Restenosis

Restenosis

Restenosis literally means the reoccurrence of stenosis, a narrowing of a blood vessel, leading to restricted blood flow. Restenosis usually pertains to an artery or other large blood vessel that has become narrowed, received treatment to clear the blockage and subsequently become renarrowed. This is usually restenosis of an artery, or other blood vessel, or possibly a vessel within an organ. This term is common in vascular surgery, cardiac surgery, and angioplasty, all branches of medicine that frequently treat narrowing of blood vessels. [1]

It can be defined as a reduction in the circumference of the lumen of 50% or more, and had a high incidence rate (25-50%) in patients who had undergone balloon angioplasty, with the majority of patients needing further angioplasty within 6 months. [2]

Angioplasty and Stenting

Contents

Causes

Usually surgery to widen or unblock a blood vessel has a long lasting beneficial effect for the patient. However in some cases, the procedure itself can cause further narrowing of the vessel, or restenosis. Angioplasty also called Percutaneous transluminal coronary angioplasty (PTCA) is commonly used to treat blockages of the coronary arteries,or peripheral arteries such as the limbs. The balloon inserted into the narrowing ‘smashes’ the cholesterol plaques (atherosclerosis) against the artery walls, thus widening the size of the lumen and increasing blood flow. However the action does damage to the artery walls, and it responds by using physiological mechanisms to repair the damage. (See physiology below) [3] A stent is a mesh tube-like structure often used in conjunction with angioplasty to permanently hold open an artery, allowing for unrestricted blood flow, or to support a weakness in the artery wall called an aneurysm. The artery can react to the stent, perceive it as a foreign body and respond by mounting an immune system response (see physiology below) which leads to further narrowing near to or inside the stent.

Physiology

Damage to the blood vessel wall by angioplasty triggers physiological response that can be divided into two stages. The first stage that occurs immediately after tissue trauma, is thrombosis. A blood clot forms at the site of damage and further hinders blood flow. This is accompanied by an inflammatory immune response.

The second stage tends to occur 3–6 months after surgery and is the result of proliferation of cells in the intima, a smooth muscle wall in the vessel. This is also known as Neointimal hyperplasia (NIHA)[4]

Prevention

In the first stage of restenosis, administering anti-platelet drugs (called IIb/IIIa inhibitors) immediately after surgery greatly reduces the chance of a thrombosis occurring.

Drug-eluting stents are now being trialled in Europe and the USA, as well as in Asia-Pacific. These stents are coated with pharmaceuticals that inhibit tissue growth and thus reduce the risk of restenosis from scar-tissue and cell proliferation. [1] There has been some success with these new stents in reducing the occurrence of restenosis, with clinical studies showing an incidence rate of 5% or lower. [5]

Treatment

If restenosis occurs without a stent, it is usually treated with more angioplasty. Once restenosis has occurred and been treated by angioplasty, the chances of restenosis occurring again are increased by a factor of 2.This treatment is also used if restenosis occurs at either end of the stent.

If restenosis occurs within a stent it may be treated with repeated angioplasty and insertion of another stent inside the original; occasionally using a drug-eluted stent.

Alternative treatments include brachytherapy, or intracoronary radiation. The radiation kills cells and inhibits tissue growth (similar to a patient undergoing cancer therapy).

Images of restenosis with bare-metal stents and drug-eluting stents are here .

References

  1. ^ a b Forgos, Richard M.D. (August 2004)http://heartdisease.about.com/cs/angioplastystents/a/restenosis.htm
  2. ^ Hamid, Huda (2007). "Miracle Stents-a future without restenosis". MJM McGill Journal of Medicine July 10: 105–111;. 
  3. ^ Kirchengast, Michael; Munter, Klaus (17th March 1988). "Endothelin and restenosis". Cardiovascular Research (Ludwigshafen, Germany: Knoll AG) 39 (3): 550–555. doi:10.1016/S0008-6363(98)00143-6. PMID 9861296. 
  4. ^ Clowes, Alexander M.D. VascularWeb, Society for Vascular Surgery https://dev.vascularweb.org/research/Pages/prevention-of-neointimal-hyperplasia-taxol-,-rapamycin-,-and-radiation.aspx
  5. ^ Hamid, Huda (2007). "Miracle Stents-a future without restenosis". MJM McGill Journal of Medicine July 10: 105–111;. 

See also

External links

  • British Heart Foundation-Angioplasty [1]
  • American Heart Association-Stenting [2]

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Look at other dictionaries:

  • restenosis — Recurrence of stenosis after corrective surgery on the heart valve; narrowing of a structure (usually a coronary artery) following the removal or reduction of a previous narrowing. [re , + G. stenosis, a narrowing] * * * re·ste·no·sis .res tə nō… …   Medical dictionary

  • restenosis — n. recurrent stenosis, usually in a blood vessel after such procedures as angioplasty or insertion of a stent. Restenosis can complicate 20–50% of such procedures …   The new mediacal dictionary

  • restenosis — noun Etymology: New Latin Date: 1954 the reoccurrence of stenosis in a blood vessel or heart valve after it has been treated with apparent success …   New Collegiate Dictionary

  • restenosis — Re occlusion of coronary arteries after angioplasty (PTCA) or after replacement with blood vessels from elsewhere. Probably due to excessive proliferation of vascular smooth muscle that inappropriately thickens the intima and narrows the lumen …   Dictionary of molecular biology

  • restenosis — noun ɹɛstɛˈnəʊsɪsˌɹiːstɛˈnəʊsɪs The recurrence of stenosis, especially that of an artery …   Wiktionary

  • restenosis — re·ste·no·sis …   English syllables

  • restenosis — ˌrestə̇ˈnōsə̇s, ˌrē noun Etymology: re + stenosis : the reoccurrence of stenosis in a blood vessel or heart valve after it has been treated with apparent success …   Useful english dictionary

  • true restenosis — restenosis occurring after complete opening of one or both of the commissures of the cardiac valve involved …   Medical dictionary

  • false restenosis — stenosis recurring after failure to divide either commissure of the cardiac valve beyond the area of incision of the papillary muscles …   Medical dictionary

  • рестеноз — (restenosis; ре + стеноз) повторное сужение просвета какого либо органа после его расширения оперативным путем …   Большой медицинский словарь

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