Stent undersizing can result in procedure-related very late stent thrombosis.

We describe a case of very late stent thrombosis (LST) occurring 18 months after implantation of a Taxus stent in an insulin-dependent diabetic patient after stopping his antiplatelet therapy. Intravascular ultrasound performed during his acute admission showed gross undersizing of his stent that was originally sized with quantitative coronary angiography. It highlights the importance of the overreliance on a single quantitative technique and suggests that the abnormally induced shear stresses through the reduced vessel caliber, augmented by a distal lesion, can result in LST when clopidogrel is stopped.