Plaque rupture, usually of a precursor lesion known as a 'vulnerable plaque' or 'thin-cap fibroatheroma', is the leading cause of thrombosis. Less-frequent aetiologies of coronary thrombosis are ...erosion, observed with greatest incidence in women aged <50 years, and eruptive calcified nodules, which are occasionally identified in older individuals. Various treatments for patients with coronary artery disease, such as CABG surgery and interventional therapies, have led to accelerated atherosclerosis. These processes occur within months to years, compared with the decades that it generally takes for native disease to develop. Morphological identifiers of accelerated atherosclerosis include macrophage-derived foam cells, intraplaque haemorrhage, and thin fibrous cap. Foam-cell infiltration can be observed within 1 year of a saphenous vein graft implantation, with subsequent necrotic core formation and rupture ensuing after 7 years in over one-third of patients. Neoatherosclerosis occurs early and with greater prevalence in drug-eluting stents than in bare-metal stents and, although rare, complications of late stent thrombosis from rupture are associated with high mortality. Comparison of lesion progression in native atherosclerotic disease, atherosclerosis in saphenous vein grafts, and in-stent neoatherosclerosis provides insight into the pathogenesis of atheroma formation in natural and iatrogenic settings.
Development of functional nanoparticles can be encumbered by unanticipated material properties and biological events, which can affect nanoparticle effectiveness in complex, physiologically relevant ...systems. Despite the advances in bottom-up nanoengineering and surface chemistry, reductionist functionalization approaches remain inadequate in replicating the complex interfaces present in nature and cannot avoid exposure of foreign materials. Here we report on the preparation of polymeric nanoparticles enclosed in the plasma membrane of human platelets, which are a unique population of cellular fragments that adhere to a variety of disease-relevant substrates. The resulting nanoparticles possess a right-side-out unilamellar membrane coating functionalized with immunomodulatory and adhesion antigens associated with platelets. Compared to uncoated particles, the platelet membrane-cloaked nanoparticles have reduced cellular uptake by macrophage-like cells and lack particle-induced complement activation in autologous human plasma. The cloaked nanoparticles also display platelet-mimicking properties such as selective adhesion to damaged human and rodent vasculatures as well as enhanced binding to platelet-adhering pathogens. In an experimental rat model of coronary restenosis and a mouse model of systemic bacterial infection, docetaxel and vancomycin, respectively, show enhanced therapeutic efficacy when delivered by the platelet-mimetic nanoparticles. The multifaceted biointerfacing enabled by the platelet membrane cloaking method provides a new approach in developing functional nanoparticles for disease-targeted delivery.
Local hemodynamic forces are well-known to modulate atherosclerotic evolution, which remains one of the largest cause of death worldwide. Percutaneous coronary interventions with stent implantation ...restores blood flow to the downstream myocardium and is only limited by stent failure caused by restenosis, stent thrombosis, or neoatherosclerosis. Cumulative evidence has shown that local hemodynamic forces affect restenosis and the platelet activation process, modulating the pathophysiological mechanisms that lead to stent failure. This article first covers the pathophysiological mechanisms through which wall shear stress regulates arterial disease formation/neointima proliferation and the role of shear rate on stent thrombosis. Subsequently, the article reviews the current evidence on (1) the implications of stent design on the local hemodynamic forces, and (2) how stent/scaffold expansion can influence local flow, thereby affecting the risk of adverse events.
Despite advances in stent technology for vascular interventions, in-stent restenosis (ISR) because of myointimal hyperplasia remains a major complication.
We investigated the regulatory role of ...microRNAs in myointimal hyperplasia/ISR, using a humanized animal model in which balloon-injured human internal mammary arteries with or without stenting were transplanted into Rowett nude rats, followed by microRNA profiling. miR-21 was the only significantly upregulated candidate. In addition, miR-21 expression was increased in human tissue samples from patients with ISR compared with coronary artery disease specimen. We systemically repressed miR-21 via intravenous fluorescein-tagged-locked nucleic acid-anti-miR-21 (anti-21) in our humanized myointimal hyperplasia model. As expected, suppression of vascular miR-21 correlated dose dependently with reduced luminal obliteration. Furthermore, anti-21 did not impede reendothelialization. However, systemic anti-miR-21 had substantial off-target effects, lowering miR-21 expression in liver, heart, lung, and kidney with concomitant increase in serum creatinine levels. We therefore assessed the feasibility of local miR-21 suppression using anti-21-coated stents. Compared with bare-metal stents, anti-21-coated stents effectively reduced ISR, whereas no significant off-target effects could be observed.
This study demonstrates the efficacy of an anti-miR-coated stent for the reduction of ISR.
The aim of this study was to compare neointimal modification with scoring balloon pre-dilation before drug-coated balloon (DCB) versus DCB standard therapy in patients presenting with drug-eluting ...stent (DES) restenosis.
