Umbilical Vein Varix: Importance of Ante

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Diagnostic and Interventional Imaging (2015) 96, 21—26

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REVIEW / Pediatric imaging

Umbilical vein varix: Importance of ante-

and post-natal monitoring by ultrasound

∗

E. Beraud , C. Rozel, J. Milon, P. Darnault

Service d’imagerie anténatale et pédiatrique, université de Rennes 1, centre hospitalier

universitaire hôpital Sud, 16, boulevard Bulgarie, BP 90347, 35203 Rennes cedex 2, France

KEYWORDS Abstract Foetal intra-abdominal umbilical vein varix is rare. Colour Doppler ultrasonography

Umbilical vein; helps distinguish this vascular anomaly. A detailed anatomic scan must be performed to exclude

Prenatal diagnosis; associated anomalies: forms associated with additional complications are found in 29 to 35% of

Venous thrombosis; the cases. Intra-uterine foetal demise (IUFD) is a complication of umbilical vein varix. However,

Dilatation; recent studies are more reassuring. When foetal intra-abdominal umbilical vein varix is isolated,

Portal vein there is no reason to change the management of the pregnancy. Foetal sonographic follow-up

is recommended, focusing on an increase in the size of the varix and the appearance of a clot.

A particular clinical form, connecting the umbilicus to the extra-hepatic portal vein should be

known, because of a high risk of thrombosis. On the basis of this ﬁnding, postnatal monitoring

by ultrasound is necessary.

Introduction

FIUVV is characterised by the dilatation of the foetal umbilical vein between its entry in

the abdomen and its ending in the portal system. The incidence is low, ranging from 0.4 to

1.1/1000 [1—3]. It accounts for about 4% of the malformations of the umbilical cord in the

foetus [4—6]. The diagnosis is based on colour Doppler sonography. It justiﬁes a full foetal

assessment, in a reference centre, to search for other anomalies that are associated in

one third of the cases [2]. To date, over 150 cases of the isolated form of FIUVV have been

reported in the literature. It was initially thought to be a serious anomaly, with a mortality

of up to 44% due to IUFD [6—8], making certain authors propose inducing labour as of 34

weeks of amenorrhoea (WA), in spite of the morbidity generated by prematurity. The foetal

Abbreviations: FIUVV, Foetal intra-abdominal umbilical vein varix; IUFD, Intra-uterine foetal demise; WA, Weeks of amenorrhoea; IUGR,

Intra-uterine growth restriction. ∗

Corresponding author.

E-mail address: [email protected] (E. Beraud).

22 E. Beraud et al.

risk, in recent publications including a larger number of the end of the umbilical vein and connecting the right and

isolated forms of FIUVV, appears to be lower, leading to a re- left portal branches. These two sonography sections do not

evaluation of the obstetric care [1]. Antenatal monitoring by allow to visualize the main portal vein. From the section of

sonography is indispensable in particular, in the search for a the abdominal perimeter, scanning to the bottom and to the

thrombus of the FIUVV. A speciﬁc clinical form, associated right reveals the junction of the main portal vein with the

with abnormal anastomosis of the umbilical vein, should be portal sinus at the place of division between the right portal

known, because of the sonography characteristics and the vein and the left portal vein [9]. The normal diameter of

frequent complications. the vein, measured at its intra-hepatic segment, increases

in a linear manner during the pregnancy, passing from 2 to

8 mm between the ﬁfteenth week of amenorrhoea and term

Sonography of the foetal umbilical vein [7,10].

