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Biomedical subjects

Antonio Colombo

Publications and source records attributed to Antonio Colombo.

At least 199 records · Page 11Linked to original sources

Estrogen-eluting, phosphorylcholine-coated stent implantation is associated with reduced neointimal formation but no delay in vascular repair in a porcine coronary model.

Estrogen can inhibit intimal proliferation and accelerate endothelial regeneration after angioplasty. This suggests that estrogen may prevent in-stent restenosis. Unlike other therapies to prevent restenosis, estrogen may also not delay endothelial regrowth, thereby avoiding the risk of late stent thrombosis. The purpose of this work was to determine the effect of a 17beta-estradiol-eluting stent on neointimal formation in a porcine model. Each artery of six pigs was randomized to either a control, low-dose, or high-dose 17beta-estradiol-eluting stent. All animals were sacrificed at 30 days for histopathological analysis. There was a 40% reduction in intimal area in the high-dose stents compared with control stents (2.54 +/- 1.0 vs. 4.13 +/- 1.1 mm(2), for high dose vs. control, respectively; P < 0.05). There was complete endothelial regeneration at 30 days and similar inflammatory response to stenting on histopathology in all the stent groups. This is the first study to show that 17beta-estradiol-eluting stents are associated with reduced neointimal formation without affecting endothelial regeneration in the pig model of in-stent restenosis. Estrogen-coated stents may have a potential benefit in the prevention and treatment of in-stent restenosis.

Animals↗

The lunar stent characteristics and clinical results.

One of the frequent long-term complications after stent implantation is restenosis due to the building up of a neointima within the artery, as well as endovascular hyperplasia (tissue growth). The interesting feature of the Lunar stent from Inflow Dynamics is that it is coated with a layer of iridium oxide. The iridium oxide coating is believed to reduce restenosis by decreasing the inflammatory response to the stent via its antioxidant action. The MOONLIGHT (Multicenter Objective ObservatioNal Lunar Iridiumoxide intimal GrowtH Trial) study was carried out to evaluate the immediate outcome and long-term angiographic success after implantation of Lunar stents. Between March 2001 and November 2001, 87 patients with 99 lesions were enrolled in this study and were treated with 12 and 16 mm long iridium-oxide coated Lunar stents. Delivery of the Lunar stent was successful in most lesions and the optimal radiopacity facilitated optimal stent positioning with optimal immediate clinical and angiographic results is an unselected patient and lesion population. Preliminary clinical and angiographic follow-up show a low rate of cardiac events at 6 months (16.1% MACE) and a moderate hyperplastic response.

Adult↗

Sirolimus-eluting stents: a review of experimental and clinical findings.

Sirolimus (rapamycin), a macrolide antibiotic with known potent immunosuppressive properties, acts in the first phase (G1) of the cell cycle, blocking its further progression to the phase of DNA synthesis (S). In experimental models, rapamycin is effective in inhibiting smooth muscle cell proliferation and migration after vessel wall injury with balloon angioplasty. These results lead to the clinical application of sirolimus-eluting stents in 45 patients in Sao Paulo and Rotterdam (FIM Registry) and 238 patients in a randomized, European multicenter trial (RAVEL). These trials showed, by angiography and intravascular ultrasound, almost complete abolition of in-stent late hyperplasia up to one year after the procedure. In this review, we describe the experimental and clinical results of sirolimus-eluting stents including our experience of 26 stents implanted in 17 patients. In elective de novo lesions has shown remarkably clear lumens at follow-up angiography and intravascular ultrasound within the stented segments were observed with no lesion progression at the stent margins or thrombosis after a 2 month regimen of aspirin, and ticlopodine or clopidogrel. New large-scale ongoing clinical trials will investigate the efficacy of sirolimus-eluting stents in lesions that are traditionally associated with high restenosis rates after stent implantation, such as long lesions, bifurcations and instent restenosis.

Angina Pectoris↗

Covered stent to exclude intravascular thrombus.

PURPOSE: To describe the utility of stent-graft implantation to avoid distal embolization from a large thrombus-containing lesion. CASE REPORT: A 67-year-old man was evaluated for recent onset of disabling left leg claudication. Angiography disclosed a mobile lobular mass occluding the left common iliac artery; irregular staining suggested an atherothrombotic lesion. Through a percutaneous ipsilateral access and an 8-F sheath, a balloon-expandable Jostent peripheral stent-graft was positioned with the distal edge immediately proximal to the internal iliac artery ostium. A prominent "waist" at the center of the balloon confirmed entrapment of the thrombotic mass. Completion angiography showed an optimal result with no residual stenosis or evidence of distal embolization. At 6-month follow-up, the patient was asymptomatic with angiographically documented luminal patency and no evidence of in-stent stenosis. CONCLUSIONS: Stent-graft implantation appears a viable treatment alternative for thrombus-containing lesions, particularly when the thrombotic material is localized or is in a large vessel.