DCB angioplasty for the treatment of coronary drug-eluting stent restenosis has demonstrated encouraging results. The efficacy of DCB treatment relies on rapid initial drug transfer and tissue retention of the antiproliferative drug. Neointimal modification with scoring balloon pre-dilation may enhance the efficacy of DCB therapy.
In this randomized, open-label, active-controlled trial, 252 patients with clinically significant DES restenosis were enrolled at 4 centers in Germany. Patients undergoing DCB angioplasty were randomly assigned to treatment with scoring balloon pre-dilation or standard therapy. The primary endpoint of the study was in-segment percentage diameter stenosis on 6- to 8-month follow-up angiography. The secondary endpoints included binary angiographic restenosis and late lumen loss on follow-up angiography, the combined incidence of death or myocardial infarction, target lesion revascularization, and target lesion thrombosis at 1 year.
Follow-up angiographic data at 6 to 8 months were available for 203 patients (80.6%). Scoring balloon pre-dilation compared with standard therapy showed significantly lower rates with respect to the primary endpoint (35.0 ± 16.8% vs. 40.4 ± 21.4%; p = 0.047) and binary angiographic restenosis (18.5% vs. 32.0%; p = 0.026). Late lumen loss was numerically lower after scoring balloon pre-dilation compared with standard therapy (0.31 ± 59 mm vs. 0.41 ± 0.74 mm; p = 0.27). There was no difference between the groups in the incidence of death or myocardial infarction (4.0% vs. 3.4%; p = 0.73). Scoring balloon versus standard therapy showed comparable rates of target lesion revascularization (16.2% vs. 21.8%; p = 0.26). No target lesion thrombosis occurred out to 1 year.
In patients presenting with drug-eluting stent restenosis, neointimal modification with scoring balloon improves the antirestenotic efficacy of DCB therapy. (Intracoronary Stenting and Angiographic Results: Optimizing Treatment of Drug Eluting Stent In-Stent Restenosis 4 ISAR-DESIRE 4; NCT01632371).
Recent reports suggest an elevated incidence of bioresorbable vascular scaffold (BVS) thrombosis (scaffold thrombosis ScT).
This study investigated occurrence rates, clinical and angiographic ...characteristics, and possible mechanisms of ScT in all-comer patients undergoing BVS implantation at 2 German and 2 Swiss hospitals.
A total of 1,305 consecutive patients (mean age 64 years, 78% male) who received 1,870 BVS (mean 1.4 ± 0.8 BVS/patient) were enrolled. Clinical/procedural characteristics, mortality, and ScT data at 485 days (range 312 to 652 days) were examined.
ScT occurred in 42 patients. The incidence of probable and definite ScT was 1.8% at 30 days and 3.0% at 12 months, without differences among centers (p = 0.60). A total of 22 (52%) ScTs presented as ST-segment elevation myocardial infarction and 6 (17%) as sudden cardiac death. In multivariable analysis, ostial lesions (p = 0.049) and impaired left ventricular ejection fraction (p = 0.019) were independently associated with ScT. Nine (21%) of the ScTs occurred in patients who had suspended dual antiplatelet therapy, in 6 cases prematurely. Lower post-procedural minimum lumen and reference vessel diameters were hallmarks of ScT (all p < 0.0001). The risk of ScT appeared to rapidly increase for post-procedural minimum lumen diameters below 2.4 mm (for the 2.5- to 3.0-mm BVS) and 2.8 mm (for the 3.5-mm BVS). When a BVS-specific implantation strategy was implemented, 12-month ScT rates fell from 3.3% to 1.0%, an effect that remained significant when adjusted for multivariable propensity score (p = 0.012; hazard ratio: 0.19; 95% confidence interval: 0.05 to 0.70).
The 12-month incidence of ScT reached 3% and could be significantly reduced when an optimized implantation strategy was employed. (retrospective multicentric registry and Mainz Intracoronary Database. The Coronary Slow-flow and Microvascular Diseases Registry MICAT; NCT02180178).
Abstract
Coronary artery disease (CAD) remains one of the most important causes of morbidity and mortality worldwide, and the availability of percutaneous or surgical revascularization procedures ...significantly improves survival. However, both strategies are daunted by complications which limit long-term effectiveness. In-stent restenosis (ISR) is a major drawback for intracoronary stenting, while graft failure is the limiting factor for coronary artery bypass graft surgery (CABG), especially using veins. Conversely, internal thoracic artery (ITA) is known to maintain long-term patency in CABG. Understanding the biology and pathophysiology of ISR and vein graft failure (VGF) and mechanisms behind ITA resistance to failure is crucial to combat these complications in CAD treatment. This review intends to provide an overview of the biological mechanisms underlying stent and VGF and of the potential therapeutic strategy to prevent these complications. Interestingly, despite being different modalities of revascularization, mechanisms of failure of stent and saphenous vein grafts are very similar from the biological standpoint.