A sagittal section centered on the umbilical opening is used

to analyse the sub-hepatic intra-abdominal segment of the Positive diagnosis

◦

umbilical vein. After its point of entry, a ﬁrst 90 angle ori-

FIUVV is detected as an anechoic, oval-shaped or rounded

ents the vein under the abdominal wall, in the direction

mass, located between the abdominal wall and the lower

of the liver (Fig. 1). A second angle directs it to the rear

edge of the liver [11,12]. It is in continuity with the umbil-

according to an ascending sub-hepatic trajectory. The trans-

ical vascular axis on sagittal sections [13]. The pulsed and

verse section used to measure the abdominal perimeter is

colour Doppler modes conﬁrm the vascular nature of the

used to visualise the intra-hepatic portion of the umbilical

abnormality and reveal a venous type ﬂow (Fig. 3a and b).

vein that connects to the left portal vein opposite the ori-

It allows to rule out other ﬂuid images that may be seen

gin of the lower left portal vein. The unit takes a horizontal

in this space: liver cyst, cyst of the bile ducts, cyst of the

trajectory to the right, forming the portal sinus (Fig. 2).

mesentery, gastric duplication. FIUVV is deﬁned according

The latter appears in the shape of an ‘‘L’’ established from

to two criteria: either a diameter exceeding 9 mm [14] or a

diameter of the sub-hepatic segment of the upper umbilical

vein exceeding 50% the diameter of the intra-hepatic seg-

ment [15]. These criteria have been used separately or most

often together, as in all of the series published over the last

10 years [1—3,5,10,15].

The diagnosis of umbilical vein varix justiﬁes a detailed

foetal anatomical assessment in a reference centre to look

for other abnormalities. These associated forms account for

29 to 35% of FIUVV [2,5]. The disorders most often seen

involve the cardiovascular system and the uro-genital tract

[2,8], but it may also consist of excess amniotic ﬂuid. No

speciﬁc association has been found. The severity of the

lesions varies. Certain minor anomalies such as pyelectasis

or a single umbilical artery are usually not used to classify

Figure 1. Ultrasound image in a 22-week foetus showing the the observation among the associated forms [3,10]. Chromo-

longitudinal course of the umbilical vein. UV: umbilical vein; B: some abnormalities are found in 6% of the cases of FIUVV,

bladder; H: heart; S: spine; arrow: umbilical vein varix. most often trisomy 21, 18 and 9 and triploidy [8]. They occur

in 28% of the associated forms and under 2% of the isolated

forms [2]. For most authors, abdominal umbilical vein varix

does not justify the systematic use of a caryotype in this

context of an isolated anomaly [1,14].

The mean age of gestation, at the time of the diagno-

sis of FIUVV, is between 27.5 and 30.5 WA ranging from 18

to 41 WA [1,3,8,10,15]. There is no difference between the

isolated forms and the associated forms [5]. In two-thirds

of the cases, the venous anomaly is detected after 28 WA

with a normal ﬁrst sonogram, supporting the hypothesis of

a disease acquired during the pregnancy [2].

Evolution during the pregnancy

When the anomaly is recognised, the umbilical vein diam-

Figure 2. Ultrasound image in a 32-week foetus showing the nor-

eter is between 9.7 and 13 mm with extremes of 5.6 and

mal intra-hepatic umbilical vein (UV) connection to the left portal

20 mm [1,3,6,8,10,16]. In 61% of the cases, the dilation

vein (LPV), creating the portal sinus, at the level at which the

does not evolve in the follow-up sonograms. The diameter

abdominal circumference is usually measured. ILPV: Inferior branch

of left portal vein; RPV: right portal vein; S: stomach; AG: adrenal remains identical that initially measured or increases by 1 to

gland. 3 mm, parallel to the linear increase in the diameter of the

Umbilical vein varix: Importance of ante- and post-natal monitoring by ultrasound 23

Figure 3. Foetal intra-abdominal umbilical vein varix: a: ultrasound image in a 37-week foetus showing an anechoic cystic mass; b: colour

Doppler ultrasonography conﬁrms this vascular anomaly.

