Eur J Cardiothorac Surg 1999;14:326-328
© 1999 Elsevier Science NL
Aortic valve stenosis causing a left-to-right shunt in persistent left superior vena cava communicating with the left atrium
Shui-Yun Wanga,
Taisto Talvensaarib,
Matti R. Tarkkaa
a Division of Thoracic and Cardiovascular Surgery, Department of Surgery, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
b Department of Medicine, Tampere University Hospital, Tampere, Finland
Received 12 January 1998;
received in revised form 18 May 1998;
accepted 26 May 1998.
Corresponding author. Fax: +358 3 2475756.
 |
Abstract
|
|---|
This study demonstrated a rare anomaly of a persistent left superior vena cava draining into the left atrium in a patient with developing left-to-right shunt caused by bicuspid aortic stenosis. The venous system, including the coronary sinus, was otherwise normal. We believe that, in this anatomic situation, a marked increase in left ventricular impedance caused a moderate left-to-right shunt from the left atrium into the left innominate vein. At operation, the aortic valve was replaced with a mechanical prosthesis and the anomalous vein was ligated. The convalescence was uneventful.
Key Words: Left superior vena cava • Left-to-right shunt • Aortic valvular stenosis
|
Introduction
|
|---|
A persistent left superior vena cava (PLSVC) is reported to occur in 2.0–4.3% of patients with congenital heart diseases, and it usually drains into the right atrium via the coronary sinus. However, in 7–8% of cases this anomalous vessel drains into the left atrium and usually results in a right-to-left shunt
[1].
We report on a patient with bicuspid aortic valve stenosis who had moderate left-to-right shunting via the PLSVC communicating with the left atrium. To our knowledge, this association has not previously been described.
|
Case report
|
|---|
A 64-year-old man was admitted to the cardiac department in August 1996 because of exertional dyspnea of NYHA class 2.
Sixteen years before admission, trivial bicuspid aortic valvular stenosis was diagnosed. There was no history of heart failure or cyanosis. Physical examination showed a grade 3/6 ejection systolic murmur. Blood pressure was 110/75 mmHg. ECG demonstrated sinus rhythm, and moderate left ventricular hypertrophy. The chest X-ray revealed moderate cardiomegaly and increased shunt vascularity.
A transthoracic echocardiogram showed a hypertrophied left ventricle, grave valvular aortic stenosis and right ventricular dilatation. Radiocardiography via the right basilic vein revealed moderate left-to-right shunt: Qp/Qs was 2.6. In biplane transesophageal echocardiography the atrial septum, the coronary sinus and all four pulmonary veins were normal; entering into the upper lateral part of the left atrium was a structure in which the flow was backwards from the atrium (
Fig. 1
).
View larger version (79K):
[in this window]
[in a new window]
|
Fig. 1. Biplane transesophageal echocardiogram (modified horizontal plane) demonstrating the persistent superior left vena cava (PLSVC) draining from the left atrium (LA). LV, left ventricle; MV, mitral valve.
|
|
At left heart catheterization, the gradient of the aortic valvular stenosis was 74 mmHg. Coronary arteries were normal. In right heart catheterization, a catheter passed via the left innominate vein. With the aid of a guide wire, the catheter was advanced down a persistent left superior vena cava into the left atrium. Oximetric studies showed a step-up in oxygen saturation at the left innominate vein. The oxygen saturation was 62.1% in the left subclavian vein and 85.4% in the left innominate vein. The mean pressure in the left and right atria was 16 mmHg and 9 mmHg, respectively. Pulmonary artery pressure was 73/23 mmHg. Cineangiograms of contrast material injected into the left atrium showed the flow from the atrium into the left ventricle and also backwards into the PLSVC. Contrast material injected into this communicating vein and into the left innominate vein flowed into the right superior vena cava, visualizing the normal venous arch between the right and left superior vena cava. Magnetic resonance imaging also showed the anomalous connection between the left atrium and the left innominate vein (
Fig. 2
).
