Stainless Steel Stents Research Articles

Desaturation during Onyx embolization for intracranial arteriovenous malformations

Desaturation during Onyx embolization for intracranial arteriovenous malformations

Valve-in-Valve Implantation Using a Novel Supravalvular Transcatheter Aortic Valve: Proof of Concept

Transcatheter valve implantation within degenerated bioprostheses is a potentially promising treatment for high-risk surgical patients. Clinical experience is limited; however, we have shown in vitro that currently available transcatheter aortic valve sizes did not provide acceptable hemodynamics in small bioprostheses. The objective of this study was to develop a new transcatheter valve that would provide good hemodynamics within degenerated bioprostheses. Supravalvular transcatheter valves were created using a Dacron covered stainless steel stent at the base and trileaflet pericardial leaflets in an open stent above the bioprosthesis. The transcatheter valves were implanted within 19-, 21-, and 23-mm Carpentier-Edwards Perimount bioprostheses with simulated degeneration using BioGlue to achieve a mean pressure gradient of 50 mm Hg. Hemodynamics of valve-in-valve implantation were studied in a pulse duplicator. Supravalvular transcatheter valves successfully relieved bioprosthetic stenosis. Acceptable hemodynamics were achieved with a significant reduction in mean pressure gradient of 54.0 +/- 3.5 to 9.2 +/- 6.3 mm Hg in 23-mm bioprostheses (p < 0.001), from 49.3 +/- 3.1 to 14.4 +/- 4.7 mmHg (p < 0.001) in 21 mm, and from 53.9 +/- 3.8 to 28.3 +/- 9.8 mm Hg (p = 0.013) in 19-mm bioprostheses. Effective orifice area after valve-in-valve implantation increased significantly and was comparable to rereplacement with the same size bioprosthesis. Valve-in-valve implantation was performed using a novel supravalvular transcatheter valve, which successfully relieved bioprosthetic stenosis. The hemodynamics were comparable with standard surgical valve replacement. Further studies are required to assess device safety and efficacy in patients.

In vitro comparison of different carotid artery stents: a pixel-by-pixel analysis using CT angiography and contrast-enhanced MR angiography at 1.5 and 3 T

CT angiography (CTA) and MR angiography (MRA) are increasingly used methods for evaluation of stented vessel segments. The purpose of this study was to compare CTA, contrast-enhanced MRA (CEMRA) at 1.5 T, and CEMRA at 3 T for the visualization of carotid artery stents and to define the best noninvasive imaging technique for each stent. CTA and CEMRA appearances of 18 carotid artery stents of different designs and sizes (4.0 to 10.0 mm) were investigated in vitro. The profile of the contrast-to-noise ratio (CNR) of the lumen of each stent was calculated semiautomatically by a pixel-by-pixel analysis using the medical imaging software OSIRIS. For each stent, artificial lumen narrowing (ALN) was calculated. In all but one stents, ALN was lower on CEMRA at 3 T than at 1.5 T. With CEMRA at 3 T and at 1.5 T, ALN in most nitinol stents was lower than in the groups of stainless steel and cobalt alloy stents. In most nitinol stents, ALN on CEMRA at 3 T was lower than on CTA. In all stainless steel stents and cobalt alloy stents, ALN was lower on CTA than on CEMRA. With CTA and CEMRA, in most stents ALN decreased with increasing stent diameter. CTA and CEMRA evaluation of vessel patency after stent placement is possible, but considerably impaired by ALN. Investigators should be informed about the method of choice for every stent.

Poly(methyl methacrylate) Grafting onto Stainless Steel Surfaces: Application to Drug-Eluting Stents

Drug-eluting stents (DESs) have been associated with adverse clinical effects. Moreover, recent publications have shown that the coating of DESs suffers from defects. The purpose of this contribution is to examine a three-step process for surface modification as a means of improving the durability of DESs. In the first step, 4-(2-bromoethyl)benzenediazonium tetrafluoroborate was electrografted onto a stainless steel (SS) stent. X-ray photoelectron spectroscopy (XPS) of the modified stent confirmed the formation of the organic layer. In the second step, methyl methacrylate was polymerized onto the grafted surface by atom-transfer radical polymerization. XPS, electrochemical impedance spectroscopy, and contact-angle measurements were used to characterize the polymer brushes. The last step involved spray-coating of the stent with a drug-in-polymer matrix [poly(n-butyl methacrylate)/poly(ethylene-co-vinyl acetate) + paclitaxel]. Scanning electron microscopy confirmed the considerably improved durability of the drug-in-polymer matrix. Bare controls showed greater cracking and delamination of the coating than did the two-step modified stents after incubation under physiological (37 degrees C) and accelerated (60 degrees C) conditions. Finally, paclitaxel controlled release from the modified SS DESs was moderate compared with that of nontreated samples. In conclusion, the proposed method significantly improves the durability of drug-in-polymer matrixes on a SS DESs.

