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Information about Stent

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Endoscopic image of self-expanding metallic stent in esophagus, which was used to palliatively treat esophageal cancer.
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Endoscopic image of biliary stent seen protruding from ampulla of Vater at the time of duodenoscopy
In medicine, a stent is a tube that is inserted into a natural conduit of the body to prevent or counteract a disease-induced localized flow constriction.

Applications

The main purpose of a stent is to counteract significant decreases in vessel or duct diameter by acutely propping open the conduit by a mechanical scaffold or stent. Stents are often used to alleviate diminished blood flow to organs and extremities beyond an obstruction in order to maintain an adequate delivery of oxygenated blood. Although the most common use of stents is in coronary arteries, they are widely used in other natural body conduits, such as central and peripheral arteries and veins, bile ducts, esophagus, colon, trachea or large bronchi, ureters, and urethra.

Etymology

The origin of the word stent remains unsettled. The verb stenting was used for centuries for the process of stiffening garments (a usage long obsolete, per the OED) and some believe this to be the origin. 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 the English dentist Charles Stent (1807–1885), which Esser employed to craft a form for facial reconstruction. The full account is described in the Journal of the History of Dentistry. [1] According to the author, from the use of Stent's compound as support for facial tissues grew the eventual use of stent to open various bodily structures. Worth noting though is that the first "stents" used in medical practice were initially called "Wallstents".

Types of stent

Vascular

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- Therapy: Stent implantation versus Coronary bypass surgery Coronary heart disease (CHD) is a major cause of morbidity and mortality throughout the world, and both surgical revascularisation (coronary artery bypass grafting, CABG) and percutaneous coronary intervention (PCI) are established treatment options. The rapid developments in both surgical and percutaneous techniques have been such that the choice of the optimum revascularisation strategy is changing, often without an established evidence base; this is particularly true in complex conditions including patients with three-vessel and left main stem anatomy. The widespread use of drug eluting stents has resulted in a significant reduction in patients referred for CABG although published data favours the surgical approach in this high-risk group.
  • The SYNTAX Trial[1] aims to explore the interface between treatment with CABG and PCI in patients with three-vessel and left main stem disease, comparing CABG using contemporary techniques and PCI using drug eluting TAXUS stents. The aim of the trial is to establish non-inferiority of PCI with CABG. The unique feature of the SYNTAX trial is the ‘all comers’ strategy. A team comprising a cardiac surgeon and an interventional cardiologist assesses each patient; if equivalent revascularisation is applicable using both techniques, the patient is accepted for randomization; if either CABG or PCI is deemed unsuitable for technical reasons or the presence of co-morbidities, then the patient is recruited into one of two parallel registries which will track these patients undergoing either CABG or PCI. The patient will not be included in the randomized cohort. 1800 patients will be randomized (1:1) between CABG and PCI. The primary end-point is a major adverse, cardiac and cerbrovascular event at one year. All patients will be followed for five years. Of the 1800 patients, 710 with left main stem disease will be randomized between CABG and PCI. In this sub-group, repeat cardiac catheterisation will be undertaken after the one-year primary endpoint to determine graft and native vessel patency (the Le Mans sub-study).
  • The SYNTAX Trial is one of the most important trials ever undertaken in the field of coronary revascularisation and will provide a rational basis for choosing the optimum revascularisation strategy in patients for many years to come.
- Problems: One of the drawbacks of vascular stents is the potential development of a thick smooth muscle tissue inside the lumen, the so-called neointima. Development of a neointima is variable but can at times be so severe as to re-occlude the vessel lumen (restenosis), especially in the case of smaller diameter vessels, which often results in reintervention. Consequently, current research focuses on the reduction of neointima after stent placement. Considerable improvements have been made, including the use of more bio-compatible materials, anti-inflammatory drug-eluting stents, resorbable stents, and others. Fortunately, even if stents are eventually covered by neointima, the minimally invasive nature of their deployment makes reintervention possible and usually straightforward.

Urinary Tract

  • Urethral/Prostatic Stents
- A urethral/prostatic stent might be needed if a man is unable to urinate. Often this situation occurs when an enlarged prostate pushes against the urethra, blocking the flow of urine. The placement of a stent can open the obstruction, allowing volitional voiding.

- In the U.S., there are currently only two FDA approved urethral stents: a temporary use stent, The SpannerTM by AbbeyMoor Medical, Inc. [2]; and a permanent stent, The UrolumeTM by American Medical Systems.
  • Ureteral Stents

Other

  • CHD Stent
  • Rectal Stent
  • Oesophageal Stent
  • Biliary Stent
  • Pancreatic Stent

See also

References

External links

Medicine is the science and "" of maintaining and/or restoring human health through the study, diagnosis, and treatment of patients. The term is derived from the Latin ars medicina meaning the art of healing.
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The coronary circulation is the circulation of blood in the blood vessels that supply blood to and from the heart muscle itself. Although blood fills the chambers of the heart, the muscle tissue of the heart, or myocardium, is so thick that it requires coronary blood vessels to
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Arteries are muscular blood vessels that carry blood away from the heart.[1] All arteries, with the exception of the pulmonary and umbilical arteries, carry oxygenated blood.

