Unidad Regiomontana de Diagnostico, 5 de Mayo # 403 Pte., Monterrey, N.L., México. CP. 64000 Monterrey, N.L., Mexico.

Definition: Patency of the ductus arteriosus is maintained during gestation by locally produced and circulating prostaglandins. As gestation proceeds, the ductus becomes less sensitive to dilating prostaglandins and more sensitive to constricting factors such as prostaglandins synthetase inhibitors. Fetal ductus arteriosus closure or constriction is caused by maternal medication of prostaglandin synthetase inhibitor or corticosteroid. Idiopathic or spontaneous ductus arteriosus closure has been also reported ^1,2,3,4.
Intrauterine closure of ductus arteriosus results in increased right ventricular afterload and right ventricular systolic dysfunction.

Case report: A 27-year-old woman who had not been received any medication or nonsteroidal anti-inflammatory agents, with no family history of malformations or genetic disorders attended the ultrasound unit at 14, 21 and 30 weeks for routine examinations. The scans revealed a normal four chamber and three vessel view.
The patient attends again at 35 weeks gestation because fetal movements were diminished the day before, and were absent the day of the examination.

The findings included:

• severe oligohydramnios,
• chamber disproportion caused by the enlargement of right atria and ventricle,
• tricuspid and pulmonary valve regurgitation,
• increased caliber of main pulmonary and right and left pulmonary arteries, and
• lack of visualization of the pulmonary end of ductus arteriosus

This is a four chamber view showing disproportion caused by enlargement of right atria and ventricle.

Three vessel view. Main pulmonary artery and its right and left branches are dilated. Constriction of ductus arteriosus at the pulmonary end. The caliber of the ascending aorta and superior vena cava are normal.

Tricuspid regurgitation and ventricular septal defect.

There are also 2 short clips in gray-scale and color. The heart rate was 187 bpm. Doppler measurement of medial cerebral and umbilical arteries was normal.

A cesarean section was immediately performed and a healthy 2800 grams female infant with an Apgar score of 8/9 was obtained. There were no further complications.
Echocardiography performed on the newborn showed the ductus arteriosus closed, proportion of cardiac chambers returned to normal, and the persistance of a little jet of tricuspid regurgitation and shunting across the ventricular septal defect, this time from left-to-right.

There is also short clips of the neonate.

On a 2 month follow-up after birth, the baby has had a good clinical outcome.

History: It has been shown experimentally as well as clinically that indomethacin constricts the fetal ductus arteriosus. There are 9 reported cases of prenatal diagnosis of spontaneous (no drug induced) premature closure of the ductus arteriosus^1,2,3,4, and all of them had the same findings seen in this case, except for the oligohydramnios (some cases mention polyhydramnios). There is a pathology report of 800 perinatal necropsies where 3 stillborn infants were found to have an almost completely closed ductus arteriosus. Each of these showed cardiomegaly, dilatation of right side chambers, and pulmonary hyperaemia. Intrauterine death was considered to be due to premature closure of the ductus arteriosus^5,6. 

Etiology:  Patency of the ductus arteriosus is no longer maintained during gestation by locally produced and circulating prostaglandins, and the ductus becomes more sensitive to constricting factors such as prostaglandins synthetase inhibitors^7,8,9

Pathogenesis:   As the ductus arteriosus closes in the fetus, blood from the right heart is totally directed to the high resistance fluid-filled lungs, resulting in increased right ventricular afterload, impaired right ventricular function, and consequently tricuspid regurgitation and right heart dilatation. After birth, blood flow from the right heart goes through low resistive air filled lungs, diminishing right ventricular afterload, which solves the heart chambers disproportion in the newborn.  

Sonographic findings: In every reported case of PCDA there have been consistent findings: cardiomegaly, dilatation of pulmonary arteries, the main pulmonary artery and the right ventricle and atria. Tricuspid regurgitation, and no visualization of ductus arteriosus in all its extension. Hydrops has been described in previous reports³. In this case PCDA was associated to severe oligohydramnios.

Differential diagnosis: The most common causes of right heart dilatation appearing in the third trimester are:
1. Coarctation of the aorta. This can be ascertained by evaluating the size of the ascending aorta (usually small), and the transverse arch. Usually bi-directional flow is present in the transverse arch.
2. Significant placental dysfunction. Usually the outflow tracts measure normal. There may be bi-directional flow in the transverse arch, but not as much as with coarctation.
3. Constriction or closure of the ductus arteriosus. 

Associated anomalies:  There are no reports of associations with other anomalies.

Prognosis:   Delaying delivery compromises very seriously the survival of the fetus. Urgent delivery results in an excellent prognosis.

References

1- Chao RC, Ho ES, Hsieh KS: Doppler echocardiographic diagnosis of intrauterine closure of the ductus arteriosus. Prenat Diagn 1993 Oct; 13(10): 989-94

2- Hofstadler G, Tulzer G, Altmann R, Schmitt K, Danford D, Huhta JC. Spontaneous closure of the human fetal ductus arteriosus. A cause of fetal congestive heart failure. Am J Obstet Gynecol 1996 Mar; 174(3): 879-83

3- Leal SD, Cavalle-Garrido T, Ryan G, Farine D, Heilbut M, Smallhorn JF. Isolated ductal closure in utero diagnosed by fetal echocardiography. Am J Perinatol 1997 Apr; 14(4): 205-10

4- M. Y. Park, Y.J. Kim, B.H. Woo and H.S. Kim S-shaped kinking and constriction of the fetal ductus arteriosus with pericardial effusion
Ultrasound in Obstetrics and Gynecology Volume 16 issue s1 Page 93 October 2000.

5- Kohler HG. Premature closure of the ductus arteriosus (P.C.D.A.): A possible cause of intrauterine circulatory failure. Early Hum Dev 1998 Apr; 2(1): 15-23

6- Becker AE, Becker MJ, Wagenvoort CA. Premature contraction of the ductus arteriosus: a cause of fetal death. J Pathol 1977 Mar;121(3): 187-91

7- Truter PJ, Franszen S, van der Merwe JV, Coetzee MJ. Premature closure of the ductus arteriosus causing intra-uterine death. A case report. S Afr Med J 1986 Oct 25; 70(9): 557-8

8- Huhta JC, Cohen AW, Wood DC. Premature constriction of the ductus arteriosus. J Am Soc Echocardiogr 1990 Jan-Feb; 3(1): 30-4

9- Tumbarello R, Pisu F, Pisano E, Puddu R, Bini RM. Timely detection of premature closure of the ductus arteriosus in a full-term fetus. Important role of fetal echocardiography. Minerva Ginecol 1999 May; 51(5): 197-201