Version July 2025
INTRODUCTION —
The ductus arteriosus (DA) is a fetal vascular connection between the main pulmonary artery and the aorta (figure 1) that diverts blood away from the pulmonary bed. After birth, the DA undergoes active constriction and eventual obliteration. A patent ductus arteriosus (PDA) occurs when the DA fails to completely close postnatally. (See "Physiologic transition from intrauterine to extrauterine life".)
The clinical manifestations and diagnosis of PDA in term infants, children, and adults will be reviewed here. Management of PDA is discussed separately. (See "Patent ductus arteriosus (PDA) in term infants, children, and adults: Management".)
PDA in preterm infants is discussed separately. (See "Patent ductus arteriosus (PDA) in preterm infants: Clinical features and diagnosis" and "Patent ductus arteriosus (PDA) in preterm infants: Management and outcome".)
ANATOMY —
The ductus arteriosus (DA) is a fetal vascular connection between the main pulmonary artery and the aorta that diverts blood away from the pulmonary bed. After birth, the DA undergoes active constriction and eventual obliteration. A PDA occurs when the DA fails to completely close postnatally (figure 1).
●Embryology – The DA is thought to derive from the embryonic left sixth aortic arch (figure 2 and image 1). In the typical left aortic arch, the aortic end of the DA arises distal to the left subclavian artery, and the pulmonary end inserts at the junction of the main and left pulmonary arteries.
●Ductal anatomy – The DA may take a variety of shapes and forms. The Krichenko classification describes the angiographic appearance of the PDA, including several subtypes broadly defined as [1]:
•Type A – Conical with the narrowest portion at the pulmonary artery side
•Type B – Short with narrowing at the aortic insertion
•Type C – Tubular without constriction
•Type D – Tubular with multiple constrictions
•Type E – Bizarre configurations, with an elongated, conical appearance and with the constriction remote from the anterior border of the trachea
An "F type" or "fetal type" ductus has also been described in premature infants presenting for catheter closure [2]. In this subtype, the elongated ductus angles like a hockey stick at the insertion to the pulmonary artery.
This classification scheme does not include the reverse-oriented ductus, which is commonly associated with congenital heart disease.
The anatomy is more varied in the presence of a right aortic arch, in which case the DA most commonly arises from the left innominate artery and inserts into the region of the proximal left pulmonary artery [3]. Less frequently, the DA arises distal to the right subclavian artery and inserts near the proximal right pulmonary artery. In rare instances, there is a bilateral DA, usually in the presence of other complex congenital cardiovascular anomalies.
Regardless of the aortic arch orientation, the vascular structures remain anterior to the trachea and esophagus, and there is no vascular ring. One exception to this general rule occurs when there is a right aortic arch with an aberrant left subclavian artery. In this setting, the DA typically arises from the aberrant subclavian artery and inserts into the proximal left pulmonary artery. This creates a vascular ring with the aorta anterior to and rightward of the trachea and esophagus; the aberrant subclavian artery is posterior, and the DA is along the left side, connecting the subclavian to the pulmonary artery. (See "Vascular rings and slings", section on 'Right aortic arch with aberrant left subclavian artery and left-sided ductus arteriosus/ligamentum'.)
●Histology – Histologically, ductal tissue differs from that of the adjacent aorta and pulmonary artery. The intima of the ductus is thicker, and the media contains more smooth muscle fibers arranged in a characteristic spiral fashion [4].
FETAL AND TRANSITIONAL DUCTAL CIRCULATION —
In the fetus, the right ventricle accommodates approximately 60 percent of the total cardiac output [5]. The pulmonary vasculature is constricted, resulting in a high vascular resistance within the pulmonary bed. In contrast, the placenta creates a very low resistance bed arising from the aorta and systemic vascular resistance is low. As a result, the majority of blood exiting from the right ventricle passes right-to-left across the DA into the descending aorta and on to the placenta. (See "Physiologic transition from intrauterine to extrauterine life", section on 'Fetus'.)
