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Biomedical subjects

E Verbeken

Publications and source records attributed to E Verbeken.

At least 55 records · Page 3Linked to original sources
PubMed1999

The No-React anticalcification treatment: a comparison of Biocor No-React II and Toronto SPV stentless bioprostheses implanted in sheep.

Calcification of stentless aortic heterografts still limits the use of these bioprostheses in young patients despite their superior hemodynamic profile. The No-React treatment is described as an anticalcification treatment for biomaterials. We compared the Biocor No-React treated stentless bioprosthesis with the routine glutaraldehyde-fixed Toronto SPV bioprosthesis in a juvenile sheep model. Toronto SPV or Biocor No-React valves were implanted in pulmonary position in juvenile sheep (n = 6). The valves were explanted after 3 months and analyzed by gross inspection, x-ray studies, histological examination, and transmission electron microscopy. The Toronto SPV valve showed calcification of the aortic wall portion at both the inflow and outflow sides of the valve. No significant calcification of the cusps was found by gross inspection or by radiographic or histological examinations. Calcification was visible with electron microscopy in cell remnants and between collagen fibers in the cusps. The Biocor No-React valve showed extensive calcification of the residual aortic wall portion that is contained in the valve. With x-ray and histological examinations, clear calcification of the pericardial wrap, largely replacing the aortic wall tissue, was seen. Calcification scattered throughout the cusp was seen by electron microscopy. We conclude that the Biocor No-React process did not prevent calcification of glutaraldehyde-fixed stentless bioprostheses in a juvenile sheep experimental model. Furthermore, replacement of a large part of the aortic wall by a pericardial wrap did not prevent calcification of the stentless valve "wall."

Animals↗
PubMed1999

Are stentless aortic heterografts suitable for right ventricular outflow tract reconstruction? An experimental study in juvenile sheep.

Allograft valved conduits are used routinely for reconstruction of the right ventricular outflow tract in children with congenital heart disease; however, allografts are scarce. The purpose of this study was to evaluate two stentless aortic valves that might be suitable alternatives for right ventricular outflow tract reconstruction. Twelve juvenile sheep underwent implantation of stentless aortic heterografts as an interposition in the pulmonary artery: six porcine aortic valves (Freestyle) and six fully pericardial valves (Pericarbon stentless). In each series, three valves were explanted after 3 months, the other three after 6 months. Valves were analyzed by gross inspection, radiography, and light microscopy. The porcine aortic stentless valve (Freestyle) showed extensive calcification of its aortic wall portion, with perfectly functioning, pliable cusps without calcification or fibrous overgrowth up to 6 months. The pericardial valves (Pericarbon stentless) showed extensive fibrous sheathing, causing progressive retraction of the leaflets and severe regurgitation. After 3 months, minimal calcification was seen in the pericardial wall. Calcification was more pronounced after 6 months, sometimes causing complete calcification of pericardial wall and leaflets, leading to a significant stenosis. We conclude that the pericardial stentless valve becomes rapidly dysfunctional after right-sided implantation as a result of fibrous sheathing and severe calcification. The porcine aortic stentless valve remains functional, but severe calcification of the aortic wall portion is problematic.

Age Factors↗
PubMed1999

Neointimal hyperplasia and late pathologic remodeling in a porcine coronary stent model.

