Scanning electron microscopic analysis of different drug eluting stents after failed implantation: From nearly undamaged to major damaged polymers

Wiemer, Marcus; Butz, Thomas; Schmidt, W. J.; Schmitz, Klaus‐Peter; Horstkotte, Dieter; Langer, C.

doi:10.1002/ccd.22347

Cited by 128 publications

(87 citation statements)

References 40 publications

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“…14 Other concerns with regard to the potential for polymer disruption involve the percutaneous coronary intervention procedure itself. Wiemer et al 54 demonstrated that in DES that had failed to be delivered to the intended implantation site in tortuous calcified lesions, significant damage and cracking of the polymer had occurred to varying extents with multiple types of second-generation DES. Scanning electron microscopy revealed many cases of deep damage to the polymer with exposure of the bare metal, in particular, the Endeavor RX stents showed up to 20% damage to the surface area.…”

Section: Polymer Disruption Peeling and Crackingmentioning

confidence: 99%

Restenosis

Farooq

Gogas

Serruys

2011

Circ: Cardiovascular Interventions

167

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In the past decade, tremendous progress has been made in reducing the incidence of restenosis with the advent of the drug-eluting stent (DES). With "plain old balloon angioplasty," rates of acute and chronic vessel occlusion were unacceptably high at Ϸ30% to 60%, secondary to acute and chronic recoil and constrictive remodeling. The advent of bare-metal stents (BMS) appeared to eliminate the issue of acute and chronic recoil but introduced a new entity, neointimal hyperplasia (NIH), with classical papers unequivocally demonstrating a strong and linear relationship between NIH formation and late lumen loss (LLL). The restenosis rates with BMS were reported to be between 16% and 44%, with higher rates of stenosis attributable to several risk factors, in particular, long lesion length and small vessel caliber. 1 DES were thus conceived as the next step in tackling this iatrogenic entity of NIH, with large-scale reductions in restenosis rates reported at 0% in highly selective lesions and up to 16% in a broader range of patients and lesions with first-generation DES. 1 In contrast to plain old balloon angioplasty and BMS, in which an almost classical gaussian distribution of LLL is seen postprocedurally, the LLL after DES implantation appears to follow a bimodal pattern of distribution ( Figure 1). 2 Despite the significant advances in the technology to reduce DES restenosis, conservative estimates still suggest that the incidence of in-stent restenosis (ISR) requiring target vessel revascularization (TVR), so-called DES failure, to be Ϸ5% to 10%, with one estimate suggesting Ϸ200 000 repeat revascularizations in the United States alone. 3 Whereas the pattern of restenosis in BMS has been shown to be primarily diffuse, with DES it has been demonstrated to be usually focal ( Figure 2) and most commonly located at the proximal DES edge, as demonstrated in Ͼ60% of ISR with either paclitaxel-eluting stent (PES) or sirolimus-eluting stent (SES) implantation. However, over one-fifth of ISR cases remain diffuse, and 10% to 20% are even occlusive. 4 In 2004, the first report of risk factors associated with DES restenosis in patients with the unrestricted use of SES since approval of its CE mark was made by our group. Despite the apparent differences in the distribution of LLL between BMS and DES as previously described, the main message of these and subsequent findings was that the usual patient characteristics, lesion types, and procedural factors incriminated with restenosis in BMS were equally responsible with DES, with diabetes mellitus implicated as one of the strongest risk factors. It should however be emphasized that the "slope" of the distribution of restenosis with DES appears to be much flatter compared with BMS, especially in long lesions and small vessels, highlighting the importance of drug elution in potentially attenuating the NIH response. 3 Histopathologic analyses of in-stent neointima taken by directional atherectomy at the time of reintervention also have been shown to be remarkably similar between BMS ...

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Section: Polymer Disruption Peeling and Crackingmentioning

confidence: 99%

Restenosis

Farooq

Gogas

Serruys

2011

Circ: Cardiovascular Interventions

167

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“…This is supported by the fact that our trial, which included the same rate of diabetic patients and lesion complexity as DELIVER, gave the same results. Increase in lesion complexity may indeed wipe off the drug 28 A preclinical study of DELIVER has also estimated that ≈40% of drug is lost during stent delivery of PF-PES. 11 Cracking drug on stent surface may result in nonuniform local drug distribution with subsequent abnormal neointimal hyperplasia, as observed in DELIVER and in the present trial.…”

Section: Discussionmentioning

confidence: 99%

Randomized Comparison Between Polymer-Free Versus Polymer-Based Paclitaxel-Eluting Stent

Shiratori

Cola

Brugaletta

et al. 2014

Circ: Cardiovascular Interventions

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Background— 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). Methods and Results— 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. Conclusions— 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. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01375855.

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“…27.10 ). The diameter differences were de fi nitely greater than the coating thicknesses, which are in the range of a few microns only [ 25 ] . The larger stent pro fi les, and probably differing friction properties, of DES compared to BMS bear the risk of a decrease in trackability and crossability of the stent systems.…”

Section: Special Parameters Of Desmentioning

confidence: 99%

“…The technical characterization concentrates on potential particle release during stent delivery, expansion, and cyclic loading as well as on the assessment of coating integrity. Surface cracking occurs in many DES during delivery, but to a very different extent [ 25 ] . Even if the study had limitations due to the extraordinary stresses experienced by the stent during failed delivery, the observed coating defects and damages are alarming.…”

Section: Special Parameters Of Desmentioning

confidence: 99%