Stents Essay

3887 Words Nov 12th, 2012 16 Pages
Introduction

Stents were first developed in the late 1970s out of a need to keep coronary arteries open after balloon angioplasty (Cohen, 2006). Balloon angioplasty can weaken the arteries, sometimes causing them to collapse within a few days (Cohen, 2006). At that time, the only treatment available was emergency bypass graft surgery (Cohen, 2006). Further, angioplasty was causing restenosis in almost one-third of all patients (Cohen, 2006). Bare metal stents were developed in the mid 1980s out of a need to prevent or lower the incidences of restenosis due to angioplasty.

While bare metal stents solved the problem of artery closure during the hospital stay, restenosis continued to occur in patients who received bare metal
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The catheter is guided by imaging technology such as a camera through the artery to the site of blockage. Once the catheter is at the site of blockage, the balloon is inflated. As the balloon inflates, plaque and calcium that are clogging the artery are pressed against the wall of the artery and held in place by the stent. The balloon is then deflated, and the catheter is retracted out through the access site.

Bare Metal Stents

Bare metal stent inserted onto a balloon catheter (Cohen 2006).

Bare metal stents were developed in the mid 1980s in an attempt to prevent artery collapse and restenosis in patients receiving an angioplasty. Bare metal stents are cylindrical and developed in a mesh pattern and is made primarily of stainless steel, but can also consist of metals such as titanium alloy and nickel and titanium alloy, platinum and platinum iridium alloys, some cobalt chromium alloys, and other metals that have a high biocompatibility with low memory. Throughout the 1990s, incremental improvements were made by various companies such as using different types of metal or changing the structure of the stent. However, restenosis was still occurring in a significant number of patients who had bare metal stents implanted.

Drug Eluting Stents

Drug eluting stents were developed in an attempt to reduce the occurrence of restenosis at the site of stent implantation. Drug eluting stents have a metal framework that is coated with the pharmaceutical mixed with

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