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Figure 2 Diagram illustrating the time course of events leading to neointimal hyperplasia in atherosclerotic human coronary arteries. In the first stage, the atherosclerotic artery is depicted before stent placement. NC = non-cellular region of the plaque. Within the first three days after stent placement, platelets/fibrin and neutrophils accumulate at the stent site. At 14 to 30 days, chronic inflammation develops (macrophages, lymphocytes) and persistent fibrin is visible. Smooth muscle cells also are beginning to appear within the stent. At three months, chronic inflammation remains, and fibrin frequently persists. Proteoglycan and matrix deposition occurs. At 6 to 12 months, there often is persistent, chronic inflammation close to the struts, and endothelialization generally is complete. A neointima rich in smooth muscle cells, with a proteoglycan and collagen matrix, has developed. Adapted from Virmani et al. (136).