Aorto-pulmonary window

Dr Cuillier F.1, Dr Defaud F.2, Dr Arsac L.A.3, Dr Alessandri J.L.4, Pr Doray B.5

1.Department of Gynecology, Félix Guyon CHU, 97400 Saint-Denis, Ile de la Réunion, France. 
2.Department of Gynecology, CHR, 97434 Saint-Paul, Ile de la Réunion, France. 
3.Department of Neonatal Cardiology, Félix Guyon CHU, 97400 Saint-Denis, Ile de la Réunion, France.
4.Department of Neonatology, Félix Guyon CHU, 97400 Saint-Denis, Ile de la Réunion, France.  
5.Department of Genetic, Félix Guyon CHU, 97400 Saint-Denis, Ile de la Réunion, France.  

Case report

We report a case of prenatal diagnosis of aorto-pulmonary window (APW) associated with ventricular septal defect, identified by fetal ultrasonography at 23 weeks of gestational age. 

A 20-year old woman (G1P0) with history of tetralogy of Fallot treated surgically at four month of life, went to our unit.

Her first trimester screening was normal (TN:1mm - 60mm CRL) and the triple test was 1:2000.

We performed an anomaly scan at 22-23 weeks of gestation and our ultrasonographic exam revealed the following findings:

Images 1 and 2: 2D images of the fetal heart showing a ventricular septal defect. 

1A-Mar_-AO-23SA
1B-Mar_-AO-23SA

Image 3: 2D image shows fetal situs and rotation of the cardiac axis to the left.

1C-Mar_-AO-23SA

Images 4 and 5; videos 1 and 2: 2D and color doppler images of the fetal heart showing overriding aorta over the ventricular septal defect.

2A-Mar_-AO-23SA
2B-Mar_-AO-23SA

Images 6, 7, 8 and 9; videos 3-7: 2D images of the fetal heart in different planes showing normal size of the pulmonary artery and its bifurcation. Also, we noticed an abnormal communication between the aorta and pulmonary artery, suggesting an aorto-pulmonary window.

3A-Mar_-AP-23SA
3B-Mar_-AP-23SA
3C-Mar_-AP-23SA
3D-Mar_-AP-23SA

The patient was informed about this cardiac anomaly. She refused an amniocentesis.

She delivered prematurely at 32 weeks of pregnancy. During the postnatal period, the cardiac anomaly was confirmed. The baby was transferred to Paris (Necker hospital) at two months of life for surgery.

Definition:

Aortic-pulmonary window (APW) is a rare heart defect, in which there is a communication between the aorta and the pulmonary artery. The defect usually begins just above of the sinus of Valsalva and extends a variable distance distally into the arch.

Synonyms:

APW; Aorto-pulmonary septal defect; Aorto-pulmonary fenestration.

Frequency:

Aorto-pulmonary septal defect is a rare congenital malformation (0,1% of all congenital heart defects). APW can occurs isolated, but is usually associated with other congenital cardiovascular abnormalities (interrupted aortic arch, ventricular septal defect ; atrial septal defect or specially tetralogy of Fallot). 

History:

Aorto-pulmonary septal defect was first described during the 19th century. The first repair was performed in 1952 by Robert E. Gross (in Boston Children's Hospital).  

Etiology:

Congenital anomaly, Aorto-pulmonary septal defect represents a failure of the conotruncus to differentiate into the aorta and pulmonary artery. 

Genetics:

No genetic associations are known with Aorto-pulmonary septal defect . Environmental risk factors are also unknown, but the two embryologic theories are: 

  • APW is part of a spectrum of conotruncal abnormalities, which includes truncus arteriosus at one end of the Spectrum; or
  • APW is unrelated to truncus arteriosus because the lesions associated with each defect are dissimilar.

Sonographics features:

APW is an uncommon fetal malformation, usually diagnosed after birth by echocardiography. The diagnosis is based on echocardiographic images:

-A septal defect between the ascending aorta and pulmonary artery.
-Normal semilunar aortic and pulmonary valves with normal size. 
-Normal four chamber view.

Differential diagnosis:

Tetralogy of Fallot and truncus arteriosus.

Consequences:

During post-natal period, because of this abnormal communication between the aorta and pulmonary artery, blood from the aorta flows into the pulmonary artery and the lungs, resulting in an increased pulmonary pressure (pulmonary hypertension and Eisenmenger syndrome), cardiac output, heart failure, and even death. 

Treatment:

Spontaneous closure is not known to occur, so the presence of an APW itself is an indication for surgical repair. Delay in repair risks development of pulmonary vascular hypertension and then Eisenmenger syndrome. Therefore, repair should be undertaken at the time of diagnosis and after initial cardiac stabilization.

Subsequent development of cardiopulmonary bypass techniques simplified the repair. Currently, an incision directly into the aortopulmonary window or the aorta is used. Most lesions are repaired by direct patch repair of the defect.

Prognosis:

Surgery to correct this rare anomaly is successful in most cases. If the diagnosis is made during fetal life, after the surgery, the baby should not have any other complications.    

Conclusion:

We demonstrated in our case a prenatal diagnosis of Aorto-pulmonary septal defect. We hope to help other collegues to keep in mind this uncommon anomaly.

Prenatally diagnosis, planning the delivery in a tertiary center and performing an early surgical correction will allow an excellent prognosis. Prenatal diagnosis of Aorto-pulmonary septal defect avoid consequences like pulmonary disease and premature death which are the common outcome of untreated Aorto-pulmonary septal defect. 

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