BACKGROUND: Although coronary stenting has been demonstrated to significantly reduce restenosis compared to conventional angioplasty, occurrence of in-stent stenosis still remains one of the major limitations. This study investigates the influence of stent strut diameter on injury, inflammatory response, thrombosis and neointimal hyperplasia in a porcine coronary artery. METHODS: Coil stents made of either a 0.12 mm, 0.15 mm or 0.18 mm wire were randomly implanted in the right coronary arteries of 30 pigs. Quantitative coronary angiography analysis was performed before, immediately after, and 6 weeks following the stenting procedure. At 6 weeks, histopathology for evaluation of injury, thrombosis and inflammation, as well as morphometry for calculation of the neointimal hyperplasia and internal elastic lamina area were performed. RESULTS: Quantitative coronary analysis showed similar quantitative data before and after stent placement in the three groups. At 6 weeks, however, a significantly bigger MLD was found in the 0.18 mm group. Morphometric analysis at 6 weeks confirmed these results, showing a significantly bigger lumen area in both the 0.18 mm (1.71 +/- 0.66 mm2) and 0.15 mm (1.36 +/- 0.53 mm2) groups compared to the 0.12 mm group (0.71 +/- 0.38 mm2). The calculated neointimal hyperplasia was similar in the three groups (0.12 mm: 1.93 +/- 0.51 mm2; 0.15 mm: 1.68 +/- 0.63 mm2; and 0.18 mm: 2.16 +/- 1.48 mm2). The internal elastic membrane area, however, was significantly bigger in the 0.18 mm (3.87 +/- 1.39 mm2) compared to the 0.12 group (2.65 +/- 0.53 mm2). CONCLUSION: These results suggest that pathologic remodeling can also play an important role in late lumen loss after stent implantation.

Animals↗
PubMed1998

Preclinical studies on thiocarboxanilide UC-781 as a virucidal agent.

BACKGROUND: Thiocarboxanilide UC-781 is a highly potent and selective non-nucleoside reverse transcriptase inhibitor (NNRTI) of HIV-1, which also has virucidal properties. Recent studies have shown that UC-781 would seem an ideal candidate for application as a vaginal virucide. OBJECTIVE: To investigate the antiviral potency and stability of UC-781 in a lipophilic gel formulation. METHODS: UC-781 was formulated in replens gel at different concentrations and administered intravaginally to rabbits at 5% in replens gel for 10 days. UC-781 was also exposed to temperatures of 4, 37 and 50 degrees C, and to low pH (6.0, 4.3, 2.0 and 1.2). A number of microorganisms were exposed in culture to serial dilutions of UC-781. RESULTS: The drug was stable under low pH conditions and did not lose its antiviral potency upon 4 h exposure to pH 3.5 (the estimated vaginal pH). UC-781 can be easily formulated into a lipophilic gel (replens; up to 5%) and proved fully stable at 50 degrees C for 30 days. There was no effect on the growth of microorganisms (i.e., Candida and Lactobacillus strains) that are present in the vaginal flora. Neither systemic side-effects, nor local inflammation or damage of the vaginal mucosa or epithelium were observed in rabbits to which 5% UC-781 in replens gel had been administered. UC-781, formulated as 0.5, 0.2 and 0.05% replens gel, and UC-38, alpha-APA and zidovudine, formulated as 0.5 or 0.2% replens gel, were effective in protecting CEM cells in the very beginning against productive HIV-1 replication. This points to an efficient diffusion of the drugs from the lipophilic gel to the hydrophilic culture medium. However, subsequent subcultivations at a dilution rate of 1:10 every 3-4 days resulted in a rapid breakthrough of virus with all drugs except UC-781 in its 0.5 and 0.2% gel formulation. These cultures were fully protected against HIV-1 and remained completely cleared from virus for at least 10 subcultivations. CONCLUSIONS: The virus that emerged under 0.05% UC-781 remained highly sensitive to the NNRTI, including UC-781, in cell culture, suggesting a lack of resistance development under our experimental conditions.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Na+/H+ exchange inhibition improves long-term myocardial preservation.

BACKGROUND: Na+/H+ exchange plays an important role in the ionic changes observed during myocardial ischemia and reperfusion. We investigated the cardioprotective efficacy of a selective Na+/H+ exchange inhibitor, 4-isopropyl-3-methylsulfonyl-benzoylguanidin-methanesulfonate (HOE642), in a canine model of long-term heart preservation. METHODS: Canine donor hearts were stored for 24 hours in hyperkalemic crystalloid cardioplegic solution; in cardioplegic solution enriched with HOE642; in cardioplegic solution enriched with HOE642, with donor and recipient treated with HOE642; in standard cardioplegic solution, with donor and recipient treated with HOE642; or in standard cardioplegic solution, with only the recipient treated. After orthotopic transplantation, pressure-volume relationships were obtained and dogs were weaned from bypass. Morphology was studied. RESULTS: Myocardial compliance was well preserved when donor and recipient were treated. These groups had the lowest myocardial water content, and no morphologic signs of irreversible damage. In these groups, weaning from cardiopulmonary bypass was successful in 10 of 10 animals, with a cardiac index around 2 L x min(-1) x m(-2). Only 3 of 5 animals in each of the other three groups could be weaned, with significantly lower cardiac indices. CONCLUSIONS: Treatment with HOE642 in both donor and recipient improves myocardial compliance, postweaning cardiac index, and ultrastructure of donor hearts preserved for 24 hours and orthotopically transplanted.

