| Measurements of Blood Flow in the Ascending and Descending Aorta by Two-Dimensional doppler Echocardiography in School children. |
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Soon Ung Kang |
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Department of Pediatrics, College of Medicine, Seoul National University |
| 도플러 심에코도에 의한 학동아의 상행 및 하행대동맥의 혈류량 측정에 관한 연구
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강순웅 |
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서울대학교 의과대학 소아과학교실 |
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| Abstract |
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Cardiac output measurements are among the most important physiologic indices of cardiovascular
function. Flow computation is one of the major capabilities of Doppler echocardiography. The basic
principle is that the average velocity of blood flow multiplied by the area through which the blood
passes yields flow volume. The normal range of diameters and velocities in the ascending and
descending aorta were established in 76 healthy children aged 7 to 12 years. Computations of the
ascending and descending aortic flows were also presented.
The results were as follows:
1) Ascending aortic diameters (AAD) and descending aortic diameters (DAD) measured from center
to center of the aortic wall image(I) and between internal margins(II) at the age of 7 years and 12
years were: (I) 17.3±0.7 mm, 20.8±l.lmm (AAD) and 14.1 ±0.6 mm, 16.8±1.0 mm (DAD), (II) 15.2±0.
8 mm, 18.2±1.0 mm (AAD) and 12.4±0.9 mm, 14.7±0.8 mm (DAD) respectively and both of aortic
diameters enlarged with increasing age (p<0.01). The ratio (DAD/A AD) was 0.80 ±0.02 ⑴ and 0.80 ±0.03
(II), and relatively constant throughout all ages.
2) Maximum velocities in the ascending aorta (VmaxAA) and the descending aorta (VmaxDA)
were 106 ±13 cm/sec and 129 ±13 cm/sec respectively and there was no significant difference with
increasing age (p>0.05). The ratio (VmaxDA/VmaxAA) was 1.22±0.05 and relatively constant
throughout all ages. 3) Ascending aortic flows (AAF) and descending aortic flows (DAF) using the diameters from
center to center of the aortic wall image (I) and between internal margins (II) at the age of 7 years
and 12 years were: (I) 2.83±0.27 L/min, 3.79 ±0.38 L/min (AAF) and 2.22 ±0.18 L/min, 3.01 ±0.40 L/
min (DAF), (II) 2.19±0.19 L/min, 2.88±0.30 L/min(AAF) and 1.72±0.17 L/min, 2.31 ±0.24 L/min (DAF)
respectively. The former was more close to the known normal cardiac output for age than the latter.
Both of the aortic flows increased with increasing age (p<0.01). The ratio (DAF/AAFX100) was 79.6±4.9% (I)
and 79.3 ±3.5% (II), and relatively constant throughout all ages.
4) The increase in the ascending aortic flows correlated closely with the increase in the aortic diameters (r=0.66, p<0.01).
Thus growth of aortic cross section keeps pace with the increase in cardiac output that occurs over this growing period. 5) Ascending aortic flows per m2 of body surface area decrease gradually with increasing age (p <0.01).
6) These findings suggest that cardiac output can be estimated through the descending aortic flow
multiplied by 1.25
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| Key Words:
Two-dimensional Doppler echocardiography, Ascending aorta, Descending aorta, Cardiac output
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