IS case 515: Uncorrected Tetralogy of Fallot with pulmonary atresia
Imaging Sciences URMC 2010
Publication Date: 2010-09-10
Patient is an 18-year-old female with congenital heart disease, diagnosed in the neonatal period. She has a history of progressively worsening exercise intolerance over the past ten years, periodic severe cyanosis, and recent pulmonary hypertension. Four years ago, the patient experienced an episode of large volume hemoptysis, which was treated conservatively. She was recently treated for endocarditis and now presents with cough and chest pain for question of pneumonia versus pulmonary congestion.
Tetralogy of Fallot with pulmonary atresia (TOF-PA) is a congenital heart defect, that is usually corrected with a 90% survival into adulthood. Uncorrected TOF-PA has a 5% survival. TOF-PA is an uncommon variant in the spectrum of TOF, accounting for 20% of TOFs and 1.5% of congenital heart disease overall. Two major classifications of TOF-PA are considered: those with confluent pulmonary arteries and those with multiple aortopulmonary collaterals.
Multiple disorders/syndromes are associated to varying degrees, with one example being CATCH22. In TOF-PA of the aortopulmonary collateral type, there is a 41% increase in CATCH22 (cardiac defect, abnormal face, thymic hypoplasia, cleft palate, hypocalcemia, microdeletion of band 22q11); by comparison, with TOF-PA of the confluent pulmonary artery type, the increase is 16%. Genetic counseling is recommended, especially if there are siblings.
Maternal causative factors include diabetes mellitus, among others.
TOF-PA requires a ventricular septal defect (VSD) and an aberrant pulmonary arterial supply to survive. Viability stems from the following scheme: 1) systemic venous return (de-oxygenated blood) enters the right ventricle via tricuspid valve inflow; 2) the systemic venous blood then traverses a VSD to the left ventricle; 3) within the left ventricle systemic venous blood mixes with pulmonary venous return (oxygenated blood via mitral valve inflow from the left atrium); 4) mixed blood is pumped out via a single outflow tract to the aorta; and 5) mixed aortic blood re-enters pulmonary circulation via aortopulmonary branch arteries and/or collateral vessels.
Pulmonary blood flow depends on the size of the arterial vessels. In this case, pulmonary arterial supply is asymmetric (right > left), which reflects the more normal caliber right-sided aortic branch vessels versus the small caliber left sided collateral network.
TOF-PA can usually be corrected in the neonatal or infant period, though a small number of children remain relatively asymptomatic, resulting in delayed correction. The current patient and family have refused surgical correction to date, despite symptom progression, including worsening extertional dyspnea, hemoptysis, periodic cyanosis, and more recent pulmonary hypertension. Follow-up has involved chest radiographs, computed tomography of the chest, and magnetic resonance imaging with gadolinium enhanced angiography of the chest. Echocardiography may also be utilized, but a suspicion of aortopulmonary collaterals warrants MR angiography and/or conventional cardiac angiography.
The patient did undergo invasive cardiac angiography, which confirmed suspected pulmonary hypertension in the setting of uncorrected Tetralogy of Fallot with pulmonary atresia and multiple aortopulmonary collaterals.
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- Pettersen M, Kulkarni A. Tetralogy of fallot with pulmonary atresia. Emedicine. Updated: Jul 9, 2010. http://emedicine.medscape.com/article/899368-overview