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The ductus venosus in the fetus and in the adult.

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AUTHOR’S ABSTRACT OF THIS PAPER 18sU E D
B Y T H E BIBLIOQRAPHIC SERVICE M A Y
7
THE DUCTUS VENOSUS I N THE FETUS AND I N THE
ADULT
WALTER BLAIR STEWART
J>epartw~enton Palhological Anatomy, The Mayo Clinic, Rocheslw, Mirmesota
TWO FIGURES
Text-books state that the ductus venosus of the fetus, following
its postnatal occlusion, persists through adult life as a fine fibrous
cord termed the ligamentum venosum. “The umbilical vein and
the ductus venosus become completely obliterated between the
second and fifth days after birth, and ultimately dwindle to
fibrous cords, the former becoming the round ligament of the
liver, and the latter the fibrous cord, which in the adult may be
traced along the fissure of the ductus venoms” (Gray’s Anatomy).
The ductus venosus is a fetal blood vessel which has been
formed secondarily by a longitudinal anastomosis of capillary
sinusoids of the liver during the early weeks of intra-uterine life,
and which, in the mature fetus, as a direct continuation of the
umbilical vein, conducts a large part of the placental blood into
the left hepatic vein just before its union with the inferior vena
cava, thus short-circuiting the liver. The purpose of this short
cut during fetal life is to permit the richly oxygenated, placental
blood to pass rapidly to the body of the fetus, through which it
may be distributed after only slight previous admixture with the
hepatic and somatic circulations. The size of the liver, relative
to that of the entire body, is much greater during early, than
during late fetal life. This is attributable to the fact that all the
placental blood must pass through the liver sinusoids up to the
time of formation of the ductus, and only a small part, after it,s
formation.
The literature on the subject of the ductus venosus is limited
t o the abbreviated statements found in current anatomical,
embryological, and obstetrical text-books and articles scattered
225
226
WALTER BLAIR STEWART
over the last seventy years of medical writing. In 1856, Meadows
reported an instance of fatal hemorrhage from the ductus veiiosus
occurring in a child twenty hours after birth, although the
evidence on which he localized the lesion t o the ductus is not clear.
He says: “But on examining the liver an enormous clot was
found lying on its upper surface, between it, and the peritoneum
which had been stripped off by the effused blood; the same thing
was also seen on the under surface of the right lobe; these two
clots were much thicker behind than before, and seemed to have
originated from the ductus venosus; but how the blood got into
the cavity of the peritoneum could not be positively ascertained.”
No cause for the accident could be allocated. There was no
history of intrapartum or postpartum injury to the child. The
labor and the first twenty hours of extra-uterine life were normal.
Jackson, as early as 1859, mentions the error of most textbooks of anatomy, including the volume ‘ recently produced by
Gray,’ in which it is said that the ductus venosus enters into the
vena cava. According t o Jackson’s own observations on dissections, “it terminates in one of the hepatic: veins near and sometimes close to the opening of this last into the vena cava.” He
said that Mr. John Bell, in his anatomy (1802) was one of the
few previous writers who had formulated this fact correctly.
Also in a small volume by Mr. John Struthers of Edinburgh
(’54) it was noted that the duetus venosus “enters not the vena
cava but the left hepatic vein, about a quarter of an inch before
the latter ends in the vena cava.” Jackson says that the present
instance is one of too many in which errors are perpetuated in the
text-books of medical science.
The interesting anomaly of absence of the ductus venosus
with a description of the consequences and a summary of four
olher reported cases is recorded by Paltauf in 1888. The condition is very rare, Kuster reporting one case and Otto three
cases. Kuster’s case was complicated by the presence of abdominal fissure, and Otto’s showed unusual points of entry of the
umbilical vejn. Paltauf’s was a normal, full-term child, except
that such a huge ascites was present that it formed an obstruction
to the natural course of labor, and paracentesis had to be resorted
DUCTUS VENOSUS I N FETUS AND I N ADULT
227
to. NIoreover, hydramnios had been present. The placenta
was very large, the umbilical cord long, its veins tortuous and
showing varicose dilatations; the subperitoneal veins were very
large and somewhat tortuous. The umbilical vein led obliquely
into the portal vein. No sign, even such as a fibrous strand,
remained of the ductus. Thus a condition of portal obstruction
in the fetus arose, analogous to the portal cirrhosis of the adult,
with a resulting hydramnios, ascites, and attempts at collateral
circulation. In this instance prominent anastomoses had been
produced on either side between the spermatic vein, emptying
into the vena cava, and the colic veins, emptying into the portal
vein, and further anastomoses with veins of the abdominal wall.
