Percutaneous transluminal angioplasty of the aorta. Light and electron microscopic observations in normal and atherosclerotic rabbits.

Histological changes which developed after percutaneous transluminal angioplasty in normal and atherosclerotic rabbit aortas were correlated with balloon size and inflation time. In normal rabbits, progressive changes were observed in the intima and media with increasing balloon size and inflation time. The atherosclerotic aortas exhibited unpredictable fragility, with limited correlation between histological changes, balloon size, and inflation time, attributable mainly to the distribution and thickness of plaques. In atherosclerotic vessels, the mechanism of angioplasty consisted of plaque dehiscence and fracture, followed by overstretching of the plaque-free wall segments. No plaque compression was observed.