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A cava filter is a special device vaguely resembling an umbrella in shape. Its main purpose is to prevent blood clots from entering large blood vessels. In fact, this is a kind of trap installed in the inferior vena cava.
What are blood clots and why are they dangerous to life?
Due to the fact that our blood has such a characteristic as clotting, a person does not die from blood loss during injuries of varying degrees of complexity. At the site of damage to the vessel, a kind of plug is formed – a blood clot, which quickly blocks the bleeding. At the same time, the blood itself contains enzymes that promote the resorption of a blood clot at a time when the vessel wall has already recovered.
This happens provided that a person has no diseases and pathologies of the blood or the circulatory system as a whole. In some cases, blood clots form not only to protect the body from blood loss, but also for no apparent reason.
Most often, this occurs against the background of a prolonged inflammatory process that affects the circulatory system. Then the clots are attached to the walls of the vessels and interfere with normal blood flow, so a complete blockage of the vessel may occur. It depends on the size of the “cork”.
The greatest danger is “fresh” blood clots. Such clots have a porous structure and can quickly increase in size, as they attract blood cells to themselves, literally sticking them to themselves. Due to the friability of the walls, a platelet can break away from the vessel wall at any time and then there is a risk of disrupting the blockage of a vital vessel.
Pulmonary embolism is considered the most severe pathology that occurs due to deep vein thrombosis. If this condition is suspected, the patient is shown an ultrasound of the vessels – this study allows you to examine the condition of the vessels in as much detail as possible and confirm or refute the life-threatening diagnosis.
In most cases, blood clots form in the veins of the lower extremities or small pelvis. The risk of getting such a clot is increased by a sedentary lifestyle, injuries that force you to be in a position of complete or partial immobility for a long time, obesity and diabetes mellitus. Ebolus, or a blood clot detached from the wall, begins to move through the vessels along with the blood. First, it enters the inferior vena cava, and then it blocks the pulmonary artery. In most cases, this causes instant death of the patient.
Ways to treat vein thrombosis
At the initial stage, the patient is prescribed medications that help thin the blood – anticoagulants. If the effectiveness of drug therapy is low enough, then radical treatment is indicated. Indications for installing a cava filter:
- confirmed diagnosis of thrombosis of the hollow veins;
- the inability to use anticoagulants or the low effectiveness of drug therapy;
- preparation of a patient with thrombosis for a complex surgical intervention;
- detection of a floating thrombus – a clot that is not attached or weakly attached to the vessel wall;
- heart failure complicated by thrombotic disease.
The main goal of surgical intervention is to catch blood clots that threaten the life and health of the patient. We are talking about installing a cava filter – a special design made of very thin wire.
After establishing a diagnosis confirming the need to install a cava filter, a complete exclusion of contraindications is necessary. Cava filters are not installed in case of septic blood diseases, in case of pathological narrowing of the lumen of the inferior vena cava or inability to access the desired vessel. In addition, childhood (adolescent) age or thrombosis of the adrenal vein, as well as oncological diseases, is also a contraindication.
Types of cava filters
Kava filters are made of corrosion-resistant materials that do not have ferromagnetic properties. The design of the device should allow easy installation and subsequent removal, while blocking all moving blood clots. Another important characteristic of a blood clot filter is that it should not interfere with normal blood flow.
Most often, for the manufacture of such structures, titanium, nitinol or high-quality steel with a heparin-saturated coating are used.
The size of the filter used is determined individually, taking into account all the factors of a particular case. Modern cava filters are delivered to medical institutions packed in special carriers. This greatly simplifies the installation process.
They can be permanent or temporary. In the first case, the fixation of the device in the vein occurs due to special spikes that cut into the walls of the vessel. Today, temporary filters are most commonly used, fixed by a subcutaneous guidewire, which is used to quickly and safely remove the cava filter.
Installing and removing the kava filter
The preparatory stage for the installation procedure includes a complete clinical examination of the patient, as well as angiography of the inferior vena cava. Based on the data obtained, the size and shape of the cava filter is selected. The diameter of the device must fully match the diameter of the vein.
It is important to understand that the installation of an additional part into the lumen of the inferior vena cava is a high-tech operation that can only be performed within the walls of a specialized medical institution equipped with the necessary equipment.
To introduce a cava filter, a special catheter is inserted into the ulnar, subclavian and femoral arteries. At the initial stage of the operation, the filter is in the folded state – the entire path of the device to the place of fixation is controlled by special motion sensors. Having reached the desired point, the filter is released from the removable packaging, then straightened and fixed.
After installation, the patient is under constant medical supervision for some time. To prevent the development of complications, he is shown taking anticoagulants and antibiotics.
Only temporary cava filters are subject to removal – such devices can be in the vessel cavity for several weeks.
The device is removed when the threat of pulmonary embolism is eliminated, that is, the thrombus is completely or partially removed. Special tools are used to remove the filter. The procedure is carried out within the walls of a medical institution only by a qualified specialist. After removal, the patient must remain in the hospital for some time to monitor the condition.