Animals↗
PubMed1998

Tracheoscopic endoluminal plugging using an inflatable device in the fetal lamb model.

OBJECTIVE: Intra-uterine tracheal occlusion has been proposed to reverse pulmonary hypoplasia, an important prognostic factor in congenital diaphragmatic hernia. We aimed to evaluate the feasibility and pulmonary effects of tracheoscopic tracheal obstruction with a detachable balloon. STUDY DESIGN: Fourteen mid-trimester fetuses out of 24 in 13 ewes underwent tracheoscopic balloon obstruction. Ten non-operated fetuses served as controls. Plugging was performed under fiber-tracheoscopy using a detachable balloon. Outcome measures consisted of: total operating time, tracheoscopy time, fetal survival, efficiency of plugging, and pulmonary effects. The Mann-Whitney test and linear regression were used for statistical analysis. RESULTS: Mean operating time and tracheoscopy time were 65+/-12 and 6.6+/-3.9 min, respectively. One intra-operative death occurred in each group. The post-operative mortality was 2/13 for cases and 2/9 for controls. In all 14 fetuses, the trachea was successfully obstructed. In the 11 treated animals born alive, the lung-to-body-weight ratio was 0.060+/-0.01, while in controls it was 0.031+/-0.01 (P = 0.0001). In a subset of six fetuses obstructed for 14-18 days, mean-terminal-bronchial density was 0.95+/-0.59, compared to 2.06+/-0.80 for controls (P = 0.046). CONCLUSIONS: Using fetal tracheoscopy, the trachea can successfully be obstructed with an inflatable balloon. Pulmonary hyperplasia is achieved when the obstruction lasts 2 weeks.

Animals↗
PubMed1998

Na+/H+ exchange inhibition improves post-transplant myocardial compliance in 4-hour stored donor hearts.

Na+/H+ exchange inhibitors have cardioprotective properties. The effects of the new Na+/H+ exchange inhibitor, HOE642 on myocardial function were assessed after transplantation of canine brain-dead and non-brain-dead donor hearts preserved for 4 h. Four groups were studied: brain-dead donors; non-brain-dead donors; brain-dead donors and recipients treated with HOE642 (2 mg/kg); and treated non brain-dead donors and recipients. Donor hearts were stored in NIH2. At the end of 60 min reperfusion after transplantation, pressure-volume curves were constructed. Biopsies were analysed histologically and ultrastructurally. Afterwards, weaning from cardiopulmonary bypass was accomplished. HOE642 improved compliance in hearts from both brain-dead and non-brain-dead donors. No differences in myocardial water content nor in myocardial performance were detected. No irreversible damage was seen ultrastructurally. It is concluded that myocardial compliance after transplantation was improved by administration of HOE642. The use of this inhibitor might improve the current myocardial preservation technique for transplantation.

Animals↗
PubMed1998

Bronchiolitis obliterans organising pneumonia. A report of 11 cases and a review of the literature.

