Post-intervention IVUS is not predictive for very late in-stent thrombosis in drug-eluting stents

Stent thrombosis is a life-threatening complication associated with sudden death and acute myocardial infarction. Histopathologic studies have linked the occurrence of very late stent thrombosis in drug-eluting stents (DES) with delayed endothealisation and stent malapposition. Our aim was to investigate if late stent malapposition in DES could be predicted by immediate postintervention intra-vascular ultrasonography (IVUS).From our MISSION! database of 184 consecutive patients with ST-elevation myocardial infarction (STEMI) who had immediate post-intervention and nine-month follow-up IVUS examinations we prospectively identified three patients with very late (> 365 days) and definite (with angiographic evidence) in-stent thrombosis in DES. Patients had completed the twelve-month clopidogrel-aspirin dual treatment period, two of them were under aspirin therapy while the third patient had aspirin temporarily discontinued before planned surgery. When assessed by serial documentary (immediate post-intervention and nine-month) IVUS, all three patients demonstrated stent malapposition at nine months: in two cases the malapposition was acquired (immediate post-intervention IVUS showed a well apposed stent) and one case presented persistent malapposition (the stent was found malapposed both at immediate post-intervention and nine-month follow-up IVUS).Immediate post-intervention IVUS showing no malapposition does not guarantee an uneventful course after DES implantation.