TOTAL ANOMALOUS PULMONARY VENOUS RETURN
In this entity both the pulmonary and systemic veins return to the right atrium. There are several anatomical possibilities in regard to the way used by the pulmonary veins to drain into the right heart instead of the left atrium, but from the hemodynamic viewpoint a simple classification is very practical:
- TPVR over the diaphragm: Where there is in general normal pulmonary artery pressures (no anatomic impediment to the blood flow).
- TPVR below the diaphragm: Where there is usually pulmonary hypertension
The pulmonary veins may drain into a left superior vena cava and from there through the left innominate vein into the superior vena cava. This is the most frequent variety. Second in frequency will be the case of direct drainage of the pulmonary veins in the right atrium; sometimes the veins will connect with the vena azygos or coronary sinus.
Less frequent, the connection occurs below the diaphragm with connections to different systemic veins.
The heart will show right auricular hypertrophy, right ventricular hypertrophy, with small left atrium and ventricles.
Patent foramen ovale, ASD or PDA, are necessary for survival.
The anomalous connection implies admixture of systemic and pulmonary venous blood, with higher oxygen saturation, beyond the point of the abnormal pulmonary return (oxygen step-up).
Patent foramen ovale, ASD or PDA are needed for the blood to pass from right to left (right to left shunt) and a variable degree of systemic artery unsaturation is the rule (cyanosis).
The degree of systemic unsaturation will also depend on the pulmonary venous resistance, with the patient more cyanotic if the venous return has any type of impediment, as is the case in subdiaphragmatic connections.
The picture will depend upon the pulmonary venous resistance.
- With normal pulmonary artery pressures (benign course)
- Mild to moderate cyanosis
- Congestive heart failure in 500/c of patients which appear usually between 10 and 15 months of life (tachypnea, crying, sweating, poor feeding).
- Hepatomegaly in relation to the congestive failure.
- Grade II to IV systolic ejection murmur at the right and/or left sternal border, but a continuous murmur can also be present.
- Shifting of S2 which varies with respiration.
- Mid diastolic tricuspid rumble.
- With pulmonary hypertension (malignant course)
- Moderate to severe cyanosis at birth. Early appearance of congestive failure which is usually more severe and progressive than in the previous type.
- Elevation of jugular venous pressure with jugular and hepatic presystolic pulsation.
- Marked heart enlargement with visible parasternal lift.
- Grade Ill to V systolic ejection murmur in the pulmonary valve area with palpable pulmonary artery if its systolic pressure is higher than 60 mm Hg. All the other auscultatory components of pulmonary hypertension may be present. Tricuspid, middiastrolic rumble is audible at times.
- More infants with this second condition die in the newborn period in congestive heart failure.
P pulmonale is present in more than 80% of cases. Normal AV conduction is prevalent, but first degree AV block is not unusual.
Right ventricular hypertrophy is noted by marked right axis deviation and QR or rsR complex in VI with inverted T waves in right precordial leads in relation to the degree of pulmonary hypertension.
Pulmonary fields with increased blood flow and prominent pulmonary artery arch are characteristic in this patient.
Right ventricular hypertrophy more easily visualized in lateral projections is almost constant.
Snowman contour if persistent left superior vena cava is present and is relatively common.
Picture of pulmonary edema with lungs granular appearance is not unusual in the category of patients with pulmonary hypertension and severe heart failure. In the cases where CHF appears during the first month of life the heart size is near normal.
ECHOCARDIOGRAM IN ANOMALOUS PULMONARY VENOUS RETURN
The findings are the ones described in cases of ASD. In case of complete anomalous return the echocardiogram may record the confluence of these veins in the form of an "extra chamber" behind the right atrium. The sign however, is not reliable and can be seen in other situations as for example, Cor Triatriatum.
CATHETERIZATION AND ANGIOCARDIOGRAPHY
The following are the main features:
Oxygen step-up beyond the point of anomalous connection in the right side catheterization. Right sided pressures will depend on the degree of pulmonary hypertension.
Many times the pulmonary arteries can be entered with the catheter depending upon the point of anomalous connection, but this is not conclusive since this can be seen in ASD.
Angiocardiography injecting contrast in the right atrium will show a large right atrium with simultaneous contrasting of a small left atrium if ASD is present. The injection of contrast into the pulmonary artery will show the enlargement of the vessel and demonstrate in general the anomalous return.
MEDICAL & SURGICAL TREATMENT
Medical management of congestive heart failure.
Treatment of the cyanosis side effects.
Prompt medical treatment of respiratory tract infections.
Surgical correction must be an emergency if pulmonary hypertension exists as is almost the rule in the sub-diaphragmatic type where congestive failure otherwise will determine the infant deaths before one year of age.
If no failure exists and the pulmonary pressure is near normal, surgical corrections can be safely delayed for several years.
Diagrammatic representation of total pulmonary anomalous venous return.
- Supradiaphragmatic type
- lnfradiaphragmatic type