ANOMALOUS PULMONARY VENOUS DRAINAGE

Anomalous pulmonary venous return can be divided into two subgroups:

1. Total anomalous pulmonary venous return (TAPVR).
• None of the pulmonary veins drain into the left atrium.
2. Partial anomalous pulmonary venous return (PAPVR).
• At least one of the pulmonary veins have an anomalous connection.

TYPES OF ANOMALOUS PATHWAYS (1)

[more information]

• Type I - Supracardiac (47%).
• Type II - Cardiac (31%).
• Type III - Infracardiac (13%).
• Type IV - Mixed anomalous connections (7%). Unknown connection (2%)

ULTRASOUND

• Antenatal diagnosis is rare as it is extremely difficult to demonstrate the abnormal venous connections.
  Problems:
1. The anomalous vein may be small or follows a complex variable course.
2. Pulmonary venous flow is minimal antenatally when compared with the postnatal appearance.
3. The right to left shunt seen in the neonate with TAPVR is normal in the fetus.
• Diagnosis is excluded if one or more pulmonary veins can be observed entering the left atrium (to exclude partial anomalous pulmonary venous return, all four veins must enter the left atrium).

PAPVD

• Four normal pulmonary veins do not enter the left atrium.
• Small left atrium from decreased venous return.
• Mild right ventricular or pulmonary artery enlargement may occur.
• Ratio of right to left blood flow across the atrioventricular, aortic and pulmonary valves of > 2:1 is highly suggestive of TAPVR.
• Associated fetal hydrops rare.
• Doppler flow demonstrates a low velocity, mildly pulsatile flow pattern representing the lack of the normal influence of left atrial hemodynamics. The pattern is due to a distant or damped connection to inferior vena caval flow (2-4).

ASSOCIATED SYNDROMES

Link to Conditions and Syndromes Associated with TAPVR

REFERENCES

1. Borroughs JT, Edwards JE. Total anomalous pulmonary venous connection. Am Heart J 1960;59:913.
2. Bonham-Carter RE, Capriles M, Noe Y. Total anomalous pulmonary venous drainage: a clinical and anatomic study of 75 children. Br Heart J 1969;31:45.
3. Smallhorn JF, Freedom RM. Pulsed doppler echocardiography in the preoperative evaluation of total anomalous pulmonary venous connection. J Am Coll Cardiol 1986;8:1413-1420.
4. Feller Printz B, Allan LD. Abnormal pulmonary venous return diagnosed prenatally by pulsed doppler flow imaging. Ultrasound Obstet Gynecol 1997;9:347-349.