This is a type of collateral circulation unknown in acquired portal
obstruction, since in the adult the portal and caval circulations
are too widely separated, and the venous channels are no longer
patulous, as during the process of development. In explaining
this absence of the ductus Paltauf invokes the statement of His,
that the ductus venosus is a secondary formation, a short cut
of the capillary sinusoids of the liver among the islands of liver
cells. In this case such a channel has not been opened up, with
the result that all the placental blood must pass through the
capillaries of the liver and hence must be under increased pressure.
As to the chief function of the ductus venosus, Paltauf believes
hhat it serves to maintain a free passage for the blood in the
umbilical and portal veins, equalizing rapidly the differences in
pressure which probably prevail in the two channels, and avoiding
any detrimental influence of the umbilical venous flow, which is
under greater pressure, on the portal flow. The liver sinusoids
of the late fetus, even as the embryonic liver sinusoids, should
suffice for the passage of the umbilical blood, provided no secondary disturbances arise. Instances of hydrops and ascites with
hydramnios in cases of fetal hepatitis, in spit,e of the presrnce of
the ductus venosus, serve only to emphasize thc prominent part
of the sinusoidal circulation even in fetal life.
Barge asks why the ductus venosus closes after birth. It is
natural enough that the umbilical vein should become obliterated
after ligation of the cord, for blood vessels usually close distal to
22s
WALTER BLAIR STEWART
a ligature. The ductus has been regarded as a continuation of
the umbilical vein-a point which would afford a simple explanation were it not for the fact that the portion of the umbilical
vein, known in the adult as the recessus umbilicalis of the portal
vein, persists and functions throughout life. In this case the
circulation disobeys the law of hydrodynamics which would have
it flow in the line of least resistance, namely, through the ductus;
but after ligation of the umbilical vein it chooses to pass through
the sinusoids of the liver where it meets much more resistance.
This raises two questions: Is it not possible that the ductus closes
during fetal life? There is no evidence to support this view, apart
from Gegenbauer’s observation that the lumen of the duct gets
narrower during fetal life. Is the closing of the duct a useful
occurrence’? Surely it is, for it does not seem practical that a
large volume of blood should dodge the liver, one of the main
organs of general metabolism. But neither this practical side,
nor the hereditary tendency defended by ROUX,explains the
mechanism of closure of the duct. Barge eniphasizes the initiation of respiration after birth and the cessation of the fetal
circulation, especially the former. During inspiration the sinusoids of the liver are compressed by the diaphragm, while during
expiration the pressure lets up and a kind of suction action then
draws the main part of the blood into the liver, resulting in a reduction of the volume of blood in the ductus which furthers the
closing of the ductus. DeVries objects t o this hypothesis on the
ground that respiration is too rapid a process to permit the endothelial lining of the duct to stick together long enough to result
in a ‘growing together’ of the duct walls. Bolk attributes the
collapse of the ductus to the negative venous pressure arising after
birth. Hoeke has found the ductus collapsed without obliteration
in sweral instances among older children.
Richter says that, the ductus venosus passes through the fissure
bctween the Spigelian lobe and the left lobe of the liver, from the
juncture of the umbilical vein with the left branch of the portal
vein, to the left branch of the hepatic vein immediately before it
empties into the inferior vena cava. During the first week of
life the ductus can be injected, and shows a lumen of 1 to 2 mm.
DUCTUS VENOSUS 1N E'E'l'US
AND I N ADULT
229
in diameter. Closure begins at the portal end of the ductus
at the end of the first, or during the second week. By the fourth
to the sixth week it is completely obliterated except for a small
pit a t the hepatic end. Although the lumen is obliterated, one
often finds endothelial-lined spaces filled with blood in the connective tissue filling the original lumen, and shoots of vessels
grown through the original vessel wall into the connective tissue
of the lumen and supplying it. In the process of closure the
incompletely obliterated lumen is in part distended with thrombi
which are in process of being replaced by a proliferating network
of fibers. In some instances openings of the lumen of the ductus
may occur, and even communications with portal branches,
which may form a basis for later communication between the
portal vein and the vena cava in cases of cirrhosis of the liver.
EMBRYOLOGY
The first paired vessels of human embryos (according t o Prentiss) are formed as longitudinal anastomoses of capillary networks which originate first in the angioblast of the yolk-sac anti
chorion. In embryos of 1.3 mm. umbilical veins from the ehorion,
fused in the body-stalk and separating to pass forward in the
somatopleure on either side to the paired tubular heart, are
already formed. At 2.5 mm. a longitudinal fusion of the paired
heart has occurred, and numerous tributary veins from the
yolk sac, united into a single vessel on either side, join the umbilical veins to empty into the sinus venosus, one of the three
primitive dilatations of the heart tube, at its base. At 4.2 min.
the umbilical vein on either side has been joined by the common
cardinal vein, the resultant trunk entering the sinus laterally.
At this stage the liver diverticulum has grown out ventrally from
the foregut cranial to the wall of the yolk-sac, and is beginning
to grow into the walls of the vitelline veins, producing minute
isolated islands of liver cells surrounded by the vitelline sinusoids.
