curves are superior to LVMI as a method for normalizing LV mass to body size in children. Table 1