In the fetus, the DA is large, with a diameter approximating that of the descending aorta. With the onset of respiration after delivery, the lungs expand and the systemic oxygen saturation rises, resulting in pulmonary vasodilatation and a drop in pulmonary vascular resistance. At the same time, systemic resistance rises with placental removal after cutting the umbilical cord. These factors lead to a sudden reversal of blood flow in the DA from right-to-left to left-to-right. (See "Physiologic transition from intrauterine to extrauterine life", section on 'Transition at delivery'.)
Patency of the ductus — The fetal DA is kept patent by low arterial oxygen content and circulating prostaglandin E2 (PGE2), which is produced in part by the placenta [6]. PGE2 appears to be mediated by its cyclooxygenase (COX)-2 isoform since constriction of the fetal DA in mice is induced by selective COX-2 inhibitors but not selective COX-1 inhibitors [7]. The rationale for the administration of nonsteroidal anti-inflammatory drugs in the treatment of PDA in preterm infants is based upon the role of PGE2 in maintaining DA patency. (See "Patent ductus arteriosus (PDA) in preterm infants: Management and outcome", section on 'Indomethacin'.)
Ductal constriction — At birth, the rise in systemic arterial oxygen tension and a decrease in circulating PGE2 levels trigger ductal constriction.
Multiple pathways have been implicated in active ductal constriction including induction of endothelin 1, production of isoprostanes, and inhibition of oxygen-sensitive potassium channels [8,9]. Other potential mediators that may play a role in promoting ductal constriction include angiotensin II, vascular endothelial growth factor, oxygen-sensitive channel, RH1 kinase family members, and cholinergic and adrenergic nerve stimulation [8-11].
After delivery, circulating PGE2 levels fall because of reduced production following removal of the placenta and increased PGE2 clearance due to increase in circulating levels of prostaglandin dehydrogenase [7,12]. Removal of the strong vasodilatory effect of PGE2 is sensed by the PGE2 receptor (EP4) and promotes further constriction of the ductus [13,14].
Constriction of the DA usually results in functional hemodynamic closure within 10 to 15 hours after delivery [15,16]. Closure begins at the pulmonary end of the DA, proceeds toward the aortic end [17], and is usually completed by two to three weeks of age. Following initial constriction, a series of histologic changes result in obliteration of the ductus and conversion into the ligamentum arteriosum [17]. It appears that these changes do not occur in a PDA, suggesting distinct anatomic differences in the DA tissue [17].
EPIDEMIOLOGY
Prevalence and risk factors — The reported prevalence of an isolated PDA among term infants ranges from 3 to 8 per 10,000 live births [18,19].
There is a female predominance for PDA, with a 2:1 female-to-male ratio in most case series of term infants [19,20]. The incidence of PDA is also greater in infants born at high altitude compared with those born at sea level [12].
There is an association between PDA and congenital rubella infection. (See "Congenital rubella", section on 'Clinical features'.)
One of the most important risk factors for PDA is preterm birth. PDA in preterm neonates is discussed separately. (See "Patent ductus arteriosus (PDA) in preterm infants: Clinical features and diagnosis".)
PDA may present with other congenital heart lesions, especially those associated with hypoxemia. PDA should be considered when the clinical features of left-to-right shunt seem out of proportion to the particular lesion being considered.
Genetic factors — It is likely that genetic factors contribute to some cases of PDA. Siblings of patients with PDA have an increased frequency of this abnormality (2 to 4 percent) [21]. PDA occasionally occurs in many members of multiple generations of a family, making simple autosomal dominant inheritance likely in these families [22]. A notable example of this is Char syndrome, which is caused by heterozygous mutation in the TFAP2B gene [23]. Affected individuals have PDA, unusual facial features (including a broad, high forehead; flat profile; and short nose with a broad, flattened tip), and abnormalities of the fifth digit of the hand (including clinodactyly and distal interphalangeal joint symphalangism). TFA2B mutations have also been found in individuals with nonsyndromic PDA [24,25]. Variants in other genes have also been associated with PDA, including MYH11, ACTA2, TRAF1, and AGTR1 [26].
