Biomedical subjects
Publications and source records attributed to Antonio Colombo.
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Drug-eluting stents (DES) represent one of the fastest-growing fields in interventional cardiology today. Paclitaxel (Taxol) is a potent antiproliferative agent that shifts the microtubule equilibrium toward assembly, favoring the formation of abnormally stable microtubules with blockage of the cell cycle in G2/M phases. A series of clinical trials (TAXUS I through VI) have been designed to test the safety and the efficacy of polymer- based paclitaxel-eluting stents (Taxus, Boston Scientific, Natick, MA, USA) at the dosage 1 microg/mm(2) in a variety of clinical settings. Except for TAXUS III and TAXUS V-ISR, in the TAXUS program de novo lesions have been evaluated. Two different release kinetics were evaluated: slow-release (SR) and moderate- release (MR) formulation. Very encouraging preliminary results also come from the "real world" data on Taxus SR stent collected in the "Web-based taxus Intercontinental obServational Data TransitiOnal registry prograM" (the WISDOM Registry) and in the "Real Life Polymer-Based Paclitaxel Registry" (the Real Life PBPaclitaxel Registry). The remarkable positive results obtained from the randomized trials offer the interventional cardiologist another effective option (besides the Cypher stent, Cordis a J & J, Warren, NJ, USA) to treat patients with a DES. This fact may certainly drive the competition and, ultimately, lower the cost. The final answer will probably come from the ongoing registries and prospective trials versus coronary artery bypass grafting (CABG), which will reveal the real impact of this new technology on everyday practice.
BACKGROUND AND METHOD: Although direct coronary stenting does not improve angiographic outcome, it makes sense by reducing procedure times, radiation exposure and costs. Other potential advantages of direct stenting may be a reduction of myocardial ischemia time, which could be clinically relevant in high-risk patients. With the introduction of drug-eluting stents, however, concern arose that direct stenting would possibly damage the polymer coating and change or diminish the efficacy of the programmed drug release. Also, concerns about safety by preventing optimal apposition of single stent struts developed. It is the purpose of this paper to retrospectively analyze the data from the TAXUS-II Trial (536 patients) regarding patients with and without direct stenting. While predilatation was recommended per protocol, direct stenting was not forbidden: thus, direct stenting was performed in 49 patients (TAXUS n = 23, control n = 26). RESULTS: In the TAXUS groups, there was no significant difference regarding major adverse cardiac events (MACE; 7.5% vs. 4.3%), angiographic restenosis in the analysis segment (4.8% vs. 4.3%), late loss (0.28 +/- 0.36 vs. 0.33 +/- 0.30 mm) or intravascular ultrasound-(IVUS-)measured volume obstruction (7.95 +/- 9.84% vs. 5.61 +/- 7.91%) at six months between the predilated and directly stented patients. The same was true for the patients receiving the control stent. Compared with the directly stented control group, the statistically significant positive effects of TAXUS direct stenting were maintained, regarding angiographic restenosis in the analysis segment (4.3% vs. 30.8%), late loss (0.33 +/- 0.30 vs. 0.80 +/- 0.62 mm) or IVUS-measured volume obstruction (5.61 +/- 7.91% vs. 22.50 +/- 21.62%) at six months. MACE was reduced from 19.2% to 4.3%; due to the small number of patients this trend did not reach statistical significance. After predilatation, all parameters were significantly improved by the TAXUS stent. CONCLUSION: Comparison of patients receiving TAXUS stents with or without predilatation revealed no differences in clinical, angiographic or IVUS parameters at six months. This suggests that direct stenting with the polymer-based paclitaxel-eluting TAXUS stent is feasible, safe and equally effective. Randomized trials comparing stenting after predilatation versus direct stenting with drug-eluting stents are warranted.
BACKGROUND: Patients with acute coronary syndromes (ACS; unstable angina and non-ST-segment elevation myocardial infarction) are at significant risk for death and myocardial infarction. Early angiography followed by revascularization is considered the treatment of choice for moderate- to high-risk patients with ACS. However, despite the integration of newer therapies including stents, glycoprotein IIb/IIIa inhibitors, and thienopyridines, the rate of adverse ischemic events still remains unacceptably high, and the intensive pharmacologic regimens used to stabilize the disrupted atherosclerotic plaque and support angioplasty and surgical revascularization procedures elicit a high rate of bleeding complications. Pilot trials suggest that the thrombin-specific anticoagulant bivalirudin may improve clinical outcomes in ACS. STUDY DESIGN: In the Acute Catheterization and Urgent Intervention Triage strategY (ACUITY) trial, 13,800 patients with moderate- to high-risk ACS are being prospectively randomly assigned at up to 600 centers to unfractionated heparin or enoxaparin + IIb/IIIa inhibition, versus bivalirudin + IIb/IIIa inhibition, versus bivalirudin + provisional IIb/IIIa inhibition. All patients undergo cardiac catheterization within 72 hours, followed by percutaneous or surgical revascularization when appropriate. In a second random assignment, patients assigned to receive IIb/IIIa inhibitors are subrandomized to upstream drug initiation, versus IIb/IIIa inhibitor administration during angioplasty only. The primary study end point is the composite of death, myocardial infarction, unplanned revascularization for ischemia, and major bleeding at 30 days. Clinical follow-up will continue for 1 year. CONCLUSIONS: The ACUITY trial is the largest study yet performed in patients with ACS undergoing an invasive strategy. In addition to evaluating the utility of bivalirudin in ACS, this study will also provide important guidance regarding the necessity for and timing of IIb/IIIa inhibitor administration.
