Tetralogy of Fallot with Absent Pulmonary Valve Syndrome

9 Tetralogy of Fallot with Absent Pulmonary Valve Syndrome



Rima S. Bader, James C. Huhta



I. CASE


A 25-year-old white woman, gravida 2, para 1, was referred at 26 weeks’ gestation because of an abnormal four-chamber view (dilated right ventricle [RV]).



A. Fetal echocardiography findings




1. The fetal echo reveals situs solitus of the atria, levocardia, left aortic arch, heart rate of 140 bpm.


2. Estimated fetal gestational age (GA) is 25.5 weeks.


3. There was cardiomegaly with increased cardiothoracic ratio (50%) and dextroposition of the heart.


4. The four-chamber view is abnormal, with a large perimembranous subaortic ventricular septal defect (VSD), large overriding aorta, and massively dilated pulmonary artery (Fig. 9-1).


5. The pulmonary valve is dysplastic with no identifiable leaflets, small pulmonary annulus (1.7 mm), and very dilated and pulsatile main pulmonary artery and branches.


6. There is pulmonary stenosis with a peak velocity of 2.2 m/s (lower panel) and pulmonary valve regurgitation. In other words, there is to (systolic) and fro (diastolic) flow through this dysplastic valve, with severe pulmonary regurgitation (Fig. 9-2).


7. There is holosystolic tricuspid regurgitation with a dP/dt (change in pressure per change in time) of 500 mm Hg per second.


8. The foramen ovale is patent, with unrestricted right-to-left shunt.


9. Aortic valve annulus is 6 mm.


10. A ductus arteriosus cannot be identified.


11. The pulmonary venous drainage is normal.


12. Tei index (myocardial performance index).


a. The RV Tei index is 0.45.


b. Left ventricle (LV) Tei index is 0.36.


13. The umbilical artery flow pattern is normal.


14. Ductus venosus flow is abnormal, with a wave reversal (3 mm).


image

Fig. 9-1 There is significant dextroposition of the heart in this fetus as a consequence of hyperinflation of the left lung due to compression by an aneurysmal left pulmonary artery (p). The main and left pulmonary artery are seen as the transducer is angled toward the fetal head. The overriding aorta (a) can be seen arising above both the left and right ventricles (LV, RV).


image

Fig. 9-2 Continuous wave Doppler in the right ventricular outflow tract shows a to-and-fro waveform with systolic pulmonary stenosis (PS) with a peak velocity >2 m/s and diastolic pulmonary valve regurgitation (PR).



B. Cardiovascular profile score




1. The cardiovascular profile score is 6/10.


2: Points deducted are 1 for cardiomegaly, 1 for abnormal ductus venosus flow, and 2 for holosystolic tricuspid regurgitation.



C. Associated extracardiac findings


None.



D. Fetal management and counseling




1. Management: Diagnosis of tetralogy of Fallot (TOF) should prompt referral for the following:


a. Thorough anatomic examination by ultrasound.


b. Amniocentesis.


    (1) Aneuploidy.

    (2) Fluorescent in situ hybridization (FISH) screen for chromosome 22q11.2 deletion.

2. Follow-up included serial antenatal studies at weekly intervals.


a. Cardiac function should be monitored by Tei index, by dP/dt if sufficient tricuspid regurgitation develops (3 m/s), and by tissue Doppler (if available).


b. Development of congestive heart failure (CHF) can indicate RV dysfunction secondary to severe pulmonary regurgitation. Severe AV or semilunar valve regurgitation, particularly if it influences filling of the other ventricle, can be very poorly tolerated. Thus, Ebstein’s anomaly and absent pulmonary valves can cause CHF.



E. Delivery




1. If the fetus remains well compensated, delivery should be at term in a tertiary care center.


2. Depending upon the severity of the pathology, which can include degree of cardiomegaly and degree of pulmonary artery dilation, the baby might require ventilatory support after birth as a result of compression of the tracheobronchial tree and coexisting tracheomalacia and bronchiomalacia.



F. Neonatal management


Mild cyanosis (pulse oximeter 90% to 92%) may be present initially. However, in some neonates who have only mild pulmonary outflow obstruction or who are born with ventricular dysfunction, as the pulmonary vascular resistance falls, there may be progressive congestive heart failure.



1. Medical.


a. Medical management of affected babies includes supporting them from a respiratory standpoint.


    (1) Infants with only mild disease might never require intubation.

    (2) In more severe cases, management of the airway issues can be extremely difficult and can require months of care and hospitalization.

b. Congestive heart failure.


    (1) Antifailure medication in the form of oral digoxin and furosemide can be started as signs of CHF appear or if the baby is born with CHF.

    (2) There is a hyperactive RV and a single and loud S2.

    (3) A loud to-and-fro murmur at the upper and middle left sternal border (resulting from pulmonary stenosis and pulmonary regurgitation) is characteristic of this condition.

Related posts:

  1. Outcome of Fetal Congenital Heart Defects
  2. Ventricular Septal Defect
  3. Pulmonary Atresia and Intact Ventricular Septum
  4. Suggested Views for Fetal Heart Imaging

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Jun 18, 2016 | Posted by in CARDIOLOGY | Comments Off on Tetralogy of Fallot with Absent Pulmonary Valve Syndrome

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