Patent Ductus Arteriosus (PDA)

• • A congenital heart lesion that increases pulmonary artery (PA) blood flow

  • Results in left-to-right shunt, results in lung infection, pulmonary vascular congestion, PA hypertension, right heart failure, pulmonary vasoconstriction, pulmonary vascular obstructive disease

  • Eisenmenger syndrome: Increased pulmonary hypertension such that left-to-right shunt ceases and shunt becomes right-to-left, requiring heart-lung transplant

  • Inhaled nitric oxide, oxygen, or IV tolazoline reverses PA vasoconstriction

  • PA band is palliative and can reduce PA flow to alleviate RV failure and progression of pulmonary hypertension

  • Ductus arteriosus normal component of fetal circulation connecting main PA to aorta distal to left subclavian artery

  • In utero, ductus carries 60% of ventricular output, patency maintained by high flow, prostaglandins (from placenta), low oxygen tension

  • At birth, increased pulmonary resistance, prostaglandin level decrease, increased oxygen tension causes duct closure

  • Closure occurs between 1 and 3 days

  • Closure does not always occur

  • Causes left-to-right shunt, heart failure, and pulmonary hypertension

  • Associated with other anomalies

  • May limit flow to systemic organs

Epidemiology

• • Incidence of PDA: 2-3% of live births

  • Increases with prematurity, > 50% in infants born at 30 wks gestation

  • 5% of untreated PDA die of heart and pulmonary failure by age 1

Symptoms and Signs

• • Older patients:

  • -Often asymptomatic

    -Continuous murmur over pulmonary area

    -Loud S2

    -Bounding peripheral pulses

  • Infants:

  • -Poor feeding

    -Respiratory distress

    -Frequent respiratory infection

    -Heart failure

  • Diagnosis by physical exam:

  • -Wide pulse pressure

    -To-and fro-murmur (usually systolic, occasionally continuous)

  • Large shunts (5%): Develop pulmonary vascular disease

  • Usually asymptomatic, found during routine exam

  • Premature infant: Distinguish heart failure from pulmonary dysfunction of prematurity

  • Inability to wean from ventilator is common presentation

• • Echocardiography done on high-risk patients

Rule Out

• • Primary pulmonary dysfunction from prematurity

• • Echocardiography diagnostic

• • Treatment varies with age

  • Premature infant: Medical therapy with indomethacin (50% success)

Surgery

• • Term infant or child: Surgical obliteration by ligation, clipping, or division

  • Larger infants/children: Video thoracoscopy

  • Transcatheter technique for larger patient may have fewer complications

Indications

• • Term infant/older child

  • Failed medical therapy in premature infant

Medications

• • Indomethacin (prostaglandin inhibitor) 50% success, efficacy decreases with age

Complications

• • Injury to recurrent laryngeal nerve, hemorrhage, chylothorax uncommon

Prognosis

• • Operative mortality near 0%

  • Recurrence < 1% among patients who are treated surgically

References