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Jai Ganesh

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Registered: 2005-06-28

Posts: 46,295

Stent

Stent

Gist

A stent is a small mesh tube typically used to hold open passages in the body, such as weak or narrowed arteries. Stents are often used to treat narrowed coronary arteries that provide the heart with oxygen-rich blood.

Summary

A stent is a tiny tube placed into a hollow structure in your body. This structure can be an artery, a vein, or another structure, such as the tube that carries urine (ureter). The stent holds the structure open.

Description

When a stent is placed into the body, the procedure is called stenting. There are different kinds of stents. Most are made of a metal or plastic mesh-like material. However, stent grafts are made of fabric. They are used in larger arteries.

A coronary artery stent is a small, self-expanding, metal mesh tube. It is placed inside a coronary artery after balloon angioplasty. This stent prevents the artery from re-closing.

A drug-eluting stent is coated with a medicine. This medicine helps further prevent the arteries from re-closing. Like other coronary artery stents, it is left permanently in the artery.

Why the Procedure is Performed

Most of the time, stents are used when arteries become narrow or blocked.

Stents are commonly used to treat the following conditions that result from blocked or damaged blood vessels:

* Coronary heart disease (CHD) (angioplasty and stent placement - heart)
* Peripheral artery disease (angioplasty and stent replacement - peripheral arteries)
* Renal artery stenosis
* Abdominal aortic aneurysm (aortic aneurysm repair - endovascular)
* Carotid artery disease (carotid artery surgery)

Other reasons to use stents include:

* Keeping open a blocked or damaged ureter (percutaneous urinary procedures)
* Treating aneurysms, including thoracic aortic aneurysms
* Keeping bile flowing in blocked bile ducts (biliary stricture)
* Helping you breathe if you have a blockage in the airways

Risks

Related topics include:

* Angioplasty and stent placement - heart
* Angioplasty and stent placement - peripheral arteries
* Percutaneous urinary procedures
* Transjugular intrahepatic portosystemic shunt (TIPS)
* Carotid artery surgery
* Aortic aneurysm repair - endovascular
* Thoracic aortic aneurysm

Alternative Names

Drug-eluting stents; Urinary or ureteral stents; Coronary stents.

Details

In medicine, a stent is a metal or plastic tube inserted into the lumen of an anatomic vessel or duct to keep the passageway open, and stenting is the placement of a stent. A wide variety of stents are used for different purposes, from expandable coronary, vascular and biliary stents, to simple plastic stents that allow urine to flow between kidney and bladder. "Stent" is also used as a verb to describe the placement of such a device, particularly when a disease such as atherosclerosis has pathologically narrowed a structure such as an artery.

A stent is different from a shunt. A shunt is a tube that connects two previously unconnected parts of the body to allow fluid to flow between them. Stents and shunts can be made of similar materials, but perform two different tasks.

Etymology

The current accepted origin of the word stent is that it derives from the name of an English dentist, Charles Thomas Stent (1807–1885), notable for his advances in the field of denture-making. A dentist in London, he is most famous for improving and modifying the denture base of the gutta-percha, creating the stent's compounding that made it practical as a material for dental impressions. Others attribute the noun stent to Jan F. Esser, a Dutch plastic surgeon who in 1916 used the word to describe a dental impression compound invented in 1856 by Charles Stent, whom Esser employed to craft a form for facial reconstruction. The full account is described in the Journal of the History of Dentistry. According to the author, from the use of Stent's compound as a support for facial tissues evolved the use of a stent to hold open various body structures.

The verb form "stenting" was used for centuries to describe the process of stiffening garments (a usage long obsolete, per the Oxford English Dictionary), and some believe this to be the origin. According to the Merriam Webster Third New International Dictionary, the noun evolved from the Middle English verb stenten, shortened from extenten 'to stretch', which in turn came from Latin extentus, the past participle of extendō 'to stretch out'.

The first (self-expanding) "stents" used in medical practice in 1986 by Ulrich Sigwart in Lausanne were initially called "Wallstents" after their inventor, Hans Wallstén. Julio Palmaz et al. created a balloon-expandable stent that is currently used.

History

The first use of a coronary stent is typically attributed to Jacques Puel [fr] and Ulrich Sigwart, who implanted a stent into a patient in Toulouse, France, in 1986. That stent was used as a scaffold to prevent a vessel from closing and to avoid restenosis in coronary surgery—a condition where scar tissue grows within the stent and interferes with vascular flow. Shortly thereafter, in 1987, Julio Palmaz (known for patenting a balloon-expandable stent) and Richard Schatz implanted their similar stent into a patient in Germany.