The clinical syndrome "Bronchiolitis Obliterans Organising Pneumonia" (BOOP) has to be considered in patients with a flu-like illness since some weeks, fine crackles, and on chest X-ray bilateral patchy infiltrates. There is no response to antibiotics. BOOP is essentially idiopathic, but associations to other conditions exist. Lung function is often restrictive; biochemistry is not pathognomonic. BAL shows a mixed cellular pattern. The gold standard for pathologic diagnosis is open or thoracoscopic lung biopsy. However, a BOOP pattern or reaction is often seen on histologic specimens without the clinical-radiologic features of the BOOP-entity. Therapy consists of corticosteroids, which have to be prescribed for a long time at a rather high dose. Recurrence is frequent, but prognosis is good. Evolution to respiratory insufficiency and death is rare and may occur in rapidly progressive BOOP. This study reports on 11 cases (6 males/5 females) of clinical-pathological BOOP-syndrome (mean age 58 yrs, range 17-73 yrs), with an unexpectedly high mortality rate of 36% (4 cases). The disease was idiopathic in 7, and was associated with intake of amiodarone (in 1), with past Mycoplasma pneumonia (in 1) and with connective tissue disease (in 2). There was a history of a flu-like syndrome, cough and dyspnea of a mean duration of 4 months (range 1 week to 8 months). Lung function was mostly restrictive or/and obstructive with a diffusing capacity ranging between 47 and 95% predicted; there was hypoxia in about half of the patients. Chest X-ray and computed tomography (CT) scan showed a patchy consolidation with linear opacities (unilateral in 4 patients, bilateral in 5) and/or a ground glass pattern (in 4 patients), and a focal pseudo-tumoral lesion (in 1). Bronchoalveolar lavage showed a variable pattern of mixed, or eosinophilic or neutrophilic alveolitis. Histologic diagnosis was based on open lung biopsy (in 3), on thoracoscopic biopsy (in 2), on transbronchial biopsy (in 2), on wedge resection of the nodular lesion (in 1) and on postmortem lung biopsy (in 3). One patient recovered spontaneously, 1 remained cured after resection of the focal lesion, 7 were treated with 16-125 mg methylprednisolone (of whom 3 had a temporary flare-up during tapering the corticosteroids and 2 died after 1 and 3 months due to infectious complications), 2 died due to rapidly progressive BOOP.

Adolescent↗
PubMed1998

Interstitial lung disease more than 40 years after a 5 year occupational exposure to talc.

A 62 yr old woman was initially diagnosed with sarcoidosis until a thoracoscopic biopsy revealed the presence of numerous birefringent particles in fibrotic areas of the centrilobular lung zones. These particles were examined by electron microscopy and X-ray spectrometry and characterized as impure talc. Further inquiry into her occupational history revealed that she had worked from the age of 14-18 yrs in a factory making rubber hoses, where she had had an intense exposure to talc. There was no evidence of silicosis or asbestosis, and other significant causes of interstitial lung disease were excluded. This case emphasizes the importance of a thorough occupational history, which may reveal a remote and forgotten exposure to a significant cause of interstitial lung disease. Although this presentation of talcosis is unusual, this case suggests that even a relatively short, but presumably intense exposure to talc more than 40 yrs previously may be a cause of progressive lung fibrosis.

Female↗
PubMed1998

Experimental Evaluation of a New Single Wire Tantalum Coil Coronary Stent (Wiktor-iª).

To improve scaffolding properties, a new more densely woven Wiktor stent, the Wiktor-iª stent, was developed. Although the metal coverage remains still low compared to other stents, increased metal/vessel area raises the concern of increased thrombogenicity and neointimal hyperplasia. In this study we evaluated the Wiktor-i stent in a porcine peripheral and coronary model and compared the thrombogenicity and neointimal hyperplasia with the Wiktor-GX coronary stent. In a first study, a Wiktor-i and a Wiktor-GX coronary stent were implanted symmetrically in a preselected side branch of the right and left iliac artery of 10 healthy pigs. Quantitative vessel analysis showed comparable data before, immediately after and at follow-up. Hyperplasia measured by morphometry was also comparable in both groups (Wiktor-GX: 1.43 mm2 vs. Wiktor-i: 1.17 mm2, NS). Also, area stenosis was very similar (Wiktor-GX: 32% vs. Wiktor-i: 29%, NS). In a second study, 20 Wiktor (Wiktor-i: n=10, Wiktor-GX: n=10) coronary stents were implanted in the right coronary artery of 20 healthy pigs. Quantitative coronary analysis before, immediately after and at follow-up was comparable in both stents. The hyperplasia measured morphometrically was also comparable in both stents. (Wiktor-GX: 1.51 +/- 0.47 mm2 vs. Wiktor-i: 1.46 +/- 0.66 mm2, NS). Also the area stenosis was not significantly different (Wiktor-GX: 31% vs. Wiktor-i: 35%). In conclusion, this study shows that the increased metal/vessel area of the Wiktor-i stent does not result in an increased neointimal hyperplasia. Both stents show to be very biocompatible when implanted in porcine coronary and peripheral vessels.

