19 Total Anomalous Pulmonary Venous Connection
A 29-year-old white woman, gravida 4, para 3, was referred at 31 weeks’ gestation by the high-risk obstetrician for abnormal triple screen with increased risk for trisomy 18 and an abnormal scan with mild disproportion at the ventricular level with increased right ventricular (RV) size. A small ventricular septal defect (VSD) was also suspected.
6. There is a small aneurysm of the fossa ovalis, and the entry of the pulmonary veins into the LA could not be visualized by two-dimensional Doppler; however, there was a gap between the descending aorta and the posterior wall of the left atrium (LA).
9. Diagnosis of total anomalous pulmonary venous return with obstruction was also suspected due to the intracardiac disproportion and the abnormal (flat) pulmonary venous Doppler (Fig. 19-1B), and failure to identify the pulmonary veins.
Fig. 19-1 Fetus with total anomalous pulmonary venous connection below the diaphragm. A, The descending vein (DV) flows toward the liver. LA, left atrium; PA, pulmonary artery. See also color version of figure in color insert. B, Absence of pulmonary venous pulsation tells us that the pulmonary vein does not connect to the heart. PA, pulmonary artery; PV, pulmonary vein.
b. Attempts at further defining the anatomy of the pulmonary venous connection are important, and in the case of the present patient, a descending vein pathway below the diaphragm was identified at follow-up studies consistent with a subdiaphragmatic connection. It is important as well that the pulmonary veins and confluence are reassessed for evidence of progressive obstruction or reduced growth. The branch pulmonary artery diameters also might not grow normally if there is high downstream resistance to flow due to pulmonary venous obstruction.
At term in the cardiac center, an elective induction will be performed at 39 weeks’ gestation with cardiology in attendance and the surgical team standing by due to the potential for important obstruction of the pulmonary veins and need for emergent corrective surgery.
a. After birth, the baby will be assessed by the cardiac team. A low level of oxygenation (pulse oximeter <50% with low pressure and high oxygen ventilation) and progressive pulmonary hypertension and edema are the primary indications for intervention.
b. Management of the pulmonary hypertension includes assisted ventilation, although hyperventilation can also worsen the pulmonary edema and thus make oxygenation more difficult. For the most severe cases, an exit type of procedure with extracorporeal membrane oxygenation (ECMO) available for resuscitation may be necessary.
b. Obstruction can occur at the site of surgical repair or can result from abnormalities of the pulmonary veins themselves. Such pulmonary vein obstruction can lead to a shortness of breath or wheezing, particularly on exertion.
d. In the first year after a neonatal repair, the infant should be seen at more frequent intervals to exclude progressive pulmonary venous obstruction. Thereafter, yearly cardiology assessments that include echocardiography should be provided.
2. Bleyl and colleagues (1993) reported on a large Utah–Idaho family in which nonsyndromic TAPVC appeared to be inherited as an autosomal dominant trait with incomplete penetrance and variable expression. The family contained 14 affected members.
3. Solymar and colleagues (1987) reported three pairs of siblings with TAPVC. The types of the anomalous venous return (supra- or infracardial connections) varied within the families, indicating that genetic regulation deals with the LA connection to the intrapulmonary veins.
e. The Baltimore–Washington Infant Study (BWIS), a population-based exploratory case-control study of cardiovascular malformations, identified 41 cases of TAPVC during the period 1981 to 1987. These constituted 1.5% of all cardiovascular malformations (N = 2659), with a regional prevalence of 6.8 per 100,000 live births.