The currently recommended duration of dual antiplatelet therapy (DAPT) in drug-eluting stent (DES) recipients is 12 months to reduce the risk of late stent thrombosis, particularly in those with ...acute coronary syndrome (ACS).
This study hypothesized that antiplatelet treatment with DAPT for 6 months may be noninferior to 24-month DAPT in aspirin-sensitive patients.
A multicenter, randomized study assigned patients undergoing implantation of everolimus-eluting stents with confirmed nonresistance to aspirin to receive 6- or 24-month DAPT. The primary endpoint was a composite of death, myocardial infarction, urgent target vessel revascularization, stroke, and major bleeding at 12 months post-stenting.
A total of 2,031 patients were enrolled in 70 European and Middle Eastern centers. The trial was prematurely terminated due to recruitment problems, leaving 941 patients randomized to 24-month DAPT and 953 to 6-month DAPT. The 2 treatment groups had similar baseline and procedural characteristics. There was no significant difference in the primary endpoint (24-month: 1.5% vs. 6-month: 1.6%; p = 0.85). Noninferiority was demonstrated for 6- versus 24-month DAPT, with an absolute risk difference of 0.11% (95% confidence interval: -1.04% to 1.26%; p for noninferiority = 0.0002). There were no significant differences in stent thrombosis or bleeding complications. In the 792 (44%) high-risk patients with ACS, primary and secondary endpoints did not significantly differ (hazard ratio: 1.7 95% confidence interval: 0.519 to 6.057; p = 0.361).
Rates of bleeding and thrombotic events were not significantly different according to 6- versus 24-month DAPT after PCI with new-generation DES in good aspirin responders. (Is There A LIfe for DES After Discontinuation of Clopidogrel ITALICplus; NCT01476020).
Clinical trials have demonstrated that the second-generation cobalt-chromium everolimus-eluting stent (CoCr-EES) is superior to the first-generation paclitaxel-eluting stent (PES) and is noninferior ...or superior to the sirolimus-eluting stent (SES) in terms of safety and efficacy. It remains unclear whether vascular responses to CoCr-EES are different from those to SES and PES because the pathology of CoCr-EES has not been described in humans.
A total of 204 lesions (SES=73; PES=85; CoCr-EES=46) from 149 autopsy cases with duration of implantation >30 days and ≤3 years were pathologically analyzed, and comparison of vascular responses was corrected for duration of implantation. The observed frequency of late and very late stent thrombosis was less in CoCr-EES (4%) versus SES (21%; P=0.029) and PES (26%; P=0.008). Neointimal thickness was comparable among the groups, whereas the percentage of uncovered struts was strikingly lower in CoCr-EES (median=2.6%) versus SES (18.0%; P<0.0005) and PES (18.7%; P<0.0005). CoCr-EES showed a lower inflammation score (with no hypersensitivity) and less fibrin deposition versus SES and PES. The observed frequency of neoatherosclerosis, however, did not differ significantly among the groups (CoCr-EES=29%; SES=35%; PES=19%). CoCr-EES had the least frequency of stent fracture (CoCr-EES=13%; SES=40%; PES=19%; P=0.007 for CoCr-EES versus SES), whereas fracture-related restenosis or thrombosis was comparable among the groups (CoCr-EES=6.5%; SES=5.5%; PES=1.2%).
CoCr-EES demonstrated greater strut coverage with less inflammation, less fibrin deposition, and less late and very late stent thrombosis compared with SES and PES in human autopsy analysis. Nevertheless, the observed frequencies of neoatherosclerosis and fracture-related adverse pathological events were comparable in these devices, indicating that careful long-term follow-up remains important even after CoCr-EES placement.
This study examined whether coronary angioscopy-verified in-stent yellow plaque at 1 year after drug-eluting stent (DES) implantation is associated with future event of very late stent failure ...(VLSF).
Atherosclerosis detected as yellow plaque by angioscopy has been associated with future events of acute coronary syndrome. Development of in-stent neoatherosclerosis is a probable mechanism of VLSF.
This study included 360 consecutive patients who received successful angioscopic examination at 1 year after implantation of a DES. They were clinically followed up for VLSF defined as cardiac death, acute myocardial infarction or unstable angina, or need for revascularization associated with the stent site.
The follow-up interval was 1,558 ± 890 days (4.3 ± 2.4 years). The incidence of VLSF was significantly higher in the patients with yellow plaque than in those without (8.1% vs. 1.6%; log rank p = 0.02). Multivariable analysis revealed the presence of yellow plaque (hazard ratio HR: 5.38; p = 0.02) and absence of statin therapy (HR: 3.25; p = 0.02) as risks of VLSF.
In-stent atherosclerosis evaluated by yellow plaque at 1 year after the implantation of DES and the absence of statin therapy were risks of VLSF. The underlying mechanism of VLSF appeared to be the progression of atherosclerosis as demonstrated by the yellow plaque.
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