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Biomedical subjects

Antonio Colombo

Publications and source records attributed to Antonio Colombo.

At least 19 recordsLinked to original sources
PubMed2003

Effectiveness of treatment of in-stent restenosis with an 8-French compatible atherectomy catheter.

The study reports the results of directional atherectomy with an 8Fr guiding catheter-compatible atherectomy catheter in a series of 31 in-stent restenotic lesions. This preliminary experience indicates a favorable safety profile, with events limited to non-Q-wave myocardial infarction occurring in 3.6% of patients. The secondary end point regarding the incidence of angiographic restenosis at 6 months showed a high restenosis rate (65%).

Aged↗
PubMed2003

Randomized study to assess the effectiveness of slow- and moderate-release polymer-based paclitaxel-eluting stents for coronary artery lesions.

BACKGROUND: Early clinical studies demonstrated the feasibility of local paclitaxel delivery in reducing restenosis after treatment of de novo coronary lesions in small patient populations. METHODS AND RESULTS: We conducted a randomized, double-blind trial of 536 patients at 38 medical centers evaluating slow-release (SR) and moderate-release (MR) formulations of a polymer-based paclitaxel-eluting stent (TAXUS) for revascularization of single, primary lesions in native coronary arteries. Cohort I compared TAXUS-SR with control stents, and Cohort II compared TAXUS-MR with a second control group. The primary end point was 6-month percent in-stent net volume obstruction measured by intravascular ultrasound. Secondary end points were 6-month angiographic restenosis and 6- and 12-month incidence of major adverse cardiac events, a composite of cardiac death, myocardial infarction, and repeat revascularization. At 6 months, percent net volume obstruction within the stent was significantly lower for TAXUS stents (7.9% SR and 7.8% MR) than for respective controls (23.2% and 20.5%; P<0.0001 for both). This corresponded with a reduction in angiographic restenosis from 17.9% to 2.3% in the SR cohort (P<0.0001) and from 20.2% to 4.7% in the MR cohort (P=0.0002). The incidence of major adverse cardiac events at 12 months was significantly lower (P=0.0192) in the TAXUS-SR (10.9%) and TAXUS-MR (9.9%) groups than in controls (22.0% and 21.4%, respectively), predominantly because of a significant reduction in repeat revascularization of the target lesion in TAXUS-treated patients. CONCLUSIONS: Compared with a bare metal stent, paclitaxel-eluting stents reduced in-stent neointimal formation and restenosis and improved 12-month clinical outcome of patients with single de novo coronary lesions.

Coated Materials, Biocompatible↗
PubMed2003

Correlation of coronary arterial remodeling determined by intravascular ultrasound with angiographic diameter reduction of 20% to 60%.

Negative remodeling is commonly observed in stenotic coronary lesions. It is unknown whether negative remodeling is an early or late event. This study was designed to elucidate when negative remodeling occurs in the development of coronary stenosis. Remodeling was assessed by preintervention intravascular ultrasound in 104 native coronary lesions with intermediate stenosis (20% to 60% of diameter stenosis measured by quantitative coronary angiography). Positive remodeling was defined as lesion external elastic membrane (EEM) cross-sectional area (CSA) greater than the proximal reference, intermediate remodeling as lesion EEM CSA between those of the proximal and distal references, and negative remodeling as lesion EEM CSA less than the distal reference. Positive, intermediate, and negative remodeling were observed in 18%, 32%, and 50%, respectively, of lesions with intermediate stenosis. Lesions with negative and intermediate remodeling had more hard plaque compared with those with positive remodeling (79% vs 70% vs 42%, p = 0.02). Calcium was more frequent in lesions with negative and intermediate remodeling than in those with positive remodeling (52% vs 55% vs 16%, p = 0.01). Lesions with negative remodeling had smaller EEM CSA (11.5 +/- 5.2 vs. 13.7 +/- 3.4 vs 14.5 +/- 5.6 mm(2), p = 0.03) and less plaque (7.9 +/- 4.6 vs 10.8 +/- 3.4 vs 10.8 +/- 4.9 mm(2), p = 0.004) compared with positive and intermediate remodeling lesions, although lumen CSA (3.7 +/- 1.7 vs 2.8 +/- 0.8 vs 3.6 +/- 1.3 mm(2), p = 0.1) and area stenosis (57 +/- 15% vs 59 +/- 14% vs 56 +/- 10%, p = 0.7) were similar. Negative remodeling is frequently observed in lesions with intermediate stenosis. This suggests that negative remodeling occurs early in lesion formation.

Aged↗
PubMed2003

Randomized evaluation of polytetrafluoroethylene-covered stent in saphenous vein grafts: the Randomized Evaluation of polytetrafluoroethylene COVERed stent in Saphenous vein grafts (RECOVERS) Trial.