Aged↗

Constitutive expression of angiopoietin-1 and -2 and modulation of their expression by inflammatory cytokines in rheumatoid arthritis synovial fibroblasts.

OBJECTIVE: Angiopoietin- I (Ang-1) and Ang-2 are ligands for the receptor tyrosine kinase, Tie-2. Ang-1, a Tie-2 agonist, may have a vascular stabilizing role in angiogenesis, while Ang-2, an endogenous antagonist of Tie-2, may have an early role in angiogenesis, destabilizing existing vasculature. We show that these ligands are expressed by rheumatoid synovial fibroblasts (RSF) and investigate whether their expression was modulated by proinflammatory cytokines present in the joint in rheumatoid arthritis (RA). METHODS: Using quantitative PCR we determined the level of expression of these 2 ligands in RSF and chronic inflamed synovial tissue. The level of expression of these ligands after treatment with proinflammatory cytokines and hypoxia was also determined. RESULTS: We observed constitutive expression of Ang-1 and Ang-2 in RSF and chronic inflamed synovial tissue. Ang-1 was the most highly expressed ligand in late stage RA synovial fibroblasts; however, in chronic inflamed synovial tissue, Ang-2 was predominant and was expressed at strikingly high levels (70 to 120-fold increase). We observed that tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta (TGF-beta), but not interleukin 1beta or hypoxia, stimulated Ang-1 gene expression in RSE This was confirmed at the protein level as media from TNF-alpha treated RSF resulted in increased autophosphorylation of Tie-2. In contrast, TNF-alpha and TGF-beta had no effect on Ang-2 expression in RSF, but augmented expression of Ang-2 in normal synovial fibroblasts. CONCLUSION: The angiopoietins are important angiogenic factors constitutively present in RA, and their expression is modulated by certain cytokines. Ang-2 may have an important role in rheumatoid tissue where vigorous angiogenesis is occurring.

Angiopoietin-1↗

[Coronary angioplasty in elderly patients].

Developed nations are experiencing an unprecedented growth in the number of elderly citizens. Thanks to the modernization of both society and medical care, over the past century, life expectancy in most countries has nearly doubled. The elderly (80 years or over) represent the fastest-growing segment of our population. Owing to their age, the elderly are more afflicted with chronic diseases, including coronary artery disease. Recently, clinicians became more aggressive in the use of invasive cardiovascular diagnostic tests in these patients. With regard to younger patients, we have a wealth of data from large, randomized trials that defined which subsets of patients benefit from revascularization therapies. However, because the very elderly were severely underrepresented in these randomized studies, we have almost no information concerning the choice of treatment in these patients. Initial results of percutaneous revascularization procedures in elderly patients come from retrospective analysis performed during the pre-stent era. In these studies a procedural mortality risk 5-fold higher in patients > 80 years compared with those < 60 is reported. With the advent of coronary stenting, a significant increase in the rate of procedural success and a reduction in the incidence of procedural mortality, acute myocardial infarction and emergency coronary artery bypass grafting were observed also in the elderly. These initial positive results prompted physicians to treat patients with impaired clinical conditions and with unfavorable angiographic characteristics, resulting in a long-term freedom from major adverse cardiac events comparable to those observed in younger patients (78% in patients < 70 years vs 75% in patients > 80 years). The comparison between the percutaneous approach and the surgical approach to coronary artery disease in the elderly has its major limitation in the lack of data from randomized trials. The available information suggests similar results with the two different strategies (5-year survival rate: 85.7% for the coronary artery bypass grafting group vs 81.4% for the percutaneous revascularization group) with a clear benefit in favor of surgery only in diabetic patients. The only constant difference is the need of a repeat intervention which is significantly higher for the percutaneous approach. Furthermore, the introduction of newer percutaneous devices suitable for the recanalization of totally occluded coronary arteries could increase the completeness of the revascularization achieved with the percutaneous approach with a positive effect on the long-term outcome. These considerations could be "out of time" if the results obtained with the use of drug-eluting stents observed in selected patient populations will be confirmed in larger trials and in routine clinical practice. Whereas the advantages of the percutaneous versus the surgical approach in the elderly have not been fully clarified in patients with stable or unstable angina, primary angioplasty appears to be a very promising strategy in old patients with acute myocardial infarction. The improved clinical success with percutaneous revascularization in the elderly (acute mortality in patients > 85 years: 28.4% reperfused vs 38.5% not reperfused; p = 0.001) has to be related to the use of stents and to IIb/IIIa antagonists. In conclusion, when an old patient needs myocardial revascularization, the percutaneous approach should, in our opinion, be considered the treatment of choice in subjects either with stable or unstable angina and in those with acute myocardial infarction. At present, surgical revascularization provides better results in diabetic patients. The advent of drug-eluting stents may change many of the current limitations of percutaneous revascularization and further expand the use of this strategy.

