Angiographic follow-up after placement of a self-expanding coronary-artery stent

Article Abstract:

The goal of coronary angioplasty is to dilate coronary arteries that have been narrowed by atherosclerotic plaques, and thus improve the blood supply of the heart and reduce the risk of heart attack. In practice, however, arteries may abruptly occlude after surgery, and are, in fact, quite likely to narrow again in the months following surgery as a result of intimal hyperplasia (the overgrowth of the intimal lining of the arteries). One device that has been used to reduce acute occlusion and restenosis is the stent. A ''stent'' has come to mean any device that holds tissue in place. In the case of artery surgery, a stent is a tubular mesh that is implanted inside the artery and presses against the arterial wall. The first use of arterial stents in coronary artery surgery occurred in 1986, and in 1988 a study was organized to evaluate the effectiveness of the method in maintaining patent vessels. While the initial results indicated that the use of a stent provided improved outcomes in some patients, acute occlusion remained a problem. Furthermore, longer term results indicated that the early improvements observed in some patients were not always sustained. Of 117 coronary patients implanted with an arterial stent, 8 patients died within the first year. Of 95 patients followed-up with angiography (X-ray of vessels), complete occlusion of the stent occurred in 24 percent (27 stents); 21 of these were early occlusions, which occurred within two weeks of surgery. Although overall the average diameter of the arteries with stents was improved immediately after surgery, within the first year fewer than 40 percent of the patients managed to avoid restenosis of the artery or death. The results demonstrate that the performance of the arterial stent is far from what had been hoped. The role of this device in the treatment of coronary artery disease is not at all clear. (Consumer Summary produced by Reliance Medical Information, Inc.)

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Coronary-artery stents and other endoluminal devices

Article Abstract:

In the January 3, 1991 issue of The New England Journal of Medicine, researchers describe the long-term follow-up of coronary patients treated with endoluminal stents. The idea is simple; insert an expanding stainless steel device into an artery that has been surgically dilated. Initial optimism soon yielded to reality, as it became clear that the risks of the device were higher than expected, and over the long term, the arteries became re-occluded in spite of, perhaps even because of, the presence of the stents. A great many techniques have been developed to open arteries obstructed by atherosclerosis (the accumulation of fatty plaques inside vessels). As clever and sophisticated as many of these techniques are, from 25 to 40 percent of the treated arteries will again become blocked. Any device will cause disruption of the atherosclerotic plaques and desquamation of the endothelial lining of the arteries. Unfortunately, these events set the stage for platelet adhesion and aggregation and the potential for clot formation. The smooth muscle of the arteries, growth factors, white blood cells, and a host of other factors contribute to events that are not sufficiently understood. In the long run, only improvements in our knowledge of the physiology of coronary arteries will eventually result in satisfactory biologic solutions to problems that can not be solved by simple mechanical devices. (Consumer Summary produced by Reliance Medical Information, Inc.)

editorial

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A pooled analysis of data comparing sirolimus-eluting stents with bare-metal stents

Article Abstract:

A pooled analysis data from four randomized trials is used to evaluate the safety of sirolimus-eluting stents as compared with bare-metal stents. The results have shown no significant differences between the two treatments in rates of death, myocardial infarction, or stent thrombosis.

United States, Care and treatment, Thrombosis, Blood clot, Clinical report

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