Patent ductus arteriosus

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Priyamvada Singh, M.B.B.S. [2], Cafer Zorkun, M.D., Ph.D. [3], Assistant Editor-In-Chief: Kristin Feeney, B.S. [4]

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Priyamvada Singh, M.B.B.S. [2], Cafer Zorkun, M.D., Ph.D. [3], Assistant Editor-In-Chief: Kristin Feeney, B.S. [4]

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ramyar Ghandriz MD[2]

Ductus arteriosus was introduced centuries ago, but it is proven that from the 17th century the presence of such a duct was announced by many anatomists working on cadavers. It’s management and treatment underwent many controversies and caregivers always had their own management criteria for surgery or not overtime.

• Ductus arteriosus has been identified at least from the 17th century by anatomists studying cadavers.
• For centuries caregivers had a controversy over treating PDA and many approaches evaluated.
• Evolution of the knowledge about ductus arteriosus can be reviewed in four overlapping epochs^[1]:
  • “The age of anatomical observation”
  • “Early decades of cardiac surgery”
  • “Golden age of fetal physiology”
  • “Era of modern neonatal intensive care”

• In 1938 The first Surgery of PDA (ligation of the duct) by DR.Robert Gross at Boston Children’s Hospital.
• It was done on a 7 years old girl with PDA.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Priyamvada Singh, M.B.B.S. [2], Cafer Zorkun, M.D., Ph.D. [3], Assistant Editor-In-Chief: Kristin Feeney, B.S. [4] Ramyar Ghandriz MD[5]

The pathophysiological consequences depend on the size of the defect and the pulmonary vascular resistance.Patent ductus arteriosus is a heart condition that is normal but reverses soon after birth. In a persistent PDA, there is an irregular transmission of blood between two of the most important arteries (aorta and pulmonary artery) in close proximity to the heart. Although the ductus arteriosus normally seals off within a few days, in PDA, the newborn‘s ductus arteriosus does not close, but remains patent.

In the developing fetus, the ductus arteriosus (DA) is a shunt connecting the pulmonary artery to the aortic arch that allows much of the blood from the right ventricle to bypass the fetus’ fluid-filled lungs.^[1] During fetal development, this shunt protects the right ventricle from pumping against the high resistance in the lungs, which can lead to right ventricular failure if the DA closes in-utero.

When the newborn takes its first breath, the lungs open and pulmonary pressure decreases below that of the left heart.[2] At the same time, the lungs release bradykinin to constrict the smooth muscle wall of the DA and reduce blood flow. Additionally, because of reduced pulmonary resistance, more blood flows from the pulmonary arteries to the lungs and thus the lungs deliver more oxygenated blood to the left heart. This further increases aortic pressure so that blood no longer flows from the pulmonary artery to the aorta via the DA.
In normal newborns, the DA is closed within 15 hours after birth and is completely sealed after three weeks. The fall in circulating maternal prostaglandins contributes to this. A nonfunctional vestige of the DA, called the ligamentum arteriosum, remains in the normal adult heart.[1]

The abnormal closure of the ductus arteriosus results in patent ductus arteriosus. Patent ductus arteriosus is a heart condition that is normal but reverses soon after birth. In a persistent PDA, there is an irregular transmission of blood between two of the most important arteries in close proximity to the heart. Although the ductus arteriosus normally seals off within a few days, in PDA, the newborn’s ductus arteriosus does not close, but remains patent.^[3] PDA is common in infants with persistent respiratory problems such as hypoxia, and has a high occurrence in premature children. In hypoxic newborns, too little oxygen reaches the lungs to produce sufficient levels of bradykinin and subsequent closing of the DA. Premature children are more likely to be hypoxic and thus have PDA because of their underdeveloped heart and lungs.In some babies, on the other hand, the ductus arteriosus remains open. This opening permits blood to surge unswerving starting from the aorta into the pulmonary artery.

A patent ductus arteriosus allows oxygenated blood to flow down its pressure gradient from the aorta to the pulmonary arteries. Thus, some of the infant‘s oxygenated blood does not reach the body, and the infant becomes short of breath. The heart rate hastens, thereby increasing the speed with which blood is oxygenated and delivered to the body. Left untreated, the infant will likely suffer from congestive heart failure, as his heart is unable to meet the metabolic demands of his body.

In some cases, such as in transposition of the great vessels (the pulmonary artery and the aorta), a PDA may need to remain open. In this cardiovascular condition, the PDA is the only way that oxygenated blood can mix with deoxygenated blood. In these cases, prostaglandins are used to keep the patent ductus arteriosus open.

Shown below is the image below shows the gross anatomy of heart with patent ductus arteriosus.

• Small left-to-right shunt (Qp/Qs < 1.5)
• Normal ratio of pulmonary artery (PA) to systemic pressure.
• Shunt throughout the cardiac cycle, continuous murmur.

