The aim of the scientific work was to improve the efficiency of prenatal diagnosis of vascular rings (VR) by fetal echocardiography.
The dissertations include clinical materials of 70 fetuses with suspected VR and 107 fetuses of the control group (47 fetuses with normal anatomy of the heart and greate arteries and 60 fetuses with congenital heart defects associated with the right aortic arch).
Scientific research was performed in three stages. In the first stage, the Echo protocol was expanded with special views: 1) the 3-vessel and trachea view, 2) the aortic arch long-axis view, 3) the transverse view of the upper abdomen, demonstrating the abdominal aorta. In the period from 2012 to 2017 we diagnosed 70 (0,9%) cases of vascular rings. In 21 (30%) cases, a fetal heart MRI was performed to diagnose the anatomical type of the VR and to diagnose the degree of tracheal compression. Since the beginning of the study, there has been a significant improvement in the accuracy (by 35%) of diagnosis of VR and a training curve has been created. During the study, additional ultrasound signs of anatomical variants of VR were identified and described.
In the second stage of the study, a comparative analysis of echocardiographic characteristics in fetuses with isolated VR (n = 39) and with normal anatomy of the heart and great arteries (n = 47) was performed. The 4-chamber view, the views of the left and right ventricular tract, and the three vessels view were normal in both groups. The sizes of all heart structures were evaluated according to normograms according to the term of pregnancy and Z-score was calculated for each of them. Despite significant difference between Z-scores of ductus arteriosus, mitral and tricuspid valves measurements, of in study groups the ROC-analysis shows that they are not diagnostic for VR – area under the curve for Z-score DA was 67,9%, P = 0,004; sensitivity and specificity is < 1,5%; for Z-score MV was 62,4%, P = 0,049; for TV was 62,7%, P = 0,044.
In the third stage, the comparison of the application of all special projections with the isolated use of each separately. To this end, two study groups were also formed. The main study group consisted of 68 fetuses with prenatal suspicion of VR. The control group was formed by 60 fetuses with the CHD combined with the right aortic arch. Primary prenatal echocardiography using all special projections for VR diagnosis is excellent: clinical utility index (93,3), sensitivity – 95,7 %, specifity – 84,6 %, positive predictive value – 95,7 %, negative predictive value – 84,6 %, positive likelihood ratio – 6,22, negative likelihood ratio – 0,05. Isolated use the transverse view of the upper abdomen, demonstrating the abnormal abdominal aorta has an average clinical utility index (83,3), sensitivity – 93,6 %, specifity – 46,2 %, positive predictive value – 86,3 %, negative predictive value – 66,7 %, positive likelihood ratio – 1,74, negative likelihood ratio – 0,14. U-shaped angle of ascent of the aortic arch and arterial ductus on the three vessels and trachea view with isolated use has a low clinical utility index (76,7), sensitivity – 85,1 %, specifity – 46,2 %, positive predictive value – 85,1 %, negative predictive value – 46,2 %, positive likelihood ratio – 1,58, negative likelihood ratio – 0,32. Isolated assessment of tracheal location has a good level: clinical utility index (90,0), sensitivity – 89,4 %, specifity – 92,3 %, positive predictive value – 97,7 %, negative predictive value – 70,6 %, positive likelihood ratio – 11,62, negative likelihood ratio – 0,12.
Diagnostic accuracy of right aortic arch with left arterial duct and aberrant subclavian artery (n = 22): sensitivity – 90,91%, specifity – 40%, positive likelihood ratio – 1,52, negative likelihood ratio – 0,23, disease prevalence – 68,75%, positive predictive value – 76,92%, negative predictive value – 66,67%, accuracy – 75%. Diagnostic accuracy of double aortic arches (n = 8): sensitivity – 50 %, specifity – 91,67 %, positive likelihood ratio – 6, negative likelihood ratio – 0,55, disease prevalence – 25 %, positive predictive value – 66,67 %, negative predictive value – 84,62 %, accuracy – 81,25%. Diagnosis of rare variants of VR is extremely low.
The result of the dissertation work was the creation of an algorithm for perinatal management, which includes an integrated approach to prenatal diagnosis of VR and postnatal management of this group of patients.
