[Use of Doppler ultrasonography in the diagnosis of aortic coarctation].

Coarctation may be suspected on two-dimensional echocardiography upon notation of an apparent narrowing of the lumen of the aorta, but sometimes the picture is not clear. The purpose of this study was the assessment the detection of coarctation in children with associated defects and if pressure gradient through the obstruction could be accurately estimated from Doppler. Methods. The study included 45 children (38 with coarctation of aorta and 7 with recoarctation) between the ages of 3 days to 14 years. The diagnosis was confirmed by cardiac catheterization and angiocardiography. Doppler echocardiographic studies were performed in all patients before surgery and in 40 patients after surgery. Doppler examination were performed with the use of continuous-wave flow meter Kardiodop KD-84 (Sonopan) with estimation of maximal velocity with histograph Doma HSD-83 (Domar) or with the use of Ultramark 4 Ultrasound System (ATL). The pressure gradient across the stenosis was calculated by using modified Bernoulli equation, and was defined as the subtraction of the square of the maximal velocity x 4 the descending and ascending aorta. Arm and tight cuff sphygmomanometer measurements were performed at the rest. Pressure drop in the descending aorta was measured by sphygmomanometry in 19 children and by catheterization in 10 children. The results were compared with Doppler calculated pressure gradients. Results. The maximal velocity in descending aorta increased on the average to 3.6 +/- 1.2 m/s was recorded in 43 children. With increasing severity velocities were higher, and with severe obstruction a pressure drop across the coarctation may persist throughout diastole and continuous forward flow was seen.(ABSTRACT TRUNCATED AT 250 WORDS)