Current interventional cardiology reports最新文献

Coronary stents have improved the short- and long-term outcomes of patients undergoing catheter-based coronary interventions. However, the use of these devices in complex coronary lesions has also created an incessant form of in-stent restenosis that still defies treatment. Plaque burden has been consistently and reproducibly recognized as an important factor that may incite neointimal proliferation after stent implantation. Prospective nonrandomized experience has shown that plaque removal prior to stent implantation using directional atherectomy is a promising approach to reduce restenosis in selected patients. However, the proof of concept awaits the results of the randomized trials. Ultimately, the clinical use (safety and efficacy) of this approach will depend on 1) further improvements on the current directional atherectomy device to make it user friendly; 2) minimizing the incidence of non-Q-wave myocardial infarction with selective use of IIb-IIIa platelet receptor antagonists or distal protection devices; and 3) targeting patients at high risk for restenosis in whom efficient debulking is feasible. This would include patients who have noncalcified lesions in vessels greater than 2.75 mm but less than 3.5 mm in diameter that require a long stent or multiple stents, aorto-ostial lesions, bifurcational lesions, and chronic total occlusions.

For more than 25 years, basic experiments using cell culture and animal experimental techniques have predicted superior thrombin inhibition with use of low molecular weight heparin (LMWH) rather than unfractionated heparin (UFH). This should have application in the cardiac laboratory, where thrombin control is essential to securing a safe and optimal therapeutic angioplasty for patients with atherosclerotic heart disease. Despite much interest, few meaningful clinical studies have been completed and there are limited clinical data to establish the magnitude of benefit actually conferred through use of LMWH rather than UFH among most patients undergoing elective or urgent cardiac catheterization procedures. At this point, the available data suggest minimal clinical advantage is to be gained through the use of LMWH over UFH. Also, obtaining this modest advantage may require an extended period of drug therapy before and after intervention. Any benefit conferred is likely restricted to the period shortly after coronary intervention. On the other hand, available data suggest that serious bleeding should not be problematic despite difficulties measuring that antithrombin effect among patients receiving LMWH, even when it is combined with potent platelet inhibitor therapy. Although cell culture and animal experiments suggest that heparin compounds should be effective in limiting intimal hyperplasia (and therefore clinical restenosis) after angioplasty, randomized clinical trials have failed thus far to show any restenosis benefit for either UFH or LMWH. Ongoing studies will clarify the use of combining LMWH with potent antiplatelet agents as combined medical adjuncts to coronary intervention.

This article reviews the field of low molecular weight heparins for arterial thrombosis and interventional cardiology. Particular emphasis is paid to the drugs dalteparin and fraxiparine. Pre-clinical and clinical trial data are summarized.

In this review, historical developments related to transcatheter occlusion of atrial septal defects (ASDs) are discussed. Since the initial description by King of transvenous closure of secundum ASDs in the mid 1970s, a variety of double disc and single disc devices have been designed and tested in animal models and human subjects. Feasibility, safety, and effectiveness have been demonstrated. Further developments are likely to result in the availability of device closure technology to all patient subsets.

The Angel Wings Das device (Microvena Corporation, White Bear Lake, MN) is a self-centering, nitinol-polyester prosthesis with two square-shaped disks and a customized delivery catheter. The implantation success rate for atrial septal defects (ASDs) was 92% and 94% in the Phase I and II trials in the United States, and 97% and 100% for patients with patent foramen ovale (PFO). Residual shunts in the Phase II United States trials at 24 hours by transthoracic echocardiography are as follows: For patients with ASDs, 86% have no or less than 1-mm shunts and 14% have 1- to 2-mm shunts. None of the patients had a large residual shunt. Patients with PFOs had no significant residual shunts at 24 hours. There were no device-related deaths, embolization after successful closure, or episodes of infective endocarditis. The device has been modified to have two circular disks. It is retrievable into the delivery catheter and repositionable. The Angel Wings II device is anticipated to enter clinical use in the near future.

Platelet glycoprotein IIb/IIIa receptors are the final common pathway leading to platelet aggregation and coronary thrombosis during acute myocardial infarction (AMI). Therefore, they are ideal candidates for pharmacologic intervention. The recent development of glycoprotein IIb/IIIa receptor antagonists has led to several studies that have shown the benefits and efficacy of these agents in the treatment of acute coronary syndromes and in the setting of percutaneous intervention. To date, six published trials have examined the safety and efficacy of intravenous abciximab, a mouse/human chimeric version of the 7E3 antibody, as an adjunct to primary mechanical reperfusion in patients with AMI. In this article, we review these trials, as well as new studies currently underway that will provide further information on the long-term benefits of combining these pharmacologic agents and stenting in the treatment of AMI.

Ultrasound at high energy, as distinct from the low energy used in ultrasound imaging, has found many uses in varied branches of medicine and surgery. Clinical trials of catheter-delivered, high-energy, low-frequency (kHz) ultrasound over the past 6 years have shown the safety of this modality in the treatment of coronary artery disease and have identified a number of indications in which its use, as an adjunct to conventional percutaneous transluminal coronary angioplasty (PTCA) techniques, may offer therapeutic advantages. Thrombus-mediated conditions--such as myocardial infarction, chronic total occlusion, and atherosclerosis in small vessels--appear to derive particular benefit from ultrasound treatment. Recent developments in these fields are reviewed.

The nonsurgical treatment of occlusive iliac arterial disease is undergoing continued improvement. No longer is conservative management the primary alternative for patients with symptomatic but noncritical limb ischemia. The low morbidity, the option for repeating the procedures, as well as good long-term results, makes these techniques a first- line treatment option. In focal iliac disease, the technique of balloon angioplasty is often adequate to allow for an acceptable result. However, in more complicated diffuse diseases, the adjunctive use of stents, thrombolysis, laser, and atherectomy may be necessary for success. Accurate patient and lesion assessment as well as following clinical outcomes is imperative for the continuing acceptance of these less invasive therapies.