PDA can occur in several genetic syndromes, including [26,27]:
●Cri-du-chat syndrome (see "Congenital cytogenetic abnormalities", section on '5p deletion syndrome (cri-du-chat syndrome)')
●DiGeorge syndrome (see "DiGeorge (22q11.2 deletion) syndrome: Clinical features and diagnosis")
●Down syndrome (see "Down syndrome: Clinical features and diagnosis")
●Loeys-Dietz syndrome (see "Genetics, clinical features, and diagnosis of Marfan syndrome and related disorders", section on 'TGFBR1 or TGFBR2 variant: Loeys-Dietz syndrome')
●Mowat-Wilson syndrome (see "Congenital aganglionic megacolon (Hirschsprung disease)", section on 'Associated syndromes')
●Noonan syndrome (see "Noonan syndrome")
●Periventricular nodular heterotopia
●Rubinstein-Taybi syndrome (see "Microdeletion syndromes (chromosomes 12 to 22)", section on '16p13.3 deletion syndrome (Rubinstein-Taybi syndrome)')
CLINICAL MANIFESTATIONS —
The clinical manifestations of a PDA are determined by the degree of left-to-right shunting, which is dependent upon the size and length of the PDA, and the difference between pulmonary and systemic vascular resistances.
The hemodynamic consequences of the PDAs can be categorized by the degree of left-to-right shunting based upon the pulmonary-to-systemic-flow ratio (Qp:Qs) [28].
●Small – Qp:Qs <1.5 to 1
●Moderate − Qp:Qs between 1.5 and 2.2 to 1
●Large − Qp:Qs >2.2 to 1
The clinical findings for term infants, older children, and adults based upon the size of PDA are discussed in the next sections. The clinical manifestations of PDA in preterm infants are discussed separately. (See "Patent ductus arteriosus (PDA) in preterm infants: Clinical features and diagnosis".)
Small PDA — A small PDA (Qp:Qs <1.5 to 1) that restricts excessive blood flow into the lungs may go undetected, and the patient will have no identifiable symptoms. These patients are commonly identified incidentally by the detection of the characteristic continuous flow murmur (movie 1) noted during a routine primary care visit or by a finding of a PDA on a diagnostic study (eg, computed tomography or echocardiography) performed for other medical conditions [29].
In patients with a small PDA, the physical examination reveals normal precordial activity and normal first and second heart sounds (S1 and S2). Pulses are normal or only mildly accentuated. The respiratory examination also is unremarkable, and there is no evidence of cyanosis.
The characteristics of the PDA murmur vary between the neonate and older patients because of changes in the relative differences between pulmonary and systemic vascular resistances:
●Neonates – In the newborn, aortic systolic pressure is greater than pulmonary systolic pressure, but this gradient may not be present during diastole. As a result, the murmur may be confined to systole.
●After the newborn period – Pulmonary artery pressure falls after the newborn period. As a result, aortic pressure is higher than pulmonary artery pressure during both systole and diastole, producing continuous flow through the ductus and a characteristic continuous murmur (movie 1) (Gibson's murmur or machinery murmur). The murmur is grade 3/6 or less and is heard best in the left infraclavicular region. The intensity of the murmur is maximal immediately before and after the S2 and is not affected by position. (See "Common causes of cardiac murmurs in infants and children", section on 'Patent ductus arteriosus' and "Auscultation of cardiac murmurs in adults".)
Infective endarteritis is an uncommon presentation and complication of small PDAs, as discussed below. (See 'Infective endocarditis' below.)