Journal Article↗
PubMed1998

Intravascular Low Power Red Laser Light as an Adjunct to Coronary Stent Implantation Evaluated in a Porcine Coronary Model.

BACKGROUND: It is believed that restenosis following coronary interventions is the result of endothelial denudation that leads to thrombus formation, vascular remodeling, and smooth muscle cell proliferation. We previously demonstrated that low power red laser light (LPRLL) irradiation enhances endothelial cell growth in vitro and in vivo and reduces restenosis in a small animal model. The present study investigated the effectiveness of intravascular LPRLL therapy in the reduction of restenosis following stenting in a porcine model. METHODS AND RESULTS: Stents were placed in the right coronary artery of domestic cross-bred pigs. After stent deployment, an additional inflation was performed with the laser-balloon. In group I (n = 18) no LPRLL was used; group II (n = 10) received LPRLL dosage of 10 mW for 1 minute; group III (n = 10) received LPRLL dosage of 34 mW for 1 minute. Quantitative coronary analysis of the stented vessel was performed before, immediately after stenting, and at 6 weeks. The pigs were sacrificed and histologic and planimetric analysis conducted. At 6 weeks, minimal luminal stent diameter was significantly narrower in the control group compared to the higher dose group (p < 0.05), late loss correlated inversely proportional to the dose used (r = 0.9; p < 0.03), these results were confirmed by morphometric analysis. Neointimal area was also significantly decreased in the higher dose group. CONCLUSIONS: Intravascular LPRLL contributes to reduction of angiographic restenosis and hyperplastic reaction in this animal model and seems to be dose dependent.

Journal Article↗
PubMed1998

Experimental Evaluation of a New Tubular Coronary Stent (V-Flexª).

The safety, efficacy, angiographic and histological effects of a new 316 L, SS seamless stainless steel tubular stent (V-Flexª, Global Therapeutics, Broomfield, Colorado) was evaluated in a porcine coronary and peripheral artery model. Implantation in the right coronary artery was successful in all 16 pigs. Eight pigs were angiographically controlled after 6 weeks and then sacrificed for morphometric analysis. All stented coronary vessels were widely patent at this moment and morphometric analysis showed only a mild fibromuscular neointimal hyperplasia resulting in a neointimal hyperplasia of 1.15 +/- 0.38 mm2. The remaining 8 pigs were controlled and sacrificed at 12 weeks. At that time, all stented vessels were patent and neointimal hyperplasia was 1.22 +/- 0.34 mm2. Comparison with the Palmaz-Schatzª coronary stent (Cordis, Miami, Florida) in a porcine peripheral artery model demonstrated significantly less neointimal hyperplasia at 6 weeks (1.11 +/- 0.73 vs. 2.40 +/- 0.36, p = 0.001) and at 12 weeks (1.53 +/- 0.42 vs. 2.47 +/- 0.63, p = 0.003) for the V-Flex stent. In conclusion, V-Flex coronary stent implantation in a porcine coronary and peripheral arteries results in a high procedural success rate without subacute thrombotic occlusions, despite no further anticoagulation nor antiplatelet therapy. Six and 12 week histopathological and morphometric evaluation demonstrated only a mild fibromuscular neointimal hyperplasia. Comparison with the Palmaz-Schatz coronary stent in a peripheral artery model showed significantly less neointimal hyperplasia in the V-Flex stent.

Journal Article↗
PubMed1997

Heparan sulfate proteoglycan expression in human lung-cancer cells.