BACKGROUND: Treatment of lesions located in saphenous vein grafts (SVGs) is associated with increased procedural risk and a high rate of restenosis. METHODS AND RESULTS: We conducted a randomized, multicenter trial to evaluate the usefulness of a polytetrafluoroethylene (PTFE)-covered stent compared with a bare stainless steel (SS) stent for prevention of restenosis and major adverse cardiac events (MACE) in patients undergoing SVG treatment. The primary end point was angiographic restenosis at 6 months. Secondary end points were 30-day and 6-month MACE rates, defined as the cumulative of death, myocardial infarction (MI), and target lesion revascularization. Between September 1999 and January 2002, 301 patients with SVG lesions were randomized to either the PTFE-covered JoStent coronary stent graft (PTFE group, n=156) or the SS JoFlex stent (control group, n=145). Angiographic and procedural success rates were similar between the 2 groups (97.4% versus 97.9% and 87.3% versus 93.8%, respectively). The incidence of 30-day MACE was higher in the PTFE group (10.9% versus 4.1%, P=0.047) and was mainly attributed to MI (10.3% versus 3.4%, P=0.037). The primary end point, the restenosis rate at 6-month follow-up, was similar between the 2 groups (24.2% versus 24.8%, P=0.237). Although the 6-month non-Q-wave MI rate was higher in the PTFE group (12.8% versus 4.1%, P=0.013), the cumulative MACE rate was not different (23.1% versus 15.9%, P=0.153). CONCLUSIONS: The study did not demonstrate a difference in restenosis rate and 6-month clinical outcome between the PTFE-covered stent and the SS stent for treatment of SVG lesions. However, a higher incidence of nonfatal myocardial infarctions was found in patients treated with the PTFE-covered stent.

Adult↗
PubMed2003

Preliminary observations regarding angiographic pattern of restenosis after rapamycin-eluting stent implantation.

BACKGROUND: Restenosis after implantation of drug-eluting stents (DES) is a rare phenomenon, occurring more frequently peri-stent. METHODS AND RESULTS: We evaluated the pattern of restenosis occurring after implantation of DES in unselected lesions. From April 15 to December 6, 2002, we treated 368 patients with 735 lesions by using 841 rapamycin-eluting stents (Cypher, Cordis, a Johnson & Johnson Company). Mean baseline lesion length was 17.48+/-12.19 mm, and mean stent length was 27.59+/-14.02 mm. Follow-up ischemia-driven angiography was performed in 24 patients. Eleven patients had angiographic restenosis (> or =50% diameter stenosis) in 14 stented segments (stent and 5 mm proximal and distal to the stent). The pattern of restenosis in all 14 stented segments was focal, and in 6 of them it was multifocal, occurring inside the stents. Mean length of restenotic lesions was 5.62+/-1.90 mm, with a range from 2.54 to 8.44 mm. One multifocal restenosis involved also the distal stent margin. Intravascular ultrasound evaluation at follow-up, performed in 2 patients, showed significant lumen obstruction attributable to in-stent hyperplasia in both cases. Individual cases can be viewed in the Data Supplement. CONCLUSIONS: The pattern of restenotic lesions after rapamycin-eluting stent implantation was focal and mostly inside the stent.

Aged↗
PubMed2003

A new dedicated stent and delivery system for the treatment of bifurcation lesions: preliminary experience.

We report the first clinical experience in eight patients with a new stent and delivery system specifically designed for the treatment of bifurcational lesions. The device (AST SLK-View system) consists of a premounted stent and a delivery system. The stent has a side aperture, which orients toward the ostium of the side branch. The system allows deployment of the stent while the access to both main and side branches is maintained by two wires. We evaluated this system in nine bifurcations. The location of bifurcations was left descending artery/diagonal branch in four lesions, left circumflex/obtuse marginal branch in three lesions, and postero-lateral branch/posterior descending artery in two lesions. Predilation was performed in six lesions of the main branches and in five lesions of the side branches. The stent was effectively delivered to all bifurcations except for one, in which the target lesion was located at a distal segment and the device could not be delivered. Following stent implantation in the main branch, two lesions at the side branches were treated by stent, while the other lesions were treated by balloon angioplasty without difficulty. Final kissing balloon was performed in four bifurcation lesions. No adverse event was observed during 1 month of clinical follow-up. Treatment of bifurcation lesions with this new dedicated device appears to be feasible. This new device may introduce a new approach for the treatment of coronary bifurcation lesions.

Aged↗
PubMed2003

Initial multicenter experience with a novel distal protection filter during carotid artery stent implantation.

Atheroembolization resulting in transient or permanent neurologic impairment is the most common complication of catheter-based percutaneous carotid artery intervention. Protection of the distal cerebral vasculature during carotid stent implantation may enhance procedural safety. Carotid stent implantation with distal cerebral protection using the FilterWire EX was performed in 35 consecutive patients undergoing 36 procedures at six centers. The FilterWire was delivered and deployed successfully in all 36 cases, and embolic material was retrieved from 74% of procedures. The 30-day rate of major adverse events (death, major or minor stroke) was 0%. Transient ipsilateral periprocedural neurologic ischemia developed in two patients (5.7%), both resolving within 30 min. Distal cerebral protection with the FilterWire during carotid stenting is feasible and safe, results in capture and extraction of atheroembolic debris in the majority of patients while affording uninterrupted cerebral perfusion, and in this initial multicenter experience was associated with a high rate of procedural success without major complications.

