Repeated intra-stent thrombus formation in a patient with acute coronary syndrome due to poor responsiveness to clopidogrel may be associated with cytochrome P-450 2C19*2 polymorphism.

A drug-eluting stent was implanted at the culprit lesion in a 65-year-old man with acute coronary syndrome. Nine days after the procedure, he suffered stent thrombosis, and a bare-metal stent was subsequently implanted. Twelve days after this second procedure, a follow-up angiogram showed a newly emerged thrombus at the site of stent implantation.