"Very" Very Late Drug-Eluting Stent Thrombosis

A long-term complication of drug-eluting stents (DES) is the occurrence of very late stent thrombosis (VLST) beyond one year after implantation. It is unclear whether DES thrombosis is a finite phenomenon which abates over time or is a risk that persists indefinitely, an important issue in light of recent data suggesting benefit to longer term dual antiplatelet therapy. We expand upon a previously published series of patients who presented to our institution with acute myocardial infarction (MI) due to "very", very late stent thrombosis (VVLST), defined as occurring more than 5 years after DES implantation. The study group consisted of 9 patients (8 men and 1 woman), ages 32 to 70 years, who had angiographically confirmed definite VVLST. Seven patients were active smokers and 4 were diabetic. The interval between stent implantation and VVLST ranged from 5.6 to 10.2 years. The DES was sirolimus-eluting in 6 patients and paclitaxel-eluting in 3 patients. None of the patients were taking clopidogrel and only 2 patients were taking aspirin at the time of VVLST. Therefore, 7 of the 9 patients were not taking any antiplatelet medication. The clinical presentation of VVLST was an acute MI in all patients, with ST segment elevation in 7 of the 9. Seven patients were treated successfully by emergent repeat percutaneous coronary intervention. Two patients (one post-operative from neurosurgery and one with thrombocytopenia from CML requiring a bone marrow transplant) were managed medically. There were no in-hospital mortalities. In conclusion, the risk of stent thrombosis persists well beyond 5 years after implantation of first generation DES. These sobering findings underscore the importance of long-term clinical vigilance in these patients and support current PCI guidelines which recommend continuing at least aspirin indefinitely after DES. Future studies are needed to assess the impact of newer generation DES and bioresorbable scaffolds on VVLST.