Moderate PDA — Patients with moderate-size PDAs (Qp:Qs between 1.5 and 2.2 to 1) may present with exercise intolerance. In these patients, the moderate left-to-right shunt increases the volume load on the left atrium and ventricle, which results in left ventricular dilation and dysfunction.
The characteristic continuous murmur (movie 1)is best appreciated in the left infraclavicular area. It is generally louder than the murmur associated with a small PDA (usually grade 2 or 3 and occasionally grade 4) and is typically accompanied by a wide systemic pulse pressure and signs of left ventricular volume overload, such as a displaced left ventricular apex.
Large PDA — A large PDA (Qp:Qs >2.2 to 1) initially causes left ventricular volume overload. Over time, there may be a progressive rise in pulmonary artery pressure, which, in the uncorrected patient, may lead to irreversible pulmonary vascular changes and ultimately right-to-left shunting across the PDA (ie, Eisenmenger physiology). (See 'Pulmonary hypertension' below and "Pulmonary hypertension with congenital heart disease: Clinical manifestations and diagnosis".)
In the setting of a very large unrestrictive PDA, there is obligatory pulmonary hypertension (ie, the pulmonary artery pressure is the same as the aortic pressure) due to the large size of the PDA.
●Early presentation – A large PDA may present in infancy with signs of heart failure, including poor feeding, poor weight gain, and respiratory distress. The older child may present with shortness of breath or easy fatigability.
In the patient with a large left-to-right shunt, precordial palpation reveals a dynamic left ventricular impulse and a thrill, and the pulses are bounding with a wide pulse pressure due to runoff into the pulmonary bed. On auscultation, S1 is normal, S2 may be split with an accentuated pulmonary component, and eddy sounds may be heard in late systole and early diastole. A grade 4 continuous murmur is heard in the left infraclavicular region. An apical diastolic rumble induced by increased flow across the mitral valve may be present, preceded by a third heart sound.
●Late presentation – In the uncorrected adult, a large PDA may present with features of Eisenmenger physiology including cyanosis and clubbing that is more pronounced in the lower extremities (ie, differential cyanosis). This is because the PDA delivers unoxygenated blood distal to the left subclavian artery. In these patients, a short systolic ejection murmur can be heard (rather than the typical continuous PDA murmur) because the diastolic runoff into the pulmonary circulation is decreased due to increasing pulmonary vascular resistance. As pulmonary pressure increases, the murmur decreases and ultimately disappears. The pulmonary component of S2 increases (movie 2).
DIAGNOSIS —
The diagnosis of PDA is usually suspected based upon its characteristic clinical findings (eg, continuous murmur (movie 1)). The diagnosis is confirmed with echocardiography.
Echocardiography — A complete echocardiographic evaluation of a PDA includes anatomic confirmation by two-dimensional imaging and Doppler echocardiography hemodynamic assessment, which provides estimates of the degree of shunting and pulmonary artery (PA) pressure [30,31].
●Two-dimensional echocardiography – The PDA can be imaged in many views using two-dimensional echocardiographic imaging and superimposed Doppler color flow mapping [30,31]. Most commonly, the ductus is imaged in the parasternal and suprasternal notch views.
•Parasternal views − In the high parasternal short-axis view, with the transducer oriented leftward toward the bifurcation of the PA, the ductus can be imaged connecting the PA and the descending aorta (movie 3 and movie 4). In this view, the ductus can be seen arising from the anterior aspect of the descending aorta, which is viewed in cross section. The ductus enters the PA near the origin of the left PA.
•Suprasternal views − In the suprasternal notch window, the ductus arises from the descending aorta at the level of the left subclavian artery and courses anteriorly to join the PA (movie 5 and movie 6). Moving the transducer just laterally and inferiorly to an infraclavicular position, and rotating clockwise, permits further imaging of the ductus and its relationship to the branch pulmonary arteries and descending aorta (movie 7).
