OBJECTIVEIn order to provide pathologic reference for therapeutic rationale, the pathological changes of the pulmonary vasculature in patients with pulmonary atresia with ventricular defect and patent ductus arteriosus were observed by contrast with normal control group.

METHODSLung biopsies were taken in the operation in 10 children suffered from pulmonary atresia with ventricular septal defect associated with patent ductus arteriosus (PA group). Autopsy specimens were obtained from 10 children died of non-cardiovascular diseases as normal control group. The tissue was fixed with buffered formalin, routinely prepared by impregnated in wax. Sections were stained by hematoxylin-eosin, Weigert's elastic stain counter-stained by van Gieoson's method. Seven parameters were obtained including percentage of media thickness (MT%), percentage of media section area (MS%), numbers of vascular per square centimeter (VPSC), mean alveolar number (MAN), mean linear intercept (MLI), proportion of parenchyma area in total area (PPA), and alveolar/vascular ratio per unit area (AVR) by a computer image processor by quantitative analysis.

RESULTSThere were significant difference between the two groups in MAN, VPSC, and AVR (P < 0.05). VPSC was significantly lower in PA group than in control group (P < 0.01). Other parameters had no significant difference. The mean alveolar diameter had an increased trend in PA group, although there was no significant difference. MS% of nearly 50% patients was closed to the normal value in PA group. The shape of pulmonary arteriole was irregular. There were few muscular arteries in a field of vision.

CONCLUSIONSThe density of muscular arteries decreases in patients with pulmonary atresia with ventricular septal defect and patent ductus arteriosus, but percentage of media thickness and percentage of media section area of pulmonary arterioles are close to the normal value. Diminished flow in pulmonary circulation has a significant effect on numbers of pulmonary arterioles per square centimeter that impact the selection of surgical method and the effect of operation because of the reduction pulmonary arterioles. The decrease of mean alveolar number results in compensatory enlargement of alveolar diameter. The impaired lung development is a major cause of abnormal lung function. Feasible and earlier operation, which can increase pulmonary flow and promote development of pulmonary vasculature will be helpful to restore lung function.