© 2013, Wiley Periodicals, Inc. DOI: 10.1111/echo.12466
Echocardiography
Persistent Left Superior Vena Cava Draining into Left Atrium as a Cause of Persistent Systemic Desaturation after Surgery Ashish Agarwal, D.M.,* Ravindranath K.S., D.M.,* Navin Agrawal, M.D.,* Soumya Patra, M.D.,* Neena Agarwal, M.D.,† and C.N. Manjunath, D.M.* *Department of Cardiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bangalore, India; and †Kempe Gowda Institute of Medical Sciences, Bangalore, India
Persistent left superior vena cava (LSVC) is a rare congenital anomaly which usually produces no physiologic derangements if it drains into the right atrium via the coronary sinus, but it may cause significant desaturation when it drains into the left atrium (LA). Failure to diagnose LSVC communicating with the LA preoperatively may lead to serious consequences. We are describing an interesting case of a boy who presented with systemic desaturation due to an undetected LSVC after having undergone corrective surgery for atrioventricular canal defect. We have demonstrated that echocardiography with agitated saline contrast is a simple, accurate, and inexpensive diagnostic modality. (Echocardiography 2014;31:E77–E79) Key words: contrast echocardiography, congenital heart defects Persistent left superior vena cava (LSVC) occurs in 0.3% to 0.5% of general population and in 1.5% to 10% of patients with congenital heart disease (CHD).1 An isolated LSVC, in itself, produces no physiologic derangements when it drains into the right atrium (RA) via the coronary sinus (CS). It is usually asymptomatic and is detected incidentally when cardiovascular imaging is performed for unrelated reasons. It becomes a significant anomaly when it drains directly into the left atrium (LA) or during procedures involving the placement of a central venous catheter. We present an interesting case wherein a patient, who had previously undergone a surgical correction of complete atrio-ventricular canal defect (AVCD), now presented with persistent systemic desaturation due to an LSVC draining in to the LA which had been missed during the preoperative course of evaluation as well as during the surgery. Case Report: A 4-year-old asymptomatic boy who had undergone corrective surgery for complete AVCD 3 months ago presented for follow-up. Address for correspondence and reprint requests: Ashish Agarwal, M.D., Department of Cardiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Jayanagar 9th Block, BG Road, Bangalore 560069, India. Fax: 0181-2620220; E-mail: [email protected], [email protected].
On examination, there was no clinically appreciable cyanosis. Cardiac examination was normal. Pulse oximetry showed a saturation of 90% at rest on room air. Transthoracic twodimensional (2D) (Philips HD7 XE, Eindhoven, The Netherlands) and color Doppler echocardiography revealed no residual shunt across the atrial and/or ventricular septum. Parasternal short-axis view at the level of aortic valve showed a persistent LSVC connected to the LA between the LA appendage and the left upper pulmonary vein and the drainage was confirmed with color Doppler examination (Fig. 1A). There was also a right superior vena cava (RSVC) draining into the RA. To further confirm the drainage site, agitated normal saline mixed with the patient’s blood was injected into the patient’s left antecubital vein. Bubble contrast appeared in the LA confirming the drainage of an LSVC into the LA (Fig. 1B and C, movie clip S1). No contrast appeared in the RA or in the right ventricle suggesting that there was no residual left to right shunt after the surgical repair. It also makes communication of the LSVC to the RSVC by a sizable innominate bridging vein less likely. Cardiac computed tomography (CT) (Philips Brillance 64) was performed to definitely establish the echocardiographic findings and to delineate the anatomy of the LSVC (Fig. 2). The patient is currently under follow-up in view of the E77
Agarwal, et al.
Figure 1. A. Echocardiogram (short-axis with color compare image) showing left superior vena cava (LSVC) draining into left atrium (LA) between left upper pulmonary vein (LUPV) and LA appendage. Short-axis view before B. and after agitated saline injection C. showing opacification of LA and aorta (Ao), while no bubbles appear in right atrium (RA) and right ventricle (RV).
Figure 2. Cardiac computed tomography with three-dimensional reconstruction. A. Anteriorrightward view shows that right superior vena cava (RSVC) is draining into right atrium (RA). There is absence of bridging innominate vein (broad white arrow). B. Posterior-leftward view shows that left superior vena cava (LSVC) is draining into left atrium (LA).