Heparan sulfate (HS) functions as a co-factor in several signal-transduction systems that affect cellular growth, differentiation, adhesion and motility. HS, therefore, may also play a role in the malignant transformation of cells, tumor growth, cell invasiveness and the formation of tumor metastases. To explore this hypothesis, we analyzed the expression of HS and heparan sulfate proteoglycan (HSPG) in histological sections of human lung-cancer tissues and assayed for the presence of HSPGs in extracts of human lung-cancer cell lines, using a panel of native HS-, delta-HS- and HSPG (syndecan, glypican, CD44 and perlecan) core protein-specific monoclonal antibodies. Compared to normal epithelia, non-small-cell lung carcinomas, particularly poorly differentiated tumors, often expressed reduced amounts of the major cell surface-associated HSPGs (most consistently of syndecan-1). CD44 or CD44-variant proteins, in contrast, were found on all tumor cells, irrespective of their differentiation. Perlecan, a matrix-associated HSPG found in the basement membrane of normal bronchial epithelium, was consistently undetectable in invasive bronchogenic carcinomas. Staining reactions for native HS were consistently reduced in squamous-cell lung carcinomas, in the cells in contact with the stroma and in the less differentiated areas of these tumors. Reactions for delta-HS, however, were not reduced, suggesting a structural change in the HS of these tumor cells. Poorly differentiated adenocarcinomas, in contrast, yielded strong HS and delta-HS reactions. Marked differences in HSPG expression also were observed among various non-small-cell lung carcinoma cell lines. Our results suggest that poorly differentiated lung tumors have markedly altered patterns of HSPG expression, which may contribute to their invasive phenotype.

Adenocarcinoma↗
PubMed1996

Concept of the homemade coronary stent: experimental results and initial clinical experience.

To defray the escalating cost of coronary stenting, we handmade a balloon expandable coil stent with stainless steel wire. Preliminary comparison with the Palmaz-Schatz stent showed that, when implanted in porcine iliac arteries, there was no difference in immediate angiographic results or in the degree of foreign body reaction at 6 wk. Subsequently, a total of 73 stents were implanted in 52 patients, either as a bailout device (54%) or for suboptimal angiographic results (46%). All but two implantations were successful. The postprocedural regimen consisted of heparin 1,000 IU/hr, aspirin 250 mg daily, and ticlopidine 500 mg daily. In-hospital complications were limited to two groin hematomas, one necessitating blood transfusion. Importantly, stent thrombosis was not observed. While 6-mo follow-up is pending, we already conclude that a balloon expandable coil stent can be handmade easily at low cost and implanted safely in patients.

Animals↗
PubMed1996

Local methylprednisolone inhibition of foreign body response to coated intracoronary stents.

BACKGROUND: When poly(organo)phosphazene coated metallic stents are implanted into normal coronary arteries of pigs a severe histolymphocytic and fibromuscular reaction is induced. Corticosteroids possess potent anti-inflammatory and immunosuppressive effects, they have been shown to decrease migration and functional capability of the cells of inflammation and they may stabilize lysosomal cell membranes. This study aims to evaluates the feasibility and efficacy of local corticosteroid delivery by implantation of methylprednisolone loaded coronary stents into coronary arteries of pigs. METHODS: Tantalum balloon expandable coronary stents were coated with poly(organo)phosphazene impregnated with 5 wt% methylprednisolone. Methylprednisolone release was calculated in vitro and then randomly either a methylprednisolone loaded stent or a plain polymercoated stent was implanted into the right coronary artery of 20 pigs. Quantitative coronary artery analysis was done before, immediately after and 6 weeks after stent implantation. The pigs were then killed and the stented arteries processed for histopathological and morphometric evaluation. RESULTS: In-vitro testing revealed that the methylprednisolone loaded stents, when incubated in physiological saline, released 96% of the drug within 24 h. Quantitative angiography of the implanted stents showed similar angiographic parameters in both treatment groups immediately after implantation, but, after 6 weeks of follow-up study the minimal luminal diameter of the stented arterial segment was considerably larger in the methylprednisolone-treated pigs than it was in the control pigs (2.74 +/- 0.34 versus 1.36 +/- 0.72 mm, P < 0.005) This angiographic finding was confirmed at post-mortem morphometry where the respective values for neointimal thickness were 0.99 +/- 0.28 and 1.74 +/- 0.84 mm (P < 0.02). CONCLUSIONS: Polymer coated stents can be loaded with methylprednisolone which inhibits the severe foreign-body reaction induced by the combination of overstretch injury and the poly(organo)phosphazene polymer coating of metallic stents.