Age Factors↗

Elective stenting in small coronary arteries: results of the Italian prospective multicenter registry MICROSCOPE.

BACKGROUND: The role of stent implantation in small coronary arteries is still controversial. The MICROSCOPE study (Ministenting in small coronary arteries, a prospective evaluation) is a multicenter registry addressed to prospectively evaluate the immediate and mid-term clinical and angiographic results of elective stenting of lesions located in coronary arteries with an angiographic reference diameter < or = 2.75 mm. METHODS: A total of 146 patients (160 lesions) were included in the study. The percentage of complex lesions (B2 and C lesions) was 49.3%. The clinical indications for stent implantation were: stable angina (55.0%), unstable angina (24.6%), and clinical evidence of myocardial ischemia in asymptomatic patients (20.4%); 60% of patients had multivessel disease. Stent deployment could be performed in 96.2% of lesions. The baseline reference diameter was 2.12 +/- 0.36 mm. In all cases the Ministent (Cordis, a J&J Company, Miami, FL, USA), specifically designed for small coronary arteries, was employed. The stent was pre-mounted on low profile balloons available in three different diameters (2.25, 2.50 and 2.75 mm) and three different lengths (11, 15 e 26 mm). RESULTS: The primary endpoint of successful stent-assisted angioplasty in all study vessels without major adverse cardiac events was achieved in 95.8% of the patients. The minimal lumen diameter increased from 0.64 +/- 0.24 to 2.02 +/- 0.43 mm and the dimensions of the stenosis (expressed as a percentage of the diameter of the coronary vessel) decreased from 68.6 +/- 10.8 to 16.2 +/- 10.7% (< 30% standard deviation in all cases). After the procedure all the patients received double antiplatelet therapy for 4 weeks. Post-procedural complications were limited to 2 patients (1.3%) who had a non-Q wave myocardial infarction at 6 months of follow-up; 13 patients (11%) required target lesion revascularization. No patient died following the procedure. Angiographic control was performed in 44% of lesions. The minimal lumen diameter decreased to 1.12 +/- 0.47 mm and the percent stenosis increased to 45.9 +/- 23.2%. The incidence of binary restenosis (stenosis > or = 50%) was 41%. CONCLUSIONS: Elective stenting of small coronary arteries with the Ministent can be safely performed and is associated with a low incidence of acute or subacute stent thrombosis. The mid-term results indicate a high rate of angiographic restenosis but a low need of target vessel revascularization. These data suggest that stenting cannot be considered the treatment of choice for unselected lesions located in coronary arteries with a small reference diameter, but represents a safe solution if unsatisfactory results are obtained with balloon angioplasty alone.

Aged↗

Provisional stenting in small vessels.

Based on the currently available data, the strategy of routine stent placement in unselected lesions located in small coronary arteries provides good immediate results but is still associated with a high incidence of in-stent restenosis. Randomized trials comparing elective stenting with balloon angioplasty have not provided the demonstration that routine stenting is the best strategy for percutaneous intervention in coronary arteries with a reference diameter smaller than 2.75-3.0 mm. This paper describes the rationale for provisional stenting in this clinical setting and reviews the role of quantitative coronary angiography, intracoronary ultrasound and intracoronary Doppler measurements in the identification of lesions that would benefit from adjunctive stent placement after balloon angioplasty and in guiding stent implantation.

Journal Article↗

The polytetrafluoroethylene-covered stent: a device with multiple potential advantages.

The polytetrafluoroethylene (PTFE)-covered stent has emerged in the past year as a device with multiple potential advantages. Its structure (a sandwich composed of a layer of PTFE membrane between two stents) makes this the ideal tool for treating coronary ruptures, and for excluding coronary aneurysms. Furthermore, this device may be useful in the treatment of aortocoronary vein graft stenosis. In the present review, the authors summarize experiences with covered stents, and focus attention on available data on the implantation of PTFE-covered stents in human beings to treat coronary ruptures, aneurysms and aortocoronary vein graft stenosis.

Journal Article↗

Subclavian artery stenting: Immediate and mid term clinical follow-up results.

