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Patent Ductus Arteriosus (PDA)

Clinical Subject Page

Patent Ductus Arteriosus (PDA)

ICD-10

Q21.3

Specialty

Cardiology

Onset

Chronic

Reviewed

July 2026

On This Page

Overview

Patent Ductus Arteriosus (PDA) is the Failure of the ductus arteriosus to completely close after birth

Etiology & Risk Factors

  • – Usually sporadic
    – Associated genetic disorders:
    – DiGeorge syndrome
    – Down syndrome
    – Maternal exposures:
    – Alcohol consumption
    – Phenylketonuria
    – Diabetes

Pathophysiology

  • – In fetal life, the ductus arteriosus provides a normal right-to-left shunt and remains patent because
    of prostaglandins and low oxygen tension.
    – After birth:
    – Pulmonary vascular resistance decreases.
    – Shunt reverses from right-to-left to left-to-right.
    – Failure of ductal closure causes:
    – Persistent communication between the aorta and pulmonary artery.
    – Left-to-right shunt.
    – Pulmonary volume overload.
    – Continuous right ventricular and/or left ventricular strain.
    – Heart failure.
    – Patent Ductus Arteriosus (PDA) is essential for survival in some ductal-dependent congenital heart defects (e.g., Tetralogy of
    Fallot, Transposition of the Great Arteries).
  • Long-standing disease may result in Eisenmenger syndrome with shunt reversal and differential cyanosis.

Clinical Presentation

  • General
    – Mild TOF:
    – May be asymptomatic initially.
    – Symptoms of heart failure may develop after 4–6 weeks.
    – Cyanosis:
    – Severity depends on RVOTO.
    – Mild obstruction:
    – Minimal cyanosis (“Pink Tet”).
    – Severe obstruction:
    – Marked cyanosis present from birth.
    Tet Spells (Hypercyanotic Spells)
    Peak incidence:
  • 2–4 months of age.
    – Triggered by:
    – Crying
    – Feeding
    – Defecation

History Taking

Assess for:
– Prematurity.
– Feeding difficulty.
– Failure to thrive.
– Tachypnea.
– Sweating during feeding.
– Recurrent respiratory infections.
– Exercise intolerance.
– Symptoms of heart failure.
– History suggestive of pulmonary hypertension.

Investigations

  • Echocardiography (Confirmatory Test)
    – Confirmatory investigation in infants.
    – Assesses:
    – Shunt volume.
    – Pulmonary artery pressure.
    – Left atrial enlargement.
    – Left ventricular enlargement.
    – Color Doppler demonstrates blood flow from the aorta into the pulmonary artery.
    ECG
    Small PDA:
    – Usually normal.
    Large PDA:
    – Left axis deviation due to left ventricular hypertrophy.
    – Right ventricular hypertrophy if pulmonary hypertension develops.
    Chest X-ray
    – Prominent pulmonary artery.
    – Prominent aortic knob.
    – Increased pulmonary vascular markings.
    Pulse Oximetry
    – Peripheral hypoxemia in the feet may occur with right-to-left shunting

Diagnosis

  • Diagnosis is confirmed by:
    – Transthoracic echocardiography with Doppler.
    Supportive investigations:
    – ECG.
    – Chest X-ray.
    – Pulse oximetry.
    – Cardiac CT/MRI.
    – Cardiac catheterization when indicated.

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Management

  • General Principles : Refer all patients to a congenital cardiac center.
  • Management depends on: –
  • Size of Patent Ductus Arteriosus (PDA).
  • Magnitude of left-to-right shunt.
  • Age. – Weight. – Assess for associated complications such as intestinal ischemia and Eisenmenger syndrome.
  • Pharmacological Closure (Premature Infants) Indications:
  • Birth weight <1 kg requiring mechanical ventilation.
  • Birth weight >1 kg with symptomatic PDA (heart failure or respiratory distress).
  • Contraindications: – Ductal-dependent congenital heart disease.
  • Persistent pulmonary hypertension of the newborn.
  • Oliguria.
  • Thrombocytopenia.
  • Recent cerebral, intestinal, or pulmonary hemorrhage.
  • Necrotizing enterocolitis.
  • Treatment:  Indomethacin & Ibuprofen.

Complications

  • Heart failure during infancy.
  • Infective endocarditis.
  • Pulmonary hypertension.
  • Eisenmenger syndrome.
  • Differential cyanosis.

Prognosis

  • – Prognosis is excellent after successful closure.
    – Untreated large Patent Ductus Arteriosus (PDA) may progress to pulmonary hypertension and Eisenmenger syndrome.
    – Patent Ductus Arteriosus (PDA) closure is contraindicated when pulmonary hypertension has resulted in right-to-left shunting
    or when the Patent Ductus Arteriosus (PDA) is required for survival in ductal-dependent congenital heart disease.

Key Points / Clinical Pearls

  • – Patent Ductus Arteriosus (PDA) is one of the three most common acyanotic congenital heart defects.
    – Prematurity is the strongest risk factor.
    – Classic murmur: continuous “machinery” murmur in the left infraclavicular region.
    – Confirmatory test: transthoracic echocardiography with Doppler.
    – Indomethacin and ibuprofen close Patent Ductus Arteriosus (PDA) by inhibiting prostaglandin synthesis.
    – Prostaglandin E1 is used to keep the ductus arteriosus open in ductal-dependent congenital heart
    disease.
    – Close significant Patent Ductus Arteriosus (PDA) before irreversible pulmonary hypertension develops.
    – Differential cyanosis suggests Eisenmenger syndrome with shunt reversal.