Stent Thrombosis: Incidence, Predictors and New Technologies

Abstract

Some concerns have been raised regarding the risk of late and very late stent thrombosis (ST) following drug-eluting stent implantation. Despite remaining an uncommon complication of percutaneous coronary intervention, when ST occurs, it can be catastrophic to the individual, commonly presenting as acute ST elevation myocardial infarction or sudden cardiac death. The incidence and predictors of ST have been reported in the literature and the role of dual antiplatelet therapies in the avoidance of such a complication remains vital. Ongoing studies are assessing the role of these therapies including platelet reactivity testing, genetic testing and optimum duration of therapy. In addition, newer polymer-free and bioabsorbable stents are under investigation in the quest to potentially minimise the risk of ST.

Long-Term Clinical Outcomes After Bioresorbable Vascular Scaffold Implantation for the Treatment of Coronary In-Stent Restenosis

“…5 Second-generation DES has shown good results for both BMS and DES ISR, but the use of DES is limited by the addition of a further permanent metallic layer into the arterial wall, especially in patients already presenting with multiple stent layers as a consequence of recurrent-resistant DES-ISR. 14 Therefore, the use of DEB has been widely encouraged as ISR therapy. [15][16][17][18] However, DEB is associated with poorer clinical and angiographic outcomes when compared with second-generation DES for the treatment of ISR.…”

Coronary Bioresorbable Vascular Scaffold Use in the Treatment of Coronary Artery Disease

“…60 Drug-eluting balloon has been proposed as a valid alternative to current DES, thanks to the ability to elute the antiproliferative drug without the longterm limitation of adding a further layer of struts. However, drug-eluting balloon are limited by the shorter therapeutic window of the antiproliferative drug, by a greater late lumen loss compared with new-generation DES, 61,62 and the frequent need for bail-out stenting because of the occurrence of flowlimiting vessel dissection.…”

Triple, simultaneous, very late coronary stent thrombosis

“…1,2 Moreover, patients who survive the event have a worse prognosis and are at increased risk of another ST in followup. 3 The risk of very late stent thrombosis (VLST) (occurring more than one year after stent placement) raises long-term safety concerns regarding the first generation of DES (sirolimus-eluting and paclitaxel-eluting stents), even though, compared with bare metal stents, they were a major breakthrough, consistently being associated with reduced rates of angiographic restenosis and ischemia-driven target vessel revascularization. 4 The reported cumulative rates of definitive VLST, according to the Academic Research Consortium definition, vary in the literature depending on the duration of follow-up used, and are slightly higher in observational studies.…”

“…3---8 Delayed neointimal coverage and a hypersensitivity reaction to components of the drug-polymer-stent combination, together with ongoing vessel inflammation, impaired healing and abnormal remodeling leading to late and very late acquired stent malapposition, have been associated with VLST, but the precise mechanism is still unknown. 9---13 Patient-related factors (including compliance with antiplatelet therapy), procedural and post-procedural factors (including type and duration of antiplatelet therapy) probably interact and predispose the patient to ST. 2,3,10 Endothelial dysfunction has also been described as an adverse consequence following coronary DES implantation, although its clinical significance is still unknown. 14 In fact, although DES target vascular smooth muscle cell proliferation and migration (neointimal hyperplasia), the key factors in the development of restenosis, they impair re-endothelialization and promote late in-stent neoatherosclerosis, a new concept whose precise mechanism is also unknown, that acts as another substrate for VLST.…”