Computed Tomography in Pulmonary Evaluation of Children with Acyanotic Congenital Heart Defect and Pulmonary Hyperflow

Abstract

Respiratory dysfunction is common in children with acyanotic congenital heart defects (ACHD) with pulmonary hyperflow; however, little is known about the pulmonary structure of those patients. The objective of this study was to quantify the volumes of air and tissue, as well as the distribution of pulmonary aeration in this population. After approval by the Ethics Committee of the institution and signing of an informed consent, seven children with ACHD with pulmonary hyperflow underwent computed tomographies of the chest. All images included the left and right pulmonary contour, and pulmonary volumes and weight were calculated using volumetric data. Paired Student t test was used to compare left and right, and exponential regression was used for correlations. Patients had a mean age of 20 months and weight of 9.9 kg. Total pulmonary volume (TPV) was 66.7 +/- 23.1 mL.kg-1, tissue volume of 33.5 +/- 15.7 mL.kg-1, and air volume of 33.1 +/- 8.3 mL.kg-1. The right lung represented 57.9% of TPV and the left, 42.1% (p < 0.001). The pulmonary volume of air on the right was 60.5% of the total air volume (p < 0.001), and the volume of pulmonary parenchyma normally aerated was significantly lower on the left (27.6 +/- 6.8 vs . 18.1 +/- 8%, p < 0.001). The volume of lung tissue was greater than expected in children with ACHD with pulmonary hyperflow, possibly due to interstitial edema. Pulmonary aeration is reduced in the left lung due to the compression of the lung by the heart.