[Compensatory enlargement versus chronic constriction. The two features of vascular remodelling after experimental...

Considerable efforts have been made to prevent post-angioplasty restenosis targeted mainly against a pathogenesis suggesting a dominant role of hyperplasia. We and others have already shown that constrictive remodelling plays a major role in restenosis. This article evaluates not only the constrictive remodeling theory but also compensatory enlargement associated with prevention of restenosis. The present study on 33 rabbits used the following protocol. Four weeks after inducing an atherosclerotic lesion by air-dessication of a femoral artery segment and a high cholesterol diet, angioplasty was performed. The angiographic minimal luminal diameter significantly increased after angioplasty. Three to four weeks later, initial gain was significantly lost. Restenosis was quantified histologically as well as a remodelling index and a hyperplasia index. No correlations were observed between degree of stenosis and hyperplasia present at the same degree in animals with and without restenosis. On the other hand, there was a strong correlation between restenosis and constrictive remodelling, and with absence of restenosis and compensatory enlargement. Moreover, there was significant a correlation between the degree of hyperplasia and the compensatory remodelling. These data point to the double nature of remodelling: compensatory enlargement observed in animals without restenosis, and constrictive remodelling, the principal mechanism observed in animals with restenosis.