asymptomatic status and the absence of clinically significant cyanosis. Discussion: In patients with CHD, the most common thoracic venous abnormality is an LSVC draining into the CS. Failure of obliteration of the left common cardinal vein results in persistent connection of an LSVC to the CS.2 It usually drains into the RA via the CS. In about 8% of cases, it directly connects to the LA3 and may result in significant right-to-left shunt. The LSVC may be the only persisting superior vena cava (SVC), or there may E78
be bilateral SVCs which fail to communicate with each other because of absence of the innominate bridge. Apart from pulmonary arteriovenous fistula, an LSVC to the LA is another cause of the syndrome of cyanosis with clubbing and normal heart. It is often stated that embryologically, an LSVC draining into the LA is associated with an absent CS and the cardiac veins drain directly into the corresponding atria.4 However, this is not always true and cases of an LSVC draining directly into the LA associated with a normally formed CS have been described.5 A clinical implication of an LSVC is a high incidence of
Left Superior Vena Cava to LA
accompanying CHDs, the most common ones being ventricular septal defect, atrial septal defect, AVCD, or tetralogy of Fallot. Identification of the drainage site of an LSVC in patients with CHDs is important if surgical intervention is contemplated. If the LSVC is missed or is allowed to remain connected to the LA following surgical repair, the patient will have persistent cyanosis due to systemic venous return to the LA. Another important aspect of the preoperative evaluation of an LSVC draining to the LA is in patients who are candidates for cavopulmonary anastomosis. Failure to diagnose an LSVC to the LA in the presence of an RSVC draining to the RA with a sizable bridging vein between the 2 SVCs might allow flow intended for the pulmonary artery to be diverted to the low resistance LA. Although 2D and Doppler echocardiography remains one of the main assessment tools, the diagnosis of an LSVC draining to the LA can be overlooked. Contrast echocardiography (CE) or echocardiography performed with agitated saline has been shown to reliably demonstrate anomalies of systemic venous return and can further delineate the drainage site.6 Absence of saline contrast in the RA in this case makes the presence of a sizable communication of the LSVC to the RSVC via an innominate bridge unlikely although it may not be able to definitively exclude the presence of a small bridging vein which usually requires other modalities like contrast CT for confirmation. CT and cardiac magnetic resonance (CMR) remain the best imaging modality for comprehensive functional and anatomical assessment. However, in this case, we have demonstrated that echocardiography with agitated saline contrast has clearly and convincingly demonstrated the drainage of the LSVC to the LA. Left superior vena cava draining into the CS can be easily suspected in the presence of a dilated CS. On the contrary, an LSVC draining directly into the LA should be looked for when CS is not visualized as in our case although it may not be always true. In fact, inability to visualize the CS can be the first clue to the diagnosis of this anomaly which can be further confirmed with CE or other imaging modalities. Vessels that resemble an LSVC on 2D echocardiography are a left vertical vein draining into the left innominate vein in an infant with total anomalous pulmonary venous return and the levoatrial cardinal vein which connects the LA to the innominate vein in mitral atresia and intact atrial septum. However, these vessels can be easily differentiated by Doppler examination because the flow is directed away from the heart which is the opposite of what is seen in cases of an LSVC.
This case demonstrates the importance of recognizing an LSVC draining to the LA prior to surgery and also underscores the importance of searching for an LSVC intraoperatively. It also demonstrates that agitated saline CE can be used with certainty to diagnose this anomaly. Conclusion: An LSVC should be specifically searched for before contemplating surgery for CHDs. The drainage site should be properly delineated by echocardiography, or preferably CT or CMR. 2D echocardiography when combined with peripheral venous injection of contrast or agitated saline can be used to diagnose the drainage site of the LSVC when other imaging modalities are not available. It is a simple, accurate and inexpensive modality to diagnose this entity and thus provides important information before more invasive procedures. If an LSVC drains into the LA and creates a large right-to-left shunt (usually in the setting of absent RSVC), surgical correction should be performed. Our patient did not have much systemic desaturation because an RSVC was normally draining into the RA. References 1. Buirski G, Jordan SC, Joffe HS: Superior vena caval abnormalities: Their occurrence rate, associated cardiac abnormalities and angiographic classification in a paediatric population with congenital heart disease. Clin Radiol 1986;37:131–138. 2. Nsah EN, Moore GW, Hutchins GM: Pathogenesis of persistent left superior vena cava with a coronary sinus connection. Pediatr Pathol 1991; 11:261–269. 3. AttenhoferJost CH, Connolly HM, Danielson GK, et al: Clinical features and surgical outcome in 25 patients with fenestrations of the coronary sinus. Cardiol Young 2007;17:592–600. 4. Raghib G, Ruttenberg HD, Anderson RC, et al: Termination of left superior vena cava in left atrium, atrial septal defect, and absence of coronary sinus: A developmental complex. Circulation 1965;31:906–918. 5. Henry B. Wiles: 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. 6. Foale R, Bourdillon PD, Somerville J, et al: Anomalous systemic venous return: Recognition by two-dimensional echocardiography. Eur Heart J 1983;4:186–195.
Supporting Information Additional Supporting Information may be found in the online version of this article: Movie clip S1: Real time parasternal shortaxis view at the level of aortic valve. After injection of saline contrast in left antecubital vein, there is uniform opacification of left atrium and aorta with no appearance of contrast in right heart.