The role of vessel geometry and material properties on the mechanics of stenting in the coronary and peripheral arteries

There have been notably higher rates of restenosis with stents used to restore blood flow to many stenosed peripheral arteries compared with their coronary counterparts. The mechanical environment of arteries such as the femoral and popliteal (and the stent fracture that this can cause) has previously been identified as a contributing factor to the relatively low success rates for this procedure. The aim of this study was to investigate how other factors, namely the differences in geometries and mechanical properties of the arteries and the stents used in them, might influence the outcome in these different arteries. Finite element models of the stents and arteries were created, and the results compared in terms of stresses induced in the arteries, the lumen gain, and the deformation of the stent due to pulsatile loading. It was found that deploying a Nitinol stent in a peripheral artery induced lower stresses in the vessel wall than expanding a stainless steel stent in a coronary artery, although the lumen gain was also lower. The predicted strain amplitude induced in Nitinol stents by the cardiac cycle was below the value required to cause fatigue failure. This study does not provide any evidence to suggest that differences in the geometry and material properties between peripheral and coronary arteries, or the types of stent used to restore vessel patency, are the dominate factors responsible for the higher rates of restenosis observed in peripheral arteries.

Nitinol stenting improves primary patency of the superficial femoral artery after percutaneous transluminal angioplasty in hemodialysis patients: A propensity-matched analysis

Although percutaneous transluminal angioplasty (PTA) has become a common therapeutic standard for peripheral artery disease (PAD), high restenosis rates in the superficial femoral artery (SFA) remain a major problem. Nitinol stent implantation is reported to reduce restenosis in SFA after PTA in the general population; however, little is known about whether the nitinol stent improves primary patency after PTA in hemodialysis patients who are at higher risk of revascularization failure. The aim of this study was to clarify the effects of nitinol stent implantation for primary patency in SFA after PTA in hemodialysis patients with PAD. Eighty consecutive hemodialysis patients (167 SFA lesions) who underwent PTA with nitinol stents from January 2006 to January 2008 were compared with 64 hemodialysis patients (128 SFA lesions) who received stainless steel stents in the preceding 2 years. In the follow-up study to 2 years, incidence of restenosis, amputation, and all-cause mortality were analyzed. End points between the groups were examined with the Kaplan-Meier and log-rank methods. Prognostic values for end points were calculated by a Cox univariate analysis and Cox multivariable regression models. To statistically minimize the differences in each stent group, a propensity-matched analysis was also performed using the model including male gender, age, diabetes, hypertension, hyperlipidemia, smoking, incidence of ulcer/gangrene, and TransAtlantic Inter-Society Consensus (TASC) type C+D. The 2-year primary patency rate was 58% in the nitinol group vs 42% in the stainless steel group (hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.39-0.84; P = .0045), despite a higher prevalence of TASC C+D lesion in the nitinol group (68% vs 49%, P = .0014). In 108 lesions matched after propensity score analysis, the primary patency for 2 years was 64% in the nitinol group vs 42% in the stainless steel group (HR, 0.39; 95% CI, 0.24-0.65; P = .0003). Cox multivariate models showed nitinol stent (HR, 0.42; 95% CI, 0.25-0.73; P = .002), age (HR, 1.04; 95% CI, 1.01-1.08; P = .031), and incidence of ulcer/gangrene (HR, 2.35; 95% CI, 1.17-4.75; P = .017) were independent predictors of restenosis. These data suggest that nitinol stent implantation improves primary patency in SFA after PTA compared with the stainless steel stent, even in hemodialysis patients with PAD.

