Serial angioscopic evidence of incomplete neointimal coverage after sirolimus-eluting stent implantation: comparison with bare-metal stents.
BACKGROUND
The time course of neointimal formation after stent implantation has not been studied extensively by angioscopy in the drug-eluting stent era.


RESULTS
Serial angioscopic findings at first follow-up (3.6+/-1.1 months), second follow-up (10.5+/-1.6 months), and third follow-up (21.2+/-2.2 months) after stent implantation were compared between sirolimus-eluting stents (SES, n=17) and bare-metal stents (BMS, n=11). Neointimal coverage, thrombus, and presence of yellow plaques underneath the stents were assessed. Neointimal coverage was graded as follows: grade 0, stent struts were fully visible; grade 1, struts bulged into the lumen, although they were covered; grade 2, struts were embedded by the neointima but were seen translucently; or grade 3, struts were fully embedded and invisible. Neointimal coverage was remarkably different between SES and BMS at each follow-up point. Neointimal coverage grade was 1.1+/-0.5 in SES versus 2.9+/-0.3 in BMS at the first follow-up (P<0.0001), 1.1+/-0.5 in SES versus 3.0+/-0.0 in BMS (P<0.0001) at the second follow-up, and 1.3+/-0.5 in SES versus 3.0+/-0.0 in BMS at the third follow-up (P=0.0009). No significant serial changes in coverage grade were noted in the BMS group, whereas coverage grade slightly but significantly increased at the third follow-up in the SES group (P<0.05). Thrombi were detected in 4 SES: a red thrombus was seen from the first to the third follow-up in 2; another was detected only at the third follow-up; and the fourth was seen at the first follow-up but disappeared at the second follow-up, associated with a new white thrombus despite dual antiplatelet therapy. Yellow plaques had disappeared by the time of the second follow-up in BMS. In contrast, yellow plaques were exposed in 71% of SES at the first follow-up and remained exposed until the third follow-up. Neointimal coverage grades correlated with thrombi (P=0.002) and with yellow plaques (P<0.0001).


CONCLUSIONS
Serial angioscopic findings up to 2 years after SES implantation were markedly different from those after BMS. Neointimal coverage was completed by 3 to 6 months in BMS. In contrast, SES demonstrated the presence of thrombi and yellow plaques even as much as 2 years after implantation.
Awata
Masaki
M
Cardiovascular Division, Kansai Rosai Hospital, Amagasaki, Japan.
Kotani
Jun-ichi
J
Uematsu
Masaaki
M
Morozumi
Takakazu
T
Watanabe
Tetsuya
T
Onishi
Toshinari
T
Iida
Osamu
O
Sera
Fusako
F
Nanto
Shinsuke
S
Hori
Masatsugu
M
Nagata
Seiki
S
D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D015331:Cohort Studies; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D023903:Coronary Restenosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000517:prevention & control; D003328:Coronary Thrombosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000517:prevention & control; D003331:Coronary Vessels / Q000187:drug effects / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage*; D008297:Male; D008670:Metals; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage; D020123:Sirolimus / Q000008:administration & dosage*; D015607:Stents; D017539:Tunica Intima / Q000187:drug effects / Q000473:pathology
D007166:Immunosuppressive Agents; D008670:Metals; D010975:Platelet Aggregation Inhibitors; D020123:Sirolimus