Dataset Information

Pediatric Heart Network Echocardiographic Z Scores: Comparison with Other Published Models.

ABSTRACT:

Background

Different methods have resulted in variable Z scores for echocardiographic measurements. Using the measurements from 3,215 healthy North American children in the Pediatric Heart Network (PHN) echocardiographic Z score database, the authors compared the PHN model with previously published Z score models.

Methods

Z scores were derived for cardiovascular measurements using four models (PHN, Boston, Italy, and Detroit). Model comparisons were performed by evaluating (1) overlaid graphs of measurement versus body surface area with curves at Z = -2, 0, and +2; (2) scatterplots of PHN versus other Z scores with correlation coefficients; (3) Bland-Altman plots of PHN versus other Z scores; and (4) comparison of median Z scores for each model.

Results

For most measurements, PHN Z score curves were similar to Boston and Italian curves but diverged from Detroit curves at high body surface areas. Correlation coefficients were high when comparing the PHN model with the others, highest with Boston (mean, 0.99) and lowest with Detroit (mean, 0.90). Scatterplots suggested systematic differences despite high correlations. Bland-Altman plots also revealed poor agreement at both extremes of size and a systematic bias for most when comparing PHN against Italian and Detroit Z scores. There were statistically significant differences when comparing median Z scores between the PHN and other models.

Conclusions

Z scores from the multicenter PHN model correlated well with previous single-center models, especially the Boston model, which also had a large sample size and similar methodology. The Detroit Z scores diverged from the PHN Z scores at high body surface area, possibly because there were more subjects in this category in the PHN database. Despite excellent correlation, significant differences in Z scores between the PHN model and others were seen for many measurements. This is important when comparing publications using different models and for clinical care, particularly when Z score thresholds are used to guide diagnosis and management.

SUBMITTER: Lopez L

PROVIDER: S-EPMC7870534 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundEchocardiographic follow-up after pediatric heart transplantation is important because of the lifelong risk for rejection and resultant ventricular dysfunction. Although adult studies have shown that echocardiographic measures of right ventricular function are changed after transplantation, similar results have not been reported in the pediatric population.MethodsA single-center retrospective study of echocardiograms obtained among pediatric heart transplant recipients was conducted. All echocardiograms were selected remote from transplantation, rejection, or graft vasculopathy. These criteria identified 127 patients. Right ventricular systolic function was measured using tricuspid annular plane systolic excursion, fractional area change (FAC), and peak systolic tricuspid annular tissue velocity (S'). Results were compared with those in 380 healthy age-matched echocardiographic control subjects.ResultsTricuspid annular plane systolic excursion values in pediatric heart transplant recipients were significantly lower than in control subjects at all ages (P < .0001), with a mean Z score of -3.38. FAC and S' did not vary by age in control patients >6 months of age. FAC values in transplantation patients were significantly decreased compared with those in control subjects (P < .0001), but 83% of transplantation patients had FAC values within the control-derived normal range. S' values were also significantly lower in transplantation patients than control subjects (P < .0001).ConclusionsHeart transplantation patients have significantly decreased quantitative metrics of right ventricular function relative to healthy control subjects; longitudinal shortening (tricuspid annular plane systolic excursion and S') is particularly affected. FAC is relatively preserved and may be a better metric in this population. These results establish nomograms of RV function in pediatric heart transplantation patients and in normal pediatric control subjects, which may allow quantification of changes in this vulnerable population.

Project description:Normalizing cardiovascular measurements for body size allows for comparison among children of different ages and for distinguishing pathologic changes from normal physiologic growth. Because of growing interest to use height for normalization, the aim of this study was to develop height-based normalization models and compare them to body surface area (BSA)-based normalization for aortic and left ventricular (LV) measurements. The study population consisted of healthy, non-obese children between 2 and 18 years of age enrolled in the Pediatric Heart Network Echo Z-Score Project. The echocardiographic study parameters included proximal aortic diameters at 3 locations, LV end-diastolic volume, and LV mass. Using the statistical methodology described in the original project, Z-scores based on height and BSA were determined for the study parameters and tested for any clinically significant relationships with age, sex, race, ethnicity, and body mass index (BMI). Normalization models based on height versus BSA were compared among underweight, normal weight, and overweight (but not obese) children in the study population. Z-scores based on height and BSA were calculated for the 5 study parameters and revealed no clinically significant relationships with age, sex, race, and ethnicity. Normalization based on height resulted in lower Z-scores in the underweight group compared to the overweight group, whereas normalization based on BSA resulted in higher Z-scores in the underweight group compared to the overweight group. In other words, increasing BMI had an opposite effect on height-based Z-scores compared to BSA-based Z-scores. Allometric normalization based on height and BSA for aortic and LV sizes is feasible. However, height-based normalization results in higher cardiovascular Z-scores in heavier children, and BSA-based normalization results in higher cardiovascular Z-scores in lighter children. Further studies are needed to assess the performance of these approaches in obese children with or without cardiac disease.