Pulmonary vascular disease in children with congenital heart defects living at high altitude—a quantitative morphometric lung biopsy study

Lung biopsies were taken from 30 children aged three months to 15 years (median, 11 months) who had pulmonary hypertensive congenital heart disease and were living at an altitude of 1750 meters. They had either a ventricular septal defect and/or patency of the arterial duct, atrioventricular septal defect or complete transposition with a ventricular septal defect. Biopsies were studied using quantitative morphometric light microscopic techniques. All patients with a ventricular septal defect with or without patency of the arterial duct showed a significant increase in mean percentage arterial medial thickness of both pre- and intraacinar pulmonary arteries compared with those of normal children of similar age living at sea level (p<0.001 for both pre- and intraacinar vessels) and with children with a ventricular septal defect living at sea level (p<0.001 for both pre- and intraacinar vessels). Extension of muscle to more peripheral pulmonary arteries was also greater. Intimal proliferation and fibrosis was seen in 10 patients, in three of whom it was severe. Intimal proliferation occurred more frequently than in children with a ventricular septal defect living at sea level. The findings were similar in patients with atrioventricular septal defect and complete transposition with ventricular septal defect. These findings suggest that patients with congenital heart disease who live at a relatively high altitude develop pulmonary vascular disease more rapidly than do those living at sea level.