A sirolimus-eluting bioabsorbable polymer-coated stent (MiStent) versus an everolimus-eluting durable polymer stent (Xience) after percutaneous coronary intervention (DESSOLVE III): a randomised, single-blind, multicentre, non-inferiority, phase 3 trial

Safety and efficacy of a sirolimus-eluting coronary stent with ultra-thin strut for treatment of atherosclerotic lesions (TALENT): a prospective multicentre randomised controlled trial

BACKGROUND

Supraflex is a sirolimus-eluting stent with a biodegradable polymer coating and ultra-thin struts. We aimed to compare Supraflex with the standard of care, Xience, an everolimus-eluting stent with a durable polymer coating, regarding clinical outcomes with a randomised trial in an all-comer population.

METHODS

We did a prospective, randomised, single-blind, multicentre study (TALENT) across 23 centres in Europe (the Netherlands, Poland, the UK, Spain, Bulgaria, Hungary, and Italy). Eligible participants were aged 18 years or older, had one or more coronary artery stenosis of 50% or greater in a native coronary artery, saphenous venous graft, or arterial bypass conduit, and had a reference vessel diameter of 2·25-4·50 mm. Patients underwent percutaneous coronary intervention in an all-comer manner. We randomly assigned patients (1:1) to implantation of either a sirolimus-eluting stent with a biodegradable polymer coating and ultra-thin struts (Supraflex) or an everolimus-eluting stent with a durable polymer coating (Xience). Randomisation was done by local investigators by use of a web-based software with random blocks according to centre. The primary endpoint was a non-inferiority comparison of a device-oriented composite endpoint-cardiac death, target-vessel myocardial infarction, or clinically indicated target lesion revascularisation-between groups at 12 months after the procedure, assessed in an intention-to-treat population. On assumption of 1-year composite endpoint prevalence of 8·3%, a margin of 4·0% was defined for non-inferiority of the Supraflex group compared with the Xience group. This trial is registered with ClinicalTrials.gov, number NCT02870140.

FINDINGS

Between Oct 21, 2016, and July 3, 2017, 1435 patients with 1046 lesions were randomly assigned to Supraflex, of whom 720 received the index procedure, and 715 patients with 1030 lesions were assigned to Xience, all receiving the index procedure. At 12 months, the primary endpoint had occurred in 35 patients (4·9 %) in the Supraflex group and in 37 patients (5·3%) in the Xience group (absolute difference -0·3% [one-sided 95% upper confidence bound 1·6%], p_{non-inferiority}<0·0001). Definite or probable stent thrombosis prevalence, a safety indicator, was low in both groups and did not differ between them.

INTERPRETATION

The Supraflex stent was non-inferior to the Xience stent for a device-oriented composite clinical endpoint at 12 months in an all-comer population. Supraflex seems a safe and effective alternative drug-eluting stent to other stents in clinical practice.

FUNDING

European Cardiovascular Research Institute.

Update on pathological platelet activation in coronary thrombosis

Although coronary thrombosis (CT) is integral to cardiovascular outcomes, the underlying pathophysiological mechanisms remain unclear. CT may occur in case of atherosclerotic plaque erosion/rupture, or even after stenting implantation. Platelets (PLT) activation is the keystone of atherothrombosis and depends on many dysregulated elements, including endothelial dysfunction, oxidized lipoproteins, and immune response. Besides the classical view of PLT as an effector of hemostatic response, a new repertoire of PLT activities is emerging. PLT lipidome oxidation is a self-maintaining process which promotes PLT reactivity, coagulation cascade, and inflammatory cell activation. PLT-innate immune cell interaction is also sustained by neutrophil extracellular traps and NLRP3 inflammasome pathways. Other noteworthy emerging mechanisms are implicated in the crosstalk between PLT and surrounding cells. Especially, microvesicles (MVs) released from PLT may extend their signaling network far beyond the classical cell-cell interactions. Moreover, the recognition of noncoding RNA in PLT MVs introduce another layer of complexity in terms of intercellular signaling by a direct regulation of messenger RNA profile and gene expression in the recipient cells. The aim of this narrative review is to update the recent advance in CT and intracoronary stent thrombosis, including causal factors and potential translation of experimental evidence into the clinical setting.

Enzyme Prodrug Therapy Achieves Site-Specific, Personalized Physiological Responses to the Locally Produced Nitric Oxide

Nitric oxide (NO) is a highly potent but short-lived endogenous radical with a wide spectrum of physiological activities. In this work, we developed an enzymatic approach to the site-specific synthesis of NO mediated by biocatalytic surface coatings. Multilayered polyelectrolyte films were optimized as host compartments for the immobilized β-galactosidase (β-Gal) enzyme through a screen of eight polycations and eight polyanions. The lead composition was used to achieve localized production of NO through the addition of β-Gal-NONOate, a prodrug that releases NO following enzymatic bioconversion. The resulting coatings afforded physiologically relevant flux of NO matching that of the healthy human endothelium. The antiproliferative effect due to the synthesized NO in cell culture was site-specific: within a multiwell dish with freely shared media and nutrients, a 10-fold inhibition of cell growth was achieved on top of the biocatalytic coatings compared to the immediately adjacent enzyme-free microwells. The physiological effect of NO produced via the enzyme prodrug therapy was validated ex vivo in isolated arteries through the measurement of vasodilation. Biocatalytic coatings were deposited on wires produced using alloys used in clinical practice and successfully mediated a NONOate concentration-dependent vasodilation in the small arteries of rats. The results of this study present an exciting opportunity to manufacture implantable biomaterials with physiological responses controlled to the desired level for personalized treatment.

Defining drug and target protein distributions after stent-based drug release: Durable versus deployable coatings

BACKGROUND

Innovations in drug eluting stent designs make it increasingly important to develop models for differentiating performance through spatial definition of drug, receptor binding and cell state.

METHODS

Two designs of sirolimus analog eluting stents were implanted into porcine coronary arteries for 28, 60 or 90 days (n = 9/time point), durable coating (Xience) and deployable absorbable coating (MiStent). Explanted arteries were evaluated for drug content (n = 3/time point) by LC-MS/MS and for drug and target protein (mTOR) distributions by immunofluorescence (IF, n = 6/time point). A computational model was developed to predict drug release and arterial distribution maps.

RESULTS

Both stents released the majority of drug load by 28 days, with different tissue retention efficiencies (91.4 ± 4.9% MiStent versus 21.5 ± 1.9% Xience, P < 0.001). Computational modeling of MiStent coating deployment and microcrystal dissolution recapitulated in vivo drug release and net tissue content and predicted that >98.5% of deployed drug remains crystalline through 90 days. Immunofluorescence and computational modeling showed peristrut drug localization for both stents, with similar peaks, but high interstrut levels only at sites of coating deployment from the absorbable coating. Co-localization of mTOR-IF with drug-IF for both devices showed persistent drug effects, though with differential drug-receptor pharmacokinetics.

CONCLUSIONS

Immunofluorescence and computational modeling provide insights into drug distribution and binding status that can help differentiate drug delivery technologies. Herein we found that tissue deployment of slow dissolving crystalline drug particles results in temporally and spatially more uniform drug delivery to interstrut zones that might otherwise be under-dosed without excess peristrut drug.