en POLSKI
eISSN: 2449-6731
ISSN: 2449-6723
Prenatal Cardiology
Current issue Archive About the journal Editorial board Abstracting and indexing Contact Instructions for authors Ethical standards and procedures
Editorial System
Submit your Manuscript
1/2022
 
Share:
Share:
Case report

Prenatal diagnosis of anomalous drainage of the right superior vena cava to the left atrium

Stacy A.S. Killen
1

  1. Pediatrics, Vanderbilt University Medical Center and Monroe Carell Jr. Children’s Hospital at Vanderbilt, United States
Prenat Cardio 2022; 12(1): 42-47
Online publish date: 2023/05/10
Article file
Get citation
 
PlumX metrics:
 

Case report

A 29-year-old G7P1504 African-American woman was referred to Vanderbilt University Medical Center’s fetal cardiology clinic at 26 1/7 weeks’ gestation for a dilated right superior vena cava (RSVC) appreciated on obstetrical ultrasound. Her pregnancy was complicated by a history of stillbirth (20 weeks’ gestation) and neonatal demise (24 weeks’ gestation), polysubstance abuse, and chronic hypertension.
The initial fetal echocardiogram demonstrated a dilated RSVC (diameter 5.2 mm; inferior vena cava diameter 3.3 mm in comparison) with prominent innominate (3.6 mm) and azygous veins (Figure 1) and with an unusual flow pattern in the rightward aspect of the left atrium (LA) in the four-chamber and long-axis views (Figure 2). Sagittal images suggested anomalous connection of the RSVC to the LA and biatrial drainage of the RSVC, with the RSVC “overriding” the atrial septum via a sinus venous defect and with associated partial anomalous pulmonary venous drainage (Figure 3). No cerebral arteriovenous malformations had been appreciated on obstetrical ultrasound, and middle cerebral artery Doppler patterns (MCA peak systolic velocity: 46.4 cm/sec; multiples of the median [MoM] 1.37) were not consistent with fetal anemia. The fetal heart was otherwise structurally normal with normal atrioventricular and ventriculoarterial connections and with normal connection of the inferior vena cava (IVC) to the right atrium (RA). A follow-up evaluation at 30 1/7 weeks’ gestation revealed similar findings.
A male infant was born at 39 1/7 weeks’ gestation via emergency Cesarean section for prolonged fetal heart rate deceleration and thick meconium. His APGAR scores were 8 and 9. He was initially admitted to the special care nursery, but oxygen desaturations to 50-60% required positive pressure ventilation and transfer to the neonatal intensive care unit. Because he was weaned off this support in 24 hours, the respiratory complications were attributed to transient tachypnea of the newborn.
Postnatal transthoracic echocardiogram confirmed an RSVC emptying into the LA, with the right upper pulmonary vein entering the LA at the RSVC-LA junction; imaging also identified an unrestrictive atrial communication, variously described as a superior secundum atrial septal defect and as a sinus venous defect (Figure 4). Left to right shunting across the atrial communication allows partial drainage of the RSVC into the RA. There is no SVC connected to the RA, but the IVC enters the RA normally. The patient’s oxygen saturations were in the upper 80s to low 90s at hospital discharge and 92-99% at subsequent follow-up visits in the pediatric cardiology clinic. He has not had any other apparent cardiac symptoms to date.
At 12 months of age, he underwent cross-sectional imaging, which demonstrated a sinus venosus defect with partial anomalous pulmonary venous drainage of the right upper lobe pulmonary veins to the RSVC, which itself inserts anomalously into the LA (Figure 5). Surgical repair is anticipated in the coming months; he is currently doing well at 21 months of age.

