Angioplasty Info and the Stent, Part 1
(reconstruction of blood vessels damaged by disease or injury usually performed by inflating a balloon inside the blood vessel lumen (tube) in order to reconstitute the flow of blood)
The Original Stent
A stent was originally a compound used in making dental molds and it is now said to include any material or device that is used to hold tissue in place or to provide a support for a graft or anastomosos (connection of normally separate parts or spaces) while healing is taking place. To put it another way, a stent is an expandable wire mesh tube that is inserted into a hollow structure of the body (a vessel or a vein, etc.) to keep it open.
Charles Stent (1807-1885) was a nineteenth-century dentist notable for his advances in the field of denturemaking. In 1847, Edwin Truman introduced gutta-percha (inelastic natural latex produced from the sap of Palaquium gutta trees) as a material for making dental impressions; however, this was unsatisfactory for several reasons, including its tendency to distort upon removal from the patient's mouth, and to shrink upon cooling.
In 1856, Stent added several other materials to the gutta-percha, notably stearine, which markedly improved the plasticity of the material as well as its stability. He also added talc as an inert filler to give more body to the material, and to its red coloring.
Main Reasons for Using Stents
The main purpose of a stent is to overcome important decreases in vessel or duct diameter. Stents are often used to diminish pressure differences in blood flow to organs beyond an obstruction in order to maintain an adequate delivery of oxygen. Although perhaps the most popular use of stents is linked to the coronary arteries, they are widely used in several other structures; such as, peripheral arteries and veins, bile ducts, esophagus, trachea or large bronchi, ureters, and the urethra.
Intraluminal Coronary Artery Stent
In this situation, this is a stent that is made of an inert material, usually stainless steel, with a self-expanding mesh introduced into the coronary artery. It is used to prevent lumen closure (restenosis: narrowing of a duct or canal) following bypass surgery and to treat acute vessel closure after angioplasty.
A Urologic Stent
This is a cylindrical device made of mesh that is inserted into the ureter or urethra during cystoscopy (the microscopic examination of cells for purposes of diagnosis). The stent is kept collapsed while being inserted. After insertion, it opens up and presses against the wall. Eventually, the normal tissue grows through the mesh, and within several months this forms a smooth unobstructed lumen.
Stents are used in ureters to relieve urinary obstructions due to edena, trauma, or pressure from kidney stones or from a tumor outside the ureter. They are used in the urethra to relieve obstruction from benign prostatic hypertrophy or strictures of the urethra.
Stents are of particular benefit to patients whose physical condition prevent them from undergoing surgery.
There is more information about angioplasty; as well as, the stent at the following links:
Angioplasty Info and the Stent, Part 2
Angioplasty Info and the Stent, Part 3
Angioplasty Info and the Stent, Part 4
Angioplasty Info and the Stent, Part 5
Angioplasty Info and the Stent, Part 6
Angioplasty Info and the Stent, Part 7