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Figure 2 Change of EEM and P&M CSA During the Follow-Up Period for All Individual SM Sites

(A) Bare-metal stent (BMS); (B) sirolimus-eluting stent (SES). The stent malapposition (SM) sites are categorized as resolved, persistent, or acquired SM. Delta () denotes change (follow-up minus post-procedure). (A) BMS: Most of the acute SM sites (resolved and persistent) are located above the x axis, indicating an increase in the plaque and media (P&M) cross-sectional area (CSA) during the follow-up period. Acquired SM sites are very rare after BMS implantation. (B) SES: The external elastic membrane (EEM) and P&M CSA are virtually unchanged in most persistent SM sites. Acquired SM sites are mostly located around the positive x axis, indicating that positive remodeling (enlargement of the EEM CSA, while the P&M CSA remains virtually unchanged) is the mechanism of development of SM in these sites. In a minority of sites, plaque reduction (decrease of the P&M CSA, while the EEM CSA remains virtually unchanged) plays a role.