Between the liver diverticulum and the yolk sac three transverse
anastomoses between the vitelline veins, one dorsal and two ventral to the primitive gut, arise. Shortly after this an oblique
venous passage is opened up among the islands of liver cells,
T H E A N l T O J l I C h L RECORD, YOL.
25, NO. 4
230
WALTER BLAIR ST’EWAlZT
passing from the juncture of the left vitelline and umbilical vein
(for the latter has now approached and tapped the former on
each side) forward to the point of entry of the right vitelline
vein into the sinus venosus. This secondary formation and short
cut for the main bulk of the placental blood, which now enters
largely through the left umbilical vein (the proximal end of this
vessel and its union with the sinus venosus disappearing), becomes
tlhe ductus venosus. The vitelline veins distal .to the liver,
through the atrophy of the parts of the two venous rings encircling
the gut and the growth of others, come t o form the portal vein
of the adult.
THE POS‘1”ATAL
DUCTI’IS VENOSIJS
The present study is based on a survey of material rcmovcd at,
fifty consecutive postmortem examinatioiis at the Mayo Clinic.
I n one case, that of a still-born child at full term (case X400979)
the ductus venoms was completely patent, although the first
signs of closure were evident. There was a sharp line of demarcation between the intima of the umbilical vein and that of the
ductus, the two being of notably different shades of color. The
circumference of the ductus at the end adjoining the portal vein
was much less than that a t the end adjoining the left hepatic
vein, 7 mm. as compared with 12 nim. The circumference of the
left branch of the portal vein a t its point, of union with the urnbilical vein was only 3.5 mm.-a fact which would lead one to
suspect that twice as much of the umbilical blood flowed through
the ductus as did through the circuitous route of the liver capillaries. The umbilical vein, too, was completely patent and
showed no narrowing, although the intima distal to the point of
entry of the veins from the quadrate lobe and the left lobe of thc
liver (the future recessus umbilicalis of the portal vein) showcl
distinct roughening arid absence of the riorrrial intimal sheen.
I n one child of eleven hours (case A398634) there were no
signs of closure, or of narrowing of the ductus, except that the
same sharp line of demarcation existjed between the intima of the
umbilical vein and the ductus as in the still-born child.
DUCTUS VENOSUS I N FETUS AND IN ADULT
231
In another child, who had lived two days (case A401005),
there was no opening or even a trace of a scar indicating an opening at the umbilical end (now the portal end) of the ductus,
although the hepatic end was widely open, as in the fetus, and
the duct itself was freely patent almost to its point of union with
the portal vein. Several small veins which drained the surrounding liver tissue emptied into the hepatic half of the ductus,
the embryologic channel thus serving also as a hepatic vein.
The umbilical vein was completely closed except for a minute
pinhole opening into the recessus umbilicalis and a channel of
similar size present in the round ligament.
In acase of congenital heart disease with pulmonary atresiain a
child of four and one-half months (case A395079), the ductus was
completely obliterated with neither opening nor scar at either end.
In a girl of thirteen years (case A400834) a ductus patent in
its hepatic half, with an opening 2 mm. in diameter into the
hepatic vein, was found. There was no sign of the portal end
of the ductus. I injected India ink into the patent end of the
ductus and the ink passed out into and distended certain small
hepatic veins draining the left lobe of the liver, small vessels
running in the hepatogastric ligament, and the vasa vasorum of
the ductus itself. I n the open part of the ductus five small
veins were seen to enter its lumen, through which the injectionmass had passed. The portal half of the ductus did not take the
India ink.
I n :m analysis of t,he (vises seen in adult life, the most striking
fact is that there persists a definite, although often semiobliteratecl
duct!, lying close to the liver in the fossa for the ductus venosus.
It appears as a scant bundle of fibrous strands, semitranslucent,
yet denser than the thin fibrous sheet, the hepatogastric ligament,
near the bottom of whose meshes it extends from portal to hepatic
vein. It is extremely difficult to locate. But in the center of
this apparently insignificant, flat, fibrous band there may be
traced in each case a definite duct, often intima-lined and
glistening, especially in its hepatic half, even though there is n o
connection with the veins at either end. I n a few instances
such R c~mrplet(ipnttwcy is shown throirgh the whole length,
232
WALTER BLAIR STEWART
but more often it is only near the hepatic end. The remainder
of the ductus may present a lumen after a passage has been gently
forced by a probe. But in every case a pathway which once
represented the lumen of the ductus venosus may be dissected
out grossly. Microscopic examination confirms this, for the
entirely patent sections present a vein of normal appearance, a
thick wall with all its coats, and a large circular lumen (fig. 1).
