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[Echocardiography determination of shunt volume in children with atrial septal defect]
H J Häusler1, I Dähnert, A Dagnachew
1Universitäts-Kinderklinik Leipzig.
Insights
Echocardiography accurately estimates left-to-right shunts in children with atrial septal defects (ASD). The pulmonary-to-aortic diameter ratio is the most reliable indicator, enabling non-invasive surgical decisions for ASD II.
Area of Science:
- Pediatric Cardiology
- Diagnostic Imaging
- Congenital Heart Disease
Background:
- Secundum atrial septal defect (ASD II) is a common congenital heart anomaly.
- Accurate quantification of left-to-right shunting is crucial for clinical management and surgical decision-making.
- Traditional methods like oximetry and cardiac catheterization are invasive.
Purpose of the Study:
- To prospectively evaluate the accuracy of echocardiographic parameters in estimating left-to-right shunt size in children with secundum ASD.
- To identify the most reliable echocardiographic index for shunt quantification.
- To assess the feasibility of using echocardiography to guide surgical decisions, potentially avoiding cardiac catheterization.
Main Methods:
- Prospective study of 51 children with secundum ASD.
- Correlation of echocardiographic measurements (atrial/ventricular areas, pulmonary/aortic diameters) with shunt size determined by oximetry.
- Development and validation of regression equations for shunt estimation.
- Comparison of echocardiographically derived shunt values with oximetric data.
Main Results:
- The ratio of pulmonary to aortic diameter showed the strongest correlation with shunt size (r = 0.95, p < 0.01) in the initial cohort.
- This ratio remained the most accurate predictor in the validation cohort (r = 0.97), with a small mean difference (0.7 +/- 3.8%) compared to oximetry.
- Echocardiographic shunt estimation > or = 48% has been used to guide surgical decisions since 1991, avoiding catheterization in 33 patients.
Conclusions:
- Echocardiography, particularly the pulmonary/aortic diameter ratio, provides an accurate and reliable method for estimating left-to-right shunts in children with secundum ASD.
- This non-invasive technique can potentially replace cardiac catheterization for surgical planning in select patients.
- Echocardiographic shunt assessment facilitates timely surgical intervention for ASD II.
Abstract:
The accuracy of echocardiographic estimation of left-to-right shunts was studied prospectively in children with secundum ASD. Fifty-one consecutive patients were examined from March 1987 to August 1991. Mean age was 64/12 years with a minimum age of 12/12 and a maximum of 131/12 years. Twenty-five children were included in the first part of the study. The ratios of right and left atrial and ventricular areas and pulmonary and aortic diameters were correlated with the left-to-right shunts determined by oximetry (mean shunt 48.7%; min. 10.1%, max. 73.2%). The pulmonary/aortic diameter ratio provided the closest correlation (r = 0.95; p < 0.01). During the second part of the study the left-to-right shunt was estimated using the regression equations developed from part one. Thus, in 26 subsequent patients these values were compared with oximetric shunt values. Again, the pulmonary/aortic diameter ratio provided the closest correlation (r = 0.97). The pair comparison yielded a difference of 0.7 +/- 3.8%. Based on these results since 1991, surgery for ASD II has been performed without preoperative cardiac catheterization in 33 patients, provided echocardiographic shunt estimation was > or = 48%.