Seminars in interventional cardiology : SIIC最新文献

The rising costs of health care have forced policy makers to make choices, and new treatments are increasingly assessed in terms of the balance between additional costs and additional effects. The recent recognition that stenting has a major and long-lasting effect enhancing balloon PTCA procedure has made it imperative to compare in patients with multivessel disease the standard surgical procedure with multiple stenting in a large scale multinational and multicentre approach (19 countries, 68 sites). Selection and inclusion of patients is based on a consensus of the cardiac surgeon and interventional cardiologist on equal 'treatability' of patients by both techniques with analysis of clinical follow-up (event-free survival) on the short (30 day), medium (1 year), and long-term (3 and 5 year) with analysis of cost-effectiveness and quality of life (EuroQol and SF-36). Of the entire trial, the primary null hypothesis which needs to be rejected is that there will be no difference in event-free survival or effectiveness (E), at 1 year and also that the direct and indirect costs (C) per event-free year are not different between surgery or stenting. For this to become significant with a power of 90% one needs 1200 patients. Between April 97 and June 98, 1205 patients have been randomized with a monthly recruitment of 83 patients. Expected costs, effects and cost-effectiveness ratio (CE ratio) are: Stent high costs 2 VDStent high costs 3 VDStent low costs 2 VDStent low costs 3 VDCABG costs (C)$19.297$24.566$16.638$20.456$21.350 effects (E)81%81%81%81%88% CE ratio$23.876$30.397$20.586$25.322$24.348 Clinically, stenting is not expected to be more effective than CABG, but should be cost effective in both the 2- and 3-VD group when using the lower cost estimate and in the 2 VD group when using the higher cost assumptions.

Inflammation has recently been shown to be an important pathogenetic component of atherosclerosis in general and of acute coronary syndromes in particular. Not only activated inflammatory cells have been found in the plaques, but, more interestingly, also activated circulating inflammatory cells as well as elevated levels of systemic markers of inflammation have been described. Among these, C-reactive protein is of clinical value, as its levels are associated with the outcome. Inflammation is important also in triggering the mechanisms of restenosis and CRP has been recently described as a useful pre-procedure marker of risk of restenosis. The cause of inflammation, what triggers the shift from an indolent disease to the acute coronary syndromes and the more appropriate therapies are still a matter of debate.

Despite considerable progress, pharmacological therapies have not provided a complete solution for common cardiovascular problems, including recurrent thrombosis, restenosis, and vein graft deterioration. Optimal drug dosage, reproducing plasma concentrations achieved in animal studies establishing proof-of-principle, would often be too toxic to administer, especially when given over prolonged periods of time. Local gene therapy aims at overexpressing proteins that: (1) regulate the cell cycle of VSMC; (2) inhibit VSMC migration; (3) endow the endothelium with its vasoprotective properties; and (4) stimulate growth of endothelium and angiogenesis. Alternatively, some approaches tend to suppress gene expression of proteins believed to promote VSMC proliferation and migration. In sharp contrast to drug treatments, local gene therapy limits expression of the beneficial agent to the injured vascular site, and there, it can extend the presence of this agent to weeks and, with some gene vectors, to many months. The clinical potential of this approach has led to the initiation of trials that currently evaluate gene therapy approaches to the attenuation of peripheral and myocardial ischaemia and the prevention of vein graft disease.

Diabetes mellitus is a potent risk factor for the development of atherosclerosis. Patients with diabetes account for approximately 20% of patients presenting with acute coronary syndromes or for percutaneous coronary intervention. Furthermore, the incidence of diabetes continues to increase world-wide, such that substantial medical resources are allocated for the care of patients with diabetic cardiovascular complications. Although great strides have been made in reducing cardiovascular events in recent years, there has been little improvement in outcomes for patients with diabetes mellitus. This review will focus in the underlying patho-biology and the current status of therapeutic interventional strategies for patients with diabetes mellitus.

In humans, circulating levels of angiotensin-converting enzyme (ACE) are linked with an insertion (I)/deletion (D) polymorphism in the ACE gene: DD genotype bearers have higher levels of ACE than either ID or II genotype bearers. Recent studies have suggested that the ACE DD genotype might be associated with a higher risk of coronary artery disease. The aim of this paper is to review studies on the influence of the I/D polymorphism on coronary restenosis. The renin-angiotensin system has been implicated in the pathogenesis of neointimal hyperplasia in experimental models. In humans, the I/D polymorphism is not associated with restenosis after balloon angioplasty, but is strongly associated with restenosis after coronary stent implantation. This may be explained by the fact that the contribution of neointimal hyperplasia to restenosis is much more important after coronary stent implantation than after balloon angioplasty.

The high frequency of premature atherosclerosis in patients with homocystinuria suggested the hypothesis of an association between hyperhomocysteinemia and coronary heart disease. Experimental studies have shown that severe homocysteinemia has toxic effects on the endothelium and may alter haemostatic balance. Although case controls studies have suggested a significant association between mild hyperhomocyst(e)inemia and coronary heart disease, prospective studies have not completely confirmed these findings. Results from the ongoing randomized trials will help determine whether reduction of homocysteine levels will be associated with a reduction of cardiac events and possibly mortality in patients.

Both the implantation of intracoronary stents and the use of glycoprotein IIb/IIIa receptor blocking agents have been proven to be of value in the invasive management of coronary artery disease. Stenting is shown to decrease restenosis rate considerably, and is of great use in countering complications of balloon angioplasty, e.g. dissection and abrupt closure. The use of glycoprotein IIb/IIIa receptor blocking agents has been demonstrated to be beneficial as an adjunctive to intracoronary interventions; it has a profound effect on the rate of acute intervention related complications, but not on the occurrence of chronic restenosis. The scope of this article is to evaluate the usefulness of the combination of stents and glycoprotein IIb/IIIa blocking agents in various manifestations of coronary artery disease. It is concluded that a glycoprotein IIb/IIIa receptor antagonist as an adjunctive to the application of a stent is especially useful when thrombus can be assumed to be present in a clinically relevant quantity.