Potential of Transthoracic Echocardiography and Cardiac CT in Pulmonary Arteries Assessment in Children With Pulmonary Atresia With Ventricular Septal Defect

Objective: To assess and compare the potential of transthoracic echocardiography (TTE) and cardiac computed tomography (CT) in determining severity of pulmonary artery hypoplasia in children with pulmonary atresia with ventricular septal defect (PA-VSD) during preoperative planning. Materials and methods: The study included 38 children (mean age, 1.5 years; 97% of the patients younger than 1 year) with a clinical diagnosis of PA-VSD. All the patients underwent TTE; 36 of them underwent cardiac CT, while 33 children had direct angiocardiography. During all diagnostic methods we performed morphometry of the pulmonary trunk (if any) and proximal and distal parts of right and left pulmonary arteries, calculated z score for every vessel, Nakata index, and McGoon ratio. All the results were compared with fi of direct angiography and/or intraoperative data. The interval between TTE, cardiac CT, and angiocardiography or open surgery was less than 10 days. The criterion for hypoplasia of the pulmonary artery and its branches was z score deviation less than (−2) from reference values. Nakata index less than 200 mm2/m2 and McGoon ratio less than 1.0 were considered contraindications for radical correction. Results: We found no statistically significant difference ( P > .05) when comparing the potential of TTE and cardiac CT with direct angiography/intraoperative data in terms of morphometry of the proximal parts of the right and left pulmonary arteries and calculating z scores. All the methods demonstrated high diagnostic efficacy. We found statistically significant differences when comparing the potential of TTE and cardiac CT in pulmonary trunk angiometry: the results of pulmonary trunk measurement using TTE were statistically significantly different from the findings of cardiac CT and angiography/intraoperative data with significant underestimation of vessel diameters ( P < .05). The results of measurements of the distal parts of the pulmonary artery using TTE were statistically significantly different from those of cardiac CT and direct angiography/intraoperative data with significant underestimation of vessel diameters ( P < .05). There were no statistically significant differences between CT and direct angiography/intraoperative data in assessing the diameters of the distal branches of the pulmonary artery. When assessing McGoon ratio and Nakata index using TTE, we found statistically significant differences (underestimation of values) in comparison with direct angiography ( P < .05). Comparison of McGoon ratios measured by TTE and cardiac CT also demonstrated their statistically significant underestimation by TTE ( P < .05). The calculated McGoon ratio during cardiac CT did not differ significantly from the direct angiography findings. Conclusions: TTE cannot be considered the final method for preoperative assessment of the pulmonary artery system development in children with PA-VSD due to the limited visualization of the distal parts of the right and left pulmonary arteries and significant underestimation of the pulmonary trunk diameter and indices. Cardiac CT proved its high effectiveness in assessment of hypoplasia severity and can be an alternative to direct angiography.