Congenital ductus arteriosus aneurysm.

Abstract

Ductus arteriosus aneurysm (DAA) is a rare congenitalmorphological abnormality that can occur in neonates.However, recent reports suggest that DAA is much morecommon among fetuses and neonates than previouslysuspected [1, 2]. Jan et al. [3] reported that DAA is avariant of normal anatomy with an incidence of 8.8 %.Although some cases of DAA regress spontaneously, oth-ers cause complications, such as compression, thrombo-embolism, infection, nerve palsy, and spontaneous rupture.TostudytheincidenceandprognosisofDAA,werecentlyperformed screening echocardiography on 157 consecutiveneonates born in our hospital. Within this population, wedetected nines cases (seven males, two females) with DAA(5.7 %), which is comparable to the incidence described in aprevious report [3]. The birth weight of individuals was1892–4085 g and gestational age was 32–42 weeks.In all cases, DAA was seen as a tortuous and dilatedvascular structure that protruded leftward from the aorticarch and that ran parallel to the descending aorta, with amean diameter of 11.3 ± 3.6 mm. Three-dimensional (3D)color Doppler echocardiography clearly showed anomalousductalflowrunningparalleltothedescendingaorta(.Fig. 1).At the pulmonary arterial end, the blood flow took a 180turn,pouringintothemainpulmonaryartery.Althoughthereare no previous reports of DAA assessed by 3D echocardi-ography, this method was able to demonstrate the spatialrelationshipbetweentheDAAandthedescendingaorta.Theflow velocity in this DAA was low, because the pressuredifference between the pulmonary artery and the descendingaorta was minimal under physiological pulmonary hyper-tension after birth.In all cases, DAA closed with a thrombus within 3 daysafter birth, and the pulmonary arterial end remained as apulmonary arterial aneurysm in seven cases (.Fig. 2). Attime points greater than 5 days after birth, the thrombuscould not be discriminated from the surrounding structures.Fetal echocardiography can detect DAA in the thirdtrimester, but not earlier in gestation [1]. Late onset ofDAA during prenatal development is due to altered circu-lation (blood pressure and output increase) or weakening ofthe wall of the ductus [4]. Jan et al. [3] reported that 70 %of affected individuals experience diminution in size of theDAA following spontaneous closure and that only 30 % ofaffected individuals showed thrombus formation. Thisdifference between those investigators’ data and the datafrom the present study may be attributed to the fact thattheir cases included smaller DAA and because the imagequality of echocardiography to detect thrombus hasrecently improved.Complications of DAA include thromboembolic eventsas well as extension of the thrombus into the pulmonaryartery or aorta. Although all cases in our study had a benigncourse, even small DAA can be dangerous, especially inpatients with connective tissue disease [4]. The true inci-dence of DAA remains unclear, and further prospectivepopulation-based study is necessary. Color Doppler 3Dechocardiography is useful to characterize the relationshipbetween DAA and the pulmonary artery or descendingaorta.