AIMS: Prophylactic administration of N-acetylcysteine (NAC) (600mg orally twice daily), along with hydration, prevents contrast agent-associated nephrotoxicity (CAN) induced by a low dose of non-ionic, low-osmolality contrast dye. We tested whether a double dose of NAC is more effective to prevent CAN. METHODS AND RESULTS: Two-hundred-twenty-four consecutive patients with chronic renal insufficiency (creatinine level > or =1.5mg/dl and/or creatinine clearance <60ml/min), referred to our institution for coronary and/or peripheral procedures, were randomly assigned to receive 0.45% saline intravenously and NAC at the standard dose (600mg orally twice daily; SD Group; n=110) or at a double dose (1200mg orally twice daily; DD Group; n=114) before and after a non-ionic, low-osmolality contrast dye administration. Increase of at least 0.5mg/dl of the creatinine concentration 48h after the procedure occurred in 12/109 patients (11%) in the SD Group and 4/114 patients (3.5%) in the DD Group (P=0.038; OR=0.29; 95% CI=0.09-0.94). In the subgroup with low (<140ml, or contrast ratio <=1) contrast dose, no significant difference in renal function deterioration occurred between the 2 groups. In the subgroup with high (> or =140ml, or contrast ratio >1) contrast dose, the event was significantly more frequent in the SD Group. Conclusions Double dose of NAC seems to be more effective than the standard dose in preventing CAN, especially with high volumes of non-ionic, low-osmolality contrast agent.
A group of investigators met for two days in Santorini, Greece, to discuss progress in the field of identification and treatment of high risk/vulnerable atherosclerotic plaques and patients. Many differences in the manner in which terms are being utilized were noted. It was recognized that increased understanding of the pathophysiology of coronary thrombosis and onset of acute coronary syndromes has created the need for agreement on nomenclature. The participants spent considerable time discussing the topic and reached agreement on their own usage of the terms as described below. It is the hope that this usage might be of value to the larger community of scientists working in this field, and that widespread adoption of a common nomenclature would accelerate progress in the prevention of acute coronary events.
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The role of inflammation in the development of restenosis after percutaneous coronary interventions has been investigated in several studies. There is an interaction of inflammatory activation and vascular wall response to injury leading to intimal hyperplasia. Percutaneous interventions trigger inflammatory reactions leading to the development of intimal hyperplasia. This reaction is even more prominent in atheromatic plaques in which inflammatory cells have already been activated. In the clinical setting there are several methods for the recognition of the inflammatory activation. In this article we review the data for the role of inflammatory process in restenosis and the significance of identifying the inflamed lesions prior to the intervention. Moreover, the therapeutic implications for the inhibition of inflammatory activation are mentioned.
AIMS: Peri-procedural non-Q-wave myocardial infarction is a frequent and prognostically important complication of percutaneous coronary intervention (PCI). It has been postulated that statins may reduce the rate of myocardial injury after PCI. METHODS AND RESULTS: Four hundred and fifty-one patients scheduled for elective PCI and not on statins were randomly assigned to either no treatment or to statin treatment. Statin administration was started at least 3 days before the procedure.Incidence of peri-procedural myocardial injury was assessed by analysis of creatinine kinase myocardial isoenzyme (CK-MB: upper limit of normal [ULN] 3.5 ng/ml) and cardiac troponin I (cTn I, ULN 0.10 ng/ml) before, 6 and 12 h after the intervention. A large non-Q-wave myocardial infarction was defined as a CK-MB elevation >5 times ULN alone or associated with chest pain or ST segment or T wave abnormalities. Median CK-MB peak after PCI was 1.70 (interquartile ranges 1.10-3.70) ng/ml in the Statin group and 2.20 (1.30-5.60) ng/ml in the Control group (p=0.015). Median peak of cTnI after PCI was 0.13 (0.05-0.45) ng/ml in the Statin group and 0.21 (0.06-0.85) ng/ml in the Control group (p=0.033). The incidence of a large non-Q-wave myocardial infarction was 8.0% in the Statin group and 15.6% in the Control group (p=0.012: OR=0.47; 95% CI=0.26-0.86). The incidence of cTnI elevation >5 times ULN was 23.5% in the Statin group and 32% in the Control group (p=0.043: OR=0.65; 95% CI=0.42-0.98). By logistic regression analysis, the independent predictors of CK-MB elevation >5 times ULN after PCI were intra-procedural angiographic complications (OR=9.36; 95% CI=3.06-28.64; p<0.001), statin pre-treatment (OR=0.33; 95% CI=0.13-0.86; p=0.023) and age >65 years (OR=2.58; 95% CI=1.09-6.11; p=0.031). CONCLUSIONS: Pre-procedural statin therapy reduces the incidence of large non-Q-wave myocardial infarction after PCI.
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PURPOSE: To report the use of endovascular stenting for treatment of patients with symptomatic obstruction of brachiocephalic surgical reconstructions. METHODS: Twenty-two patients (17 men; mean age 65+/-6 years) with 24 symptomatic obstructions of brachiocephalic Dacron bypass grafts (2 aorto-innominate, 9 subclavian-carotid, and 11 carotid-subclavian) were treated with balloon-expandable stents delivered via a percutaneous brachial access or surgical exposure of the common carotid artery. A distal protection device was utilized in the 9 patients with subclavian-carotid bypass grafts. All patients were followed by clinical and Doppler examinations. RESULTS: Procedural success was 100%; 1 (4.5%) patient developed transient intraprocedural aphasia owing to intolerance to the distal protection balloon occlusion. All 22 patients reported complete relief of their presenting symptoms. Over a 29-month follow-up, 3 (13.6%) restenoses were found, but none was due to stent compression. CONCLUSIONS: Stenting for obstructed brachiocephalic reconstructions appears to be a safe, effective, and durable therapeutic strategy.
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