E79
Echocardiography
Persistent Left Superior Vena Cava Draining into Left Atrium as a Cause of Persistent Systemic Desaturation after Surgery Ashish Agarwal, D.M.,* Ravindranath K.S., D.M.,* Navin Agrawal, M.D.,* Soumya Patra, M.D.,* Neena Agarwal, M.D.,† and C.N. Manjunath, D.M.* *Department of Cardiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bangalore, India; and †Kempe Gowda Institute of Medical Sciences, Bangalore, India
Persistent left superior vena cava (LSVC) is a rare congenital anomaly which usually produces no physiologic derangements if it drains into the right atrium via the coronary sinus, but it may cause significant desaturation when it drains into the left atrium (LA). Failure to diagnose LSVC communicating with the LA preoperatively may lead to serious consequences. We are describing an interesting case of a boy who presented with systemic desaturation due to an undetected LSVC after having undergone corrective surgery for atrioventricular canal defect. We have demonstrated that echocardiography with agitated saline contrast is a simple, accurate, and inexpensive diagnostic modality. (Echocardiography 2014;31:E77–E79) Key words: contrast echocardiography, congenital heart defects Persistent left superior vena cava (LSVC) occurs in 0.3% to 0.5% of general population and in 1.5% to 10% of patients with congenital heart disease (CHD).1 An isolated LSVC, in itself, produces no physiologic derangements when it drains into the right atrium (RA) via the coronary sinus (CS). It is usually asymptomatic and is detected incidentally when cardiovascular imaging is performed for unrelated reasons. It becomes a significant anomaly when it drains directly into the left atrium (LA) or during procedures involving the placement of a central venous catheter. We present an interesting case wherein a patient, who had previously undergone a surgical correction of complete atrio-ventricular canal defect (AVCD), now presented with persistent systemic desaturation due to an LSVC draining in to the LA which had been missed during the preoperative course of evaluation as well as during the surgery. Case Report: A 4-year-old asymptomatic boy who had undergone corrective surgery for complete AVCD 3 months ago presented for follow-up. Address for correspondence and reprint requests: Ashish Agarwal, M.D., Department of Cardiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Jayanagar 9th Block, BG Road, Bangalore 560069, India. Fax: 0181-2620220; E-mail: [email protected], [email protected].
On examination, there was no clinically appreciable cyanosis. Cardiac examination was normal. Pulse oximetry showed a saturation of 90% at rest on room air. Transthoracic twodimensional (2D) (Philips HD7 XE, Eindhoven, The Netherlands) and color Doppler echocardiography revealed no residual shunt across the atrial and/or ventricular septum. Parasternal short-axis view at the level of aortic valve showed a persistent LSVC connected to the LA between the LA appendage and the left upper pulmonary vein and the drainage was confirmed with color Doppler examination (Fig. 1A). There was also a right superior vena cava (RSVC) draining into the RA. To further confirm the drainage site, agitated normal saline mixed with the patient’s blood was injected into the patient’s left antecubital vein. Bubble contrast appeared in the LA confirming the drainage of an LSVC into the LA (Fig. 1B and C, movie clip S1). No contrast appeared in the RA or in the right ventricle suggesting that there was no residual left to right shunt after the surgical repair. It also makes communication of the LSVC to the RSVC by a sizable innominate bridging vein less likely. Cardiac computed tomography (CT) (Philips Brillance 64) was performed to definitely establish the echocardiographic findings and to delineate the anatomy of the LSVC (Fig. 2). The patient is currently under follow-up in view of the E77
Agarwal, et al.
Figure 1. A. Echocardiogram (short-axis with color compare image) showing left superior vena cava (LSVC) draining into left atrium (LA) between left upper pulmonary vein (LUPV) and LA appendage. Short-axis view before B. and after agitated saline injection C. showing opacification of LA and aorta (Ao), while no bubbles appear in right atrium (RA) and right ventricle (RV).
Figure 2. Cardiac computed tomography with three-dimensional reconstruction. A. Anteriorrightward view shows that right superior vena cava (RSVC) is draining into right atrium (RA). There is absence of bridging innominate vein (broad white arrow). B. Posterior-leftward view shows that left superior vena cava (LSVC) is draining into left atrium (LA).
