Prevention Of Thrombosis

Posted on September 28, 2008
Filed Under Hypertension |

What is thrombosis?
Thrombosis is a pathological phenomenon in which a vein or an artery of the circulatory system becomes blocked by a thrombus, which is a kind of cap formed by cells and blood clots, thus preventing further blood flow by the glass from that point .

The circulatory system consists of a network of blood vessels that transport blood from the heart to various organs and tissues (arterioles and capillaries) and a net return of vessels (venules and veins) that allows the return of blood to lungs. There, the red blood cells expel carbon monoxide and load carrying oxygen again. The lungs, returns to the heart through the pulmonary veins (only veins that carry blood from the body oxygenated blood), in turn, the heart of the new power through the arteries throughout the body.

The risks of not preventing thrombosis
Both as an artery into a vein thrombosis can occur. The effects are quite different depending on the case of either type of blood vessel. Thrombosis in a blood vessel is very serious because it prevents oxygenated blood flow to continue from that point to the tissues that depend on the artery. The result is ischemia (tissue suffering at the lack of blood supply causing anoxia, which means cellular asphyxia by lack of oxygen.) When ischemia lasts longer than the fabric can resist death occurs irreversibly cells of that tissue, which is called infarction. Depending on how vital it is the organ affected and the extent of ischemia, there will be more or less serious effects for the rest of the body.

In the case of a heart attack for example, the impact is severe because of the coronary artery (heart artery) occluded depends much of the blood of the heart muscle (myocardium) or nerve tissue that controls the rhythm of the heartbeat. If the thrombus does not resolve the heart ends in a few hours taking a large infarction or a malignant arrhythmia serious him to make it impossible to maintain its pumping function and thus is death.

Thrombosis that occurs in other organs such as brain, eye, kidney, limbs, etc.. May not be as strict at the time of death, but always involves the loss of the body depended on the irrigation cut off, with significant functional losses resulting there from (hemiplegia, paralysis of half side of the body, loss of speech, visual loss, dementia, etc.)…

In the case of the veins, thrombosis is not usually endanger a person’s life unless it affects the veins leading blood to the lungs (pulmonary embolism) because that leaves open the possibility of venous blood deoxygenating. Thrombosis is much more serious is the largest amount of lung that is without blood flow.

With venous thrombosis (excluding pulmonary embolism and commented) that is produced is not a situation such as ischemia, but the obstruction of blood leaving the organ to which the vein, which usually causes inflammation, with pain and swelling of affected tissues (accumulation of stagnant water from the blood into the tissues that are drained by this vein).

Is that the same one that a thrombosis embolism?
No, not the same. The circulatory system requires two basic conditions to serve their vital function; one is the condition of the permeability and the defense of the structural integrity and homeostasis. The first concerns the need for blood is always free for the passage of blood, and the second refers to the need to be able to repair the walls of the glass in the event that they suffer some kind of injury.

The body has very complex systems that, by keeping a delicate balance, ensuring a perfect line of defense provided that the permeability and integrity as essential. In the case of the haemostatic system have to mention two fundamental system of platelet aggregation and coagulation system.

The aggregation system
The first consists of blood cells (platelets), as floor tiles, stick to where it needed to plug a break.

The coagulation system
The second consists of the blood proteins that promote the formation of anchors and cables of the conglomerate of platelets and other cellular debris, thus what is called a thrombus or blood clot.

Sometimes, there are pathological situations that go well for injuring the vessel wall (eg atherosclerosis) or by promoting an active role improperly or inadequately controlled aggregation of systems and / or coagulation, breakage occurs and the resulting balance formation of thrombus that completely occluded just the glass.

Thrombosis occurs if for some unusual circumstance that favors the formation of a thrombus attached to the vessel wall. Embolism, however, is the blockage of a blood vessel by a thrombus that has formed in the circulation or that is a fragment of a thrombus that has traveled the bloodstream to a halt at the point where it can not continue and arising from a point prior to the vessel wall where it was formed. Therefore thrombosis occurs at the point where the vessel wall has suffered an injury and embolism occurs at a distance, at a different point from where the first thrombus was generated.

What diseases cause thrombosis?
The list of processes that encourage the production of thrombosis is quite large:
Arterial thrombosis
Arteriosclerosis

It should be noted at the head of arteriosclerosis, a process facilitated by vascular degeneration of certain risk factors are well known to all (hypertension, snuff, obesity, high cholesterol, excessive alcohol consumption, sedentary lifestyle, diabetes, etc…).

In atherosclerosis is causing the deposit of cholesterol and other fats in the wall of large vessels, which will close the inside of them and producing a break in the innermost layer of the glass (known as intimae layer.) This leads multiple platelet adherences and the formation of a blood clot just completely occluding the passage of blood.

Heart Disease
Other processes that can cause arterial thrombosis are those that promote heart disease haven or turbulent flow of blood in its passage through the chambers of the heart, because if the blood stops are also stimulates the formation of clots.

