Radionuclide evaluation of lung perfusion after the Fontan procedure.

Lung perfusion was evaluated in 19 patients in whom a Fontan operation had been performed at a mean age of 3.7 years. First pass and equilibrium data were acquired during the lung particle perfusion scan 0.5 to 7.9 years (mean 3.7 years) following the Fontan procedure. Abnormalities of lung perfusion were documented in 8 patients. Minimal underperfusion of small areas of either right or left lung were noted in 4 patients, while the remaining 4 had evidence of major perfusion defects, involving both lungs. The perfusion defects were localized, in the majority of cases, on the side where a palliative procedure had been performed before the Fontan operation: it is of note that all our patients without palliative procedures did not show abnormalities in lung perfusion. Major abnormalities of lung perfusion seemed related to possible intimal thrombosis or emboli due to prolonged polycythemia or to pulmonary vessel distortion due to long-standing shunts.