Diagnostic Methods Congenital Heart Disease

Twenty-nine patients with a patent ductus arteriosus (PDA) in isolation (n = 17) or in combination with other lesions (n = 12) underwent simultaneous hemodynamic assessment and evaluation of PDA flow velocity by the Doppler method. The accuracy with which Doppler velocity across the PDA predicted pulmonary arterial pressure and the influence of PDA size and shape on the Doppler velocity-pressure relationship were examined. Seventy percent had a cone-shaped PDA (narrowest at the pulmonary artery end), and the remainder were tubular. Narrowest PDA diameter ranged from 1.5 to 9 mm (mean 3.5 mm). Peak systolic and mean pulmonary arterial pressure ranged from 10 to 1 16 and 8 to 72mm Hg, respectively. Twenty-one patients (group 1) had left-to-right shunting only. The following variables showed significant correlation in this group: peak instantaneous systolic aortic-to-main pulmonary arterial (MPA) pressure gradient and maximum Doppler velocity across the PDA (slope = 1.03, SEE = 13 mm Hg, r = .94, p < .001), mean aortic-to-MPA pressure gradient and mean Doppler velocity (slope = 1.06, SEE = 10 mm Hg, r = .95, p < .001), and end-diastolic aortic-to-MPA pressure gradient and minimum Doppler velocity (slope = 1.12, SEE = 8 mm Hg, r = .96, p < .001). Eight patients (group 2) had bidirectional shunting. In this group peak instantaneous aortic-to-MPA pressure gradient significantly correlated with maximum Doppler velocity measured from the left-to-right shunt (slope = .70, SEE = 2 mm Hg, r = .92, p < .002) and mean pressure gradient correlated with mean Doppler velocity (slope = .83, SEE = 3 mm Hg, r = .78, p < .003). Right-to-left Doppler velocities showed no correlation with pressures. In six patients with pulmonary hypertension Doppler velocity changes accurately predicted the effect of pulmonary vasodilation on pulmonary arterial pressure. Doppler velocity ofPDA flow reliably predicts pulmonary arterial pressure over a wide range of pressures and PDA shapes and sizes. Circulation 76, No. 5, 1081-1091, 1987. ONE OFTHE most common lesions encountered either in isolation or in association with other forms of congenital heart disease is the patent ductus arteriosus (PDA). By combined two-dimensional and Doppler echocardiography both direct imaging and blood flow evaluation are possible. 1-5 Until recently, Doppler measurement of systolic pulmonary arterial pressure in the setting of a PDA has been accomplished by indirect assessment with the use of time intervals,6 which does not provide easily reproducible absolute values. EstiFrom the Department of Pediatrics, Division of Cardiology, Variety Club Cardiac Catheterization Laboratories, and Department of Radiology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario. Address for correspondence: Jeffrey F. Smallhom, M.D., Division of Cardiology, The Hospital for Sick Children, 555 University Ave. Toronto, M5G 1X8. Received May 5, 1987; revision accepted July 9, 1987. mation of pulmonary arterial systolic pressure has been attempted in the clinical setting of an aorticopulmonary shunt including PDA,7 where Doppler and pressure measurements were not all simultaneous. More recently, in an experimental preparation of discrete ductal constriction in the fetal lamb,8 simultaneous systolic and diastolic pressure measurements showed good correlation with Doppler velocity measurements. While it appears that peak systolic pressures correlate with Doppler velocities in the experimental setting, similar information is not available from a patient population incorporating a wide age range and variety of ductal sizes. Furthermore, previous studies have not provided information about mean pulmonary arterial pressure, which is necessary for assessment of alterations in pulmonary vascular resistance. This study addresses the reliability of Doppler-deVol. 76, No. 5, November 1987 1081 by gest on A ril 7, 2017 http://ciajournals.org/ D ow nladed from