• Qp/Qs 1.5 to 2.0 yet small enough to offer some resistance to flow.
• PA systolic to systemic pressures are < 0.5
• Unusual for this group to have markedly increased PVR.
• Due to increased return to the left heart, there is volume overload of the left atrium (LA) and the left ventricle (LV).

• Defect does not restrict flow.
• There is pulmonary hypertension at near systemic pressures (PA systolic/systolic pressure is >0.5).
• Because of the physiologic decrease in the PVR over the first three months of life there is a large left-to-right shunt with Qp/Qs > 2.
• The large volume overload of the left ventricle may result in LV failure.
• There is pulmonary hypertension.
• There may be two courses:
  • A decrease in the relative size of the ductus compared with other cardiovascular structures. This results in a medium-sized defect compared with the course expected for a medium-sized defect.
  • The development of severe pulmonary vascular obstructive disease, can occur at any time from age 3 until early adulthood. The left-to-right shunt converts to a right-to-left shunt with cyanosis and disappearance of the continuous murmur.

Shown below is the pictoral image of pathophysiology of patent ductus arteriosus

Shown below is the image of pathophysiology of patent ductus arteriosus in the cross-section of the heart

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Diagram of heart showing a patent ductus arteriosus

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Priyamvada Singh, M.B.B.S. [2], Cafer Zorkun, M.D., Ph.D. [3], Assistant Editor-In-Chief: Kristin Feeney, B.S. [4] Ramyar Ghandriz MD[5]

Causes of Patent ductus arteriosus is not known. However, increased incidence have been associated with mother’s rubella and genetic causes

Common causes of patent ductus arteriosus may include:

• Genetic factors^[1]
  • PDA has is highly familial. It is shown that with the effect of environmental elements.
  • Studies shown the inheritance is more contributed to autosomal dominant.^[2]
• Congenital rubella^[3]
• Fetal alcohol syndrome^[4]

Less common causes of PDA include:

• Maternal teratogen drug use^[5]:
  • Amphetamine
  • Clomifene
  • Phenytoin

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief:Cafer Zorkun, M.D., Ph.D. [2]; Keri Shafer, M.D. [3] Priyamvada Singh, MBBS[4] Ramyar Ghandriz MD[5]

Patent ductus arteriosus is very famouse due to its continuous machine-like murmur. There are some certain conditions that may make continuous murmur.

• Patent ductus arteriosus should be differentiated from other conditions producing machine-like continuous murmur.

^{[1] [2] [3] [4] [5] [6] [4]}

• Frequently heard in children over the base of the neck, usually best on the right side.
• Changes with position. Disappears in the supine position or with compression.
• Louder in diastole

• Heard during late pregnancy and the early postpartum period in lactating women.
• Thought to be arterial in origin
• Can be bilateral
• Is louder, peaks in systole
• Vanishes in the upright position
• Abolishes by local compression

• It’s a rare congenital opening between the aorta and the pulmonary trunk just above the aortic valve.
• It can be associated with other abnormalities like anomalous origin of the coronary arteries from the pulmonary trunk and coarctation of the aorta.
• The murmur is lower and more medial in location.
• In adults is presented without a murmur and clinical features of the Eisenmenger’s syndrome.

• It can rupture into a cardiac chamber. Almost always arise from the right or the noncoronary cusps and rupture into the RV and RA respectively. Occasionally is acquired as a result of endocarditis. Large acute perforations tend to occur between puberty and age 30 causing severe retrosternal chest pain, dyspnea related to the large left-to-right shunt. The murmur is louder in a lower parasternal position. People with VSDs and sudden development of chest pain have frequently experienced rupture of a coexistent sinus of valsalva aneurysm. A rupture of the sinus of valsalva can distort or compress the coronary arteries and cause an infarction, distort the conduction system, cause AV block, distort the aortic valve, and cause AS or AI. Patients with rupture of the sinus of valsalva, should undergo surgical correction because mortality is high within a year of rupture.

• Generally a coronary artery that arises normally will communicate with the RV.
• Occasionally drain into the pulmonary trunk.
• The artery that forms the fistula is generally dilated, elongated, and tortuous. The left-to-right shunt is small.
• It may not be recognized radiographically.
• Patients with small fistula are generally asymptomatic. Therefore, no justification to repair it.
• On the other hand, if the shunt is extremely large, then failure may develop in the 4th, 5th or 6th decade of life. It can be treated with ligation.

• Usually refers to the origin of the left coronary artery from the pulmonary trunk.
• Approximately, 80 to 90% of the patients die in their first year of life due to ischemia.
• Blood from the high pressure RCA flows to the low pressure left coronary artery and the pulmonary artery.
• Anomalous origin of the RCA from the PA is much rarer, but these patients stand a better chance of surviving into adulthood because it is less likely to cause ischemia early in life.