umbilical vein during the pregnancy. A 4 to 9 mm increase represented by IUFD, thrombosis and intra-uterine growth

in the dilation is only observed in 28% of the foetuses and restriction (IUGR). The overall frequency is assessed at 10%

does not seem to be related to the precocity of the diag- (Table 1). In the work ﬁrst published by Mahony et al. in

nosis [1,6,8,10,17,18]. The disappearance of FIUVV is only 1992, three IUFD were observed in seven cases of isolated

reported in 4 cases [1,6]. According to Mankuta et al., it forms of FIUVV, representing a very high rate of mortality

probably involves an error in the interpretation of the initial of 43% [7]. Since, 5 deaths have been reported between 29

sonogram, incorrectly measured at the non-linear segment and 38 WA [6,8,15]. Among all of the cases, the occurrence

of the vein, and not a real regression in the dilation [1]. A of IUFD is assessed at 4.8%, and is inferior to the occur-

turbulent ﬂow, deﬁned in colour Doppler sonography by a bi- rence reported in associated forms of FIUVV [8,15] although

directional ﬂow, is reported in 28 to 50% of the cases at the superior to the 0.7 % rate generally reported during preg-

level of the dilated segment of the umbilical vein [1,3,10]. nancy [19]. The occurrence is not related to the precocity

According to Weissmann-Brenner et al., it is in part related of the appearance or the extent of the dilation [10]. Tw o

to the size of the lesion, since the diameter of the dilation mechanisms have been proposed: the formation of a throm-

is greater in foetuses presenting turbulences [10]. bus at the level of the dilation creating an obstacle for the

venous return or an increase in the cardiac pre-load that may

be responsible for heart failure [1,8]. The histopathological

examination of the in utero deceased foetuses has not con-

FIUVV complications during pregnancy

ﬁrmed these hypotheses. The appearance of a thrombus at

The potential gravity of the isolated forms of FIUVV is due to the level of the umbilical vein varix has to be searched for

complications arising during the pregnancy. They are mainly systematically. The diagnosis is based on the detection of

Table 1 Isolated FIUVV.

Authors Year FIUVV Ante-natal thrombosis IUGR IUFD

Jeanty [11] 1989 1 — — 0

Mahony et al. [7] 1992 7 1 0 3

Estroff and Benacerraf [16] 1992 4 — — 0

Rizzo et al. [18] 1992 1 0 0 0

Moore et al. [12] 1996 1 0 0 0

Sepulveda et al. [15] 1998 7 0 0 1

Zalel et al. [17] 2000 1 0 0 0

Rahemtullah et al. [5] 2001 20 0 0 0

Prefumo et al. [21] 2001 1 0 0 0

Viora et al. [20] 2002 1 1 0 0

Valsky et al. [6] 2004 7 0 0 2

Fung et al. [8] 2005 12 0 1 2

Ipek et al. [4] 2008 2 0 0 0

Weissmann-Brenner et al. [10] 2009 14 0 1 0

Byers et al. [2] 2009 37 0 1 0

Mankuta et al. [1] 2010 28 0 3 0

Bas Lando et al. [3] 2013 23 0 1 0

Total 167

FIUVV: foetal intra-abdominal umbilical vein varix; IUGR: intra-uterine growth restriction; IUFD: intra-uterine foetal demise.

24 E. Beraud et al.

incomplete ﬁlling of the vascular lumen in colour Doppler for by the failures in inducing labour [3]. The indications

sonography, although the clot may also be detected in the for a caesarean-section correspond to the usual obstetri-

form of an intravascular echogenic image [20]. Only two cal criteria, FIUVV only justifying two cases, of which one

cases of thrombosis have been observed, one at 22 and the case of antenatally diagnosed thrombosis [20]. No obstetric

other at 32 WA [7,20]. In once case, the foetus died at 29 WA complications were reported in the literature, indepen-

without the death being formally attributed to the throm- dently from the type of delivery, including deliveries at

bosis [7]. The risk of seeing a thrombus appear is higher term.

with major dilation of the umbilical vein and the presence The birth weight reﬂects the obstetric care. The mean

of turbulences. IUGR is deﬁned by a foetal biometry inferior is 2850 grams in centers proposing induced labour and

to the tenth percentile for the term. While only one obser- 3200 grams in the others [3,5,10]. Induced labour also

vation has been reported before 2005, the occurrence, in accounts for the lower weight at birth in cases of FIUVV

recent works, is estimated at between 4 and 10%, higher associated with turbulences [10] and the higher frequency

than the 3% occurrence of IUGR usually reported [1,3]. To of intensive care hospitalisation in the series published by

account for this difference, the hypothesis of a reduction in Bas-Lando et al. [3]. In view of these results, several authors

the oxygen supply to the foetus related to the presence of do not recommend inducing labour in the isolated forms of

