Intravascular ultrasound study for pediatric pulmonary valvuloplasty

Background: Intravascular ultrasound examination is a relatively new tool for cardiac evaluation during cardiac catheterization. A special ultrasound-transducer, mounted on the tip of a catheter is introduced into the cardiac chambers and vessel lumen to detect abnormalities in the cardiovascular structures, valves, the thickness of the intima and medium layers of the vessels. This study is designed to evaluate the application of intravascular ultrasound imaging in children undergoing balloon pulmonary valvuloplasty. Materials and Methods: A total of 10 children who received balloon dilation for simple or complex valvular pulmonary stenosis were enrolled in the study. After routine cardiac catheterization to confirm the accuracy of the diagnosis, intravascular ultrasound imaging was performed using an ultrasound catheter (Cardiovascular Imaging Systems Inc., Sunnyvale, CA, USA). The diameters of the superior vena cava, the inferior vena cava, the pulmonary annulus, the left and right pulmonary arteries and the thickness of the pulmonary valve were recorded before and immediately after the percutaneous balloon pulmonary valvuloplasty. Results: The diameters of the pulmonary annulus and the left and right pulmonary arteries measured by intravascular ultrasound were compared with those measured by angiocardiography. The results correlated very well (p < 0.0001). Conclusion: Intravascular ultrasound imaging not only provides detailed information of cardiovascular structures in children with pulmonary stenosis before and immediately after balloon valvuloplasty, but also gives the physician useful information for choosing the correct size of balloon for dilation.