Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. Thromboembolism is a general term describing both thrombosis and its main complication: dislodgement of a clot and embolisation.
Classically, thrombosis is caused by abnormalities in one or more of the following (Virchow's triad):
The composition of the blood
Quality of the vessel wall
Nature of the blood flow
The formation of a thrombus is usually caused by an injury to the vessel's wall, either by trauma or infection, and by the slowing or stagnation of blood flow past the point of injury. Occasionally, abnormalities in coagulation are to blame. Intravascular coagulation follows, forming a structureless mass of red blood cells, leukocytes, and fibrin.
If a bacterial infection is present at the site of thrombosis, the thrombus may break down, spreading particles of infected material throughout the circulatory system (pyemia, septic embolus) and setting up metastatic abscesses wherever they come to rest. Without an infection, the thrombus may become detached and enter circulation as an embolus, finally lodging in and completely obstructing a blood vessel (an infarction). The effects of an infarction depend on where it occurs.
Most thrombi, however, become organized into fibrous tissue, and the thrombosed vessel is gradually recanalized.
Stent thrombosis in patients who receive DES is a primary area of interest for the agency because of the potential for serious adverse outcomes—even though stent thrombosis occurs at low rates.
The CYPHER Sirolimus-eluting Coronary Stent is indicated for improving coronary luminal diameter in patients with symptomatic ischemic disease due to discrete de novo lesions of length ≤ 30 mm in native coronary arteries with reference vessel diameter of ≥2.5 mm to ≤3.5 mm.
The TAXUS Express Paclitaxel-Eluting Coronary Stent System is indicated for improving luminal diameter for the treatment of de novo lesions ≤28 mm in length in native coronary arteries ≥2.5 to ≤3.75 mm in diameter.
Such plaques, which cannot be detected by commonly-used tests such as a treadmill examination and even coronary angiography, are suspected to be the cause of most sudden cardiac deaths and non-fatal heart attacks.
Coronary artery disease is the leading cause of death in developed nations.
The cause of most heart attacks is rupture of a plaque in the coronary arteries followed by formation of a clot that blocks the flow of blood to heart muscle.
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