• Instead of being localized to the precordium, these murmurs are localized to the lung fields. Cyanosis is presented with a normal heart size. Seen in Rendu-Osler-Weber syndrome. A fistula causing cyanosis could be treated with lobectomy if it is confined to a single lobe.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Priyamvada Singh, M.B.B.S. [2], Cafer Zorkun, M.D., Ph.D. [3], Ramyar Ghandriz MD[4]Assistant Editor-In-Chief: Kristin Feeney, B.S. [5]

The Patent ductus arteriosus (PDA) is commonly found in infants and constitutes only 2% of all congenital defects found in adults. The incidence is greater is in children who are born prematurely with history of perinatal asphyxia and infants with congenital rubella.

• The PDA is commonly found in infants and constitutes only 2% of all congenital defects found in adults.^[1][2][3][4]
• It is an isolated defect in 75% of cases, and is isolated in almost all adult cases.

• In the United States, the estimated incidence in children born at term is between 3 to 8 per 10,000 live births.^[5][6]
• The incidence of patent ductus arteriosus has increased over the past few decades. This is in part due to increased survival in the premature infants.
• The incidence is greater in children who are born:^[7][8][9]
  • Prematurely, with a history of perinatal asphyxia, perinatal asphyxia delays the closure of the ductus.
  • Approximately, 20% of neonates with respiratory distress syndrome have a patent ductus arteriosus.
  • In babies who are less than 1500 g at birth, many studies show the incidence of a PDA to exceed 30%.
  • The increased patency in these groups is thought to be due to both hypoxia in babies with respiratory distress and premature ductal closure mechanisms in premature babies.
  • Increased incidences in infants with congenital rubella.
  • Children born at high altitude.

• Females are more commonly affected by PDA than males. The female-to-male ratio is approximately 2:1.^[10]

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Priyamvada Singh, M.B.B.S. [2], Cafer Zorkun, M.D., Ph.D. [3],Ramyar Ghandriz MD[4] Assistant Editor-In-Chief: Kristin Feeney, B.S.[5]

Like many congenital heart disease, the cause of patent ductus arteriosus is not clear. Clinical studies suggest that the genetic and environmental factors both play an important role during the pregnancy.

Factors in the mother that may increase the risk of patent ductus arteriosus condition include:^[1]

• Age over 40
• Alcoholism
• Diabetes
• Prenatal nutrition
• Rubella or other viral illness during pregnancy
• Genetic disorders such as Down syndrome

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Priyamvada Singh, M.B.B.S. [2], Cafer Zorkun, M.D., Ph.D. [3], Ramyar Ghandriz MD[4] Assistant Editor-In-Chief: Kristin Feeney, B.S. [5]

The natural history of unoperated patients of patent ductus arteriosus (PDA) depends on the amount of left to right shunting. The left to right shunting in turn depends on the size of ductus and the difference in resistance between the left and right side of heart. PDA can cause complications such as heart failure, infective endocarditis, rhythm disturbance, pulmonary hypertension and Eisenmenger syndrome.

• May remain asymptomatic^[1]
• Rarely can increase the risk of endarteritis^[2]

• Left sided heart dysfunction
• Rhythm disturbances like atrial fibrillation as a result of left sided dysfunction

• Left ventricular volume overload
• Increased pulmonary resistance
• Eisenmenger’s syndrome

• Clinical feature – failure to thrive, feeding difficulties and respiratory distress^[3]
• If PDA left untreated it will lead to cardiac volume overload which ultimately results in heart failure
• Management involves:^[4]
  • Medical treatment with digoxin and diuretic
  • Surgical closure

• Infective endocarditis is a very complication of persistent ductus arteriosus.^[5]

• Increases risk of septic emboli to lung^[6]
• PDA complicated with infective endocarditis is an indication for closure of PDA.^[7]

• Often associated with atrial fibrillation (left sided dysfunction).^[8]

• Right ventricular impulse on palpation^[9][10]
• Pulmonary ejection sound
• A loud single second heart sound
• Graham-Steel murmur: The Graham-Steel murmur of pulmonic regurgitation and hypertension. It is high-pitched and “blowing.”

Complications during pregnancy

• In pregnancy PDA posses a very high significant risk for both the mother and the baby.^{[11][12][13][14]}
• If PDA is small it is mostly asymptomatic.
• If PDA is moderate it might lead to increased pulmonary vascular resistance which complicates the pregnancy.
• If PDA is large it might lead to eisenmenger syndrome which increases both morbidity and mortality of the baby and the mother.

Prognosis of patent ductus arteriosus varies widely. It depends on:^[15]

• The size of patent ductus arteriosus
• Whether the patient has been treated with closure medicines.
• Whether surgery has been done.
• Whether the patient with complications or not, such as heart failure, problems with lung development, or infective endocarditis.

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