Doppler blood flow measurements and derived pressure differences, through the Bernoulli equation, are used in the diagnosis of @entity1498 , a @entity850 distal to the left subclavian artery. Doppler velocities remain elevated at the @entity1498 site after successful repair of @entity1498 , leading to high Doppler derived pressure differences without significant arm-leg pressure differences. We studied this apparent contradiction of two diagnostic methods, in vivo using @entity1 and control data, and in vitro using a hydraulic model. Clinical and echocardiographic data from 31 @entity1 , aged 13.0 +/- 4.0, 10.5 +/- 4.7 yr after coarctectomy by end-to-end @entity254 , and 18 age-matched healthy subjects were reviewed. Doppler peak velocities at the aortic isthmus were elevated in @entity1 (2.2 +/- 0.4 vs. 1.2 +/- 0.2m/s, P < 0.001), corresponding to significant Doppler differences (20 +/- 7 mmHg), however, without significant arm-leg pressure differences. In all @entity1 , a mild @entity850 could still be observed. Local stiffness was increased. The hypothesis that the less distensible surgical scar in post-coarctectomy @entity1 leads to a significant @entity3885 in systole was validated in a latex model of the aorta. Rigid rings (0.5-1.5 cm), matching the unloaded aortic diameter, were mounted around the aorta. Under loading conditions, Doppler peak velocities increased by 40 +/-7%, yielding Doppler differences of 21 +/- 3 mmHg, without a significant pressure drop. An alternative expression to calculate pressure differences, using both velocity and geometric information, was validated in the model. In conclusion, post-operatively, Doppler velocities remain elevated due to a mild anatomical and significant dynamic narrowing, but the specific geometry, resembling a @entity6554 rather than an abrupt stenosis, permits an almost complete pressure recovery explaining the occurrence of Doppler differences in disagreement with the negligible arm-leg pressure difference.

Limitations of Doppler echocardiography for the post-operative evaluation of XXXX .

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity254 :: ('MESH:C563598', 'Disease') :: ['anastomosis'] @entity3885 :: ('MESH:D008173', 'Disease') :: ['dynamic obstruction'] @entity1498 :: ('MESH:D001017', 'Disease') :: ['aortic coarctation', 'coarctation'] @entity6554 :: ('MESH:D015499', 'Disease') :: ['tubular hypoplasia'] @entity850 :: ('MESH:D003251', 'Disease') :: ['anatomic stenosis', 'congenital stenosis']
@entity1498 :: (MESH:D001017,Disease) :: ['aortic coarctation']
