Performance Of Drug-eluting Stents Research Articles

Investigation of Drug Eluting Stents performance in human atherosclerotic artery through in silico modeling.

Atherosclerosis is a chronic inflammatory disease associated with heart attack and stroke. It causes the growth of atherosclerotic plaques inside the arterial vessels, which in turn results to the reduction of the blood flow to the different organs. Drug-Eluting Stents (DES) are mesh-like wires, carrying pharmaceutical coating, designed to dilate and support the arterial vessel, restore blood flow and through the controlled local drug delivery inhibit neo-intimal thickening. In silico modeling is an efficient method of accurately predicting and assessing the performance of the stenting procedure. The present in silico study investigates the performance of two different stents (Bare Metal Stent, Drug-Eluting Stent) in a patient-specific coronary artery and assesses the effect of stent coating, considering that the same procedural approach is followed by the interventional cardiologist. The results demonstrate that even if small differences are obtained in the two models, the incorporation of the stent coatings (in DES) does not significantly affect the outcomes of the stent deployment, the stresses and strains in the scaffold and the arterial tissue. Nevertheless, it is suggested that regarding the DES expansion, higher pressure should be applied at the inner surface of the stent.

TCT-585 Drug Eluting Stent With Bioresorbable Polymer For Chronic Total Occlusion: 1 Year Outcomes From e-NOBORI Registry

Chronic total occlusion (CTO) recanalization is still a very challenging topic in the field of coronary intervention. Data on the performance of drug eluting stent (DES) with bioresorbable polymer in CTO are limited. The aim of our study is to assess 1-year clinical outcomes in CTO lesion management

Randomized comparison between polymer-free versus polymer-based paclitaxel-eluting stent: two-year final clinical results.

Most drug-eluting stents currently in use are coated with a polymer carrying the drug that is released for several weeks. However, a durable polymer may provoke hypersensitive reaction, delayed artery healing, and eventually stent thrombosis. The aim of this study was to investigate the safety and efficacy of a polymer-free paclitaxel-eluting stent (PF-PES) versus a polymer-based PES (PB-PES). Eligible patients undergoing percutaneous coronary intervention were randomized 1:1 to receive either PF-PES or PB-PES. The primary end point was late loss at 9 months. Intravascular ultrasound analysis at 9 months and final 2-year clinical follow-up were also performed. From October 2007 to April 2009, 164 patients were enrolled and randomized into 2 groups (PF-PES: n = 84; PB-PES: n = 80). Mean in-stent lumen loss was 0.90 ± 0.59 mm for PF-PES and 0.49 ± 0.52 mm for PB-PES (P < 0.001). Mean neointimal area by intravascular ultrasound was higher in PF-PES than in PB-PES (1.42 ± 1.09 versus 0.51 ± 0.61 mm(2); P < 0.001). At 2 years, a composite end point of all-cause death, any myocardial infarction, and target vessel revascularization occurred in 36.9% for PF-PES and 16.3% for PB-PES (P = 0.004), mainly driven by a higher rate of target vessel revascularization (PF-PES: 35.7%; PB-PES: 13.8%; P = 0.001). One late stent thrombosis was observed in PF-PES. Compared with PB-PES, PF-PES was associated with increased neointimal proliferation and subsequent clinical restenosis. Polymer plays an essential role in the performance of drug-eluting stents. http://www.clinicaltrials.gov. Unique identifier: NCT01375855.

