Thrombosis

A clot developing inside a blood vessel (an artery or vein) in your body, or occasionally inside your heart, is called thrombosis. This is a risk because blood vessel clots can restrict blood flow. They can also separate and move around inside your body, and if a clot lodges itself in a vital organ like your brain or lungs, it may result in emergencies that could endanger your life.

Depending on the type of blood vessel where it begins, thrombosis can be divided into two categories.

Arterial Thrombosis

This is thrombosis that happens in arteries, which are blood vessels that carry blood from your heart to the rest of your body. Arterial thrombosis is the most common cause of heart attacks and strokes.

Venous Thrombosis

This is thrombosis that happens in veins, which are blood vessels that carry blood back to your heart from your body. Venous thrombosis is the most common cause of pulmonary embolism (blood clot in your lung).

Early symptoms of ischemia from a blood clot include:

• Visible color changes on your skin: Areas beyond the blockage (meaning the clot is between that area and your heart) will typically look paler than other areas.
• Temperature change in the affected area: Lack of blood flow will make the affected part of your body feel cooler to the touch than other areas.
• Weakness: This can also involve not being able to move the affected body part.
• Numbness or tingling (pins and needles feeling): This can also sometimes involve pain in the affected area.

The symptoms that follow usually are more severe. They include:

• Blisters, wounds or sores: These can happen when skin wears away or tears open.
• Skin sloughing (pronounced “sluffing”): This is when skin falls away or separates from the tissue underneath.
• Necrosis: This causes skin and tissue to die and turn black. The area of dead or dying tissue will spread gradually outward.

Venous Thrombosis

Vein blockages, which are also very common in your legs, slow down the rate at which blood can return to the heart. Your veins are under too much pressure as a result, and blood and fluid leak into the tissues nearby.

Symptoms of this include typically include:

• Color changes, especially redness or darkening of the affected area.
• Pain, especially around the affected area.
• Swelling from the fluid buildup.
• Skin that feels noticeably warmer than other areas.
• Thrombosis can happen for many reasons, but certain conditions are more likely to cause clots to form. These conditions fall under the following types or categories.
• Circulatory and heart problems.
• Conditions like atherosclerosis, where arteries stiffen because of a buildup of plaque (a waxy substance related to cholesterol) inside them, often cause clots. This happens when a clot forms over a rupture or break in a section of plaque. This is often what causes heart attacks.
• Other similar problems include:
  • Heart valve disease. Problems with your heart valves, such as mitral valve stenosis (narrowing), can make clot formation more likely.
  • Atrial fibrillation. This is a condition where the upper chambers of your heart beat so fast, they can’t pump blood correctly. Blood that lingers in these chambers can form clots, which can then travel elsewhere in your body. Atrial fibrillation is a common cause of stroke.
  • High blood pressure and high cholesterol. Both of these conditions, over time, can damage your heart and blood vessels, limit circulation and make it easier for clots to form.

Blood Clotting Problems

Causes

• Inherited or genetic clotting disorders: Several genetic conditions, which you inherit from your parents, can make your blood clot too easily. These conditions are usually treatable but typically aren’t curable.
• Other medical conditions: Certain types of cancer can make blood clots much more likely. Other conditions like HIV, inflammatory bowel syndrome or immune disorders can also cause clotting problems.
• Medical procedures: Surgeries can cause your body to try to clot in ways that can be harmful. That’s why medical providers often prescribe blood-thinning medications after surgery or other types of procedures.
• Medications: Certain medications can cause your blood to clot more easily. In some cases, that’s on purpose. In others, it can be an unexpected and unintended side effect of or reaction to a medication. Certain types of hormonal treatments, including those used in birth control, can also cause blood clotting issues.
• Lack of activity: Sitting or lying still for long periods can cause your blood to circulate poorly in some parts of your body, especially your legs. That makes it easier for clots to form. This often happens to people on long airplane or car trips, people who have some form of paralysis or who are on bed rest. It can also happen to people who aren’t physically active, especially those who sit for extended periods.

Some of the possible tests include the following methods:

• X-rays: This also includes computed tomography (CT) scans, which use a computer to assemble X-ray images into a 3D picture of the inside of your body. These methods may also involve substances that a healthcare provider injects into your body. These substances are highly visible depending on the imaging method, which can help highlight any areas where blood isn’t circulating.
• Ultrasound: Tests that use this involve ultra-high-frequency sound waves that help generate a picture of the inside of your body. The sound waves bounce off different areas inside of your body, much like how dolphins and bats use sonar to “see” in places where there’s no light.
• Magnetic resonance imaging (MRI): This imaging method uses a very powerful magnet and computer processing to create a high-resolution picture of the inside of your body.

Laboratory Tests

• Because clotting is something your blood does naturally, lab tests on your blood can help analyze and determine if your blood clots too easily. These tests can also help discover why your blood is clotting and can help decide on possible treatments.

These tests usually look for the following:

• Blood components: This includes several tests that measure certain types of blood cells like platelets and chemical compounds, especially ones that affect clotting.
• Clot-formation markers: These are chemicals that typically only show up in your blood if you have a clot at the time. They can help healthcare providers confirm or rule out an active clot as the source of a blockage.
• Heart damage markers: An example of this is troponin, a protein found in muscle cells. Your heart muscle cells contain a very specific type of troponin that doesn’t occur elsewhere in your body. Damage to your heart cells, such as from a heart attack, causes troponin to leak out of those cells and into your blood. Tests that detect troponin can help confirm or rule out heart attacks, which often happen because of thrombosis.

 Treatments for thrombosis typically involve a few different classes of medications. These usually include one or more of the following:

• Blood-thinners: These medications keep your blood from clotting too easily. There are different types of blood-thinners, including antiplatelet, anticoagulant and fibrinolytic drugs.
• Blood pressure-lowering medications: Over time, high blood pressure puts too much stress and wear on the inside of your blood vessels. This kind of wear and tear can make it easier for blood clots to form and grow on your vessel walls. Blood pressure medications prevent clots by not giving them new places to form.
• Cholesterol-lowering medications: Your cholesterol levels directly influence the buildup of plaque on the inside of your blood vessels. Lowering your cholesterol limits that buildup.

Acute Medications

Acute blood clots (meaning they started very recently) are also treatable with medications. These medications usually include the following:

• Blood-thinners (for the same reasons mentioned under “Preventive treatments” above).
• Clot-busting drugs. These drugs break down existing clots, which is especially helpful when a clot is in a critical area. Drugs like this are common in the treatment of heart attack, stroke and other thrombosis-related conditions.

Surgery and Catheter Procedures

Depending on the location and size of the clot, healthcare providers may be able to go in and remove the clot directly. This kind of clot removal, known as thrombectomy, can happen in a few different ways:

• Surgery: One of the most direct ways to remove a clot is for a surgeon to access it directly and remove it. In some cases, they may also use surgery to do a bypass, where the surgeon takes a section of blood vessel from elsewhere in your body and uses it to construct a bypass, or detour, around an area of another blood vessel that’s very narrow. This restores blood flow to the affected parts of your body.
• Catheter Procedures: These types of procedures use a long, thin, tube-like device called a catheter. A healthcare provider inserts this device into a major blood vessel somewhere on your body and steers the catheter through your blood vessels to the blocked area. Once there, they can use devices on the tip of the catheter to break apart and suck up the clot fragments (rheolytic thrombectomy), and/or inflate a small balloon on the tip of the catheter to widen narrow sections of a blood vessel. They can also sometimes place a stent, a scaffold-like device, which acts as a support to hold your blood vessel open.