Patent ductus arteriosus

Background

• Ductus arteriosus is a blood vessel connecting main pulmonary artery to proximal descending aorta
  • Shunts blood from right ventricle to bypass fetus's non-functioning lungs in utero
• In PDA, ductus fails to close after birth
• Second most common congenital heart disease
• Approximately 1 in 1600 to 5000 live births in the US.

Pathophysiology

• Ductus arteriosus shunts blood from the pulmonary artery to the aorta bypassing the lungs while in utero
• Normally closes soon after birth via complex process
  • Regulated by oxygen tension and decreases in prostaglandin E2
  • Becomes ligamentum arteriosum
• In PDA, ductus fails to close
  • Results in shunting of blood between aorta and pulmonary artery
  • Some oxygenated blood from high-pressure aorta shunts to lower pressure pulmonary artery
  • A large shunt can cause increased fluid return to lungs and increased lung pressure, leading to pulmonary hypertension
• Some congenital heart defects, such as transposition of the great arteries, are incompatible with life 'without a PDA; may be necessary to allow oxygenated and deoxygenated blood to mix
  • In these cases prostaglandins are used to keep the ductus arteriosus open.

Clinical Features

• Continuous machine like heart murmur
• Differential cyanosis (cyanosis of lower extremities and not the upper extremities)
• Dyspnea
• Tachycardia
• Widened pulse pressure
• Congestive heart failure
• Failure to thrive

Differential Diagnosis

• Acute pericarditis
• Aortopulmonary Septal Defect
• Coarctation of the Aorta
• Coronary Artery Fistula
• Pediatric Acute Respiratory Distress Syndrome
• Pediatric Sinus of Valsalva Aneurysm
• Pediatric Tachycardia
• Pulmonic Valvular Stenosis
• Sickle cell anemia
• Tetralogy of Fallot With Absent Pulmonary Valve

Congenital Heart Disease Types

• Cyanotic
  • Tetralogy of fallot
  • Total anomalous pulmonary venous return
  • Transposition of the great arteries
  • Tricuspid atresia
  • Truncus arteriosus
  • Ebstein anomaly
  • Hypoplastic left heart syndrome
• Acyanotic
  • AV canal defect
  • Atrial septal defect (ASD)
  • Ventricular septal defect (VSD)
  • Cor triatriatum
  • Patent ductus arteriosus (PDA)
  • Pulmonary/aortic stenosis
  • Coarctation of the aorta
• Differentiation by pulmonary vascularity on CXR
  • Increased pulmonary vascularity
    • Large ASD
    • Large VSD
    • Total anomalous pulmonary venous return
    • Transposition of the great arteries
    • Truncus arteriosus
  • Decreased pulmonary vascularity
    • Tetralogy of fallot
    • Rare heart diseases with pulmonic stenosis

Evaluation

Echocardiography demonstrating PDA

• Careful physical examination demonstrating characteristic machine like murmur
• Echocardiography
  • MRA and Cardiac CT can also be used as diagnostic tools
• Laboratory tests usually not helpful

Management

• Spontaneous closure is usually common but if significant respiratory distress or impaired oxygen delivery is present, therapy is usually required.

Medical Therapy

• IV indomethacin: usually effective when administered in the first 10-14 days of life.

Surgical Therapy:

Cardiac catheterization and catheter closure in addition to surgical ligation are also options if medical therapy fails.

See Also

• Congenital Heart Disease