FIUVV is unlikely, because of the lack of correlation between FIUVV [1,3], others propose inducing labour at 36—37 WA in

the size of the dilation and the presence of turbulences case of major umbilical vein varix, especially if there are

[15,21]. Heart failure has often been suggested as a poten- turbulences [10]. Delivery by caesarean section is proposed

tial complication of the venous anomaly. However, in the in case of complications, in particular in case of thrombus

isolated forms, no correlation has been found between the of the umbilical vein.

presence of anasarca and FIUVV [2]. According to Bas-Lando Because of the risks for the newborn, delivery in a level

et al., there is currently no reason to perform a system- three establishment should be considered.

atic foetal echocardiogram [3], even though the majority of

teams recommend it [1].

Recently published studies modulate the global occur- Speciﬁc form: the umbilical vein ending in

rence of complications and reconsider their relative

the extra-hepatic portal system

importance. Only taking into account the last ﬁve pub-

lications, accounting for two-thirds of the cases, the

Although the sonographic presentation is identical that of

complications only arise in 6% of the isolated forms of FIUVV

FIUVV, this form should be distinguished due to its anatom-

and are essentially represented by IUGR without cases of

ical particularity, its evolution during the pregnancy and

IUFD.

especially the frequent complications. Six cases have been

identiﬁed in the literature, to which we can add a case

Prenatal monitoring monitored in our centre [22—27].

Due to potential complications and the still limited num-

Anatomical particularity

ber of case reports published, attentive monitoring is

recommended, in particular during the third trimester of The description is based on the post-natal imaging but above

pregnancy. The frequency of the sonograms varies, depend- all, on the intra-operative ﬁndings. In this form, the venous

ing on the teams, from one examination every two weeks dilation is associated with a malformation of the umbilical-

to two examinations per week. The main goal is to detect portal system, the dilated venous segment not ending at the

a thrombus [3,10]. The existence of major dilation, supe- portal sinus but at the caudal part of the superior mesenteric

rior to the mean diameter of a FIUVV (10—12 mm) and the vein, just opposite the conﬂuence with the splenic vein.

detection of turbulences, are risk factors justifying obstetric There is no round ligament and the falciform ligament is

monitoring and repeated sonograms. short. Embryologically, the portal system arises from a dou-

ble venous system: the umbilical veins from the placenta and

Birth the vitelline veins from the yolk sac. Under the inﬂuence, in

particular, of the hepatic cords, these two systems undergo

The obstetric care of the delivery is not the same. Certain major modiﬁcations. The right vitelline vein gives rise to

teams recommend inducing labour, as of 34 WA, mainly due the deﬁnitive portal vein, the proximal segment of the left

to the risk of IUFD [1,6]. The mean age of gestation at the umbilical vein becomes the umbilical vein itself. According

time of delivery ranges from 36 to 38.7 WA [1,3,5,10]. Vagi- to Benoist et al., this anomaly may be the result of early

nal delivery accounts for 64 to 83% of births, after induction and proximal anastomosis between the left umbilical vein

motivated by the existence of FIUVV in more than half of and the right vitelline vein [22].

them. The frequency of inducing labour, when not system-

atic, is high, between 62 and 89% of the deliveries, and Diagnosis and evolution

superior to the rate of induction usually observed [3,10].

In 54% of cases, it is induced between 34 and 36 WA, either As in the previous form, venous dilation presents as an ane-

due to the size of the dilation or the presence of turbu- choic formation located between the lower side of the liver

lences [10] or de facto for some teams [1]. The frequency of and the umbilicus. As opposed to FIUVV, venous dilation is

caesarean-section births is 17 to 20% [1,3]. According to Bas- always diagnosed before 28 WA (mean: 23 WA), the initial

Lando et al., it is signiﬁcantly higher than the 10% frequency diameter is about twice as wide (mean: 20 mm), and there is

usually observed by this team, the difference accounted always the presence of turbulences (Table 2). The evolution,

Umbilical vein varix: Importance of ante- and post-natal monitoring by ultrasound 25

Table 2 Speciﬁc cases of FIUVV.

