Scanning electron microscopy of human lungs in various forms of heart disease

The surface morphologic features of the lung obtained from 21 patients with various forms of heart disease were investigated by scanning electron microscopy, with particular emphasis on the correlation between the surface pathology and cardiopulmonary hemodynamics. There were almost no pathologic findings on the bronchiolar and alveolar surfaces in patients with normal pulmonary arterial wedge pressure (PAWP). The characteristic changes of the surface morphology of the lung parenchyma in patients with abnormal elevation of PAWP included various degrees of desquamating loss of the bronchiolar epithelium associated with inflammatory cell infiltration and fibrotic changes and focal epithelial disruption of the individual alveoli which often extended to involve the surface of the entire alveoli with perforated rupture of the alveolar septa. The severity of abnormal surface morphologic findings of the lung seemed to correlate to the degree of PAWP. From our results it is concluded that chronic lung congestion plays a major role in the pathogenesis of the surface pathologic changes of the lung in patients with heart disease of various etiologies. Our findings may provide a clearer understanding of the structural and functional relationship of congestive lung and a clinical explanation for pulmonary manifestations in patients with chronic congestive heart failure.