Abstract 3164: Angioscopic Findings of Sirolimus-Eluting Stent for Acute Myocardial Infarction: An Intermediate-term Follow-up Study
Background: Sirolimus-Eluting Stent (SES) is effective in reducing restenosis. Although several studies have reported the usefulness of SES in patients with acute myocardial infarction (AMI), the current major concerns of the use of SES in AMI are over-suppression of neointimal formation and late thrombosis. Coronary angioscopic examination provides an opportunity to assess neointimal coverage over stent and adherent thrombus in patients.
Method: This study consisted of 18 patients who underwent primary angioplasty with SES for AMI. A mean average of 7.6 ± 2.5 months after SES implantation, coronary angioscopic examination was performed. Neointimal coverage of the SES was assessed by the grading as: grade 0 = complete exposure of the stent struts, grade 1 = dull light reflex from stent struts, grade 2 = no light reflex, but slightly visible stent struts, and grade 3 = complete coverage. Because the grade of neointimal coverage may vary from struts to struts, both maximum and minimum grade of neointimal coverage were assessed. The presence of thrombus was also evaluated.
Results: All but one patient had at least 2 different grades of neointimal coverage; one patient had only grade 0. When the maximum grade of neointimal coverage was assessed, grade 0 was observed in 1 patient, grade 1 in 4 patients, grade 2 in 8 patients, and grade 3 in 5 patients. As to minimum grade, grade 0 was observed in 11 patients and grade 1 in 7 patients, however, grade 2 and 3 was not observed. Thrombus adherent to uncovered stent struts (grade 0 or 1) was observed in 8 patients (44%).
Conclusion: The process of neointimal coverage over SES was heterogeneous. Even 7 months after SES implantation for AMI, most of the stent struts were not covered by neointimal with high incidence of adherent thrombus. Long-term aggressive anti-platelet therapy should be advocated for patients with AMI who were treated with SES.