['To test the hypothesis that major aorto-pulmonary collaterals (MAPCAs) have the same anatomy as bronchial arteries.', 'Two hundred and thirty-eight angiographies performed on 61 patients with pulmonary atresia, ventricular septal defect (VSD), and MAPCAs constituted the basis for this study. This represented all available angiographies performed on this patient group at our institution during the period 1972-2001. MAPCA anatomy was compared to bronchial artery anatomy as described in previous publications.', 'Each patient had one to five MAPCAs (mean 3.2+/-0.94). A mean of 2.6+/-0.66 MAPCAs came from the descending aorta. MAPCAs with anatomy similar to right intercosto-bronchial arteries were found in 87% of the patients. Fifty percent of the patients had MAPCAs originating from the subclavian artery regions. These numbers were all similar to those previously described for bronchial arteries. All MAPCAs had anatomy similar to bronchial arteries. The distribution in different branching patterns of MAPCAs arising from the aorta was similar to the distribution of bronchial arteries described in previous angiographic studies (p=0.32 and p=0.24).'] Are major aorto-pulmonary collateral arteries of patients with pulmonary atresia and ventricular septal defect dilated bronchial arteries?