Umbilical and paraumbilical veins in ligamentum teres. Their significance as collaterals in portal hypertension

Persistent right umbilical vein: a study using serial sections of human embryos and fetuses

Persistent right umbilical vein (PRUV) is a common anomaly of the venous system. Although candidates for future PRUV were expected to occur more frequently in earlier specimens, evaluation of serial horizontal sections from 58 embryos and fetuses of gestational age 5–7 weeks found that only two of these embryos and fetuses were candidates for anomalies. In a specimen, a degenerating right umbilical vein (UV) joined the thick left UV in a narrow peritoneal space between the liver and abdominal cavity, and in the other specimen, a degenerating left UV joined a thick right UV in the abdominal wall near the liver. In these two specimens, the UV drained into the normal, umbilical portion of the left liver. These results strongly suggested that, other than the usual PRUV draining into the right liver, another type of PRUV was likely to consist of the right UV draining into the left liver.

CT of the paraumbilical and ensiform veins in patients with superior vena cava or left brachiocephalic vein obstruction

The purpose of this study was to elaborate on the anastomoses between the paraumbilical and systemic veins, particularly the ensiform veins. The connections with the ensiform veins have received little attention in the anatomical and radiological literature, and remain incompletely described. Too small to be reliably traced in normal CT scans, the paraumbilical veins can dilate in response to increased blood flow from systemic veins in superior vena cava obstruction (SVCO), allowing a study of their arrangement and connections. Collateral paraumbilical veins were therefore analyzed retrospectively in 28 patients with SVCO using CT. We observed inferior and superior groups of collateral vessels in 23/28 (82%) and 17/28 (61%) patients, respectively. Inferior veins ascended towards the liver and drained into portal veins (19/28, 68%) or the umbilical vein (8/28, 29%); superior veins descended and drained into portal veins. The inferior veins (N = 27) could be traced to ensiform veins in almost all of the cases (26/27, 96%), and a little over half (14/27, 52%) were also traceable to subcutaneous and deep epigastric veins. They were opacified by ensiform (25/27, 93%), deep epigastric (4/27, 15%) and subcutaneous (4/27, 15%) veins. The superior veins (N = 17) were supplied by diaphragmatic (13/17, 76%) and ensiform veins (4/17, 24%); the diaphragmatic veins were branches of collateral internal thoracic, left pericardiacophrenic and anterior mediastinal veins. Collateral ensiform veins were observed in 22 patients and anastomosed with internal thoracic (19/22, 86%), superior epigastric (9/22, 41%), diaphragmatic (4/22, 18%), subcutaneous (3/22, 14%) and anterior mediastinal veins (1/22, 5%). These observations show that the paraumbilical veins communicate with ensiform, deep epigastric, subcutaneous and diaphragmatic veins, joining the liver to the properitoneal fat pad, anterior trunk, diaphragm and mediastinum. In SVCO, the most common sources of collateral flow to the paraumbilical veins are the ensiform and diaphragmatic branches of the internal thoracic veins.

The vascular anatomy of the ligaments of the liver: gross anatomy, imaging and clinical applications

The vessels that communicate between the liver and adjacent structures require bridges between them. The bridges comprise the ligaments of the liver as follows: the falciform ligament, right and left coronary ligaments, lesser omentum including the hepatogastric ligament and hepatoduodenal ligament. Each ligament has specific communications between the intrahepatic and extrahapetic vessels. The venous communications called as the portosystemic shunt would become apparent in patients with portal hypertension, intrahepatic portal vein thrombosis and superior vena cava syndrome. The location of the venous communication is related to the pseudolesion or focal enhancement of the liver demonstrated on the CT scan. The arterial communications called collateral vascularization would become apparent in patients with hepatic artery occlusion, especially post-transhepatic arterial embolization, or in patients with the hepatic tumour abutting diaphragm. The knowledge of these collateral arteries is necessary to accomplish the effective transarterial embolization for the hepatic tumours. We reviewed the vessels in these ligaments using contrast-enhanced CT scans and angiography and discussed the clinical applications. Cadaver dissection photos were included as supplementary images for readers to recognize the actual spatial anatomy of the vessel in each ligament.

Paraumbilical venous collateral circulations: color Doppler ultrasound features

Using Color Doppler ultrasonography to trace the dilated paraumbilical vein to its connection with systemic veins in 27 patients, we have found four major pathways: In type 1 (63%), the vein connected with the external iliac vein via the inferior epigastric vein. In type 2 (3.7%), the vein connected with the saphenous vein via the superficial epigastric vein. In type 3 (22.2%), the vein connected with the internal thoracic vein via the superior epigastric vein. Type 4 (11.1%) is a combination of types 1 and 2. A frank caput medusa was not seen, but occult caput medusa were seen in two patients. Turbulent flow was seen at the junction between inferior epigastric and external iliac veins, paraumbilical and superficial epigastric veins, and superficial epigastric and saphenous veins in some patients. Color Doppler ultrasonography is a convenient, noninvasive method for determining the course and associated hemodynamic changes in the paraumbilical collateral circulation.

Diagnosis of an accessory portal vein and its clinical implications for portosystemic shunts

PURPOSE

To present a peculiar anatomic portal veins variant and evaluate its clinical implications.

METHODS

Among 118 consecutive patients undergoing transjugular intrahepatic portosystemic shunting (TIPS), six male patients were found to have an accessory portal vein, which was seen during direct portography.R ESULTS: In all six patients, portograms showed an accessory small-caliber vein parallel to the trunk of the main portal vein ending in the right lobe of the liver. Two of the six accessory portal veins drained blood from coronary veins, precluding access to coronary vein embolization during TIPS.

CONCLUSION

An accessory portal vein is a rare anatomical variation with clinical significance for both surgical shunt placement and TIPS, as well as for transportal embolization of coronary veins.

Umbilical vein variations: review of the literature and a case report of a persistent right umbilical vein

A case of a ligamentum teres formed from an obliterated right umbilical vein is described. It passed to the right branch of the portal vein. The quadrate and left lobes of the liver were not separated by the usual fissure. Very few cases of anomalous umbilical veins or persistent right umbilical veins have been recorded. Of these, several have been recorded only in the umbilical cord, while in others the persistent right umbilical vein has been found intra-abdominally, in an extrahepatic position, and passing directly to the right atrium or to the inferior vena cava. Its presence is generally associated with severe congenital abnormalities, in contrast with the present case. In view of the high incidence of congenital defects associated with aberrant or accessory umbilical veins, when these are detected either in the umbilical cord or in the abdomen by umbilical phlebography, it is suggested that the patient should be carefully investigated for other congenital abnormalities.