In patients with a right aortic arch, the ductus usually arises from the left brachiocephalic vessels instead of the descending aorta and can be followed caudally to its insertion on the PA in the suprasternal view.
The presence of a PDA may mask an aortic coarctation since the ductus augments the left aortic arch at its origin. Findings that should alert the echocardiographer to the possible presence of a coexistent coarctation include a bicuspid aortic valve, hypoplasia of the transverse arch or aortic isthmus, a long distance between the left carotid and subclavian origins, or a posterior shelf. A clinical prediction model has been developed to help identify coarctation in neonates with PDA [32]. The model evaluates three parameters (the ratio of the diameters of the carotid artery to distal transverse arch, carotid artery to subclavian artery, and isthmus to descending aorta). (See "Clinical manifestations and diagnosis of coarctation of the aorta", section on 'Echocardiography'.)
Two-dimensional imaging may give important qualitative information regarding the hemodynamic significance of a PDA. Left atrial and ventricular dilation are seen in the presence of a large left-to-right shunt.
●Doppler color flow – Doppler color flow mapping can supplement imaging of the PDA, which is most commonly seen as a retrograde color flow jet in the PA. This jet usually occurs along the leftward aspect of the PA but may be directed into the center or more rightward. In patients with normal PA pressure, the high-velocity turbulent flow is easily seen in both systole and diastole (movie 3). In patients with high pulmonary vascular resistance, the retrograde jet may be visible only in diastole (movie 4).
Color flow mapping is particularly helpful in the setting of a small PDA that may be difficult to identify by two-dimensional imaging, especially in adults in whom resolution is more limited than in infants and small children. Determining the origin of the retrograde flow into the PA using two-dimensional imaging as well as color flow mapping is crucial to avoid confusion of the patent ductus with other aortopulmonary shunts, such as collateral vessels, coronary artery fistulae, or an aortopulmonary window. (See 'Differential diagnosis' below.)
●Estimating the PA pressure – Doppler echocardiography can estimate the PA pressure. When the PA pressure is lower than systemic arterial pressure, there is continuous left-to-right shunting, demonstrated by both color flow mapping and pulsed Doppler interrogation. The peak velocity of flow across the ductus, measured by either pulsed or continuous-wave Doppler, can be translated into the gradient between the aorta and the PA using the modified Bernoulli equation. This Doppler-derived gradient correlates with gradients measured at catheterization and can be subtracted from the cuff pressure to estimate PA pressure (image 2).
Low peak velocity and corresponding low gradient suggest high PA pressure. Low peak velocity that further decreases rapidly in diastole suggests a hemodynamically significant PDA.
PA pressure can also be estimated quantitatively using the tricuspid regurgitation velocity and, qualitatively, by ventricular septal configuration. (See "Echocardiographic assessment of the right heart", section on 'Estimation of pulmonary artery systolic pressure'.)
As with any Doppler-derived measurement, care must be taken to minimize the angle between the Doppler interrogation and the direction of flow in the ductus. The length and shape of the ductus may influence the accuracy of gradient estimates using the Bernoulli equation; longer and more "tunnel"-like structures are less reliably evaluated using this equation [31].
In the setting of a large left-to-right shunt at the DA, continuous runoff can be seen in the branch pulmonary arteries and in the aorta proximal to the PDA by pulsed Doppler echocardiography (image 3). Distal to the origin of the PDA, diastolic retrograde flow can be demonstrated, corresponding to the runoff into the PA (image 4) [33].
When the PA pressure is equal to systemic pressure, pulsed Doppler echocardiography within the ductus demonstrates systolic right-to-left shunting, with diastolic left-to-right flow within the ductus (movie 4 and image 5). The finding of systolic right-to-left flow within the ductus may be confused with normal antegrade systolic flow in the left PA if the sample volume is not placed within the ductus. In rare cases of arch abnormalities and pulmonary hypertension, right-to-left shunting may be seen throughout the cardiac cycle [34,35].
