Borodinova O. Features of the echocardiographic method in prediction and determination of the optimal technique for tetralogy of Fallot repair

The dissertation is devoted to the improvement of preoperative and intraoperative echocardiographic criteria for planning the optimal surgical technique for tetralogy of Fallot repair. In the dissertation work the clinical material of 58 patients who underwent tetralogy of Fallot repair was used and prospectively analyzed. The median age of the patients was 7.6 months (from 0.9 months to 46.3 months). The age of most patients (n = 38; 66%) ranged from 5 to 12 months. The average weight of operated patients was 7.5 kg (from 3.2 kg to 24.4 kg). ToF repair was performed by two techniques  with the preservation of the pulmonary artery valve (Group I, 42 patients) and with transannular plasty (Group II, 16 patients). The paper presents an assessment of preoperative and intraoperative indicators that affect the results of tetralogy of Fallot repair in two study groups. As a result of the study, it was suggested to use the position along the long axis of the RVOT to measure the size of the pulmonary artery valve before and after the tetralogy of Fallot as the most accurate method for evaluating the size of the valve. The study proposed a method of intraoperative measurement of RVOT size and echocardiographic RVOT z-score. The RVOT z-score <-3.2 in multifactor logistic regression analysis was determined as a reliable predictor of the development of significant RVOT obstruction after ToF correction. Comparison of patients with RVOT z-score  -3.2 and RVOT z-score < -3.2 using ANOVA two-way repeated measures revealed a significant difference in the change of RVOT gradient in these patients during the year (p<0.0009). Patients with RVOT z-score < -3.2 showed a significant increase in the RVOT gradient according to TTE one year after the operation due to increase of subpulmonary and pulmonary valve stenosis (maximum RVOT gradient > 40 mm Hg). ) Patients with RVOT z-score  -3.2 showed a significant decrease in the RVOT gradient according to TTE due to the lack of subvalvular stenosis and pulmonary arterial valve growth during the year after correction (maximum RVOT gradient < 40 mm Hg). It was found that a year after surgery, significantly more patients with transanular plasty had significant PV insufficiency than patients with preserved PV, which indicates the physiological function of PV. When comparing the RV function in the groups, a reliable difference was found between the MPI value one year after the operation. MPI was greater in the group of patients with transannular patch and was equal to an average of 0.54 ± 0.14, indicating a deterioration of the global RV function. The optimal method of ToF correction was defined as PV preservation technique due to physiological PV function, the absence of a significant difference in the occurrence of significant RVOT obstruction and significantly better right ventricular function one year after surgery.