Carotid Artery Stents: In Vitro Comparison of Different Stent Designs and Sizes Using CT Angiography and Contrast-Enhanced MR Angiography at 1.5T and 3T

CT angiography (CTA) and MR angiography (MRA) are increasingly used methods for evaluation of stented vessel segments. Our aim was to compare CTA, contrast-enhanced MRA (CE-MRA) at 1.5T, and CE-MRA at 3T for the visualization of carotid artery stents and to define the best noninvasive imaging technique as an alternative to conventional angiography for each stent. CTA and CE-MRA appearances of 18 carotid artery stents of different designs and sizes (4.0 to 10.0 mm) were investigated in vitro. For each stent, artificial lumen narrowing (ALN) was calculated. With CE-MRA at 3T and at 1.5T, ALN in most nitinol stents was lower than that in the groups of stainless steel and cobalt alloy stents. In most nitinol stents and in both cobalt alloy stents, ALN was lower on CE-MRA at 3T than at 1.5T. In all stainless steel stents, ALN was lower on CTA than on CE-MRA. With CTA and CE-MRA, in most stents ALN decreased with increasing stent diameter. CTA and CE-MRA evaluation of vessel patency after stent placement is possible but is considerably impaired by ALN. Investigators should be informed about the method of choice for every stent. Stent manufacturers should be aware of potential artifacts caused by their stents during noninvasive diagnostic methods such as CTA and CE-MRA.

Resultados clínicos iniciais do primeiro stent de cromo-cobalto concebido no Brasil

Initial Clinical Results of the First Cobalt-Chromium Stent Designed in Brazil Background: Thin-strut cobalt-chromium stents have greater flexibility and probably have less neointimal proliferation than stainless steel stents. Methods: The Cronus (Scitech Produtos Medicos, Goiânia, Brazil) registry is an international, non-randomized, prospective study designed to evaluate the efficacy and safety of a novel thin-strut cobalt-chromium stent in patients with coronary artery disease. A total of 69 lesions were treated in 53 patients included in this analysis. Results: The device success was 98.5%. Mean late luminal loss was 0.7 ± 0.5 mm, binary restenosis occurred in 15% and target vessel revascularization in 11.3% of the cases. The incidence of major adverse cardiac events (death, myocardial infarction or target vessel revascularization) was 24.4% after 317 ± 80 days of follow-up. Conclusion: Our initial results demonstrate that the novel Cronus stent proved to be safe and effective, with clinical results similar to other available thin-strut stents. DESCRIPTORS: Stents. Angioplasty, transluminal, percutaneous coronary. Prostheses and implants.

Quantificação volumétrica da hiperplasia neointimal em artérias ilíacas após implante de suporte intravascular metálico

OBJETIVO: Quantificar a hiperplasia neointimal em artérias ilíacas após stent, correlacionando fatores clínicos, arteriais e materiais dos stents. MATERIAIS E MÉTODOS: De junho de 2003 a agosto de 2005, 60 pacientes realizaram angioplastia transluminal percutânea e stent. Desses, 30 foram reestudados com ultrassonografia intravascular. Os dados foram analisados no laboratório de análise quantitativa. RESULTA-DOS: Dezesseis pacientes eram do sexo masculino (53,3%) e 14 (46,7%), do sexo feminino. A média de idade foi de 60,3 anos. Apresentaram hipertensão arterial 22 pacientes (73,3%), tabagismo, 18 (62,1%), hiperlipidemia, 20 (66,7%), e diabetes, 9 (30%). Foram implantados 20 stents de nitinol (66,7%) e 10 de aço inoxidável (33,3%). Quatro pacientes eram TASC A (13,3%), 15 eram TASC B (50%) e 11, TASC C (36,7%). O volume da hiperplasia variou de 49,02 mm³ a 112,87 mm³ (média de 80,33 mm³). O percentual de obstrução intra-stent variou de 18% a 47% (média de 27,4%). Os resultados clínicos obtidos com stent se mantiveram até o reestudo. CONCLUSÃO: A hiperplasia neointimal sempre ocorre após a angioplastia transluminal percutânea e stent, porém os percentuais de obstrução não foram superiores a 50% em nenhum caso. Não houve diferença estatisticamente significante dos percentuais de obstrução intra-stent quanto aos materiais dos stents, aos fatores clínicos e aos fatores arteriais.

Neointimal hyperplasia in a thin-strut cobalt–chromium stent: Insights from detailed 3-D intravascular ultrasound analysis

The effect of current generation cobalt-chromium stents on neointimal proliferation has not been fully elucidated. IVUS images of 137 patients treated with a single thin-strut cobalt-chromium stent (Driver: DRI, n=74) or stainless steel stent (Multilink plus: ML, n=63) were selected. Although % neointima volume (neointimal volume divided by stent volume) were comparable, DRI showed significantly smaller maximum %cross-sectional narrowing (%CSN: neointimal area divided by stent area) (P=0.006) with significantly less %CSN>60 (percent stent length with %CSN>60%) than ML (P=0.04). In conclusion, the amount of neointimal hyperplasia after DRI implantation was comparable to that after ML. However, current generation cobalt-chromium DRI may show less and shorter severe narrowing than the stainless steel ML.