View larger version (122K):
[in this window]
[in a new window]
|
Fig. 2. T-1-weighted magnetic resonance image in coronal plane displaying the persistent superior left vena cava (PLSVC) entering from the left atrium (LA). LV, left ventricle; RA, right atrium.
|
|
An operation was performed on February 19th, 1997 which verified the sizes of the left innominate vein, the right superior vena cava and the PLSVC as 2.0, 2.5 and 1.5 cm in diameter, respectively. The PLSVC was found to enter the cephalic left lateral portion of the left atrium without any juxtaposition of pulmonary veins, and it ligated at its point of entry. The coronary sinus was normal. The bicuspid aortic valve, with very severe calcification, was replaced using a mechanical Carbomedics 25 prosthesis. The patient had an uneventful convalescence and was discharged on the eighth post-operative day.
|
Discussion
|
|---|
Embryologically, failure of invagination between the left sinus horn and the left atrium allows for a PLSVC terminating in the left atrium
[2]. Furthermore, in the sinoatrial region of the heart, the left atriovenous fold is commonly involved, creating a PLSVC draining into the left atrium associated with atrial septal defect and absence of the coronary sinus. If the left atriovenous fold develops in a normal condition, the atrial septum is intact and the coronary sinus is normal. Davis has presented a patient with a right-to-left shunt of the PLSVC draining into the left atrium as an isolated anomaly very rarely found
[3]. To our knowledge, this rare anomaly associated with a rather common bicuspid aortic valvular stenosis in adults has not been described.
Usually, when the PLSVC terminates in the left atrium, the left innominate vein is absent. In this instance, the venous blood from the left arm and the left side of the head is drained into the left atrium via the PLSVC, resulting in a right-to-left shunt. If the bilateral superior vena cava communicates freely through a large left innominate vein, the shunt is also right-to-left because of the normal left ventricle impedance. This was demonstrated in a patient in whom cyanosis disappeared immediately after the PLSVC was ligated
[3].
In the present case the direction of the flow in PLSVC remained unknown before the severe hypertrophy of the left ventricle formed. If the shunt was at that time from right-to-left, the volume might have been limited because the patient had never had cyanosis in his history. We believe that the PLSVC and bicuspid aortic valve developed independently. Without worsened aortic stenosis and increased left ventricular compliance, the shunt in the PLSVC might have remained minimal and the patient without symptoms. This combination, however, caused an increase in left atrial pressure and changed the shunt into left-to-right.
Three other cases have been reported to have a shunt from left-to-right via the superior vena cava
[4]
[5]
[6]. In one case the left-to-right shunt was due partly to obstruction of the blood flow from left atrium to left ventricle because of mitral stenosis
[4]. Communication of the PLSVC with the left atrium at the opening of the left or right superior pulmonary vein into the left atrium existed in all three patients. By reason of this anatomic juxtaposition, the left-to-right shunt was probably partly due to streaming directly from the superior pulmonary vein to the left superior vena cava, especially in the case associated with Ebstein's anomaly and Wolff–Parkinson–White syndrome
[5]. The situation associated with coarctation of the aorta was similar to that of our patient. The markedly increased left ventricular impedance was sufficient to overcome the resistance to flow of the normal venous arch, formed by the two superior vena cavae and the left innominate vein, and caused a left-to-right shunt in these two patients
[6].
|
References
|
|---|
- Meadows W.R., Sharp J.T. Persistent left superior vena cava draining into the left atrium without arterial oxygen unsaturation. Am J Cardiol 1965;16:273-279.
- Wiles H.B. Two cases of left superior vena cava draining directly to a left atrium with a normal coronary sinus. Br Heart J 1991;65:158-160.[Abstract/Free Full Text]
- Davis W.H., Jordaan F.R., Snyman H.W. Persistent left superior vena cava draining into the left atrium, as an isolated anomaly. Am Heart J 1959;57(4):616-622.[Medline]
- Stein J.H., Broderick L., Neumann A., Snell R.J., Hanashiro P.K., Caralis D.G. A unique left-to-right shunt characterized by multimodality cardiac imaging. Chest 1995;107:1162-1164.[Abstract/Free Full Text]
- Lam W., Danoviz J., Witham D., Wyndham C., Rosen K.M. Left-to-right shunt via left superior vena cava communicating with left atrium. Chest 1981;79:700-702.[Abstract/Free Full Text]
- Ödman P.A. Persistent left superior vena cava communicating with the left atrium and pulmonary vein. Acta Radiol 1953;40:554-560.[Medline]
Top
Abstract
Introduction