Modeling the transport of drugs eluted from stents: physical phenomena driving drug distribution in the arterial wall

Despite recent data that suggest that the overall performance of drug-eluting stents (DES) is superior to that of bare-metal stents, the long-term safety and efficacy of DES remain controversial. The risk of late stent thrombosis associated with the use of DES has also motivated the development of a new and promising treatment option in recent years, namely drug-coated balloons (DCB). Contrary to DES where the drug of choice is typically sirolimus and its derivatives, DCB use paclitaxel since the use of sirolimus does not appear to lead to satisfactory results. Since both sirolimus and paclitaxel are highly lipophilic drugs with similar transport properties, the reason for the success of paclitaxel but not sirolimus in DCB remains unclear. Computational models of the transport of drugs eluted from DES or DCB within the arterial wall promise to enhance our understanding of the performance of these devices. The present study develops a computational model of the transport of the two drugs paclitaxel and sirolimus eluted from DES in the arterial wall. The model takes into account the multilayered structure of the arterial wall and incorporates a reversible binding model to describe drug interactions with the constituents of the arterial wall. The present results demonstrate that the transport of paclitaxel in the arterial wall is dominated by convection while the transport of sirolimus is dominated by the binding process. These marked differences suggest that drug release kinetics of DES should be tailored to the type of drug used.

Carrier free rapamycin loaded drug eluting stent: In vitro and in vivo evaluation

In the search for improving the performance of drug eluting stent (DES) various developments are in progress worldwide including use of carrier free DES, use of biodegradable polymers, biodegradable stents etc. In this work, carrier free-rapamycin (RM) coated DES has been prepared, and evaluated by in vitro and in vivo procedures necessary for clinical development. In vitro drug release from the developed stents was carried in different release media, normal saline–isopropanol (NS-IP), phosphate buffer (PB), phosphate buffer saline (PBS) and in human plasma. Simultaneously, drug released at site of implantation and biocompatibility of developed stents was determined after subcutaneous implantation in the SD rats. Developed stent coating method enables fabrication of controllable and homogeneous crystalline RM coatings on stent scaffolds. Continuous release of RM was observed in different release conditions with different release rate, maximum in NS-IP and least in PB. Similarly, after subcutaneous implantation of these stents, RM was found in surrounding tissues and in implanted stent up to 28days. Biocompatibility studies showed no evidence for presence of necrosis, foreign body giant cell reaction or any type of increased severity of inflammatory reaction, proving potential of developed stents for further clinical development.

Bioelectronics meets nanomedicine for cardiovascular implants: PEDOT-based nanocoatings for tissue regeneration

BackgroundAn exciting direction in nanomedicine would be to analyze how living cells respond to conducting polymers. Their application for tissue regeneration may advance the performance of drug eluting stents by addressing the delayed stent re-endothelialization and late stent thrombosis. MethodsThe suitability of poly (3, 4-ethylenedioxythiophene) (PEDOT) thin films for stents to promote cell adhesion and proliferation is tested in correlation with doping and physicochemical properties. PEDOT doped either with poly (styrenesulfonate) (PSS) or tosylate anion (TOS) was used for films' fabrication by spin coating and vapor phase polymerization respectively. PEGylation of PEDOT: TOS for reduced immunogenicity and biofunctionalization of PEDOT: PSS with RGD peptides for induced cell proliferation was further applied. Atomic Force Microscopy and Spectroscopic Ellipsometry were implemented for nanotopographical, structural, optical and conductivity measurements in parallel with wettability and protein adsorption studies. Direct and extract testing of cell viability and proliferation of L929 fibroblasts on PEDOT samples by MTT assay in line with SEM studies follow. ResultsAll PEDOT thin films are cytocompatible and promote human serum albumin adsorption. PEDOT:TOS films were found superior regarding cell adhesion as compared to controls. Their nanotopography and hydrophilicity are significant factors that influence cytocompatibility. PEGylation of PEDOT:TOS increases their conductivity and hydrophilicity with similar results on cell viability with bare PEDOT:TOS. The biofunctionalized PEDOT:PSS thin films show enhanced cell proliferation. ConclusionsThe application of PEDOT polymers has evolved as a new perspective to advance stents. General significanceIn this work, nanomedicine involving nanotools and novel nanomaterials merges with bioelectronics to stimulate tissue regeneration for cardiovascular implants. This article is part of a Special Issue entitled Organic Bioelectronics — Novel Applications in Biomedicine.

