Abstract
Persistent extrahepatic right umbilical vein without ductus venosus is a rare anomaly of systemic venous drainage and is reported to be associated with cardiac anomalies. We report the case of an 8-year-old boy diagnosed to have an ostium secundum atrial septal defect, in whom an abnormal vascular channel and its opening in the right atrium in close relationship to the inferior vena cava and coronary sinus opening was identified at operation. Post-operative evaluation of this vascular channel was diagnosed to be an extrahepatic persistent right umbilical vein.
Keywords: Congenital heart disease, Extrahepatic persistent umbilical vein, Persistent umbilical vein
Introduction
The incidence of persistent right umbilical vein (PRUV) ranges from 0.19 to 0.46% [1]. The presence of PRUV is considered a marker for heart disease. In such cases, fetal echocardiography is recommended for identification of associated cardiovascular anomalies such as transposition of great arteries with pulmonary stenosis or tetralogy of Fallot [2, 3].
It has two variants: the intrahepatic (type 1, IH-PRUV) and an extrahepatic variant (type 2, EH-PRUV). In type 2, the umbilical vein connects directly to the right atrium or infracardiac portion of the inferior vena cava (IVC) without a ductus venosus (DV) [2]. Although the possible course of termination of PRUV to the right atrium is reported [3], we present the intracardiac relationship of type 2 PRUV: an unreported anatomical finding in the literature.
Case report
An 8-year-old asymptomatic boy, incidentally diagnosed to have ostium secundum atrial septal defect (ASD) with a left to right shunt, was referred for surgical closure. There was also a 14-mm displacement of the septal leaflet of the tricuspid valve with adequate right ventricular volume and absent tricuspid regurgitation, with no hemodynamic consequences.
During surgery, upon pericardiotomy, an aberrant vascular channel was seen entering the right atrium medial to the IVC (Fig. 1). The course of this channel was dissected below the diaphragm, the peritoneum was opened, and the patent course of the vascular channel in the falciform ligament of the liver identified. A diagnosis of EH-PRUV was made. On opening the right atrium, the vascular channel/EH-PRUV was found to open between the IVC and coronary sinus openings cranially and the septal leaflet of the tricuspid valve caudally (Fig. 2). This opening into the right atrium therefore was probably causing the downward displacement of the attachment of the septal leaflet of the tricuspid valve. ASD was closed with an autologous pericardial patch and the EH-PRUV was left alone.
Fig. 1.
An aberrant vascular channel seen entering the right atrium medial to the inferior vena cava (yellow looped structure). Yellow rhombus pointing to PRUV
Fig. 2.
On right atriotomy, PRUV was seen draining between the IVC and coronary sinus openings cranially and the septal leaflet of the tricuspid valve caudally. Yellow rhombus shows opening of this channel. Blue star shows opening of coronary sinus. A, ASD patch; IVC cannula, inferior vena cava; PRUV, persistent right umbilical vein; RAA. right atrial appendage; SVC, superior vena cava; T, tricuspid valve
Post-operatively, a contrast-enhanced computed tomography scan was done to delineate the course of the vascular channel and the EH-PRUV was found traversing in the falciform ligament, without any vascular communication, and diagnosis was re-confirmed (Fig. 3).
Fig. 3.
Sagittal section and three-dimensional reconstruction of CT showing course of extrahepatic persistent right umbilical vein running anteriorly over the diaphragm. Yellow rhombus showing this vessel. CT, computed tomography
Discussion
During development, both the umbilical veins are connected to the sinus venosus. The right umbilical vein (UV) starts to regress by the 4th week of life and disappears by the 7th week of life. PRUV is an altered embryonic development, in which the right vein remains patent. The left vein can remain patent or may regress while only the right remains open [4].
Typically, PRUV is an isolated anomaly; however, type 2 PRUVs (~ 25%) can be associated with cardiac abnormalities, placental or umbilical cord anomalies, gastrointestinal and genitourinary malformations, or central nervous system malformations [1, 4, 5]. Prognosis depends on the presence of DV and also the natural history of associated malformations [5]. The clinical course can vary from hydrops fetalis to an asymptomatic course (as in this case) [5].
The differential diagnosis of a vascular channel draining into the right atrium adjacent to the IVC is usually a hepatic vein, wherein the intraparenchymal course of the venous structure into the liver can be traced. The course of the vein in this case was traced to the falciform ligament, rather than to the liver parenchyma. The displacement of the tricuspid septal leaflet can be a reason for the wrong diagnosis of Ebstein’s anomaly, if the entity is not recognized and other diagnostic parameters are not taken into consideration [6].
Awareness of this anomaly will help manage an unexpected presentation intraoperatively and add to the armamentarium of literature.
Funding
No sources of funding were obtained for the study.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Informed consent
Consent for participation and publication was obtained.
Footnotes
Publisher’s note
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References
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