Deposition of collagen in the alveolar wall of lungs from patients with tetralogy of Fallot and pulmonary atresia with major aortopulmonary collateral arteries—an ultrastructural study

Abstract

AbstractAbstract Lung biopsies were taken at surgery from five patients (age 2–13, average 7.6 years) with tetralogy of Fallot and pulmonary atresia with major aortopulmonary collateral arteries. The biopsies were then processed for ultrastructural study, comparing paired samples taken, on the one hand, from a segment connected to central pulmonary arteries and, on the other hand, from a segment supplied directly by collateral arteries. Specimens from patients with isolated ventricular septal defect, and from those without cardiac disease, were used as controls. In the patients with tetralogy of Fallot and pulmonary atresia, all biopsies taken from segments supplied by the major collateral arteries showed marked deposition of collagen in the alveolar wall, with an increase in the thickness of the basement membrane (3.6±1.2 µm, mean±SD) greater than seen in those taken from segments connected to central pulmonary arteries (0.9±0.6, p<0.05). The proportional fibrosis of the alveolar interstitial space was also significantly greater in the biopsies from the segments supplied by collateral arteries (30±9%) compared to those from segments fed by central pulmonary arteries (15±8%, p<0.05). No significant differences were found in these indices between the biopsies from segments connected to the central pulmonary arteries in patients with tetralogy of Fallot and pulmonary atresia and those from patients with isolated ventricular septal defect or normal controls. There was no apparent relation to the pulmonary arterial pressure in these findings. The results suggest that the pulmonary segments fed directly by major aortopulmonary collateral arteries in patients with tetralogy of Fallot and pulmonary atresia seem likely to be afflicted by alveolar wall fibrosis, although the etiology and clinical implications of this finding remain unclear.