Wednesday, June 9, 2010

Lasers in Angioplasty/Angiography

Laser Angioplasty


Angioplasty
Angioplasty is used to widen arteries, which are narrowed by stenoses or occlusions. This procedure is helpful in many ways, like, clearing of plaque from coronary arteries, emergency relief from a heart attack that is in progress, and widening narrowed arteries in limbs, such as the femoral or iliac artery to the leg. It is also useful in relieving chest pain, caused by narrowing down of coronary arteries. Angioplasty performed earlier was done by dilating the blood vessel with the introduction of larger stiff catheters, through the narrowed space. However, complications involved in this procedure gave motive to scientists and researchers, to develop a means of widening the vessel using a minimally sized device. Now lasers may be used to assist in the break up of fat or calcium plaque and catheters may also be equipped with spinning wires or drill tips to clean out the plaque.

Laser Angioplasty
In the laser angioplasty technique, a thin and flexible plastic tube called a catheter, with a laser at its tip, is used. It is inserted into an artery that opens into coronary arteries blocked by plaque, a build-up of cholesterol, cells and other fatty substances in an artery's inner lining. Then the plastic tube is advanced through the artery to the blockage in the coronary artery, and it emits pulsating beams of light from where the laser is in position. These lasers help in vaporizing the plaque. The laser technology can be used alone, or in combination with balloon angioplasty. If used along with balloon angioplasty, the balloon is inserted first to attack the hard plaque.

In laser angioplasty mostly eximer laser is used.

Eximer Laser

An excimer laser (sometimes, and more correctly, called an exciplex laser) is a form of ultraviolet laser which is commonly used in angioplasty, eye surgery and semiconductor manufacturing.

The term excimer is short for 'excited dimer', while exciplex is short for 'excited complex'. An excimer laser typically uses a combination of an inert gas (argon, krypton, or xenon) and a reactive gas (fluorine or chlorine).

Under the appropriate conditions of electrical stimulation, a pseudo-molecule called an excimer (or in case of noble gas halides, exciplex) is created, which can only exist in an energized state and can give rise to laser light in the ultraviolet range.

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