Possibilities of modern methods of cardiac imaging in the diagnosis and preoperative planning of transposition of the great arteries in children: a prospective study

INTRODUCTION: Transposition of the great arteries (TGA) is the classic, most common and severe form of cyanotic congenital heart defects in children, which is characterized by a variety of anatomical and hemodynamic variants, combined with other cardiac anomalies and high infant mortality rates. The surgical treatment and the possibility of performing simultaneous correction of TGA depend on the anatomical and hemodynamic features of the TGA and the presence of combined intra- and extracardiac anomalies, which must be determined using cardiac imaging techniques on the preoperative stage. OBJECTIVE: To evaluate the capabilities of TTE and cardiac CT in the diagnosis and surgical planning of TGA in children. MATERIALS AND METHODS: The study included 29 children with an incoming diagnosis of transposition of the great arteries. The average age of the patients was 31 (14.5; 67) days. All children underwent TTE, 21 — cardiac CT with intravenous contrast enhancement, 6 — catheterization of the cardiac cavities with conventional angiography. Cardiac MRI was not performed due to the severe and unstable general condition of all patients and the significant risks from a longer stay in anesthesia. Capabilities of TTE and cardiac CT in determining combined intra- and extracardiac anomalies were assessed and compared. All data from TTE and cardiac CT were compared with the results of conventional angiography and intraoperative data. The interval between TTE, cardiac CT and angiography or surgery was less than 10 days. RESULTS: The accuracy of TTE and cardiac CT in TGA diagnosis and determining its type was 100% for both methods, however, with regard to determining combined intra- and extracardiac anomalies, the methods play a different role: the accuracy of cardiac CT in determining combined intracardiac anomalies in patients with TGA was 87.7% (AUC 89.3%), for TTE — 97.1% (AUC 97.3%). Comparing the capabilities of the techniques in determining intracardial anomalies, no statistically significant difference was obtained (p=0.092). The diagnostic accuracy of cardiac CT in determining concomitant anomalies of the great vessels and extracardiac pathology was 98% (AUC=98.9%). The sensitivity and specificity of TTE in the comprehensive assessment of concomitant extracardiac anomalies were 58% and 98%, respectively (accuracy 89.1%), AUC 81.1%. Comparing the capabilities of techniques in determining intracardial anomalies, cardiac CT showed to be a more accurate tool in comparison with TTE (p=0.041). DISCUSSION: Results of our study demonstrate the high efficiency of TTE in determining indications for emergency palliative correction of transposition of the great arteries, however, the method has limited diagnostic capabilities in assessing surgical risks when planning radical correction of the defect. Cardiac CT has proven to be a highly accurate tool both in making a diagnosis and in identifying combined intra- and extracardiac anomalies, which play a decisive role in planning open surgical correction of transposition of the great arteries in children. CONCLUSION: For patients with TMA and critical hypoxia, transthoracic echocardiography is the definitive diagnostic tool for planning endovascular repair. When planning open surgery, transthoracic echocardiography should be complemented by cardiac CT with ECG gating to assess the anatomy of the coronary arteries and possible associated extracardiac anomalies.