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Significance of the Doppler-derived gradient across a residual aortic coarctation
A W Aldousany1, T G DiSessa, B S Alpert
1Department of Pediatrics, University of Tennessee, School of Medicine, Memphis.
Insights
Doppler echocardiography accurately measures pressure gradients after coarctation repair in children when precoarctation velocity is included. This method improves correlation with catheterization, aiding in assessing residual aortic obstruction.
Area of Science:
- Pediatric Cardiology
- Echocardiography
- Cardiovascular Surgery
Background:
- Limited data exist on Doppler gradient significance in children with repaired coarctation and residual narrowing.
- Accurate assessment of residual obstruction is crucial for long-term outcomes.
Purpose of the Study:
- To evaluate Doppler echocardiography's accuracy in measuring transcoarctation pressure gradients in children post-coarctation repair.
- To compare Doppler-derived gradients with catheterization measurements.
Main Methods:
- Doppler echocardiography was used in 11 patients with repaired aortic coarctation.
- Transcoarctation pressure gradients were calculated using the simplified Bernoulli equation, with and without precoarctation velocity.
- Doppler gradients were compared to catheter-measured peak-to-peak and maximal instantaneous gradients.
Main Results:
- Using only maximal velocity showed poor correlation with catheter gradients (r=0.73, r=0.56).
- Including precoarctation velocity significantly improved correlation (r=0.95, r=0.94 for maximal gradients; r=0.97 for mean gradients).
- Doppler mean gradient showed excellent agreement with catheter mean gradient (r=0.97, SEE=0.85 mmHg).
Conclusions:
- Doppler echocardiography, incorporating precoarctation velocity, is a reliable method for assessing residual obstruction after coarctation repair in children.
- This improved accuracy aids in clinical decision-making for managing post-coarctation syndrome.
Abstract:
Few data exist which address the significance of the Doppler gradient across a residual narrowing in older children who have had a coarctation repaired. Therefore, we evaluated 11 patients with repaired aortic coarctation with and without residual obstruction by Doppler echocardiography. The Doppler-derived transcoarctation pressure gradient correlated poorly with catheter-measured peak-to-peak and catheter maximal instantaneous gradients when only the maximal velocity across the repair was utilized in the simplified Bernoulli equation, [r = 0.73, standard of error of the estimate (SEE) = 5.0 mmHg and r = 0.56, SEE = 7.6 mmHg, respectively]. However, when the precoarctation velocity was included in the simplified Bernoulli equation, the correlation between Doppler-derived and catheter-measured gradients became excellent. The maximal Doppler gradient correlated well with catheter peak-to-peak gradient (r = 0.95, SEE = 2.2 mmHg) and catheter maximal instantaneous gradient (r = 0.94, SEE = 3.2 mmHg). However, the maximal Doppler gradient slightly overestimated the catheter peak-to-peak gradient and underestimated the catheter maximal instantaneous gradient. The Doppler mean gradient showed excellent correlation with the catheter mean gradient (r = 0.97, SEE = 0.85 mmHg). Precoarctation velocities were generally twofold greater than published normals due to a spatial acceleration phenomenon. All subjects had residual hypoplasia of the transverse aorta such that its transverse diameter was 29% less than, and its cross-sectional area was 50% less than, the ascending and descending aorta.(ABSTRACT TRUNCATED AT 250 WORDS)