Clinical vignette
Late coronary thrombosis in a sirolimus-eluting stent due to the lack of neointimal coverage
Masamichi Takano, and Kyoichi Mizuno*
Department of Internal Medicine, Chiba-Hokusoh Hospital, Nippon Medical School, 1715 Kamakari, Imba, Chiba 270-1694, Japan
*Corresponding author. E-mail address: mizunok@nms.ac.jp
A 44-year-old man was admitted to our hospital because of a diagnosis of acute myocardial infarction (AMI). Thirty-one months before the onset, he underwent elective percutaneous coronary intervention of the first diagonal branch, with one sirolimus-eluting stent (SES; Cypher, 2.5 mm diameter, 18 mm long) due to a diagnosis of prior AMI. Clopidogrel was discontinued at the 3-month clinical follow-up after stenting. The regular intake of aspirin 150 mg/day had been continued. Immediately, coronary angiography was performed. The struts of the SES that had previously been deployed were recognized through fluoroscopy (white arrowheads in Panel A). A coronary angiogram showed a total occlusion in the SES (white arrow in Panel B). Coronary angioscopy showed some of the struts were visible under a thin neointima at the proximal portion of the SES (black arrow in Panel C, asterisk indicates the guidewire). At the mid-portion, the struts covered with a very thin neointima were seen more clearly (black arrows in Panel D). Massive and protruding red thrombi adjacent to the exposed struts were found. Parts of the thrombi were located outside the struts, and the exposed struts had become detached from the vessel wall (white arrows in Panels E and F). Our angioscopic findings verified the lack of neointimal coverage following the stent malapposition was related to the occurrence of late stent thrombosis. Although it has been believed that the stent malapposition after drug-eluting stent deployment does not result in any adverse events, further careful long-term follow-up studies, especially for cases of stent malapposition, are required.
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