Though several doctors have been credited with the creation of the stent, the first FDA-approved stent in the U.S. was created by Julio Palmaz, Richard Schatz and coworkers. Named the Palmaz-Schatz (Johnson & Johnson), it was developed in 1987.

To further reduce the incidence of restenosis, the drug-eluting stent was introduced in 2003. Research has led to general stent design changes and improvements since that time. Bioresorbable scaffolds have also entered the market, though a large-scale clinical trial showed higher acute risks compared to drug-eluding stents. As a result, the FDA issued an official warning for their use in 2013, and research on the design and performance optimisation of stents is ongoing.

Additional Information

A stent is a tiny tube that your doctor can insert into a blocked passageway to keep it open. The stent restores the flow of blood or other fluids, depending on where it’s placed.

Stents are made of either metal or plastic. Stent grafts are larger stents used for larger arteries. They may be made of a specialized fabric. Stents can also be coated with medication to help keep a blocked artery from closing.

Why would I need a stent?

Stents are usually needed when plaque blocks a blood vessel. Plaque is made of cholesterol and other substances that attach to the walls of a vessel.

You may need a stent during an emergency procedure. An emergency procedure is more common if an artery of the heart called a coronary artery is blocked. Your doctor will first place a catheter into the blocked coronary artery. This will allow them to do a balloon angioplasty to open the blockage. They’ll then place a stent in the artery to keep the vessel open.

Stents can also be useful to prevent aneurysms from rupturing in your brain, aorta, or other blood vessels.

Besides blood vessels, stents can open any of the following passageways:

* bile ducts, which are tubes that carry bile to and from digestive organs
* bronchi, which are small airways in the lungs
* ureters, which are tubes that carry urine from the kidneys to the bladder

These tubes can become blocked or damaged just like blood vessels can.

How do I prepare for a stent?

Preparing for a stent depends on the type of stent being used. For a stent placed in a blood vessel, you’ll usually prepare by taking these steps:

* Tell your doctor about any drugs, herbs, or supplements you take.
* Don’t take any drugs that make it harder for your blood to clot, such as aspirin, clopidogrel, ibuprofen, and naproxen.
* Follow your doctor’s instructions about any other drugs you should stop taking.
* Quit smoking if you smoke.
* Inform your doctor of any illnesses, including a common cold or flu.
* Don’t drink water or any other fluids the night before your surgery.
* Take any medications your doctor prescribes.
* Arrive at the hospital with plenty of time to prepare for surgery.
* Follow any other instructions your doctor gives you.

You’ll receive numbing medicine at the site of the incision. You’ll also get intravenous (IV) medication to help you relax during the procedure.

How is a stent performed?

There are several ways to insert a stent.

Your doctor usually inserts a stent using a minimally invasive procedure. They will make a small incision and use a catheter to guide specialized tools through your blood vessels to reach the area that needs a stent. This incision is usually in the groin or arm. One of those tools may have a camera on the end to help your doctor guide the stent.

During the procedure, your doctor may also use an imaging technique called an angiogram to help guide the stent through the vessel.

Using the necessary tools, your doctor will locate the broken or blocked vessel and install the stent. Then they will remove the instruments from your body and close the incision.

What are the complications associated with inserting a stent?

Any surgical procedure carries risks. Inserting a stent may require accessing arteries of the heart or brain. This leads to an increased risk of adverse effects.

The risks associated with stenting include:

* an allergic reaction to medications or dyes used in the procedure
* breathing problems due to anesthesia or using a stent in the bronchi
* bleeding
* a blockage of the artery
* blood clots
* a heart attack
* an infection of the vessel
* kidney stones due to using a stent in the ureters
* a re-narrowing of the artery

Rare side effects include strokes and seizures.

Few complications have been reported with stents, but there’s a slight chance the body will reject the stent. This risk should be discussed with your doctor. Stents have metal components, and some people are allergic or sensitive to metals. Stent manufacturers recommend that if anyone has a sensitivity to metal, they should not receive a stent. Speak with your doctor for more information.

If you have bleeding issues, you will need to be evaluated by your doctor. In general, you should discuss these issues with your doctor. They can give you the most current information related to your personal concerns.

More often than not, the risks of not getting a stent outweigh the risks associated with getting one. Limited blood flow or blocked vessels can create serious and deadly consequences.

What happens after a stent insertion?

You may feel a bit of soreness at the incision site. Mild painkillers can treat this. Your doctor will probably prescribe anticoagulant medication to prevent clotting.

Your doctor will typically want you to remain in the hospital overnight. This helps ensure there are no complications. You might need to stay even longer if you needed the stent because of a coronary event, such as a heart attack or stroke.

When you return home, drink plenty of fluids and restrict physical activity for some time. Make sure to follow all of your doctor’s instructions.

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