Noninvasive Detection of Aortic Coarctation in Neonates with Patent Ductus Arteriosus

• Main Authors: Chun-Wei Lu, 盧俊維
• Other Authors: Mei-Hwan Wu
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/86248263968460272128

碩士 === 國立臺灣大學 === 臨床醫學研究所 === 90 === Identification of coarctation in the neonatal period can be very difficult when a widely open ductus arteriosus is present. This study sought to find a noninvasive method for detecting the coarctation of aorta (CoA) in the presence of a patent ductus arteriosus (PDA) in the neonates. Fourty-five eonates (including four premature babies) with coarctation of the aorta confirmed after aortogram or surgery were enrolled to this study. Seven of them were excluded because the ductus arteriosus closed before our diagnosis. Their medical records were reviewed for the blood pressure of four limbs. We performed 2-D and Doppler echocardiography in all patients. The presence of the posterior shelf was checked for each patient. The inner diameters along the aortic arch were measured and Doppler flow mappings were undertaken over isthmus, ductus arteriosus and descending aorta. In addition, nineteen neonates with isolated patent ductus arteriosus proved after cardiac catheterization, surgery or follow-up longer than one year were selected for control. The degree of isthmus hypoplasia was reflected by the index: ratio of isthmus/descending aorta diameters (I/D ratio) for the correction of body size. The most significant diagnostic index for detecting CoA in the presence of PDA was the ratio of isthmus/descending aorta diameters (I/D ratio). The I/D ratio in coarctation group ranged from 0.30 to 0.68, (0.49 + 0.15, 95% C.l.= 0.45, 0.54) whereas the I/D ratio in control group ranged from 0.65 to 1.0, (0.84 + 0.14, 95% C.l.= 0.77, 0.91). We wish to find a critical point to differentiate between the two groups. Then new diagnostic criteria can be proposed. If any neonate who has one of the three conditions below, we can establish the diagnosis of aortic coarctation in the presence of PDA. First, there is significant blood pressure discrepancy between arm and leg without interrupted aortic arch noted by echocardiogram. Second, a posterior infolding at the aorta is demonstrated by echocardiogram. Third, the I/D ratio is lower than 0.64. Using above criteria, we found the diagnostic sensitivity and specificity both achieved 100%. Furthermore, an I/D ratio lower than 0.64 was more common in patients with associated intracardiac anomalies whereas the posterior shelf was more frequently seen in those without intracardiac anomalies. In conclusions, echocardiographic measurement of the aortic isthmus and descending aorta and delineation of the posterior infolding of isthmus can satisfactorily detect the presence of CoA and PDA in the neonates.