In this group of processes are some cardiac arrhythmias (atria fibrillation, heart disease, etc…), vascular malformations, diseases of the heart muscle (cardiomyopathies), diseases of the heart valves (valve) and atria maxima (tumor formed in the heart atrium).

Another heart disease also produces high risk of thrombosis is endocarditic (infection of the inner cell layer that covers the heart chambers.)

Coagulation disorders
The list of diseases that promote arterial thrombosis is complete with some blood clotting disorders, certain diseases that increase the number of blood platelets (essential thrombocytosis) or viscosity (polycythemia, monoclonal gammopathy, leukemia) and other diseases such as vacuities, drepanocytosis, etc..

Venous thrombosis
Processes that favor venous thrombosis are mostly different from those that increase the risk of arterial thrombosis.

The classically described as provocative factors for venous thrombosis (venous stasis, increased blood viscosity and hypercoagulability) are still in full force and at least one of them is always present in such diseases.

In this group are the diseases in which there is no proper control over the power coagulant:
* Primary hypercoagulation syndromes or primary thrombophilias (antithrombin III deficiency, protein C deficiency disease, Leaden, disfrinogenemias, etc.).
* The states of hypercoagulability secondary (cancer, antiphospholipid syndrome, pregnancy, nephrotic syndrome, intake of some oral inoculators);
* Other causes such as prolonged immobilization in bed or certain blood diseases (essential thrombocytosis, polycythemia vera, paroxysmal nocturnal hemoglobinuria, sickle cell disease, heparin-induced thrombocytopenia).

What means exist to treat thrombosis?
Logically, when a thrombosis or arterial embolism far more useful and urgent treatment is one that allows for restoring the permeability of blood vessel obstruction before the ischemic stroke becomes final.

The time available to attempt this, in the heart attack for example, is just a few hours (6 to 12 hours.) One of the most used in this type of illness is the fibrinolytic therapy, which consists in administering a or more drugs capable of dissolving the thrombus and restore obstructed vessel permeability.

There is also the possibility of an urgent catheterization reach the point of occlusion, fragmenting the thrombus and the vessel dilated (angioplasties.) Within this technique there is also the possibility to place inside the vessel coronary stent permanent which is a semi-rigid device that prevents the artery may close again. A technique of catheterization interventionist is called PTCA (percutaneous translational coronary angioplasty).

In the case of venous thrombosis, which in most cases usually happen in the veins of the legs, is not as pressing to recover the permeability of the vessel as it is to relieve pain and other symptoms, and especially to prevent detachment of the thrombus or fragments thereof, cavil veins, ascending, reached the territory pulmonary venous and pulmonary thromboembolism may occur as described. To avoid this, should be implemented so early treatment with anticoagulant medication. In this type of medication heparin is the drug most commonly used as treatment initiation and may subsequently be replaced by drugs such as dicumarínicos Acenocumarol (Sintrom) for maintenance therapy, which must be met for a longer time (generally 1 to 3 months.)

What means exist to prevent thrombosis?
Undoubtedly, for the thrombotic disease prevention there is no better than get reduce or eliminate the effect of those diseases that are conducive to the deterioration of the circulatory vessels and the formation of thrombosis. Thus, a measure of great benefit to prevent myocardial infarction, cerebral thrombosis or arterial thrombosis in the legs is to try to be free of the risk factors for atherosclerosis, for example.

Nevertheless, there is the possibility of reducing the role of aggregation and coagulation systems with antiplatelet drugs such as aspirin, clopidogrel, etc. or anticoagulants such as heparin, dicumarínicos (acenocoumarol, warfarin) or other recent or imminent occurrence (Lepirudina, ximelagatran, Fondaparina, etc.)… The indication of some other states depending on the degree of thrombotic risk, the type of disease that favors the risk, the patient’s physical condition and age.

The risks of anticoagulant and antiplatelet
The indication of antiplatelet or anticoagulant preventive physician should consider the individual case and the decision was taken when you are sure that the reduction of thrombotic risk clearly offset the risks of such treatments. Both antiaggregated as the anticoagulant, but the second, presented as the main risk of the employment increase in the incidence of bleeding tables. This danger is now the main factor limiting its use and is much greater when the older person is implying that the anticoagulant treatment is indicated with great reservation in the case of older people.

The antiplatelet (primarily aspirin) usually take special risk of injury of gastric mucosa, which can lead to erosive gastritis and gastroduodenal ulcer, although it must be said that in recent years have aroused new antiplatelet agents whose job involves lower frequency of this adverse effect.

There are other potential effects was chosen as a drug or another, but the fact is that the risk of bleeding which most concerns doctors. Therefore, research continues to focus on antithrombotic pharmacology today it’s utmost to find new active ingredients with more selective effect on the processes of hemostasis, so as to obtain more effective and safer drugs to be able to prevent thrombosis without it being significantly increased the risk of bleeding.

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