Objectives: The purpose of this study was to evaluate the prevalence of and risk factors for aortopulmonary collateral vessels in patients who have undergone a bidirectional Glenn or Fontan procedure, or both.
Background: Aortopulmonary collateral vessels are frequently observed angiographically in patients after a bidirectional Glenn or Fontan procedure. These vessels may provide a source of pulmonary blood flow competitive with anterograde cavopulmonary flow.
Methods: We performed a retrospective study of all patients (n = 196) who underwent catheterization between January 1, 1988 and February 29, 1992 (n = 268) after bidirectional Glenn or Fontan procedures and reviewed clinical, hemodynamic and angiographic phone data.
Results: Collateral vessels were diagnosed in 36% of patients. Patients who underwent the bidirectional Glenn procedure were more likely to have collateral vessels than patients who underwent the Fontan procedure (65% vs. 30%, respectively; p < 0.0001). Patients with a history of a Blalock-Taussig shunt were more likely to have collateral vessels than those without (50% vs. 24%, respectively; p = 0.0006). Discretely identifiable collateral vessels were measurable in 54 (20%) of 268 catheterizations. The total estimated cross-sectional area of these vessels averaged 10.7 +/- 7.2 mm2. In patients who underwent the bidirectional Glenn procedure, a step-up in oxygen saturation from the superior vena cava to the distal pulmonary arteries or an upper lobe filling defect, or both, on pulmonary angiogram predicted total estimated cross-sectional area of collateral vessels. Most collateral vessels originated from the internal mammary arteries (34%) and the thyrocervical trunks (22%). Only 9% of collateral vessels arising from the brachiocephalic vessels were visualized by aortogram; the remainder required selective angiography in the subclavian or more distal arteries.
Conclusions: Aortopulmonary collateral vessels are common after bidirectional Glenn and Fontan procedures. Aortograms often fail to diagnose their presence. The left to right shunt carried by these vessels is associated with a step-up in oxygen saturation in the distal pulmonary arteries. The clinical significance and indications for closure of these vessels are not known.