The ''ductus arteriosus'', also called the ''ductus Botalli'', named after the Italian physiologist Leonardo Botallo, is a blood vessel in the developing

fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal dev ...

connecting the trunk of the pulmonary artery to the proximal descending aorta. It allows most of the

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...

from the

right ventricle A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the uppe ...

to bypass the fetus's fluid-filled non-functioning

lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of ...

s. Upon closure at birth, it becomes the ''

ligamentum arteriosum The ligamentum arteriosum (arterial ligament), also known as the Ligament of Botallo or Harvey's ligament, is a small ligament attaching the aorta to the pulmonary artery. It serves no function in adults but is the remnant of the ductus arteriosus ...

''.

Development and structure

The ''ductus arteriosus'' is formed from the left 6th

aortic arch The aortic arch, arch of the aorta, or transverse aortic arch () is the part of the aorta between the ascending and descending aorta. The arch travels backward, so that it ultimately runs to the left of the trachea. Structure The aorta begins ...

during embryonic development and attaches to the final part of the

(the

isthmus of aorta The aortic arch, arch of the aorta, or transverse aortic arch () is the part of the aorta between the ascending and descending aorta. The arch travels backward, so that it ultimately runs to the left of the trachea. Structure The aorta begins a ...

) and the first part of the pulmonary artery.

Disorder: Patent ductus arteriosus

Consequences

Failure of the ''ductus arteriosus'' to close after birth results in a condition called ''

patent ductus arteriosus ''Patent ductus arteriosus'' (PDA) is a medical condition in which the ''ductus arteriosus'' fails to close after birth: this allows a portion of oxygenated blood from the left heart to flow back to the lungs by flowing from the aorta, which has ...

'', which results in the abnormal flow of blood from the aorta to the pulmonary artery: a

left-to-right shunt A cardiac shunt is a pattern of blood flow in the heart that deviates from the normal circuit of the circulatory system. It may be described as right-left, left-right or bidirectional, or as systemic-to-pulmonary or pulmonary-to-systemic. The dir ...

. If left uncorrected, this usually leads to pulmonary hypertension followed by right ventricular

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

, as well as possible

cardiac arrhythmia Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adult ...

Role of prostaglandins

The "E" series of

prostaglandins The prostaglandins (PG) are a group of physiologically active lipid compounds called eicosanoids having diverse hormone-like effects in animals. Prostaglandins have been found in almost every tissue in humans and other animals. They are deri ...

are responsible for maintaining the openness of the ''ductus arteriosus'' (by dilation of vascular smooth muscle) throughout the fetal period. Prostaglandin E2 (PGE₂), produced by both the placenta and the DA itself, is the most potent of the E prostaglandins, but prostaglandin E1 (PGE₁) also has a role in keeping the ''DA'' open. PGE₁ and PGE₂ keep the ductus arteriosus open via involvement of specific PGE-sensitive receptors (such as EP4 and EP2). EP4 is the major receptor associated with PGE₂-induced dilation of the DA and can be found across the DA in smooth muscle cells. Immediately after birth, the levels of both PGE₂ and the EP4 receptors reduce significantly, allowing for closure of the DA and establishment of normal postnatal circulation.

Role of non-steroidal anti-inflammatory drugs

Ductus arteriosus closure may be induced by administration of nonsteroidal anti-inflammatory drugs (NSAIDs), which inhibit prostaglandin production. The most common NSAID used is

Indomethacin Indometacin, also known as indomethacin, is a nonsteroidal anti-inflammatory drug (NSAID) commonly used as a prescription medication to reduce fever, pain, stiffness, and swelling from inflammation. It works by inhibiting the production o ...

, which is usually administered in the first week after birth. However, in the presence of a congenital defect with impaired lung perfusion (e.g. Pulmonary stenosis and left-to-right shunt through the ductus), it may be advisable to improve oxygenation by maintaining the ductus open with prostaglandin treatment. However, such treatments are ineffective in an abnormal ductus. Persistence of the ductus may be associated with other abnormalities, and is much more common in females. By inhibiting PGE₂ formation, EP4 receptor activation will decrease and normal circulation can begin. NSAIDs taken late in pregnancy can cross the placenta and lead to premature closure of the DA in the fetus. In this case, exogenous PDE₂ can be administered to reverse the effects of the NSAIDs and maintain the patency of the DA for the remainder of the pregnancy.

Incidence

A ''patent ductus arteriosus'' affects approximately 4% of infants with

Down syndrome Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual d ...

(DS). A failure to thrive is a very common sign of this condition.

Maintaining patency

In some types of congenital heart defect (e.g., transposition of the great arteries), prostaglandins may be administered to maintain the DA open, allowing for the continual circulation and oxygenation of blood, until surgery can be performed.

Other animals

Ductus arteriosus evolved with the lung in the ancestors of the

lungfish Lungfish are freshwater vertebrates belonging to the order Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, i ...

as a connection between the pulmonary arteries and dorsal aorta. During embryonic development, reptiles, birds, and mammals all have either one or two paired ductus arteriosi that provide a fetal shunt of blood away from the lungs.

References

External links

Circulatory changes at birth
at berkeley.edu {{Authority control Embryology of cardiovascular system