Patent Ductus Arteriosus (PDA) Complications Clinical features and Diagnosis

  • The ductus normally closes at birth.
  • When the ductus remains patent then a left-to-right shunt exists between the aorta to the pulmonary ar­ery. The ductus is attached to the aorta just after he origin of the left subclavian artery.
  • he ductus is attached to the pulmonary artery just close to its bifurcation or to the left pulmonary artery just at its origin from the pulmonary artery.
  • normally aortic pressure is 56 times that in the pul­monary artery so that flow across the ductus is from the aorta to the pulmonary artery i.e. left-to-ri ht. When the pulmonary artery pressure and resistance increase gradually then a time comes when the flow is reversed i.e. from the pulmonary artery to the aorta i.e. right-to-Ieft. then PDA occurs due to maternal rubella in the other during pregnancy then other features of this
  • syndrome may also be seen like microcephaly, cata­ct, deafness.
Patent Ductus Arteriosus (PDA)

Patent Ductus Arteriosus (PDA) Complications Clinical features and Diagnosis

Complications of Patent Ductus Arteriosus (PDA)

  • Impairment of growth and nutrition
  • Pulmonary hypertension
  • Infective endocarditis V Congestive heart failure
  • Recurrent respiratory infections ~ Aneurysm of the pulmonary artery

Clinical features and Diagnosis of Patent Ductus Arteriosus (PDA)

  •  Female: male ratio 3 : 1
  • The pulse pressure is widened
  • The peripheral pulse is of high volume.
  • There may be differential cyanosis i.e. cyanosis 9nd clubbing of the lower extremities only.
  • There is hyperdynamic apical impulse
  • There may be left ventricular hypertrophy
  • There is reversed splitting of S2
  •  S3 may be present
  •  An aortic systolic ejection sound may be heard at the base of the heart.
  • There is a continuous murmur with thrill best heard in the 2ndleft intercostal space radiating to beneath the left clavicle.
  • It may well be heard all over the precordiut!1.
  • The murmur starts with systole and engulfs the second sound with late systolic accentuation and extends to mid or late diastole.
  • When pulmonary hypertension occurs, the dias­tolic component disappears and later the sys­tolic component also shortens and finally there Tay be no murmur at all.
  • In the newborn, aortic systolic pressure is greater than pulmonary systolic pressure, but this gradient may not be present during diastole
  • flow murmur i.e. a mid-diastolic rumbling murmur at the apex is present.PDAs can be categorized by the degree of left-to-right shunting based upon the pulmonary to systemic flow ratio (Qp:Qs)
    • 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


  • patients with a large PDA, these features become more pronounced with enlargement,
  • · Left ventricular hypertrophy
  • · Left atrial enlargement
  • · Right ventricular hypertrophy
  • findings on chest radiography vary with the size of the ductus and the degree of left-to-right shunting


  • large PDA with a large left-to-right shunt typically produces ECG findings of biventricular hypertrophy and a left atrial abnormality
  • Left ventricular hypertrophy
  • Left atrial enlargement
  • Left axis deviation Biventricular hypertrophy

2D echocardiography and Doppler flow

  • In the high parasternal short axis view the ductus can be seen arising from the anterior aspect of the descending aorta,
  • · The ductus can be seen and the pulmonary pres­sures estimated.
  • · Associated lesions and complications can be seen.

Patent Ductus Arteriosus (PDA) Treatment

  • Elective closure of the ductus as early as pos­sible.
  • It cannot be done after the reversal of flow across the ductus i.e. when Eisenmenger syndrome develops.

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