Objectives: 1--To determine the accuracy of the echocardiographic selection and characterization of the pulmonary stenosis (PS) for balloon valvuloplasty; 2--To analyze the differences between children and adults in obtaining the echocardiographic parameters used for pulmonary stenosis characterization.
Material and methods: We studied 53 consecutive patients with PS and a peak Doppler gradient > or = 40 mmHg, submitted to cardiac catheterization to perform balloon valvuloplasty if the right ventricle to pulmonary artery peak-to-peak systolic pressure gradient was > or = 40 mmHg. The patients were divided into 3 groups on the basis of age: < or = 5 years (group 1; n = 18), 6-16 years (group 2; n = 17) and > 16 years (group 3; n = 18). A complete echocardiographic study was performed including identification of valvular morphology (commissural fusion, dysplasia or mixed), determination of right ventricle to pulmonary artery peak Doppler gradient and the transducer position that yielded the highest transvalvular flow velocity (V), evaluation of the right ventricular outflow tract morphology and measurement of the valvular annulus diameter.
Results: Technically adequate recordings were obtained in all patients. Fifty patients (94%) were submitted to pulmonary valvuloplasty. The echo-Doppler recording of V was obtained from the parasternal position in 27 patients (51%), suprasternal in 14 (26%), subcostal in 10 (19%) and apical in 2. In group 1, the V was obtained from the suprasternal position in 8 patients (44%), subcostal in 5 (28%), parasternal in 4 (22%) and apical in 1. In group 2, it was the parasternal position in 8 patients (47%), suprasternal in 6 (35%), subcostal in 2 (12%) and apical in 1. In group 3, it was the parasternal position in 15 patients (83%) and subcostal in 3. The peak Doppler gradient ranged from 40 to 215 mmHg (mean +/- SD = 78 +/- 37) and the peak-to-peak gradient at cardiac catheterization from 32 to 220 mmHg (mean +/- SD = 81 +/- 41). The correlation between eco-Doppler peak gradient and peak-to-peak gradient at cardiac catheterization was r = 0.95 (SEE = 12 mmHg) being, for group 1, r = 0.89 (SEE = 14 mmHg), for group 2, r = 0.97 (SEE = 8 mmHg) and, for group 3, r = 0.98 (SEE = 10 mmHg). The right ventricular outflow tract shows dynamic reaction 48 patients. Two patients had an infundibular gradient > 25 mmHg, significantly underestimated by echo-Doppler in one. All 5 patients (9%) but one with angiographic criteria for valvular dysplasia, were identified by echocardiography. One patient had a mixed form. The remaining 47 patients had valvular commissural fusion. The annulus size measured by echocardiography ranged from 10 to 28 mm (mean +/- SD = 17.7 +/- 4.3) and by angiography from 10 to 28 mm (mean +/- SD = 17.6 +/- 4.4). Close correlations were found between echocardiographic and angiographic measurements: r = 0.97 (SEE = 1.1 mm) being, for group 1, r = 0.90 (SEE = 1.1 mm), for group 2, r = 0.94 (SEE = 0.8 mm) and, for group 3, r = 0.87 (SEE = 1.3 mm).
Conclusion: The echocardiographic examination allows an accurate selection and characterization of the PS for balloon valvuloplasty. The most significant difference in the study of PS in children and adults, was the lack in the ability of the eco-Doppler to record the V from the suprasternal position in adults. 2D echocardiography can reliably measure the annulus diameter in children and adults, providing precise information for balloon diameter selection before valvuloplasty.