Speciﬁc form Authors Gestational Diameter Increase in Thrombosis Evolution

of FIUVV age at the (mm) size (mm) (WA or days)

diagnosis (WA)

Case 1 Allen et al. [23] 27 24 — 31 Regression

Case 2 Benoist et al. [22], 24 21 14 3 Full portal thrombosis

Héry et al. [26]

Case 3 Moon et al. [24] — — — 3 Regression

Case 4 Kivilevitch and 23 15 12 34 Regression

Achiron [25]

Case 5 Scalabre et al. [27], 20 28 19 1 Regression

Héry et al. [26]

Case 6 Héry et al. [26] 20 25 23 1 Full portal thrombosis

Our case Rennes 24 12 0 4 Full portal thrombosis

Mean 23 20,1 13,6 7/7 Regression: 4/7

WA: weeks of amenorrhoea; D: days; FIUVV: foetal intra-abdominal umbilical vein varix.

during the pregnancy, is usually marked by an increase in the and quickly treat a thrombosis of the portal system. The

dilation that may reach 23 mm. Our case report is the only diagnosis may be suspected, as in one of the case reports,

one in which the vein was moderately dilated at the time of when the dilated segment of the umbilical vein has, under

the diagnosis and stable during the follow-up controls. the bile duct, a trajectory directed towards the rear [25].

When the malformation is not suggested during the preg-

Thrombosis nancy, only the post-natal sonography can distinguish the

ending of the umbilical vein at the level of the distal seg-

Found in all case reports, thrombosis is initially found in the ment of the superior mesenteric vein from its usual ending at

distal segment of the superior mesenteric vein and/or the the left portal branch. However, this examination is not sys-

origin of the portal vein. The diagnosis may be antenatal, tematic [3]. In the case reports published in the literature,

as observed in two case reports [23,25], although in ﬁve besides one case of thrombocytopenia, sonographs have

out of seven cases, it was post-natal during the ﬁrst three been prescribed only after the FIUVV has been diagnosed

days of life [22,24,26,27]. The evolution may be favourable antenatally.

[23,25], although the thrombosis is often extensive towards

the intra-hepatic portal system (Fig. 4), justifying a laparo-

tomy in ﬁve case reports [22,24,26,27]. In spite of the Conclusion

resection of the aneurismal lesion and thrombectomy, it

evolved towards full portal thrombosis in three cases. FIUVV is a rare foetal vascular anomaly. After reviewing the

studies recently published, the evolution may be consid-

ered favourable when isolated. It is necessary, at the time

Value of early post natal sonography

of the diagnosis, to obtain a reference obstetric sonogram.

Without an associated lesion, the probability of a chromo-

Confronted with FIUVV, it is important to recognise an abnor-

some abnormality is low and the systematic obtention of a

mal anastomosis of the umbilical cord in order to screen

caryotype is not justiﬁed. In view of the still limited num-

ber of cases, sonography monitoring is indicated during the

third trimester of the pregnancy in order to search for a

distinct increase in the dilatation or the appearance of a

thrombus. Without any complications and considering that

no cases of IUFD have been reported over the last years,

the induction of labour before term is not justiﬁed. A sono-

graphic assessment should be obtained during the ﬁrst days

of life in order to search for an abnormal anastomosis of the

umbilical vein in the extra-hepatic portal system, requiring

the immediate care of the infant in a specialised paediatrics

unit.

Disclosure of interest

Figure 4. Ultrasound image in a newborn with a particular form

The authors declare that they have no conﬂicts of interest

of an intra-abdominal umbilical vein varix showing a portal system

concerning this article. thrombosis (arrow).

26 E. Beraud et al.

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