The circulatory system is extremely important for sustaining life.
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vein is a blood vessel that carries blood toward the heart. The majority of veins in the body carry low-oxygen blood from the tissues back to the heart; the exceptions being the pulmonary and umbilical veins which both carry oxygenated blood.
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A bile duct is any of a number of long tube-like structures that carry bile.

Bile, required for the digestion of food, is excreted by the liver into passages that carry bile toward the hepatic duct, which joins with the cystic duct (carrying bile to and from the
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The esophagus (also spelled oesophagus/œsophagus, Greek οἰσοφάγος), or gullet
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colon is another name for the large intestine. The main function of the colon appears to be extraction of water from feces. In mammals, it consists of the ascending colon, transverse colon, the descending colon, and the sigmoid colon.
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trachea, or windpipe, is a tube that has an inner diameter of about 20-25 mm and a length of about 10-16cm. It extends from the larynx to the primary (main) bronchi in mammals, and from the pharynx to the syrinx in birds, allowing the passage of air to the lungs.
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A bronchus (plural bronchi, adjective bronchial) is a caliber of airway in the respiratory tract that conducts air into the lungs. No gas exchange takes place in this part of the lungs.
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In human anatomy, the ureters are the ducts that carry urine from the kidneys to the urinary bladder, passing anterior to the psoas major. The ureters are muscular tubes that can propel urine along by the motions of peristalsis. In the adult, the ureters are usually 25-30cm long.
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In anatomy, the urethra is a tube which connects the urinary bladder to the outside of the body. The urethra has an excretory function in both genders to pass urine to the outside, and also a reproductive function in the male, as a passage for sperm.
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The Oxford English Dictionary (OED) is a dictionary published by the Oxford University Press (OUP), and is the most comprehensive dictionary of the English language.
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Johannes "Jan" Fredericus Samuel Esser (1877–1946) was a Dutch plastic surgeon who pioneered innovative methods of reconstructive surgery on soldiers wounded in the First World War.
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Charles Stent (1807-1885) was a nineteenth-century English dentist notable for his advances in the field of denture making.

In 1847, Edwin Truman introduced gutta-percha as a material for making dental impressions; however, this was unsatisfactory for several reasons,
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stent graft is a tubular device, which is composed of special fabric supported by a rigid structure, usually metal. The rigid structure is called a stent. An average stent on its own has no covering, and therefore is usually just a metal mesh.
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drug-eluting stent is a stent (a scaffold) placed into narrowed, diseased coronary arteries that slowly releases a drug to block cell proliferation. This prevents scar-tissue–like growth that, together with clots (thrombus), could otherwise block the stented artery.
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Coronary heart disease
Classification & external resources

ICD-10 I20-I25
ICD-9 410 - 414 , 429.2

Coronary heart disease (CHD), also called coronary artery disease (CAD), ischaemic heart disease, atherosclerotic heart disease, is the end result
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Percutaneous coronary intervention (PCI), commonly known as coronary angioplasty or simply angioplasty, is a therapeutic procedure to treat the stenotic (narrowed) coronary arteries of the heart found in coronary heart disease.
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Smooth muscle is a type of non-striated muscle, found within the "walls" of hollow organs and elsewhere like the bladder and abdominal cavity, the uterus, male and female reproductive tracts, the gastrointestinal tract, the respiratory tract, the vasculature, the skin and the
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A lumen (pl. lumina) is an inner space, lining or cavity.
  • The interior of a vessel within the body, such as the small central space in an artery or vein, or any of their relating vessels through which blood flows.

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Restenosis literally means the reoccurrence of stenosis. This is usually restenosis of an artery, or other blood vessel, but possibly any hollow organ that has been "unblocked".
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drug-eluting stent is a stent (a scaffold) placed into narrowed, diseased coronary arteries that slowly releases a drug to block cell proliferation. This prevents scar-tissue–like growth that, together with clots (thrombus), could otherwise block the stented artery.
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International or internationally most often describes interaction between nations, or encompassing two or more nations, constituting a group or association having members in two or more nations, or generally reaching beyond national boundaries.
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Myocardial infarction
Classification & external resources

Diagram of a myocardial infarction (2) of the tip of the anterior wall of the heart (an apical infarct
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patient is any person who receives medical attention, care, or treatment. The person is most often ill or injured and in need of treatment by a physician or other medical professional.
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An emergency is a situation which poses an immediate risk to health, life, property or environment.[1] Most emergencies require urgent intervention to prevent a worsening of the situation, although in some situations, mitigation may not be possible and agencies
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Arteries are muscular blood vessels that carry blood away from the heart.[1] All arteries, with the exception of the pulmonary and umbilical arteries, carry oxygenated blood.

The circulatory system is extremely important for sustaining life.
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The Macro Expansion Template Attribute Language complements TAL, providing macros which allow the reuse of code across template files. Both were created for Zope but are used in other Python projects as well.
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Mount Sinai School of Medicine is a medical school found in the borough of Manhattan in New York City. The official name is Mount Sinai School of Medicine of New York University due to its academic affiliation with New York University (NYU).
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State of New York

Flag of New York Seal
Nickname(s): The Empire State
Motto(s): Excelsior!

Official language(s) None

Capital Albany
Largest city New York City

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