Stent Thrombosis and Complications with Drug-Eluting Stents

Stent Thrombosis Risk

The most catastrophic complication of drug-eluting stents is stent thrombosis, which results in death or myocardial infarction in 64.4% of cases, with mortality rates ranging from 20-45% 1, 2, 3
In the current era of dual antiplatelet therapy, subacute stent thrombosis occurs in approximately 1% of patients 1, 2, 4
Late stent thrombosis (1-12 months post-implantation) occurs in 0.19% of patients with drug-eluting stents 1, 2, 3
Very late stent thrombosis can occur up to 1.5 years after implantation, particularly when antiplatelet agents are discontinued 5

Premature discontinuation of antiplatelet therapy is the single most important predictor of stent thrombosis 6
Stenting of small vessels increases the risk of stent thrombosis 6
Multiple or long stents increase the risk of stent thrombosis 6
Overlapping stents increase the risk of stent thrombosis 3
Ostial or bifurcation lesions increase the risk of stent thrombosis 2
Prior brachytherapy increases the risk of stent thrombosis 2
Suboptimal stent result (underexpansion, malapposition, or residual dissection) increases the risk of stent thrombosis 2
Low ejection fraction increases the risk of stent thrombosis 6
Advanced age increases the risk of stent thrombosis 2
Diabetes mellitus increases the risk of stent thrombosis 6
Renal failure increases the risk of stent thrombosis 2
Acute coronary syndrome presentation increases the risk of stent thrombosis 2

Stopping dual antiplatelet therapy prematurely is associated with catastrophic outcomes and is the leading independent predictor of stent thrombosis 1, 2, 3
Stent thrombosis occurred in 29% of patients who discontinued antiplatelet therapy prematurely 1, 2, 3
Premature discontinuation carries a hazard ratio of 161 (95% CI: 26-998) for subacute stent thrombosis and 57 (95% CI: 15-220) for late stent thrombosis 1, 2, 3

For patients requiring noncardiac surgery within the first 6 weeks to 12 months after stent placement, the risk of major adverse cardiac events is substantially elevated 5, 7
Early surgery (within required DAPT timeframe) resulted in 13.3% major adverse cardiac events versus 0.6% in late surgery 5
When antiplatelet therapy was discontinued in the early-surgery group, the incidence of major adverse cardiac events was 30.7% (all fatal) versus 0% in those who continued therapy 5

Drug-eluting stents delay endothelialization and healing, which increases the risk of late thrombosis 5, 8
The antiproliferative drugs (everolimus in the Synergy stent) inhibit neointimal formation but also delay endothelialization 5, 8
Very late stent thrombosis results from delayed hypersensitivity to components of the drug-polymer-device combination, causing necrotizing vasculitis and late malapposition 9, 8

Dual antiplatelet therapy required after drug-eluting stent placement carries significant bleeding risk 9, 8
Patients at increased bleeding risk represent a relative contraindication to drug-eluting stent use 9, 8
In perioperative studies, major bleeding occurred in approximately 4-5% of patients continuing antiplatelet therapy 5, 7

The Synergy stent requires dual antiplatelet therapy for a minimum of 6-12 months to minimize thrombotic complications 9, 8, 6
The American College of Cardiology/American Heart Association recommends ideally up to 12 months if patients are not at high risk for bleeding 1, 2, 4
Diabetic patients may require longer duration of dual antiplatelet therapy 9, 8