In vitro and In vivo studies of local arterial gene delivery and transfection using lipopolyplexes‐embedded stents

Gene-eluting stents can have profound impact in the treatment of coronary restenosis, especially when the encoded protein can re-endothelialize the arterial lumen. In this study, we have examined gene delivery in vitro and in vivo using poly(beta-amino ester) (PbAE) precondensed plasmid DNA-containing cationic liposomes or lipopolyplexes (LPP) immobilized on stainless steel meshes and stents using gelatin coatings. In vitro studies using LPP-immobilized on 50 mm round meshes using type A and B gelatin coatings showed that LPP were efficiently internalized in human aortic smooth muscle cells (SMC) over time, leading to green fluorescent protein (GFP) expression. Type B gelatin coating was found to be more effective in intracellular delivery and transgene expression efficiency and, as such, was used for stent coating. In vivo studies, carried out in iliac artery restenosis model in New Zealand white rabbits, also showed GFP expression in arterial tissues after 24 h of implantation. Based on these encouraging preliminary results, LPP-based formulations can serve as a safe and effective nonviral gene delivery system for effective treatment of coronary restenosis.

Is Coronary Stent Assessment Improved with Spectral Analysis of Dual Energy CT?

The aims of this study were to distinguish stents from iodinated contrast on the basis of spectral characteristics on dual-energy computed tomographic (DECT) imaging and to determine whether DECT imaging might provide a more accurate measurement of true stent lumen. Three stainless steel stents and one cobalt chromium stent were scanned using a multidetector, single-source DECT scanner. Stents 2.5, 3.5, and 4.0 mm in diameter were filled with iodinated contrast, submerged in water, and scanned. Spectral analysis was performed to assess the separation of stents from iodinated contrast. Two independent reviewers measured stent lumen diameter and strut thickness on low-energy (L(0)), high-energy (L(1)), and combined-energy (L(c)) images. Dual-energy full-width half-maximum edge detection analysis was used to provide an independent assessment of stent luminal diameter and strut thickness. Two-dimensional graphical plots of computed tomographic attenuation for the L(0) and L(1) images did not demonstrate a sharp separation between the absorption characteristics of stents and iodinated contrast material. Stent lumens were underestimated by approximately 50% on L(c) images. Observer measurements on L(1) images demonstrated a 24% decrease in strut thickness and a 25% increase in stent luminal diameter compared to L(0) images (P < .0001). Full-width half-maximum measurements did not demonstrate significant changes in stent luminal diameters or strut thicknesses between L(0) and L(1) images. Spectral analysis did not clearly distinguish stents from iodinated contrast with the DECT system used in this study. The larger stent lumens visualized by the high-energy components of the x-ray spectrum were not related to improved computed tomographic delineation of stent thickness.

O stent descoberto não promove reações em artérias renais e parênquima renal em suínos

To assess the histological changes of the aorta, the renal arteries and the renal parenchyma in swine, induced by a metalic uncovered stent implanted in transrenal position in the abdominal aorta. Ten pigs with a mean weight of 86.6 kg and mean age of 6 months underwent implantation of metal stent graft placed in the aorta at the level of the renal arteries after 100 days of implantation. The self-expanding stents were released by laparotomy. Anatomic and histological analyses of the abdominal aorta, the renal arteries and the renal parenchyma were performed. Histological slices were performed in the following sites: 1) transitional zone between the aorta with and without stent graft; 2) portion of the renal arteries ostia; 3) renal parenchyma. The slices were stained through the hematoxylin and eosin stain technique and analyzed according the protocol of histological analyses applied in the clinical practice of pathology labs. The macroscopic findings showed thickening of the aortic wall; patent renal arteries; and normal anatomic renal structures. Microscopic analyses, close to the stents, showed thickening of the vascular wall, renal arteries without changes, and preserved renal parenchyma. The uncovered stainless steel stent caused a significant inflammatory reaction with thickening of the aortic wall. However, the renal arteries remained patent and the renal parenchyma did not present embolic or ischemic changes.

