Backscatter evaluation of myocardial functional and textural findings in children with right ventricular pressure and/or volume overload
摘要
Integrated backscatter (IBS) analysis represents a recent echocardiographic technique for evaluating the textural and functional state of the right ventricular (RV) myocardium. We undertook our study to (1) define the potential impact of age or morphometric parameters (height, weight, and body surface area) on RV IBS indexes, and (2) compare RV IBS data among normal subjects and children with different conditions of RV overload. We studied 34 patients (mean age 14.6 ± 4.7 years) divided into 3 groups: 14 patients with RV volume overload related to moderate to large atrial septal defect (group I); (2) 10 patients with RV pressure overload due to transposition of the great arteries after the Mustard procedure (group II); and (3) 10 patients with RV volume and pressure overload due to pulmonary regurgitation and stenosis after corrective surgery for tetralogy of Fallot (group III). In addition, 20 children with structurally normal hearts were enrolled as the control group. The 4 groups were comparable with regard to age and morphometric parameters. IBS parameters were assessed as the magnitude of cyclic variation, determined as the difference between peak and nadir IBS values and the averaged myocardial IBS intensity. In the control group and group I, IBS parameters did not change significantly with age, height, weight, and body surface area. In contrast, in groups II and III, a significant correlation was found between cyclic variation and age at the study (p = 0.021, r = −0.71, and p = 0.006, r = −0.79, respectively). Furthermore, compared with the control group, cyclic variation and IBS intensity were significantly different only in groups II (p = 0.01 and p = 0.006, respectively) and III (both p <0.0001) but not in group I (p = 0.23 and p = 0.38, respectively). The lowest values of cyclic variation and the highest values of intensity were detected in group III patients. Thus, our data suggest that (1) in normal subjects, there is no correlation between RV IBS indexes and age or any morphometric parameters, and (2) IBS analysis is able to noninvasively detect differences in myocardial functional and textural properties in the presence of different conditions of RV overload.