asymptomatic status and the absence of clinically significant cyanosis. Discussion: In patients with CHD, the most common thoracic venous abnormality is an LSVC draining into the CS. Failure of obliteration of the left common cardinal vein results in persistent connection of an LSVC to the CS.2 It usually drains into the RA via the CS. In about 8% of cases, it directly connects to the LA3 and may result in significant right-to-left shunt. The LSVC may be the only persisting superior vena cava (SVC), or there may E78
be bilateral SVCs which fail to communicate with each other because of absence of the innominate bridge. Apart from pulmonary arteriovenous fistula, an LSVC to the LA is another cause of the syndrome of cyanosis with clubbing and normal heart. It is often stated that embryologically, an LSVC draining into the LA is associated with an absent CS and the cardiac veins drain directly into the corresponding atria.4 However, this is not always true and cases of an LSVC draining directly into the LA associated with a normally formed CS have been described.5 A clinical implication of an LSVC is a high incidence of
Left Superior Vena Cava to LA
accompanying CHDs, the most common ones being ventricular septal defect, atrial septal defect, AVCD, or tetralogy of Fallot. Identification of the drainage site of an LSVC in patients with CHDs is important if surgical intervention is contemplated. If the LSVC is missed or is allowed to remain connected to the LA following surgical repair, the patient will have persistent cyanosis due to systemic venous return to the LA. Another important aspect of the preoperative evaluation of an LSVC draining to the LA is in patients who are candidates for cavopulmonary anastomosis. Failure to diagnose an LSVC to the LA in the presence of an RSVC draining to the RA with a sizable bridging vein between the 2 SVCs might allow flow intended for the pulmonary artery to be diverted to the low resistance LA. Although 2D and Doppler echocardiography remains one of the main assessment tools, the diagnosis of an LSVC draining to the LA can be overlooked. Contrast echocardiography (CE) or echocardiography performed with agitated saline has been shown to reliably demonstrate anomalies of systemic venous return and can further delineate the drainage site.6 Absence of saline contrast in the RA in this case makes the presence of a sizable communication of the LSVC to the RSVC via an innominate bridge unlikely although it may not be able to definitively exclude the presence of a small bridging vein which usually requires other modalities like contrast CT for confirmation. CT and cardiac magnetic resonance (CMR) remain the best imaging modality for comprehensive functional and anatomical assessment. However, in this case, we have demonstrated that echocardiography with agitated saline contrast has clearly and convincingly demonstrated the drainage of the LSVC to the LA. Left superior vena cava draining into the CS can be easily suspected in the presence of a dilated CS. On the contrary, an LSVC draining directly into the LA should be looked for when CS is not visualized as in our case although it may not be always true. In fact, inability to visualize the CS can be the first clue to the diagnosis of this anomaly which can be further confirmed with CE or other imaging modalities. Vessels that resemble an LSVC on 2D echocardiography are a left vertical vein draining into the left innominate vein in an infant with total anomalous pulmonary venous return and the levoatrial cardinal vein which connects the LA to the innominate vein in mitral atresia and intact atrial septum. However, these vessels can be easily differentiated by Doppler examination because the flow is directed away from the heart which is the opposite of what is seen in cases of an LSVC.
This case demonstrates the importance of recognizing an LSVC draining to the LA prior to surgery and also underscores the importance of searching for an LSVC intraoperatively. It also demonstrates that agitated saline CE can be used with certainty to diagnose this anomaly. Conclusion: An LSVC should be specifically searched for before contemplating surgery for CHDs. The drainage site should be properly delineated by echocardiography, or preferably CT or CMR. 2D echocardiography when combined with peripheral venous injection of contrast or agitated saline can be used to diagnose the drainage site of the LSVC when other imaging modalities are not available. It is a simple, accurate and inexpensive modality to diagnose this entity and thus provides important information before more invasive procedures. If an LSVC drains into the LA and creates a large right-to-left shunt (usually in the setting of absent RSVC), surgical correction should be performed. Our patient did not have much systemic desaturation because an RSVC was normally draining into the RA. References 1. Buirski G, Jordan SC, Joffe HS: Superior vena caval abnormalities: Their occurrence rate, associated cardiac abnormalities and angiographic classification in a paediatric population with congenital heart disease. Clin Radiol 1986;37:131–138. 2. Nsah EN, Moore GW, Hutchins GM: Pathogenesis of persistent left superior vena cava with a coronary sinus connection. Pediatr Pathol 1991; 11:261–269. 3. AttenhoferJost CH, Connolly HM, Danielson GK, et al: Clinical features and surgical outcome in 25 patients with fenestrations of the coronary sinus. Cardiol Young 2007;17:592–600. 4. Raghib G, Ruttenberg HD, Anderson RC, et al: Termination of left superior vena cava in left atrium, atrial septal defect, and absence of coronary sinus: A developmental complex. Circulation 1965;31:906–918. 5. Henry B. Wiles: 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. 6. Foale R, Bourdillon PD, Somerville J, et al: Anomalous systemic venous return: Recognition by two-dimensional echocardiography. Eur Heart J 1983;4:186–195.
Supporting Information Additional Supporting Information may be found in the online version of this article: Movie clip S1: Real time parasternal shortaxis view at the level of aortic valve. After injection of saline contrast in left antecubital vein, there is uniform opacification of left atrium and aorta with no appearance of contrast in right heart.
E79