Preparation and in vitro release profiles of drug-eluting controlled biodegradable polymer coating stents

In the present study, the different drug-eluting controlled biodegradable polymer coatings were fabricated on stainless steel stents. The coatings were not only uniform and smooth but also had excellent mechanical property. The drug release profiles of drug-eluting stents were studied in detail in this study. Depending on the drug type, different drug-eluting stents exhibited different drug release profile. There were two basic release profiles for different drug-eluting stents, i.e., two-phase release profile with burst release or linear release profile without burst release. Incorporating heparin in the rapamycin or curcumin eluting stents can improve the average drug release rate of both and the burst release of rapamycin. The average drug release rate increased with the increase of drug loading but was not proportional to increase of the ratio of drug/polymer. Fabricating the control release layer on rapamycin-eluting stent surface can prevent the burst release of rapamycin and prolong the release period of rapamycin. All results showed that the drug release profile of drug-eluting stents depends on many parameters including drug type, ratio of drug/polymer, and drug carrier properties.

Clinical outcomes after percutaneous peripheral intervention for chronic total occlusion of superficial femoral arteries: Comparison between self-expandable nitinol stent and stainless steel stent

It has been reported that nitinol stents provide higher patency in chronic phase than stainless steel stents after intervention to superficial femoral artery (SFA). However, there are few reports about stent patency for chronic total occlusion of SFA (SFA CTO). To compare clinical outcomes of self-expanding nitinol stents and stainless steel stents after percutaneous peripheral intervention (PPI) for SFA CTO. Between April 2004 and August 2007, a total of 25 SFA CTO lesions (nitinol stent group, 13; stainless steel stent group, 12) in 21 patients were treated with PPI, all patients were followed clinically, and 21 lesions (nitinol, 9; stainless steel, 12) received follow-up angiography. There was no significant difference in baseline characteristics, mean stent diameter (7.3+/-0.7 mm vs. 6.9+/-1.2 mm, p=0.32), pre-ankle-brachial index (ABI), and Fontaine stage between groups. Mean occlusion length and stent length were significantly longer (129.5+/-54.9 mm vs. 39.0+/-20.6 mm, 250.8+/-90.0 mm vs. 145.2+/-64.6 mm, respectively, p<0.01) and number of stents was significantly larger (2.8+/-0.9 vs. 1.6+/-0.5, p<0.01) in the nitinol stent group. At follow-up, ABI was significantly lower (0.73+/-0.20 vs. 0.95+/-0.13, p=0.04), restenosis rate and target lesion revascularization was significantly higher (58.3% vs. 15.4%, p=0.03; 50.0% vs. 7.7%, p=0.02, respectively) in the stainless steel stent group. Our study demonstrates the superiority of nitinol stent implantation compared with stainless steel stent implantation for SFA CTO.

Biological response of stainless steel surface modified by N 2O/O 2 glow discharge plasma

Stainless steel wafers were treated with the glow discharge plasma of mixed N 2O and O 2 at different molar ratios at a certain discharge condition to create desirable biological characteristics to the surfaces. It was found that the molar ratio of N 2O to O 2 in the mixture at 1:1 used for plasma surface modification caused high apoptotic percentage. Contact angle measurement showed that the surface of stainless steel samples became very hydrophilic after the plasma modification with a value of 15°–30°. The control stainless steel chips without plasma treatment had a contact angle of 40 ± 2°. The data of Electron Spectroscopy for Chemical Analysis (ESCA) indicated that there was a certain amount of oxynitrites formed on the plasma treated surfaces, which was considered to play an important role to cell apoptosis and anti-clot formation in cell culture tests. The ESCA depth profile of up to 250 Å from the top surface showed the change of elemental compositions within 40–50 Å of the surface by the plasma treatment. The decreased platelet attachment, combined with increased apoptosis in fibroblasts is a distinct combination of biological responses arising from the mixed gas plasma treatment. These initial results suggest it may be of particular use relative to stainless steel stents where decreased platelet attachments are advantageous and induction of apoptosis could limit in-stent restenosis.

New stent design for percutaneous aortic valve replacement

Vascular support structures are an important tool for treating valve stenosis. A large population of patients are treated for valvular disease and the principal mode of treatment is the use of percutaneous valvuloplasty. Stent devices are proving to be an improved treatment method; these devices now account for 20% of treatments in Europe. This new technology provides highly effective results at minimal cost and with reduced hospital stays. Accurate and reliable structural analysis provides essential information to the design team in an environment where in vivo experimentation is extremely expensive or impossible. This paper describes the design of a new vascular support structure (stent), to provide designers with estimates of the critical parameters which are essential. Stainless steel stents are preferred to be used as balloon-expanded prostheses as they are cost-effective.

