Pulmonary Atresia and Intact Ventricular Septum

Published on 07/06/2015 by admin

Filed under Neonatal - Perinatal Medicine

Last modified 07/06/2015

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10 Pulmonary Atresia and Intact Ventricular Septum

I. CASE

A 30-year-old white woman, gravida 2, para 1+0, referred at 21 weeks’ gestation for an abnormal fetal four-chamber view on prenatal ultrasound. The mother has a 2-year-old daughter with a hypoplastic right heart and pulmonary atresia.

A. Fetal echocardiography findings

1. The fetal echo reveals situs solitus of the atria, levocardia, left aortic arch, and heart rate of 142 bpm.

2. The four-chamber view is abnormal, with a small right ventricle (RV), which is hypertrophied and has reduced systolic function, and a dilated right atrium (RA) (Fig. 10-1).

3. Cardiac axis and position are normal.

4. Cardiac size is increased (cardiothoracic ratio = 0.40).

5. The outflow assessment reveals normally related great arteries with significant asymmetry (aorta–to–pulmonary artery diameter ratio = 1:0.5).

6. The pulmonary valve is atretic, with no antegrade flow in systole and no pulmonary insufficiency.

7. There are good-sized confluent branch pulmonary arteries.

8. The tricuspid valve diameter is small (0.24 cm) (z score = −3), with normal inflow waves (E/A waves).

9. A narrow jet of tricuspid regurgitation (4 m/s) and a dP/dt (change in pressure per change in time) of 600 mm Hg per second.

10. There are possible RV coronary sinusoids.

11. The aortic arch is leftward, with normal antegrade flow.

12. The ductal arch shows flow reversal in systole.

13. There is unrestricted flow through the foramen ovale, with a right- to-left shunt.

14. The pulmonary venous flow pattern is normal. There is also normal flow in the inferior vena cava (IVC), ductus venosus, and umbilical vein.

15. The left ventricular (LV) Tei index (myocardial performance index) is normal to mildly increased (0.48). The RV Tei index could not be calculated due to the pulmonary atresia.

D. Fetal management and counseling

1. Amniocentesis should be offered, although chromosomal anomalies are unlikely with pulmonary atresia with intact ventricular septum.

2. Follow-up includes serial antenatal studies at 4-week intervals.

a. Assess RV size and function and endocardial fibroelastosis.

b. Look for congestive heart failure (CHF), which can develop if there is:

c. Assess LV function.

d. Assess the growth of pulmonary arteries and branches. Ductal flow has already been shown to be reverse of normal due to the atretic pulmonary valve.

3. Delivery.

a. Conditions for vaginal delivery.

b. Conditions for cesarean delivery.

c. Cesarean section practice varies with institution preference.

E. Neonatal management

1. Medical.

a. Administer prostaglandin E1 (PGE1) infusion to keep the ductus open to increase pulmonary blood flow and raise arterial oxygen saturation.

b. Oxygen administration can increase oxygen saturation by decreasing pulmonary venous regurgitation and increasing blood flow.

c. Therapeutic balloon atrial septostomy should be performed in the rare situation of restrictive patent foramen ovale.

d. Cardiac catheterization and angiography are recommended to demonstrate coronary sinusoids (by RV angiogram) and rule out coronary artery anomalies such as stenosis. In many pediatric cardiac centers, radiofrequency perforation of the RV outflow tract (RVOT) is possible at cardiac catheterization, eliminating the need for surgery when the RV can otherwise sustain sufficient pulmonary circulation.

2. Surgical.

a. Palliative.

b. Corrective.