The early phenomena of restenosis following percutaneous transluminal coronary angioplasty.

In man the early onset of fibrocellular tissue reaction, which leads to restenosis following an initial successful percutaneous transluminal coronary angioplasty, has been poorly documented because of limited opportunities to study this phenomenon. The present study focused on early changes in seven patients who died within 20 days of a percutaneous transluminal coronary angioplasty procedure. Differences in the mode of laceration were noted between concentric and eccentric plaques. In the former, tears occur at the thinnest site of the plaque or within an already attenuated fibrous cap. The injury usually remains limited to the plaque. In eccentric lesions lacerations tend to occur in the non-atherosclerotic wall segment, affecting the musculoelastic layers and the media. A further site of predilection is the border zone between the non-affected wall and the plaque. Early tissue response is characterized by fibrin-platelet depositions, and a proliferation of macrophages and spindle-shaped cells. The latter express the immunocytochemical characteristics of smooth muscle cells. However, differences occur according to the type of tissue injured. Laceration of the musculoelastic layers or media causes a rapid and extensive cellular response. Injury to an atheroma, on the other hand, mainly causes plaque fissures with either mural thrombosis and total luminal obstruction, extensive plaque haemorrhage or a 'wash-out' of the atheromatous debris. In the latter case the lining of the 'crater' shows an accumulation of macrophages and, once more, a proliferation of spindle-shaped cells. The present observations support the concept that the early response is due to an interaction of platelet-fibrin thrombus and smooth muscle cells, with a possible role for macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)