Comparison of Tissue Reaction with Three Different Endografts Used for Exclusion of Carotid Artery Aneurysm in a Dog Model

To assess the efficacy and biocompatibility of balloon-expandable stainless-steel stents covered with various membrane types. Stents covered with biomembrane (ie, piglet greater omentum vein), polyurethane, or expanded polytetrafluoroethylene (ePTFE; n = 12 each) were implanted into the 36 bilateral carotid arteries of 18 dogs to treat 36 surgically created saccular side wall aneurysms. Treated dogs were administered anticoagulation therapy after stent implantation. Angiography was performed immediately after the procedure and at 2, 4, and 12 weeks. Aneurysm isolation, primary parent artery patency, acute thrombosis in the stent, and endoleak were investigated. Two dogs in each group were killed at each follow-up interval, the stent-implanted arteries were removed for light and electron microscopy, and aneurysm thrombosis, stenosis rate, and endothelialization progress were observed. Thirty-six stents were successfully placed and 36 aneurysms completely isolated, with no endoleaks revealed by immediate or follow-up angiography. The primary patency rates of the biomembrane-, polyurethane-, and ePTFE-covered stents were 91.7%, 50%, and 66.7%, respectively. At 12 weeks, a luminal narrowing of 24.27% +/- 6.23% was seen in the biomembrane group, compared with 30.78% +/- 1.41% (P = .025) in the polyurethane group and 20.56% +/- 7.22% (P = .247) in the ePTFE group. All treated aneurysmal pouches had filled with thrombi and stent wires were encased by extended neointima. Endothelialization in the biomembrane group had begun by 2 weeks, which was earlier than in the polyurethane or ePTFE groups. All three stent-grafts successfully excluded carotid aneurysms. Biomembrane-covered stents showed better primary patency and less intimal hyperplasia than polyurethane- or ePTFE-covered stents.

XPS, AES, and Electrochemical Study of Iridium Oxide Coating Materials for Cardiovascular Stent Application

The surface composition and morphology of iridium oxide (IrO2) coatings prepared by a multi-step physical vapor deposition process on 316L stainless steel stent substrates has been investigated by XPS, AES, and FESEM. The obtained data show that even though the morphologies of iridium oxide films produced within the examined range of PVD process parameters are almost identical, there is a difference in their surface composition, in particular in the ratios of Ir-O σ and Ir=O π bonds. A correlation between the surface stoichiometries of the IrO2 films and their electrochemical CV and EIS responses has been established. The observed differences in the O 1s photoemission line shape of the investigated iridium oxide films were strikingly reflected in their voltammetric curve features. The implication of these finding on the mechanism of the catalytic decomposition of hydrogen peroxide by IrO2 is discussed.

Comparison of two different paclitaxel-coated balloon catheters in the porcine coronary restenosis model

Drug-eluting balloon (DEB) catheters coated with paclitaxel in a water-soluble matrix have shown beneficial effects in the treatment and prevention of restenosis in the porcine coronary overstretch model and in clinical trials. Adherence of paclitaxel, same dose, on another recently introduced coated percutaneous coronary intervention (PCI) catheter (DIOR) is mediated by a roughened balloon surface. Only scarce experimental and clinical data has been published on the new coating method. The aim of the present study was to compare the safety and efficacy of the two coatings in the porcine model. Twenty-eight stainless steel stents were implanted in the left anterior descending and circumflex coronary arteries of 14 domestic pigs using either matrix-coated (n = 8), roughened DEB (n = 9), or uncoated PCI catheters, which served as control (n = 11). After 28 days, quantitative angiography and histomorphometry of the stented arteries were performed. Matrix-coated DEB led to a highly significant (P < 0.01) reduction of all parameters indicating neointimal proliferation compared to both, uncoated control and the roughened DEB; late lumen loss in-segment was 0.4 +/- 0.2, 1.9 +/- 0.5, and 1.4 +/- 0.5 mm, respectively. In contrast, the roughened DEB failed to produce statistically significant effects on angiographic measures of stenosis or morphometric parameters such as maximal neointimal thickness and luminal area, except for neointimal area (5.7 +/- 1.5 mm(2) in the control group, 4.1 +/- 1.7 mm(2) roughened DEB, P < 0.05 vs. control, and 2.5 +/- 0.8 mm(2) matrix-coated DEB, P < 0.01 vs. control). Inhibition of neointimal proliferation in the porcine coronary overstretch model by paclitaxel depends critically on the coating method.