Common Arterial Trunk or Truncus Arteriosus

Published on 07/06/2015 by admin

Filed under Neonatal - Perinatal Medicine

Last modified 07/06/2015

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17 Common Arterial Trunk or Truncus Arteriosus

I. CASE

A 33-year-old white woman, gravida 4, para 3+0, with DiGeorge’s syndrome was referred at 25 weeks’ gestation by her obstetrician for fetal echocardiogram, given the autosomal dominance of her condition. She had had an otherwise uncomplicated pregnancy. She has two other children, one normal and one with suspected DiGeorge’s syndrome.

A. Fetal echocardiography findings

F. Neonatal management

1. Clinical manifestations.

a. Cyanosis might not be noted immediately at birth.

b. A grade 2/6 systolic murmur with a systolic click is present along the lower sternal border.

c. A high-pitched diastolic murmur of truncal regurgitation might not be present at birth.

d. Signs of CHF can develop within days to weeks of birth as the pulmonary vascular resistance falls.

e. The clinical picture in most infants is that of a large left-to-right shunt with intracardiac mixing, the latter of which results in mild cyanosis.

2. Medical treatment.

a. Vigorous anticongestive measures with digitalis and diuretics could be required.

b. Close observation is necessary for evidence of significant diastolic steal, particularly affecting the coronary artery perfusion.

c. Metabolic acidosis, hypoglycemia, hypocalcemia should be treated.

d. Administration of oxygen is usually contraindicated in this disease in the absence of significant pulmonary pathology because it decreases the pulmonary vascular resistance, which would increase pulmonary blood flow further.

e. Given the presence of 22q11.2 microdeletion, the infant will need assessment of T-cell subsets and serum calcium levels. Affected infants often require calcium supplements. Given the potential for immunocompromise, CMV-negative and irradiated blood is critical.

3. Surgical correction.

a. Complete correction of common arterial trunk of this type is usually performed in the first 4 to 6 weeks of life. Waiting later than this places the baby at risk for significant pulmonary hypertension.

b. Correction includes closing the VSD, leaving the LV in continuity with the truncal valve, and placing a valved RV–to–pulmonary artery conduit (usually a homograft). The surgeon should attempt to repair the truncal valve, if necessary.

c. The surgical mortality ranges from 2% to 5%.

d. Timing of the operation varies by institution but is generally performed electively at 1 to 3 months of age. Earlier corrective repair may be necessary in a baby with severe heart failure or coronary artery steal.