Sir,—We read with interest the paper of Buheitelet al dealing with the important topic of pulmonary artery size in children before and after total cavopulmonary connection.1 We congratulate the authors on their contribution to the ongoing discussion about the fate of pulmonary arteries following various forms of right heart bypass operation.2 ,3 However, there are several issues related to the paper that were not clear.

In our opinion the authors do not provide enough information about the surgical techniques used in the treatment of the patients either at primary palliation or during the so called total cavopulmonary connection. We particularly miss data related to the type of systemic–pulmonary arterial shunt preceding the total cavopulmonary connection, the extent of surgical reconstruction of the central pulmonary arteries, or the use of atrial baffle fenestration. It is not clear whether the total cavopulmonary connection was done as a primary right heart bypass operation or as a completion of previous hemi-Fontan or bidirectional superior cavopulmonary anastomosis. We believe that this information is crucial if the results of this study are to be compared with other published series.4 ,5

The authors studied two distinctly different groups of patients, which deserve closer analysis. The first, much younger group of patients (group I; mean age 1.5 month) had severely hypoplastic pulmonary arteries (Z score of the right and left pulmonary arteries −6.0 and −9.6, respectively) at the time of their first cardiac catheterisation. One can only assume that these patients had very low pulmonary blood flow and that they went on to have some form of initial palliation to augment pulmonary blood flow. …