BACKGROUND: Intravascular stents are increasingly being used to treat subclavian artery obstructive disease. This study aimed to assess the immediate and mid-term clinical outcome of subclavian artery stenting. METHODS AND RESULTS: Total occlusion of the subclavian artery was seen in 7 (28%) out of the 25 consecutive patients treated for subclavican artery stenosis. Mean lesion length was 14 +/- 4.3 mm. The mean preprocedure diameter stenosis was reduced from 83.2 +/- 14.9% to 9.6 +/- 5.4% postprocedure. Procedural success was achieved in all patients. Clinical follow-up was obtained in all patients. The initial success was maintained at follow-up (mean = 12 +/- 4 months) in 24 (96%) patients. Recurrence of symptoms occurred in 1 (4%) patient who had an angiographically documented restenosis four months after the procedure. It was successfully redilated. CONCLUSION: Stenting for subclavian artery obstructive disease is safe, technically feasible and has favorable clinical outcomes. It may be considered as the therapy of choice for subclavian artery obstructive disease.

Journal Article↗

Clinical and angiographic results with the NIR stent: First International NIR Endovascular Stent Study (FINESS-II).

BACKGROUND: Although safety and efficacy of the NIR trade mark stent have been reported, the long-term angiographic and clinical outcomes have yet to be investigated. The FINESS-II study (First International NIR Endovascular Stent Study) was designed to assess the procedural safety of single 9 and 16 mm NIR stent implantation, the six-month restenosis rate and finally the six- and 12-month clinical outcome of patients treated with this novel coronary stent. METHODS: Patients with angina and a single de novo lesion in a native coronary artery of >3 and <5 mm diameter were included in this multicentre, prospective, observational trial. Clinical follow-up was obtained at one, six and 12 months. Angiography was performed before and after the stent implantation and at six months. The primary endpoint included major adverse cardiac events (death, myocardial infarction and target lesion revascularization) within 30 days after the procedure. Major bleeding complications and subacute stent thrombosis within the first 30 days were also reported as specific endpoints. Secondary endpoints were major cardiac-event-free survival at six- and 12-month follow-up and angiographic restenosis at six months. RESULTS: A total of 156 patients (81% male, mean age 60 +/- 10 years), with stable (54%), unstable (40%) angina pectoris or silent ischemia (6%) were enrolled. The target vessel diameter was 2.94 +/- 0.54 mm. The minimal lumen diameter pre, post and at follow-up was 1.04 +/- 0.32 mm, 2.64 +/- 0.42 mm and 1.88 +/- 0.63 mm, respectively. Restenosis rate according to the >50% diameter stenosis criterion at six month follow-up was 19% (26/136). At 12 months, the event-free survival rate was 83% (two deaths, one Q-wave and three non-Q-wave myocardial infarctions, four bypass surgery and 17 target lesion revascularizations), while 87% of the patients were free of angina pectoris. CONCLUSION: the outcome of the FINESS-II trial is comparable to those observed in previous stent trials (Benestent II), indicating that the coronary NIR stent is safe and effective as a primary device for the treatment of native coronary artery lesions in patients with (un)stable angina pectoris.

Journal Article↗

Recanalization of chronic total coronary occlusions: the impact of a new specific guidewire on primary success rate.

BACKGROUND: Although chronic total occlusions are encountered frequently in patients with coronary artery disease, an effective strategy to deal with them has yet to be devised. Various new guidewires have been designed in an attempt to negotiate chronic occlusions successfully. The authors have analysed the impact of the Athlete guidewire on procedural success in this lesion subset. METHODS: Sixty-two consecutive patients undergoing percutaneous intervention for chronic total occlusions over a two-year period were retrospectively studied. For the initial attempt, conventional guidewires were used. In case of failure, further attempts were made using the Athlete guidewire. Procedural success rates with the use of conventional and Athlete guidewires were assessed. RESULTS: Failure of the first attempt with the conventional guidewire occurred in 32 (51.6%) patients and success was achieved in 30 (48.4%) patients. In the former patients, a second attempt was made using the Athlete guidewire to cross the occlusion. The second attempt was successful in 20 patients (60%) in whom the first attempt was unsuccessful, while in the remaining 12 (40%) patients the occlusion could not be crossed even during the second attempt and the procedure was then terminated. Following the use of the Athlete guidewire, the success rate increased to 62% (p < 0.001). No complication occurred during the first attempt, while one patient had a coronary perforation using the Athlete guidewire, which was managed successfully without the need for bypass surgery. CONCLUSION: The use of the Athlete guidewire is feasible and safe, and enhances the chances of successfully treating chronic total occlusions during percutaneous coronary revascularization procedures.

Journal Article↗