●Estimating the degree of shunting – The ratio of pulmonary-to-systemic blood flow (Qp:Qs) can be estimated with echocardiography using the area of the left and right ventricular outflow tracts and Doppler-derived velocity and flow data. Paradoxically, in the setting of the PDA, the systemic blood flow is calculated by using the area of the right ventricular and pulmonary outflow tracts and velocity time integrals, and the pulmonary blood flow is calculated utilizing the aortic outflow tract area and velocity time integral. However, the ductal jet frequently distorts the antegrade pulmonary flow signal; as a result, this measurement is not usually helpful [30].
●M-mode echocardiography – Although M-mode echocardiography may reveal findings suggesting a left-to-right shunt, it is not diagnostic for a PDA. A ratio of left atrial-to-aortic diameter greater than 1.5:1 is usually associated with significant left-to-right shunting.
●Transesophageal echocardiography – Transesophageal echocardiography can be used for identification of a PDA, but the PDA may be difficult to visualize using this technique.
Other tests — Chest radiography and electrocardiography (ECG) are often performed in the initial evaluation of suspected congenital heart disease. These tests may be normal or may show nonspecific findings suggestive of chamber enlargement. Other advanced imaging tests (eg, magnetic resonance imaging [MRI], computed tomography [CT], or cardiac catheterization) are generally not necessary for the diagnosis of PDA.
●Chest radiograph – The findings on chest radiography vary with the size of the ductus and the degree of left-to-right shunting. In patients with a small PDA (ie, restrictive), the chest radiograph is normal.
The earliest radiographic finding usually is a prominent main pulmonary artery segment blending with a prominent aortic knob along the upper left heart border. In patients with moderate-size PDAs, the heart is slightly enlarged and the pulmonary vascular markings are increased. In patients with a large PDA, these features become more pronounced, with enlargement of the left ventricle and atrium and increased pulmonary vascular markings.
●ECG – The ECG is often normal in patients with a small PDA. In contrast, a large PDA with a large left-to-right shunt typically produces electrocardiographic findings of biventricular hypertrophy and a left atrial abnormality. With longstanding pulmonary hypertension, the ductus shunt is reversed and signs of right ventricular hypertrophy predominate. (See "ECG tutorial: Chamber enlargement and hypertrophy".)
●Cardiac catheterization – Cardiac catheterization and angiography (image 1) are generally only necessary when percutaneous therapy is being considered or in the context of more complex congenital heart disease. (See "Patent ductus arteriosus (PDA) in term infants, children, and adults: Management", section on 'Transcatheter closure'.)
●MRI and CT – MRI and CT are not routinely used in the diagnosis of PDA. This is because echocardiography typically provides adequate imaging and is less costly. In addition, Doppler echocardiography provided functional information not provided by CT or MRI.
DIFFERENTIAL DIAGNOSIS —
The physical examination helps to differentiate PDA from other lesions associated with continuous murmurs, bounding pulses, and heart failure. However, echocardiography is required to definitively make the distinction.
