Banding of the pulmonary trunk in preparation for a Fontan operation.

Banding of the pulmonary trunk is an important surgical procedure for patients who have congenital cardiac malformations with unrestricted pulmonary flow. We propose a new concept for determining in such circumstances the most appropriate length of the band used to constrict the pulmonary trunk in preparation for a Fontan operation. We studied 14 patients undergoing banding of the pulmonary trunk and measured the following parameters: diameter of aorta, diameter of pulmonary trunk, length of pulmonary arterial band and maximum flow velocity across the banded segment. We calculated an index from our original parameter based on the formula; length of band/(diameter of aorta diameter of pulmonary trunk). The diameter of aorta was 9.5 +/- 1.4 mm, and that of the pulmonary trunk was 9.6 +/- 2.3 mm. The length of the band was 16.5 +/- 3.4 mm, giving a calculated index of 0.188 +/- 0.038. The maximum flow velocity was 4.02 +/- 0.46 m/s. No correlation was found between the length of the band and body weight, and also no correlation was found between the length of the band and maximum flow velocity. The calculated index had a negative correlation with the maximum velocity of flow across the band (y = -8.13x +/- 5.56, R = 0.74, p < 0.01). We believe that the proposed index is a useful guide in determining the length of a pulmonary band when preparing patients for a Fontan operation.