Very late stent thrombosis with bare-metal stent: identifying severe stent malapposition and underexpansion by intravascular ultrasound.

A 60-year-old man with a history of implantation of two bare-metal stents 2 years prior presented to the emergency department with new-onset chest pain. He has been regularly taking angiotensinconverting enzyme inhibitors, beta blockers and aspirin. Aspirin was suspended for 10 days prior to the current hospitalization in order to perform surgery to remove a kidney tumor. He underwent coronary angiography, which revealed a right coronary artery with a distal intraluminal defect within the stents, suggesting thrombus. Intravascular ultrasound demonstrated a severe malapposition and underexpansion throughout the entire length of the stents containing thrombus. In this case, the mechanisms of very late stent thrombosis after bare-metal stent most likely were a combination of mechanical factors (severe stent undersizing during the index procedure) and pharmacological factors (aspirin discontinuation).