Truncus Arteriosus

• • A congenital heart lesion that increases pulmonary arterial blood flow

  • Results in left-to-right shunt, results in lung infection, pulmonary vascular congestion, pulmonary artery (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

  • Single large truncal vessel overrides ventricular septum and distributes all blood ejected from heart

  • Truncal root bifurcates into pulmonary trunk and aorta

  • Ventricular septal defect (VSD) present usually direct beneath truncal valve

  • Atrial septal defect (ASD) (> 40%), interrupted aortic arch (10%), abnormal origins of coronary artery

  • In most cases, pulmonary flow is increased

Symptoms and Signs

• • Heart failure in most

  • Pulmonary vascular disease early

• • Evaluate for associated cardiac and extracardiac anomalies

• • Echocardiography: Diagnostic

  • Catheterization: Assess coronary arteries or truncal valve, or if age > 3 mos to assess for pulmonary hypertension

• • Surgical repair: Closure of VSD, separation pulmonary arteries from truncal root, placing pulmonary allograft valve from RV, correct truncal insufficiency

Surgery

Indications

• • Warranted once diagnosis made

Contraindications

• • Eisenmenger physiology (irreversible)

Prognosis

• • Operative mortality 5-30% (related to truncal valve insufficiency, interrupted arch, coronary anomalies, and pulmonary hypertension)

  • Survivors often need future repair or replacement of truncal or pulmonary valve

References