●Continuous murmurs – The PDA murmur (movie 1) is distinguished from other causes of continuous murmurs based on the location and quality of the murmur (see "Approach to the infant or child with a cardiac murmur"):
•A venous hum (movie 8) is more often located on the right side and changes with position and local compression
•Murmurs of systemic arteriovenous malformations or fistulas are heard in extracardiac locations
•Murmurs of coronary artery fistulas (movie 9) are most often located over the lower precordium
•The aortopulmonary window often has only a systolic murmur
•Combined aortic stenosis and aortic regurgitation (movie 10), combined pulmonic stenosis and pulmonic regurgitation (movie 11), and ventricular septal defect associated with semilunar valve regurgitation are characterized by systolic and diastolic murmurs (ie, to-and-fro murmurs), rather than continuous murmurs
•The murmur of a ruptured sinus of Valsalva aneurysm is typically a new continuous murmur loudest at the second left interspace
●Bounding pulses – Bounding pulses may be seen with other aortic runoff lesions and in systemic infection (ie, early septic shock):
•Aortic regurgitation produces a diastolic murmur (movie 12A-B) (see "Aortic regurgitation in children" and "Clinical manifestations and diagnosis of chronic aortic regurgitation in adults")
•Truncus arteriosus is associated with cyanosis (see "Truncus arteriosus")
•Aortopulmonary window (see "Auscultation of cardiac murmurs in adults")
•Sepsis is associated with other signs of systemic infection (eg, fever, abnormal white blood cell count) (see "Sepsis in children: Definitions, clinical manifestations, and diagnosis", section on 'Shock')
●Heart failure – Symptoms of heart failure (eg, poor feeding in infants, shortness of breath, or easy fatigability in older children) may be seen with other lesions that cause pulmonary overcirculation in the setting of a large amount of left-to-right shunting. Large ventricular septal defects are a common cause of heart failure in infants. The murmur associated with a ventricular septal defect is typically holosystolic (movie 13). Other lesions that cause volume overload are discussed separately. (See "Heart failure in children: Etiology, clinical manifestations, and diagnosis", section on 'Volume overload with preserved ventricular contractility'.)
COMPLICATIONS —
Individuals with PDA have increased morbidity and mortality, primarily due to heart failure and, rarely, infective endocarditis (IE) [36]. Pulmonary hypertension is an uncommon problem unless the PDA is not recognized until later in life.
Heart failure — A large PDA can cause volume overload and congestive heart failure.
Signs of heart failure may be the presenting findings in young infants with large PDAs. (See 'Large PDA' above.)
In addition, adult patients with unrepaired PDA can develop heart failure due to impaired left ventricular function in the setting of chronic volume overload. In these patients, heart failure is often associated with atrial fibrillation.
Infective endocarditis — IE is a rare complication of PDA [37-39]. When IE does occur, the vegetations usually accumulate at the pulmonary end of the PDA and shower the lungs with septic emboli.
Estimates of the magnitude of risk of IE in patients with PDA vary. In one report, PDA was the underlying lesion in 15 percent of pediatric IE cases [40]. In a population-based registry that included 620 patients who underwent surgical PDA ligation in childhood, there were no cases of IE over a total of 8751 patient-years of follow-up [38]. In another study that reviewed the records of 270 pediatric and adult patients with PDA, no cases of IE were observed over an aggregate of 1196 patient-years [37]. In a study of adult patients with congenital heart disease, the incidence of IE among those with PDA was 0.24 per 1000 patient-years [41]. Some experts have argued that the risk of endocarditis is so low that closure of a small PDA for the sole purpose of preventing IE may not be warranted [37,42]. (See "Native valve endocarditis: Epidemiology, risk factors, and microbiology", section on 'Congenital heart disease'.)
Patients with isolated PDA do not require antibiotic prophylaxis for IE. Indications for prophylaxis are discussed separately. (See "Patent ductus arteriosus (PDA) in term infants, children, and adults: Management", section on 'Antibiotic prophylaxis' and "Prevention of endocarditis: Antibiotic prophylaxis and other measures".)
Pulmonary hypertension — An isolated large PDA, as with any large left-to-right shunt, is a risk factor for irreversible pulmonary vascular disease. (See "Pulmonary hypertension with congenital heart disease: Clinical manifestations and diagnosis", section on 'Pathophysiology of shunt-related PH-CHD'.)
In patients with PDA who develop pulmonary hypertension, the continuous PDA murmur is absent and auscultation typically reveals a loud single second heart sound (S2) (movie 2).I In some cases, a Graham Steell murmur may be heard. The Graham Steell murmur is a high pitched and blowing early diastolic murmur of pulmonic regurgitation associated with pulmonary hypertension. It begins with an accentuated P2 of S2 and can be of variable duration. In addition, precordial palpation often reveals a right ventricular impulse. (See "Auscultation of cardiac murmurs in adults".)