Regarding “Clinical performance of drug-eluting stents with biodegradable polymeric coating: a meta-analysis and systematic review”

Regarding “Clinical performance of drug-eluting stents with biodegradable polymeric coating: a meta-analysis and systematic review”

The Role of Stent Design and Polymers in Safety Outcomes – A Review

Each component of a drug-eluting stent (DES) contributes to the safety of the device. Continuous efforts are being dedicated to the search of the optimal compromise between facility of use, safety and long-term efficacy. Shorter balloons reduce the vascular trauma beyond the stent struts; the metallic composition of the stent platform and the platform itself interact with the vascular wall in a long-lasting equilibrium between radial force, vessel patency and reparative cellular regrowth. The modality of drug elution is largely regulated by the chosen drug carrier, rather than by the chemical properties of the drug itself. Drug elution can be accomplished by permanent polymers that remain in the vessel wall forever, by biodegradable polymers that leave the naked metallic structure behind after their complete absorption, or even by direct release of the drug from stent reservoirs. The clinical performance of DESs has been exhaustively assessed in a large number of studies that have showed rapid and continuous improvements, from the first-generation DESs to the latest devices, based on substantial changes in stent design and polymer composition.

Comparison of sirolimus-eluting and bare metal stent for treatment of patients with total coronary occlusions: results of the GISSOC II-GISE multicentre randomized trial

Percutaneous coronary intervention with bare metal stent (BMS) in chronic total coronary occlusions (CTOs) is associated with a higher rate of angiographic restenosis and reocclusion than that observed in subtotal stenoses. Preliminary reports have suggested a better performance of drug-eluting stents in CTO. In this multicentre, randomized trial, we compared the mid-term angiographic and clinical outcome of sirolimus-eluting stent (SES) or BMS implantation after successful recanalization of CTO. Patients with CTO older than 1 month, after successful recanalization, were randomized to implantation of SES (78 patients) or BMS (74 patients) in 13 Italian centres. Clopidogrel therapy was prescribed for 6 months. The primary endpoint was in-segment minimal luminal diameter (MLD) at 8-month follow-up. Secondary clinical endpoints included death, myocardial infarction (MI), target lesion revascularization (TLR), and target vessel revascularization (TVR) at 24 months. Patients treated with SES showed, at in-segment analysis, a larger MLD (1.98 +/- 0.57 vs. 0.98 +/- 0.80 mm, P < 0.001), a lower late luminal loss (-0.06 +/- 0.49 vs. 1.11 +/- 0.79 mm, P < 0.001), and lower restenosis (9.8 vs. 67.7%, P < 0.001) and reocclusion (0 vs. 17%, P = 0.001) rates. At 24-month follow-up, patients in the SES group experienced fewer major adverse cardiac events (50.0 vs. 17.6%, P < 0.001) mainly due to a lower rate of both TLR (44.9 vs. 8.1%, P < 0.001) and TVR (44.9 vs. 14.9%, P < 0.001). In CTO, SES is markedly superior to BMS in terms of restenosis and reocclusion rate, and incidence of repeat revascularization at 24 months. Clinicaltrials.gov identifier: NCT00220558.

Drug-Eluting Stents Versus Bare-Metal Stents in Diabetic Patients With ST-Segment Elevation Acute Myocardial Infarction: A Pooled Analysis of Individual Patient Data From 7 Randomized Trials

The performance of drug-eluting stents (DESs) in high-risk patients with diabetes and acute ST-elevation myocardial infarction (STEMI) who have undergone primary angioplasty has not been previously studied. The objective was to evaluate the efficacy and safety of DESs in diabetic patients with STEMI. We performed a pooled analysis of individual patient data from seven randomized trials that compared DESs (i.e., sirolimus- or paclitaxel-eluting stents) with bare-metal stents (BMSs) in patients with STEMI. The analysis involved 389 patients with diabetes mellitus from a total of 2476 patients. The outcomes of interest were target-lesion revascularization, stent thrombosis, death and the composite endpoint of death or recurrent myocardial infarction during a follow-up of 12-24 months. Overall, 206 diabetic patients received a DES and 183, a BMS. The risk of target-lesion revascularization was significantly lower in patients treated with a DES compared to those treated with a BMS (hazard ratio [HR] 0.44, 95% confidence interval [CI] 0.23-0.88; P=.02). There was no significant difference in the risk of stent thrombosis between those treated with a DES or a BMS (HR 0.33, 95% CI 0.09-1.13; P=.08). Similarly, the risk of the combined endpoint of death or myocardial infarction was not significantly different between patients treated with a DES or a BMS (HR 0.64, 95% CI 0.36-1.13; P=.12). Compared with BMSs, DES use improved clinical outcomes in diabetic patients undergoing primary angioplasty for STEMI: the need for reintervention was reduced, with no increase in mortality or myocardial infarction.

