Repair is carried out using cardiopulmonary bypass with moderate hypother- mia, aortic clamping, cardioplegia, and profound local cardiac cooling. The left ventricle is vented.

1 Anomalous Systemic Venous Return

Abnormal connections between the inferior vena cava, or right or left superior venae cavae to the right or left atrium may occur. A right-side anomaly (e.g., per- sistent left superior vena cava to the coronary sinus or azygos continuation of the inferior vena cava) may be of no consequence and require no treatment, although when other intracardiac anomalies require repair, the right-side abnormality may require an alteration in cardiopulmonary bypass cannulation techniques. When systemic veins connect to the left atrium, there is a right-to-left shunt with cyanosis, and repair is necessary. With a persistent left superior vena cava that connects directly to the left atrial roof (also known as unroofed coronary sinus), ligation of the structure obliterates the intracardiac shunt but is dangerous unless there is a normal innominate vein or large collateral connections in the head that allow unobstructed left head and neck flow into the heart. This left cava other- wise can be anastomosed directly to the right superior vena cava in certain cir- cumstances or requires intracardiac tunneling to the right atrium.

These anomalies are usually diagnosed by echocardiography, cardiac catheter- ization and angiography, or cardiac magnetic resonance imaging (MRI), but occa- sionally are discovered as incidental findings at the time of intracardiac surgery for another anomaly.

Repair is carried out using cardiopulmonary bypass with moderate hypother- mia, aortic clamping, cardioplegia, and profound local cardiac cooling. The left ventricle is vented.

1

ceph R < - - • L

caud

atrial septal defect

cannula in anomalous left superior vena cava

FIGURE 1-1. The patient is on cardiopulmonary bypass and cannulae are placed in the right superior and inferior venae cavae. The right atrium is opened, and a large secundum atrial septal defect (ASD) is seen. A third caval cannula passes through the ASD and is placed in the left superior vena cava, which enters the upper posterior wall of the left atrium.

ceph

R^- - • L

caud

orifice of right upper pulmonary

caval cannula placed in orifice of left superior vena cava

FIGURE

1-2. The atrial septum is retracted, and the cannula is seen at the orifice of the

left superior vena cava.

ceph R < - - * L

caud

Dacron patch stitched to lower rim of orifice of left superior vena cava

atrial septal defect

FIGURE

1-3. A thin, knitted Dacron® patch is stitched along the lower rim of the orifice of the left superior vena cava.

ceph

R<-

caud

suture around orifice of left superior vena cava

patch

FIGURE

1-4. The suture is continued around the right and left sides of the caval orifice and

then runs anteriorly toward the upper rim of the atrial septum. The patch is placed caudad

over the atrial septal defect and will be stitched to the atrial septum to close that defect.

cannula In left superior vena cava

patch stitched to atrial septum

The atrial septal defect is closed, and drainage from the left superior vena cava is now diverted to the right atrium.

1-2. Right Superior Vena Cava Draining to Roof of Left Atrium

The preoperative diagnosis in this patient was sinus venosus ASD with possible partial anomalous pulmonary venous connection.

ceph R « - - > L

caud

rim of atrial septal defect

orifice of right superior vena cava

FIGURE

1-6. The child has been placed on cardiopulmonary bypass and the superior vena

cava is cannulated directly and remotely from the caval atrial junction. An atriotomy is

made in the mid right atrium. The ASD is identified in the high lateral septum in the sinus

venosus region. The right upper and middle pulmonary veins were seen draining to the

left atrium immediately posterior to the atrial septal defect. The superior vena cava orifice

is adjacent to the pulmonary veins in the left atrium.

probing clamp in superior vena cava

FIGURE

1-7. A clamp is passed through the ASD and into the caval orifice to verify its location.

R <

upper segment of superior vena cava

closure of lower segment of superior vena cava

FIGURE

1-8. The superior vena cava is divided above the region of the upper and middle

lobe pulmonary veins. The lower caval segment is closed primarily.

ceph R « - - > L

caud

atrial septal defect

FIGURE

1-9. The ASD is exposed and the lower caval closure suture line identified from within to ensure there is no encroachment on the pulmonary veins.

ceph R<- - * L

caud

FIGURE

1-10. The ASD is closed with a Dacron® patch.

ceph

R<-

caud

upper segment of divided superior vena cava

atriotomy at base of right atrial appendage

FIGURE

1-11. A generous transverse incision is made in an appropriate area at the base of the right atrial appendage for a direct cava to atrium anastomosis. A spot for the anas- tomosis is chosen to avoid undue tension on the new connection.

posterior anastomosis

FIGURE

1-12. A continuous fine polypropylene suture is used for the posterior anasto-

mosis. A similar continuous suture is used for part of the anterior anastomosis with the

remainder closed with three or four interrupted sutures to ensure growth potential of the

new anastomosis.

ceph R < - - • L

caud

cava to

atrium anastomosis

closed atriotomy

FIGURE

1-13. The completed anastomosis is seen and there is no undue tension from the

right atrium.