The sections from the semiobliterated zones show a minute,
circular, or a flat, elongated lumen, endothelium-lined in some
places, and with rough, fibrous elevations or irregular projections
from the intima at others (fig. 2). In no case was an open passage
persistent from the portal vein t o the hepatic vein. It is interesting to speculate as to what clinical syndrome, if any, a ductus
venosus, completely patent throughout adult life, would give.
Certainly it would lead to some metabolic disorder, possibly to a
condition similar to that resulting from an Eck’s fistula. It is
worthy of note that a patent ductus is not found as one of the
channels of collateral circulation in cases of secondary portal
obstruction, such as cirrhosis of the liver.
The duct ranged between 35 and 65 mm. in length in the adult
cases, the average being 45 mm. The livers from these weighed
between 825 and 2600 grams, with an average weight of 1680
grams. There seemed to be no correlation between the length
of the ductus and the weight of the liver. In the portal vein at
the end of the ductus there was almost invariably a smooth int h a l lining showing no opening into the ductus and no pit. or
scar to mark the site of the former opening, except that by
traction on the ductus the intima could be depressed, revealing
its former location. One case presented a minute depression.
Another showed a minute, pinhole opening leading into the
ductus, which was widely patent down to within 1 em. of its
hepatic end, where it had closed without leaving a scar.
Fig. 1 (A401367.) Patient aged thirty-three. Section through hepatic end of
ductus venosus. Both openings closed without scars. X 50.
Fig. 2. (h397718.) Patient aged seventy-one. Section through middle of
tfiirtiiq venows. Both openings closetl without srarq. x 50.
233
234
\f-ALTER BLAIR STEWART
In fifteen cases the hepatic vein presented an opening into the
ductus, varying from the size of a pin-point to 2 mm. in diameter.
The lumen of the ductus was either definitely patent, or could be
forced open by the probe in most of these cases. In a few instances an oval thinning of the intima of the hepatic vein was
evident; in a few there were fatty changes in this intima; in one,
a narrow, fibrous, intima-covered bridge, 5 mm. long, across the
closed oval, and in one, two circular depressions in the intima,
side by side, partly covered over by a thin sheet of intima. The
location of this hepatic end of the ductus is quite constant, usually
just above, occasionally beside the juncture of the upper and lower
branches of the left hepatic vein, this common left hepatic vein
being a very short vessel which empties almost at once into the
inferior vena cava. The portal end of the ductus lies in the upper
part of the left main branch of the portal vein, directly opposite
to, or a little to the left of the point of juncture of the round
ligament with the processus globularis of the portal vein.
In eight instances a definite opening, in one 7 mm. in circuniference, led from the portal vein into a patent channel in the
round ligament, usually soon ending in a fibrous obliteration,
but in one case of Laennec’s cirrhosis, extending as a wide, somewhat tortuous channel through the whole length of the round
ligament.
SUMMARY
1. The ductus venosus extends from the left branch of the
portal vein, opposite the point of entry of the umbilical vein, in
the left posterior fossa of the liver in the folds of the hepat,ogastric
ligament, to the point of union of the upper and lower branches
of the left hepatic vein, just before the common trunk empties
into the inferior vena cava.
2. The portal end of the ductus venosus closes within the first
two days after birth, the hepatic end may present a functioning
stoma throughout life. The hepatic half of the ductus venoms
may remain open, receive tributaries from the parenchyma of the
liver and the hepatogastric ligament, and thus function as a
hepatic vein in the adult.
DUCTUS VENOGUS IN FETUS APiD IN ADULT
235
3. In every adult the remains of the fetal ductus venosus persist
as a fine, flat, fibrous cord with a lumen only semiobliterated
even though both ends are completely closed.
4. No cases of complete patency of the entire ductus in adult
life were observed personally or seen recorded in the literature.
5. The ductus venosus is a short cut around the liver for the
oxygenated fetal blood in its passage from the placenta to the
heart.
BIBLIOGRAPHY
BARGE,J. A. J. 1919 Waarom sluit zich de ductus venosus Arantii. Nederl.
Tijdschr. v. Geneesk., vol. 1, pp. 718-722.
JACKSON,
J. B. S. 1859 The ductus venosus. Extra. Rec. Bost. Soc. Med. Impr.,
vol. 3, p. 296.
MEADOWS,
A. 1856-1857 Case of fatal hemorrhage from the ductus venosus
occurring in a child twenty hours after birth. Tr. Med. Soc. King’s
Coll., London, vol. 1, pp. 224-226.
PALTAUF,R. 1888 Ein Fall von Mange1 des Ductus venos. Arantii. Wen.
klin. Wchnschr., Bd. 1, S. 165-167.
RICHTER,
E. 1911 Giber den Verschlws des Ductus Ienosus Arantii nebst Bemerkungen iiber die Anatomie der Pfortader. Virchows Arch. f. path.
Anat., Bd. 205, S. 257-263.
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