Influence of pulmonary artery size on early outcome after the Fontan operation

BACKGROUND: Small pulmonary arteries (PAs) are often considered as a contraindication for the Fontan operation (FO). The aim of this study was to evaluate if the PA size is still one of the major impact factors on the postoperative early outcome.

METHODS: Data of 146 patients, with a median age of 2.0 years (range, 1.5 to 18 years) and a median weight of 12.45 kg (range, 7.7 to 64.7 kg) who underwent a modified FO in the same center between 2007 and 2012 were retrospectively analyzed with respect to the traditional McGoon ratio, Nakata index, and modified indices (measuring the narrowest diameters).

RESULTS: Patients with a McGoon ratio of 1.6 or less (modified≤1.2) or a Nakata index of 150 mm2/m2 or less (modified≤100 mm2/m2) were not at a higher risk of longer mechanical ventilation (p=0.87 [0.1] and p=0.68 [0.52], respectively), longer stay (p=0.52 [0.18] and p=0.54 [0.38], respectively) in the intensive care unit, prolonged hospital stay (p=0.08 [0.26] and p=0.22 [0.29], respectively) or effusions (p=0.25 [0.37] and p=0.13 [0.06]), respectively). Younger and smaller children tended to have smaller PAs, but younger age (<24 months) and lower weight (<12 kg) were not predictive for poor early postoperative outcome.

CONCLUSIONS: Small PAs do not significantly affect the early postoperative period after FO. In our opinion, there is no need to postpone the FO due to "smaller" PAs. The palliative procedures performed before FO to increase the size of the PA at the expense of volume overload of the single ventricle and the possible complications of prolonged cyanosis must be carefully weighed.