[Calculation of the pulmonary to systemic flow ratio using echo-Doppler in septal defects--correlation with oximetry].
OBJECTIVE
1. local validation of a protocol of measurement of pulmonary to systemic flow ratio (QP/QS) by echo-Doppler in children with septal defects; 2. to assess continuous wave Doppler efficacy mainly in those patients where peak pulmonary flow velocity was beyond the Nyquist limit of pulsed Doppler.


METHODS
To correlate QP/QS ratio determined by echo-Doppler with that obtained by cardiac catheterization (oximetric method) performed within 48 hours, in children with isolated septal defects.


METHODS
The QP/QS ratio was evaluated by pulsed and or continuous wave echo-Doppler in 50 children who were submitted within 48 hours to cardiac catheterization. All children had an intracardiac shunt (12 atrial septal defects--ASD; 26 ventricular septal defects--VSD and 12 atrio ventricular septal defects--AVDS). Identical measurements were performed in a group of 20 children without cardiac malformation--control group. To test inter-observer variability, all the measurement in 31 patients were repeated by a second observer. Pulmonary and aortic flow was calculated as: Q = A x V x ET x CF where, A is the valvular orifice area (cm2), V the mean flow velocity (cm/sec), ET the ejection time (sec) and CF the cardiac frequency (cycles/min). The Doppler beam-flow direction angle in the pulmonary (P) artery and ascending aorta (Ao) was less than 20 degrees. Results were correlated with those obtained by catheterization (oximetric method).


RESULTS
We obtained a fairly good correlation with both pulsed wave Doppler (n = 43; r = 0.88; p less than 0.001; y = 0.84x + 0.40) and continuous wave Doppler (n = 50; r = 0.91; p less than 0.001; y = 0.86x + 0.35) or with pulsed wave Doppler in the P artery and continuous wave Doppler in the Ao (n = 43; r = 0.92; p less than 0.001; y = 0.86x + 0.27). In the control group, QP/QS ratio was evaluated by echo-Doppler: pulsed wave Doppler at 1.05 +/- 0.15 (mean +/- DS); continuous wave Doppler at 1.05 +/- 0.12 and, pulsed wave Doppler in the P artery and continuous wave Doppler in the Ao at 1.03 +/- 0.12. There was no significant difference in all three groups to the normal range of 1.00 (p less than 0.01). Inter-observer variability was less than 5.5% (p less than 0.001).


CONCLUSIONS
Pulsed and/or continuous wave echo-Doppler measurements are a reliable noninvasive method in evaluating QP/QS ratio in children with isolated septal defects.
Rufino Nascimento
L G
LG
Dehant
P
P
Jimenez
M
M
Dequeker
J L
JL
Castela
E
E
Choussat
A
A
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003326:Coronary Circulation; D015150:Echocardiography, Doppler; D005069:Evaluation Studies as Topic; D006343:Heart Septal Defects / Q000503:physiopathology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D010092:Oximetry; D011652:Pulmonary Circulation; D013318:Stroke Volume
Cálculo da relação dos débitos pelo eco-Doppler nos defeitos septais--correlação com a oximetria.