Patent ductus arteriosus

Background

• Abbreviation: PDA
• A condition where the ductus arteriosus does not close after birth. It is the second most common congenital heart disease affecting 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.
• In a PDA, the vessel fails to close, resulting in shunting of blood between the aorta and the pulmonary artery.
• This shunting allows some oxygenated blood from the aorta, which has a higher pressure, to the pulmonary artery, which has the lower pressure.
• If the shunt is large enough, can cause increase fluid return to the lungs, increased lung pressure, and thus increased energy demands to fill the lungs.
• 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

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
• Laboratory tests are usually not helpful. MRA and Cardiac CT can also be used as diagnostic tools

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