Aged↗
PubMed2003

Intravascular ultrasound based dose assessment in endovascular brachytherapy.

BACKGROUND: the role of endovascular brachytherapy in restenosis prevention is well documented. Dose is usually prescribed at a fixed distance from the source axis by angiographic quantification of vessel diameter. Recently, intravascular ultrasound (IVUS) was introduced in dose prescription, allowing a better evaluation of the vessel anatomy. This study retrospectively explores the difference between prescription following angiographic vessel sizing and delivered dose calculated with IVUS. METHODS AND RESULTS: Seventeen lesions were studied with IVUS, identifying on irradiated segment, three sections on which measuring minimal and maximal distance from the centre of IVUS catheter to the adventitia; using dedicated software, corresponding doses were calculated. The dose ranged widely, with maximal and minimal values of 71.6 and 4.9 Gy; furthermore, heterogeneity in dose among different sections was observed. In the central section, the maximal dose was 206% of the one prescribed with the QCA model at 2 mm from the source axis, while the minimal dose was 96%. In proximal and distal sections, respective values were 182, 45, 243, and 122%. CONCLUSIONS: Our analysis confirmed the dose inhomogeneity delivered with an angiographic fixed-dose prescription strategy. A dose variation was found along the irradiated segment due to the differences in vessel thickness. IVUS emerged as an important tool in endovascular brachytherapy, especially for irregular-shaped vessels.

Angioplasty, Balloon, Coronary↗
PubMed2003

Transplantation of autologous endothelial cells induces angiogenesis.

This study examined the feasibility and efficacy of autologous endothelial cell (EC) transplantation using a fibrin matrix in the ischemic myocardium of sheep. Four weeks after placing an ameroid constrictor in the circumflex artery of 12 adult sheep, four animals (EC group) were subjected to EC transplantation. In four others (saline [SAL] group) saline with added inactivated cells was injected and four animals served as controls. Eight weeks after treatment the animals were sacrificed to assess histology and ultrastructure. Eight weeks after injection, ventricular function was markedly improved in the EC transplant group, but had deteriorated in the SAL and control groups. Myocardial blood flow was also increased in the EC group. Histology and electron microscopy revealed extensive neovascularization after EC transplantation and improved myocardial appearance. Heterotopic transplantation of EC within a fibrin matrix enhances neovascularization, increases myocardial blood flow, and improves left ventricular function.

Animals↗
PubMed2003

Elective versus provisional intra-aortic balloon pumping in high-risk percutaneous transluminal coronary angioplasty.

BACKGROUND: Elective intra-aortic balloon pump (IABP) support may reduce acute complications occurring during percutaneous coronary interventions (PCI) in patients with severe depression of the left ventricular ejection fraction (EF < or = 30%). METHODS: Since February 1998, 133 consecutive patients with EF < or =30% underwent elective PCI in our institution; 61 had elective preprocedural IABP support (group A) and 72 patients had conventional PCI (group B). Jeopardy score was calculated in each patient from the coronary angiograms to quantify the myocardium at risk. RESULTS: EF was similar in the 2 groups. Jeopardy score was higher in group A (8.0 +/- 2.8 vs 6.7 +/- 2.4, P =.008). The other principal clinical and angiographic characteristics were similar in the 2 groups. Severe hypotension and/or shock occurred in 11 patients, all in group B (P =.001). All required urgent IABP support, and 3 eventually died. Intraprocedural major adverse cardiac and cerebral events (eg, myocardial infarction, severe hypotension and/or shock, urgent bypass surgery, stroke, and death) were higher in group B (17% vs 0%, P =.001). By stepwise logistic regression analysis, elective IABP support (odds ration [OR] 0.11 [95% CI 0.21-0.60], P =.011), jeopardy score (OR 5.37 [95% CI 1.10-8.70], P =.040), and female sex (OR 2.72 [95% CI 1.85-3.10], P =.015), were the correlates of intraprocedural events. CONCLUSIONS: This study supports the potential usefulness of elective versus provisional IABP to prevent intraprocedural major adverse cardiac and cerebral events in high-risk PCI.

Aged↗
PubMed2003

Regional thrombolytic therapy and stent implantation in an acutely occluded aortobifemoral bypass graft.

PURPOSE: To present a case highlighting the efficacy of local thrombolysis followed by stent implantation in acute occlusion of an aortobifemoral bypass graft. CASE REPORT: A 47-year-old man was referred to our catheterization laboratory for acute bilateral limb ischemia occurring 18 hours after an aortobifemoral bypass procedure. Angiography documented total occlusion due to massive thrombosis of the grafts. After 24 hours of local thrombolysis, repeat angiography showed complete lysis of the thrombus and an intimal flap in the abdominal aorta. A Palmaz stent was successfully implanted to cover the flap and restore adequate flow. At 1 year, the patient remains asymptomatic, and angiography showed patency of both the stent and the grafts. CONCLUSIONS: Based on this patient's response, local thrombolysis followed by stenting may be a safe and effective alternative to reoperation for the treatment of acute graft thrombosis caused by an intimal aortic flap. More experience with this approach is necessary to determine if this is an acceptable and effective mode of treatment.

Acute Disease↗