Progressive pulmonary hypertension may lead to reversal of the direction of shunting with right-to-left flow across the PDA (ie, Eisenmenger physiology). This results in cyanosis and clubbing in the lower extremities. (See "Pulmonary hypertension with congenital heart disease: Clinical manifestations and diagnosis", section on 'Clinical manifestations'.)
Complications during pregnancy — Pregnancy in individuals with congenital heart disease (unrepaired or repaired) poses potential risks to both the pregnant person and the fetus. The general principles of preconception counseling and pregnancy management in patients with congenital heart disease are discussed separately. (See "Pregnancy in women with congenital heart disease: General principles".)
An asymptomatic individual with a restrictive small PDA is unlikely to experience any complications related to the PDA during pregnancy. Similarly, individuals who underwent successful PDA closure in childhood who lack long-term complications (ie, no residual shunt, no stenosis or obstruction of the pulmonary artery or aorta, and no concerns for pulmonary hypertension) are unlikely to experience complications during pregnancy.
However, individuals with unrepaired moderate to large PDAs and those with repaired PDAs who have associated pulmonary vascular disease or ventricular dysfunction are at risk for adverse pregnancy outcomes, including maternal complications (cyanosis, heart failure, arrythmia, bleeding, thromboembolism) and fetal complications (eg, fetal growth restriction, fetal death, preterm birth) [43]. Patients with significant pulmonary hypertension and shunt reversal (ie, Eisenmenger physiology) are at high risk for significant morbidity and mortality and are advised against pregnancy [44,45]. (See "Pulmonary hypertension with congenital heart disease: Pregnancy and contraception".)
Systemic vascular resistance generally decreases during pregnancy, and this may serve to decrease ductal flow. However, this change is unlikely to fully compensate for the hemodynamic burden of pregnancy.
SUMMARY AND RECOMMENDATIONS
●Anatomy – The ductus arteriosus (DA) is a fetal vascular connection between the main pulmonary artery and the aorta that normally closes soon after birth. Patent ductus arteriosus (PDA) (figure 1) results from failure of the DA to completely close postnatally. (See 'Anatomy' above and 'Fetal and transitional ductal circulation' above.)
●Prevalence – Among term infants, PDA occurs in 3 to 8 per 10,000 live births. (See 'Epidemiology' above.)
●Clinical manifestations – The clinical manifestations of a PDA vary depending on the size and length of the PDA and the degree of left-to-right shunting (see 'Clinical manifestations' above):
•Patients with small PDAs generally are asymptomatic. These patients are usually diagnosed after a murmur (movie 1) is heard incidentally during routine physical examination or when an echocardiogram performed testing for another reason. (See 'Small PDA' above.)
•In patients with moderate and large PDAs, symptoms can range from exertional dyspnea to heart failure. (See 'Moderate PDA' above and 'Large PDA' above.)
•Adults with uncorrected large PDAs may develop pulmonary vascular disease, resulting in right-to-left shunting and cyanosis (ie, Eisenmenger physiology). (See "Pulmonary hypertension with congenital heart disease: Clinical manifestations and diagnosis".)
●Diagnosis – The diagnosis of PDA is usually suspected based upon the presence of a characteristic continuous flow murmur (movie 1). The diagnosis is confirmed with echocardiography. (See 'Diagnosis' above.)
●Differential diagnosis – The differential diagnosis of PDA includes other causes of diastolic murmurs, bounding pulses, and heart failure. (See 'Differential diagnosis' above.)
●Complications – Complications of PDA can include heart failure, infective endocarditis (IE), and pulmonary hypertension. (See 'Complications' above.)
ACKNOWLEDGMENT —
The UpToDate editorial staff acknowledges Thomas Graham Jr, MD, who contributed to an earlier version of this topic review.