Performance of Drug-Eluting Stents in Usual Clinical Practice

The comparative performance of paclitaxel- and sirolimus-eluting stents has been difficult to assess, especially among nonselected patients in clinical

Sirolimus-eluting stents in the treatment of chronic total coronary occlusions

We assessed the effectiveness and safety of the sirolimus-eluting stent (SES) in the treatment of chronic total coronary occlusions. Chronic total occlusions (CTO) of coronary vessels have an unacceptable high restenosis rate of approximately 50% after stenting. Few data exist about the performance of drug eluting stents (DES) in the treatment of CTO. All coronary interventions using the Cypher stent performed at 122 centers engaged in the German Cypher registry between April 2002 and December 2004 were analyzed; a total of 5,344 patients; 374 with and 4,970 without CTO were compared. There was no significant difference between both groups regarding demographics, coronary status and left ventricular function. Patients in the CTO group had a higher level of angina symptoms, the coronary lesions were more complex and the stents used were smaller and longer than in the No-CTO group. The In-hospital outcome was similar in both groups, with importantly no difference regarding mortality and complications. Stenting was as successful in the CTO as in the No-CTO group; during a follow-up of 6.6 months we found no significant difference regarding the rate of mortality, complications, and revascularization between both groups. Implantation of the Cypher stent reduces the restenosis rate and seems to be a safe and effective tool for the treatment of chronic total coronary occlusions.

Transition from bare metal to drug eluting stenting in contemporary US practice: Effect on incidence and predictors of clinically driven target lesion revascularization

The performance of drug eluting stents (DES) and impact on every day practice in the USA, where complex, nonselective cases are the rule, remain unknown. The Brigham and Women's Hospital interventional experience in the bare metal stents (BMS) (6/2002 to 2/2003) and after abrupt and near universal adoption of DES (4/2003 to 9/2004) were compared. Demographic, procedural and in-hospital outcomes for all consecutive cases where investigated. Predictors and angiographic characteristics of patients returning for clinically driven target lesion revascularization (TLR) in both eras were analyzed. Of 2,555 DES cases (3,061 lesions, 87.9% Cypher, 12.1% Taxus), 47 underwent TLR during follow-up (68 lesions, 2.2%). Of the 1,731 BMS cases (1,798 lesions), 162 underwent clinically indicated TLR (209 lesions, 11.6%), representing an 81% DES era TLR risk reduction. Multivariate predictors of TLR in the DES era: left main lesion (LM) (odds ratio (OR) 7.65, 95% confidence interval (CI) 3.33-17.53, P<0.01, treatment of restenosis (OR 5.96, CI 3.21-11.08, P<0.01), and diabetes (OR 1.68, CI 0.92-3.04, P=0.07). Predictors of restenosis in the BMS era included additional clinical, lesion, and stent characteristics, while LM lesion was absent. Angiographic patterns of stent restenosis differed in the DES (focal) and BMS (diffuse) era. The transition from BMS to DES in the setting of a large USA hospital practice is safe and associated with significant reduction in clinically driven TLR. Treatment of specific lesions types (repeat restenosis, distal LM) and diabetic patients remain suboptimal and warrant further investigation.

Computational analysis of the performance of drug-eluting stents

Computational analysis of the performance of drug-eluting stents