Echocardiographic Assessment of Ductal Anatomy in Premature Infants-Lessons for Device Design

Objective: Echocardiographic analysis of patent ductus arteriosus (PDA), proximal left main pulmonary artery (LPA) and descending thoracic aorta (Ao) dimensions in preterm infants who undergo surgical ligation of the PDA. A discussion for percutaneous ductal occlusion in preterm infants. Methods: Echocardiographic analysis of the LPA diameter, PDA diameter, PDA length, and descending thoracic aorta diameter in 55 preterm infants who underwent surgical ligation of the PDA from 2004 to 2008. Patients were stratified by weight into four groups: those less than 750 g, 751-1,000 g, 1,001-1,250 g, and those greater than 1,250 g. Mean and standard deviation for each structure dimension was calculated in each weight group. Structural dimensions were compared between groups using ANOVA for multiple comparisions. Results: The mean patient weight was 1,018 g (560-2,400 g). The mean ductal length was 4.1 mm (2.5-5.3 mm). The mean ductal diameter was 2.2 mm (1.5-3.6 mm). The mean LPA diameter was 3 mm (1.5-4.5 mm). The mean aortic diameter was 4.3 mm (2.7-7.8 mm). The alpha value for between weight groups for PDA length was 0.21, PDA diameter 0.16, LPA diameter 0.39, and aortic diameter 0.1. Discussion: No statistical significance was seen when comparing structure dimension by weight. This suggests uniform structural dimensions across a broad weight distribution in this patient population. To date, there has been no attempt to standardize dimensions of these vascular structures. The information gathered in this study may be useful in developing an implantable device for ductal occlusion in preterm infants. (ECHOCARDIOGRAPHY 2010;27:575-579).