Discussion

Anomalous drainage of the RSVC to the LA, as an isolated abnormality (Figure 6), is a very rare form of congenital heart disease (0.5%) that causes hypoxemia [1, 2]. It was first described in 1914 as biatrial drainage of the SVC [1, 3, 4]. There is only one other case reported in the literature of this anomaly diagnosed prenatally [1].
Various theories have been suggested to explain the embryologic origin of this developmental malformation, which is effectively a type of interatrial communication [5]. The original theory by Kirsch et al. in 1961 encompassed an abnormal position of the right horn of the sinus venosus, involving “relative leftward and cephalic distortion that resulted in placing the aperture of the SVC alone in the LA” [6]. An alternative theory postulated that the cephalic portion of the right valve of the sinus venosus fuses with the atrial septum superior to the coronary sinus inlet, forming a seal that prevents the SVC from draining into the RA [7]. In 2003 the Drs. Van Praagh described this abnormality as a localized cavopulmonary venous defect in the wall between the RSVC and the right upper pulmonary veins; the posterior wall of the RSVC is contiguous with the anterior wall of the right pulmonary veins, creating a venovenous bridge [8]. If the RSVC blood flows preferentially into the LA, its right atrial orifice will become atretic such that the RSVC drains into the LA [8]. Dr. Anderson et al. recently refuted this theory, stating that the SVC and the pulmonary veins never share a common wall; rather, the right pulmonary veins can drain anomalously into the SVC while retaining their connection to the LA [9].
Although usually associated with mild degrees of cyanosis and hypoxemia, anomalous drainage of the RSVC to the LA is not expected to cause problems prenatally or in the neonatal period. It may be associated with anomalous pulmonary venous connections, and careful prenatal and postnatal assessment for associated pulmonary venous abnormalities is warranted [10]. Those without atrial septal defects typically have lower baseline oxygen saturations [10]. There is a low incidence of associated cardiac or extracardiac anomalies [1].
Cross-sectional imaging with CT or cardiac MRI can help confirm a prenatal diagnosis of biatrial or left atrial drainage of the RSVC and further define the combined anomalous systemic and pulmonary venous drainage [5, 11]. Surgical repair includes trans-section and re-anastomosis of the RSVC to the RA/right atrial appendage to prevent the long-term complications of cyanosis and right-to-left shunting, including brain abscesses, paradoxical emboli, renal and splenic infarcts, and atrial arrhythmias associated with right atrial dilation [8-11]. A Warden procedure transects the SVC superior to the SVC-pulmonary venous junction, when there is associated partial anomalous pulmonary venous drainage, to preserve pulmonary venous return to the LA [11, 12].
Dilation of the RSVC prompted referral to fetal cardiology for our patient and for the only other prenatally-diagnosed case of anomalous drainage of the RSVC to the LA in the literature [1]. The differential diagnosis of in utero dilation of the RSVC includes abnormalities that either obstruct drainage into the RA or increase blood flow into the RSVC [1]. These include vein of Galen or other cerebrovascular arteriovenous malformations, fetal anemia, thoracic masses/tumors causing SVC obstruction, supracardiac total or partial anomalous pulmonary venous return, and anomalous drainage of the RSVC into the LA.
In the coronal imaging plane, a vein of Galen malformation appears as a tubular, cystic, anechoic structure (“comet tail”) below the corpus callosum and cavum septum pellucidum; it is superior to the thalami and contiguous with the dilated sagittal sinus [13]. Cardiac manifestations of this cerebrovascular arteriovenous malformation range from asymptomatic cardiomegaly with preserved ventricular function to severe congestive cardiac failure and persistent pulmonary hypertension [13, 14]. Cardiac chamber dilation, especially right heart enlargement, hydrops, flow reversal in the aortic arch from “cerebral steal”, and abnormal flow patterns (elevated systolic and diastolic velocities) in the MCA may be apparent prenatally [14]. Dilation of the RSCV out of proportion to the IVC occurs because of increased volume load to the cerebral venous system leading to increased blood flow through the RSVC [14]. Hoda et al. reported 2 patients with both vein of Galen malformations and anomalous drainage of the RSVC to the LA, who were only mildly symptomatic; they concluded that the combination of abnormalities may provide a physiological advantage by ameliorating the left-to-right shunt from the arteriovenous malformation [15].
Fetal anemia may be due to red blood cell alloimmunization, infection (especially with parvovirus B19, CMV, and toxoplasmosis), hemoglobinopathies, fetomaternal hemorrhage, placental/fetal tumors, and complications of monochorionic placentation [16, 17]. In the setting of fetal anemia, more oxygen-rich blood from the umbilical vein is shunted to the brain; this increased flow to the brain increases venous return to the RSVC and dilates this vessel and the right heart. An MCA-PSV > 1.50 MoM correlates with moderate to severe fetal anemia [16, 17].
Thoracic masses, including lymphoma, teratoma, neurogenic tumors, foregut cysts, hemangiomas, lymphatic malformations, chest wall sarcomas and hamartomas, vascular malformations, pleuropulmonary blastoma, and congenital pulmonary airway malformations, can cause RSVC dilation by obstructing flow into the RA [18, 19]. Fetal MRI may help identify these abnormalities prenatally [19].
With supracardiac total or partial anomalous pulmonary venous return (TAPVR/PAPVR), dilation of the RSVC occurs from pulmonary venous drainage through this vessel. While prenatal diagnosis of TAPVR remains challenging, identifying a smooth-walled left atrium, an increased/hypoechoic “space” between the LA and the descending aorta, and a confluence posterior to the LA (“twig sign”) can aid in this diagnosis [20-22].
Finally, as demonstrated in our case and in the case reported by Vassallo et al. [1], drainage of the RSVC to the LA can cause RSVC and innominate vein dilation with a relatively normal-sized IVC because of associated partial anomalous venous drainage to the RSVC. Those cases of RSVC to the LA without associated pulmonary venous anomalies may not manifest such enlargement.

