Pulmonary Atresia

• • A congenital heart lesion that decreases pulmonary arterial blood flow resulting in a right-to-left shunt

  • Cyanosis and decreased oxygen delivery causes compensatory polycythemia (Hct > 70%) and spontaneous thrombosis

  • Exercise, acidosis, pain worsens cyanosis, can cause hypoxic spells

  • Squatting increases systemic resistance, causing increased pulmonary flow and oxygen

  • β-Blockers (decreases spasm), fluid intake, HCO3 administration, norepinephrine (increases systemic resistance) may help decrease hypoxia

  • Clubbing due to proliferation of capillaries and AV fistulas in extremities

  • Bronchial and mediastinal arteries enlarge

  • Ductus arteriosus maintains flow to lungs during fetal development

  • Alprostadil early can allow time for optimization before definitive treatment

  • Operative options to increase pulmonary flow:

  • -Blalock-Taussig shunt: Subclavian artery to ipsilateral pulmonary artery (PA) end to side fashion

    -Modified Blalock-Taussig shunt: Subclavian to PA using PTFE

    -Glenn: Superior vena cava (SVC) to PA shunt

    -Fontan: SVC and inferior vena cava (IVC) rerouted to PA

    -Excision of obstructive muscle, patch enlargement of infundibulum, and valve replacement

  • Pulmonary valve replaced by diaphragm of tissue, causing obstruction

  • PA normal size

  • Atrial septal defect (ASD) or patent ductus arteriosus (PDA) necessary for survival after first few hours of birth

  • RV and tricuspid annulus typically small

  • RV: Coronary artery fistulas and coronary artery stenoses are common

  • Some coronary flow dependent on increased pressures in RV

Symptoms and Signs

• • Cyanosis present at birth

  • Duct closure: Profound hypoxia, acidosis

Laboratory Findings

• • ECG: Lack of normal RV dominance

Imaging Findings

• • Chest film: Diminished flow into lungs

  • Echocardiography: Diagnostic

  • Catheterization: Define coronary anatomy, RV-dependent coronary circulation

• • Echocardiography, catheterization needed

• • Chest x-ray

  • ECG

  • Echocardiography

  • Catheterization

• • ASD creation or ductus maintenance (alprostadil) necessary for early survival

  • Surgical treatment depends on RV development and right heart dependent coronary circulation

  • Systemic-PA shunt + patch reconstruction of right heart outlow tract (not performed if poor RV development or right-dependent coronary circulation)

  • With further ventricle development, may close shunt and ASD

  • If ventricles do not develop, consider Fontan

Surgery

Indications

• • Indicated if diagnosed

Prognosis

• • 1-year mortality, 10-20%

  • Prognosis improving

References