A paradigm for restenosis based on cell biology: clues for the development of new preventive therapies.

Angioplasty causes substantial injury to the coronary artery intima and media that is unrecognizable by angiography. On the basis of a substantial body of research in oncology and wound healing, it is hypothesized that restenosis is a manifestation of the general wound healing response expressed specifically in vascular tissue. The temporal response to injury occurs in three characteristic phases: inflammation, granulation and extracellular matrix remodeling. The specific expression of these phases in the coronary artery leads to intimal hyperplasia at 1 to 4 months. The major milestones in the temporal sequence of restenosis are platelet aggregation, inflammatory cell infiltration, release of growth factors, medial smooth muscle cell modulation and proliferation, proteoglycan deposition and extracellular matrix remodeling. Each step has potential inhibitors that could be used for preventive therapy. Resolution of restenosis, however, probably requires both creation of the largest possible residual lumen and substantial inhibition of intimal hyperplasia.