Conclusions

Anomalous drainage of the RSVC to the LA, as an isolated abnormality, is a very rare form of congenital heart disease that causes postnatal hypoxemia, which may be mild and not clinically apparent in the newborn period. Most reported cases in the literature have been identified in later childhood or adulthood, but universal pulse oximetry newborn screening may increase postnatal detection. Prenatal diagnosis, though challenging, is possible in the current era, as our case illustrates, and can prepare families and clinicians for postnatal care. In utero dilation of the RSVC should prompt careful evaluation for extracardiac, systemic venous, and pulmonary venous anomalies and may facilitate prenatal detection of this rare cardiac anomaly.

Acknowledgments

Thank you to Jennifer Sutton, BS, RDMS, RDCS and to J. Michael Newton, MD, PhD for their assistance with this case.

Conflict of interest

The author declares no conflicts of interest.

REFERENCES

1. Vassallo M, Pascotto M, Pisacane C, Santoro G, Paladini D, Russo MG, et al. Right superior vena cava draining into the left atrium: prenatal diagnosis and postnatal management. Ultrasound Obstet Gynecol 2006; 27: 445-448.
2. de Leval MR, Ritter DG, McGoon DC, Danielson GK. Anomalous systemic venous connection. Surgical considerations. Mayo Clin Proc 1975; 50: 599-610.
3. Nützel H. Beitrag zur Kenntnis der Missbildungen im Bereiche der oberen Hohlvene. Frankf Z Path 1914; 15: 1-19.
4. Iwata Y, Kojima A, Nakayama Y, Omoya K, Kuwahara T, Takeuchi T. A case of biatrial drainage of the right superior vena cava. Asian Cardiovasc Thorac Ann 2017; 25: 292-295.
5. Patel MD, Balasubramanian S, Dorfman AL, Joshi A, Lu JC, Ghadimi Mahani M, et al. Biatrial drainage of the right superior vena cava: imaging findings. Radiol Cardiothorac Imaging 2020; 2: e200414.
6. Kirsch WM, Carlsson E, Hartmann AF Jr. A case of anomalous drainage of the superior vena cava into the left atrium. J Thorac Cardiovasc Surg 1961; 41: 550-556.
7. Braudo M, Beanlands DS, Trusler G. Anomalous drainage of the right superior vena cava into the left atrium. Can Med Assoc J 1968; 99: 715-719.
8. Van Praagh S, Geva T, Lock JE, Nido PJ, Vance MS, Van Praagh R. Biatrial or left atrial drainage of the right superior vena cava: anatomic, morphogenetic, and surgical considerations – report of three new cases and literature review. Pediatr Cardiol 2003; 24: 350-563.
9. Chowdhury UK, Anderson RH, George N, Singh S, Sankhyan LK, Gayatri SB, et al. A review of the surgical management of anomalous connection of the right superior caval vein to the morphologically left atrium and biatrial drainage of right superior caval vein. World J Pediatr Congenit Heart Surg 2020; 11: 466-484.
