Patent Ductus Arteriosus

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Continuous machinery-like murmur, loudest below the left clavicle

• Left ventricular hypertrophy

• Pulmonary plethora, left atrial and ventricular enlargement

• In older adults, calcification of the ductus on chest radiograph

• Left atrial and ventricular dilatation with normal right heart chambers on echocardiography

• Continuous high-velocity color Doppler jet with retrograde flow along lateral wall of main pulmonary artery near left branch

GENERAL CONSIDERATIONS

• Remnant of the normal fetal circulation with a connection between the left pulmonary artery and descending aorta distal to the left subclavian artery

• A nonrestrictive patent ductus arteriosus (large left-to-right shunt) usually causes congestive heart failure within first year of life

• Causes volume overload and enlargement of the left heart chambers due to recirculation of blood from the aorta to pulmonary circulation and back to the left atrium

• Usually associated with other defects, such as pulmonary or tricuspid atresia

• In a minority of patients, pulmonary vascular disease may develop with reversal of the shunt

• Differential cyanosis may develop when the shunt reverses and results in desaturated blood flowing into the descending aorta distal to the left subclavian artery

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Usually presents in childhood

• Rarely presents in a young adult

• Congestive heart failure or rarely as Eisenmenger physiology

• Adults may present with exertional dyspnea, chest pain, palpitations

PHYSICAL EXAM FINDINGS

• Differential cyanosis

• Sometimes clubbing and cyanosis of the lower extremities and occasionally the left hand

• Widened pulse pressure

• Hyperdynamic, laterally displaced apical impulse

• Continuous, machinery-like murmur, loudest below the left clavicle

• Murmur decreases and may disappear as pulmonary vascular resistance increases and shunt reverses

• S₃ gallop

• Diastolic murmur across the mitral valve

DIFFERENTIAL DIAGNOSIS

• Other causes of exertional dyspnea, chest pain, and palpitations

• Other causes of left heart dilatation and failure

• The characteristic continuous murmur can be mimicked by aortic stenosis with regurgitation, mitral stenosis with regurgitation, and ventricular septal defect with aortic regurgitation

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• No specific tests

ELECTROCARDIOGRAPHY

• Normal when the shunt is small

• Left atrial enlargement

• Left ventricular hypertrophy

• P pulmonale, right-axis deviation, right ventricular hypertrophy if pulmonary hypertension develops and the shunt reverses

IMAGING STUDIES

• Chest x-ray:

  • – Normal if the shunt is small

  • – Left ventricular enlargement, pulmonary vascular plethora

  • – Enlarged pulmonary artery and peripheral pulmonary artery pruning in the presence of pulmonary hypertension

  • – Patent ductus arteriosus may be calcified in the adult

• Echocardiography:

  • – Left atrial and left ventricular enlargement

  • – Continuous high-velocity Doppler flow in the main pulmonary artery near the left branch

  • – Right ventricular hypertrophy and high-velocity Doppler tricuspid ...