Reference Values of Aortic Flow Velocity Integral in 1193 Healthy Infants, Children, and Adolescents to Quickly Estimate Cardiac Stroke Volume

Abstract

The aortic velocity time integral (VTI) is an echocardiographic tool used to estimate cardiac output (CO) by multiplying it with the aortic valve (AV) area and heart rate (HR). Inaccurate measurement of AV diameter will lead to squared miscalculation of CO. The aortic VTI itself can serve as a left-ventricular (LV) output parameter. The normal range of aortic VTI in adulthood is relatively stable, compared with childhood, but reference data are lacking. The aim of this study was to establish reference values of VTI in infants, children, and adolescents. A retrospective analysis of 1223 echocardiographic examinations of healthy children (age 0-20 years, body surface area [BSA] 0.11-2.23 m(2)) was performed. Data were correlated with age, BSA, and HR, and age subgroups with normal distribution were determined. Interobserver and intraobserver variability was calculated. Aortic VTI ranged from mean 13.8 cm (10.0-18.4 cm 5-95th percentile) in neonates to 25.1 cm (19.6-32.8 cm 5-95th percentile) in children >17 years of age and had a positive correlation with age (r = 0.685, p < 0.001), BSA (r = 0.645, p < 0.001) and a negative correlation with HR (r = -0.710, p < 0.001). Interobserver and intraobserver variability were excellent (3.9 ± 3.1 and 4.6 ± 3.7 %, respectively). Calculated mean values and percentile charts for the different age groups can serve as reference data to easily judge LV output in patients with or without congenital heart disease without enlargement or dysfunction of the AV.

Reference intervals and percentile curve for left ventricular outflow tract (LVOT), velocity time integral (VTI), and LVOT‐VTI‐derived hemodynamic parameters in healthy children and adolescents: Analysis of echocardiographic methods association and agreement

“…In agreement with Pees et al findings, we found that sex‐related RIs for LVOT‐VTI data were not necessary. On the contrary, as was described, VTI and BSA were associated and BSA should be considered when analyzing VTI data.…”

“…Related with that, Poutanen et al found that increases in aortic VTI and those in BSA were associated in healthy subjects (n = 168; 11.1 ± 5 years). Pees et al also reported a strong correlation between aortic VTI and BSA in infants, children, and adolescents (n = 1200) distributed in 15 BSA groups (from 0.11 to 2.23 m 2 ) . In the present work, healthy children, adolescents, and young adults within a wide BSA range (mean 1.65 ± 0.26 m 2 , range from 0.75 to 2.44 m 2 ) were studied and the associations between hemodynamic data and BSA were analyzed (assessing the potential role of BSA as an explanatory factor).…”

“…Despite the recognized clinical value of echocardiographic CO estimation, the lack of RIs for LVOT‐VTI‐derived parameters obtained in healthy populations has contributed to limit their widespread use in clinical practice. On the other hand, available works have mainly assessed a single parameter; obtained data from retrospective analysis; considered a unique cutoff value for the studied parameters, and/or did not analyze explanatory factors …”

“…Higher LVOT dimensions and VTI‐derived parameters were associated with higher weight, height, BSA, and BMI values. Data about the relationship between BSA and VTI in children and adolescents are scarce, controversial, and inconsistent, which could be explained, at least partially by methodological differences among studies …”

Does a two‐minute mini‐fluid challenge predict fluid responsiveness in pediatric patients under general anesthesia?

“…Furthermore, differences in cardiovascular physiology are usually reported between population of children under and over 6 months of age. Indeed, Pees C. et al showed in a retrospective analysis of 1223 echocardiographic examinations of healthy awake children (age 0‐20 years) that the aortic VTI ranged from 13.8 cm in neonates to 25.1 cm in children >17 years of age . For these reasons, we cannot currently recommend using VTI at baseline to guide the use of fluid challenge in children.…”