Animals↗
PubMed1996

Local Angiopeptin Delivery Using Coated Stents Reduces Neointimal Proliferation in Overstretched Porcine Coronary Arteries.

BACKGROUND: Systemic administration of angiopeptin has been shown to inhibit myointimal thickening after arterial injury in several animal species. METHODS AND RESULTS: To explore to what extent high and long-lasting local concentrations of angiopeptin influence the healing process after vascular injury, tantalum balloon-expandable stents were first coated with a polymer loaded with angiopeptin 250 µg. Implantation of these stents in porcine coronary arteries resulted in tissue concentrations of 10.7 pg/ml wet weight in the stented arterial segment 24 hours after stent implantation, gradually declining to 2.0 pg/ml wet weight at day 8. Finally, 20 pigs were randomly treated with either an angiopeptin-loaded or a blank-coated stent. At baseline, the angiographic parameters were similar between both groups but, after 6 weeks, the minimal luminal diameter of the stented arterial segment was larger in the angiopeptin-treated pigs when compared to controls (2.20 +/- 0.57 mm vs 1.57 +/- 0.68 mm, p < 0.01) This angiographic finding was confirmed by post-mortem morphometry where the respective lumen area values were 1.00 +/- 0.54 mm2 and 0.43 +/- 0.28 mm2 (p < 0.01). CONCLUSION: Polymer coated stents can be loaded with angiopeptin, which after implantation in porcine right coronary arteries result in high local tissue concentrations gradually declining over more than 8 days. These high local concentrations inhibit myointimal proliferation induced by poly(organo)phosphazene coated overstretched stents.

Journal Article↗
PubMed1996

Experimental Evaluation of a New Single Wire Stainless Steel Fishscale Coronary Stent (Freedomª).

Recent randomized clinical trials revealed a significant reduction in angiographic restenosis rates when adjunctive stenting was performed after conventional coronary balloon angioplasty. Current approved coronary stents are however hampered by their rigidity, limiting their trackability in tortuous vessels and furthermore, needing high pressure deployment for optimal vessel apposition. New coronary stents are currently under development, using more biocompatible metal alloys and/or designs which better align to the vessel wall at moderate deployment pressures. We evaluated the safety, efficacy, angiographic and histological effect of a new stainless steel fishscale designed stent (Freedomª, Global Therapeutics, Co., USA) in a porcine coronary and peripheral artery model. Implantation in the right coronary artery was successful in all 20 pigs. Control angiograms at 6 weeks follow-up demonstrated patent vessels and morphologic evaluation showed only a mild fibromuscular neointimal response resulting in an area stenosis of 28.7 +/- 0.18% and a mean neointimal hyperplasia of 0.18 +/- 0.25 mm. Comparison with the Palmaz-Schatzª coronary stent in a porcine peripheral artery model demonstrated similar quantitative angiographic and morphologic vessel analysis results. Also the morphometric data were comparable. Area stenosis: Palmaz-Schatz: 37 +/- 0.24%, Freedom: 21 +/- 0.14%, p = 0.07. Mean neointimal hyperplasia: Palmaz-Schatz: 0.33 +/- 0.24 mm, Freedom: 0.18 +/- 0.08 mm, p = 0.08. CONCLUSION: Freedom coronary stent implantation in a porcine model resulted in a high procedural success without subacute thrombotic occlusions, despite no further anticoagulation nor antiplatelet therapy. Six weeks histopathological and morphometric evaluation demonstrated only a mild fibromuscular neointimal hyperplasia.

Journal Article↗