10. Al Sehly AA, Hrfi A, BinSalahuddin A. Right superior vena cava connected left atrium with partial anomalous pulmonary venous return and intact atrial septum: an unusual cause of paradoxical embolism. J Saudi Heart Assoc 2022; 34: 66-69.
11. Gerrah R, Fonseca Escalante E, Gorenflo M, Loukanov T. The cavoatrial anastomosis procedure in anomalous connection of superior vena cava to left atrium. World J Pediatr Congenit Heart Surg 2019; 10: 803-805.
12. Warden HE, Gustafson RA, Tarnay TJ, Neal WA. An alternative method for repair of partial anomalous pulmonary venous connection to the superior vena cava. Ann Thorac Surg 1984; 38: 601-605.
13. Society for Maternal-Fetal Medicine; Monteagudo A. Vein of Galen aneurysmal malformation. Am J Obstet Gynecol 2020; 223: B27-B29.
14. Rychik J, Tian Z. Fetal cardiovascular imaging: a disease-based approach. Saunders, Philadelphia 2012.
15. Hoda M, Lemler M, Cory M. Vein of Galen aneurysmal malformation with anomalous right superior vena cava to the left atrium leading to atypical clinical and echocardiographic findings. Pediatr Cardiol 2023; 44: 254-259.
16. Mari G, Deter RL, Carpenter RL, Rahman F, Zimmerman R, Moise KJ Jr, et al. Noninvasive diagnosis by Doppler ultrasonography of fetal anemia due to maternal red-cell alloimmunization. Collaborative Group for Doppler Assessment of the Blood Velocity in Anemic Fetuses. N Engl J Med 2000; 342: 9-14.
17. Abbasi N, Johnson JA, Ryan G. Fetal anemia. Ultrasound Obstet Gynecol 2017; 50: 145-153.
18. Orman G, Masand P, Hicks J, Huisman TAGM, Guillerman RP. Pediatric thoracic mass lesions: beyond the common. Eur J Radiol Open 2020; 7: 100240.
19. Quinn TM, Hubbard AM, Adzick NS. Prenatal magnetic resonance imaging enhances fetal diagnosis. J Pediatr Surg 1998; 33: 553-558.
20. Heard J, Soni R, Nikel K, Day C, Pylypjuk C. Can prenatal diagnosis of total anomalous pulmonary venous return (TAPVR) using routine fetal ultrasound be improved? A case-control study. Radiol Res Pract 2022; 2022: 7141866.
21. Paladini D, Pistorio A, Wu LH, Meccariello G, Lei T, Tuo G, et al. Prenatal diagnosis of total and partial anomalous pulmonary venous connection: multicenter cohort study and meta-analysis. Ultrasound Obstet Gynecol 2018; 52: 24-34.
22. Kao CC, Hsieh CC, Cheng PJ, Chiang CH, Huang SY. Total anomalous pulmonary venous connection: from embryology to a prenatal ultrasound diagnostic update. J Med Ultrasound 2017; 25: 130-137.
This is an Open Access journal, all articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0). License (http://creativecommons.org/licenses/by-nc-sa/4.0/), allowing third parties to copy and redistribute the material in any medium or format and to remix, transform, and build upon the material, provided the original work is properly cited and states its license.
Quick links
© 2024 Termedia Sp. z o.o.
Developed by Bentus.