Ultrastructural changes of pulmonary tissue in congenital heart disease with pulmonary hypertension

Objective To study the pathological changes of pulmonary tissue of congenital heart disease (CHD) with pulmonary hypertension (PH). Methods Twenty one patients (12 males and 9 females) with CHD and PH underwent operation between November 1997 and February 1999. Their mPAP was 58±21?mmHg and mPVP was 760±206?dyn·s·cm -5 . There were 14 cases with severe PH and 7 cases with medium PH. All the patients underwent cardiac repairing with cardiopulmonary bypass (CPB) except for 4 cases of PDA ligations. Ultrastructural changes of pulmonary tissue were examined. Results Fibrosis of pulmonary tissue was asymmetrical on both sides of capillary vessels. It was more pronounced on non gas blood exchange side. The histological hyperplasia was more prominent in collagenous fiber than the elastic fiber. There was general thickening of alveolo capillary membrane. The intimal proliferation of capillary vessel and pulmonary arteries caused the narrowing of vessel lumen. Type Ⅱ alveolar cells increased considerably. There were abundant mitochondria, rough surfaced endoplasmic recticulum, and significantly increased ply bodies. The contents of most ply bodies were lost in cytoplasm of type Ⅱ alveolar cells. Basal lamina of type Ⅰ alveolar cells was thickened. Conclusions The results indicate that the ultrastructure of pulmonary tissue has changed considerably in the patients with congenital heart disease and pulmonary hypertension. To minimize PH, surgical intervention should be carried out as early as possible.