Coronary angioscopic findings eight months after sirolimus-eluting stent implantation: A comparison between ST-elevation myocardial infarction and stable angina pectoris

Aims: Conflicting data exist about the safety of the sirolimus-eluting stent (SES) for patients with ST-elevation myocardial infarction (STEMI). Previous studies have reported delayed neointimal proliferation over SES with high incidence of adhering thrombus. This study was undertaken to assess the neointimal coverage and thrombus formation after SES implantation between patients with STEMI and those with stable angina pectoris (SAP). Methods and results: We studied 23 patients with STEMI who underwent primary percutaneous coronary intervention (PCI) with SES and 18 patients with SAP who were treated with SES. Coronary angioscopic examination was performed 8.1±2.4 months after PCI. Neointimal coverage of the stent was classified into four grades (grade 0 to 3). Uncovered stent strut was defined as grade 0 or 1. All the patients with STEMI and 94% of patients with SAP had uncovered stent struts. There was no significant difference in minimum, maximum, and dominant neointimal coverage grade between STEMI and SAP. 96% of patients with STEMI and all the patients with SAP showed heterogeneous neointimal coverage. Thrombus adhering to uncovered stent struts was observed in eight patients after STEMI and in four patients after SAP (35% vs. 22%, p=0.38). There was no significant difference in the maximum colour grade of the plaques between STEMI and SAP (2.1±0.8 vs. 1.8±0.9, p=0.33). Most thrombus was observed at the site of yellow plaques (83%). Conclusions: There was no significant difference in the neointimal coverage and thrombus formation between STEMI and SAP.