DIAGNOSTIC METHODS CONGENITAL HEART DISEASE Noninvasive Doppler echocardiographic evaluation of shunt flow dynamics of the ductus arteriosus

The pulsed Doppler technique was used to record the flow velocity patterns in the ductus arteriosus and the pulmonary artery in 26 patients with either isolated or complicated patent ductus arteriosus (PDA). In all patients, abnormal Doppler signals indicating left-to-right (L-R) or right-to-left shunt flow or both could be obtained at the site of the ductus arteriosus. These Doppler flow patterns determined within the ductus coincided with the direction of ductal flow seen on the contrast two-dimensional echocardiogram. No Doppler signals of shunt flow were demonstrated in any of 42 control subjects. The peak, mean, and diastolic velocities of the L-R shunt flow within the ductus were measured from the ductal flow velocity profiles. With the Doppler-derived measurements of the mean and diastolic velocities, patients with normal pulmonary arterial pressure and those with evidence of pulmonary hypertension could be correctly identified. In addition, the mean velocity of the diastolic antegrade flow portion obtained from the proximal left pulmonary artery, which was related to ductal L-R shunting, was measured in 16 patients with isolated PDA. This Doppler flow determinant showed a good linear correlation with the L-R shunt ratio determined by Fick's method (r = .88, p < .01). Our technique permits the noninvasive evaluation of shunt flow dynamics in patients with PDA. Circulation 75, No. 6, 1146-1153, 1987. ALTERATION of Doppler flow patterns in the pulmonary artery and descending aorta has been useful in the diagnosis of patent ductus arteriosus (PDA).1 Twodimensional echocardiography has allowed visualization of the ductus from the parasternal, suprasternal, and subxyphoid windows.6'7 Recent reports8'9 have demonstrated that two-dimensional/Doppler echocardiography is a highly sensitive technique for detection of ductal patency. However, few studies have been reported concerning the assessment of shunt flow within the ductus.° l ` We therefore designed the present study to (1) evaluate the ability of two-dimensional/ Doppler echocardiography to determine the direction of shunt flow in the ductus and (2) assess the pulmonary-to-systemic peak pressure ratio and the degree of left-to-right (L-R) shunting with Doppler-derived indexes of the flow velocity. From the Department of Pediatrics, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan. Address for correspondence: Satoshi Hiraishi, M.D., Department of Pediatrics, Kitasato University School of Medicine, 1-15-1, Kitasato, Sagamihara, Kanagawa, 228, Japan. Received May 28, 1986; revision accepted Feb. 12, 1987.