thromboembolism is the name for when a blood clot (thrombus) that forms in a blood vessel ruptures, is carried by the bloodstream, and blocks another blood vessel. This is a dangerous condition that affects multiple organs, leading to organ damage and even death.
Therefore, it requires immediate treatment. Knowing the signs of thromboembolism and who is at risk can help you better identify when you or a loved one needs medical care.
This article takes a closer look at the different types of thromboembolism, including possible causes and symptoms. It also explains how to diagnose thromboembolism and the different options for treating blocked arteries and veins.
There are two main types of thromboembolism – venous thromboembolism and arterial thromboembolism. As their names suggest, they differ by the type of blood vessels they affect.
Venous thromboembolism occurs when a blood clot ruptures and blocks a vein — a blood vessel that brings blood that needs oxygen back to the heart.
Venous thromboembolism usually begins in the legs and is called deep vein thrombosis (DVT).
If the clot ruptures and becomes lodged in the lungs, it can lead to a serious condition called pulmonary embolism (PE). PE can be fatal, depending on the location of the clot (also called an embolus) and the degree of obstruction to blood flow.
broad term Venous thromboembolism Generally refers to DVT, PE or a combination of the two (called DVT/PE). That being said, thromboembolism can involve other veins in the body, including deep and superficial veins.
Less common sites of venous thromboembolism include the arms, liver, kidneys, and brain.
Arterial thromboembolism occurs when a blood clot ruptures and blocks an artery, the blood vessel that carries oxygen-rich blood from the heart to the rest of the body.This causes ischemia, or restrict blood flow and oxygen. Occasionally, an infarction — tissue death due to insufficient blood supply — also occurs.
Arterial thromboembolism often occurs in the legs and feet. Some can occur in the brain, causing a stroke, or in the heart, causing a heart attack (myocardial infarction). Less common sites include the kidneys, intestines, and eyes.
There are two types of thromboembolism. Venous thromboembolism occurs in veins and includes deep vein thrombosis (DVT) and pulmonary embolism (PE). Arterial thromboembolism occurs in arteries and is associated with ischemia (restriction of blood flow due to blockage).
Symptoms of thromboembolism vary depending on the location of the embolus, the degree of blood flow obstruction, and whether ischemia is involved.
When veins are affected
The most common form of venous thromboembolism can be identified by the following signs and symptoms:
- Deep vein thrombosis (legs): throbbing, cramping, swelling, warmth, pain, hardening of the veins, redness or darkening of the skin in one leg
- Pulmonary embolism (lung): sudden shortness of breath, shortness of breath, chest pain, coughing up blood, blue lips or fingers (Cyanosis)
- Cerebral vein thrombosis (brain): headache, drooping face, limb weakness, difficulty speaking, and in some cases, seizures
- Portal vein thrombosis (liver): epigastric pain, nausea, abdominal swelling, and persistent fever
- Renal vein thrombosis (kidney): low back pain or pain, decreased urine output, blood in the urine, and swelling of the lower extremities
when arteries are affected
Sudden pain is a characteristic symptom of arterial thromboembolism. The most common form can be identified by the following signs and symptoms:
- Limb infarction: Chills, numbness, tingling, pain, muscle weakness, muscle spasms, pale skin, slowed pulse in the affected arm or leg
- Heart attack: chest pain, shortness of breath, profuse sweating, weakness, dizziness, nausea, vomiting, and palpitations
- Stroke: Sudden difficulty walking, speaking, and understanding, and paralysis or numbness of the face, arms, or legs
Symptoms of thromboembolism can vary depending on whether the blockage occurs in the legs, lungs, brain, heart, liver, or kidneys. Symptoms of blocked veins may differ from those of blocked arteries.
What is an embolic stroke?
Venous thromboembolism and arterial thromboembolism affect many of the same people and share several risk factors, but there are key differences between the two.
Why Venous Thromboembolism Occurs
Almost anyone can have DVT, and in combination they can have a pulmonary embolism. You can change or control some risk factors for DVT/PE and you cannot change or control other risk factors. These include:
- Family history of venous thromboembolism
- Chronic diseases such as heart disease, lung disease, inflammatory bowel disease and cancer
- Vein injury (due to trauma or major surgery)
- Use a central venous catheter
- wearing plaster
- bed confinement
- Sitting for long periods of time, especially cross-legged
- Estrogen-based treatments (including birth control pills)
What can cause a pulmonary embolism?
Why Arterial Thromboembolism Occurs
Arterial thromboembolism is closely associated with the same risk factors for heart disease. These include:
- sedentary lifestyle
- high cholesterol
- recent surgery
- Previous cardiovascular disease stroke
- Mitral valve stenosis (a heart valve disease)
- Atrial fibrillation (rapid, irregular rhythm of the heart valves)
Risk factors for venous thromboembolism include bed rest and prolonged sitting still (eg, on an airplane). Risk factors for arterial thromboembolism are essentially the same as for heart disease. Obesity and old age affect both.
How to Diagnose Thromboembolism
The diagnosis of thromboembolism mainly involves imaging studies and blood and laboratory tests. Some tests are for organs.
Confirm DVT and PE
A major challenge in diagnosing DVT and PE is that symptoms can be very similar to those of a heart attack, limb infarction, or even pneumonia.
To confirm the diagnosis and differentiate DVT/PE from other disorders, doctors may order the following tests:
- D-dimer blood test: used to detect substances released as the clot breaks
- Factor VIII blood test: used to detect proteins necessary for blood clotting
- Platelet aggregation test: a blood test that measures how well blood cells called platelets clump together
- Duplex Ultrasound: A Non-Invasive Imaging Test That Can Use Sound Waves to Detect Deep Vein Occlusions
- Contrast venography: an X-ray procedure that involves injecting a contrast medium into a vein
- Magnetic Resonance Imaging (MRI): An imaging study that uses powerful magnetic fields and radio waves to create highly detailed images of soft tissue
- Pulmonary angiography: a specialized X-ray that delivers contrast agents to the blood vessels in the lungs
- Computed Tomography Pulmonary Angiography: An imaging test that involves injection of a contrast agent to locate lung blockages using a computed tomography (CT) scan
- Ventilation-perfusion (V/Q) scan: a special procedure that uses radioactive material to highlight parts of the lung that are receiving and not receiving oxygen
Confirmed arterial blockage
Some of the same tests used to diagnose venous thromboembolism can be used to diagnose arterial thromboembolism. Others are professional and specific. These include:
- Blood tests: including D-dimer, factor VII, and platelet aggregation
- Doppler or duplex ultrasound: used to detect arterial clots using sound waves
- Echocardiography: used to visualize heart motion using reflected sound waves
- Transesophageal echocardiography (TEE): A form of echocardiography that involves inserting a transducer into the throat and esophagus
- Myocardial Contrast Echocardiography (MCE): A form of ultrasound that uses the injection of very tiny air bubbles to provide a more accurate picture of the heart’s movements
- Plethysmography: A test to measure changes in arterial volume using a blood pressure cuff and sensor
- Transcranial Doppler: used to detect any blockages in the arteries that serve the brain
Thromboembolism is diagnosed by specialized imaging tests, such as duplex ultrasound and echocardiography, and blood tests called D-dimer and factor VII.
How to diagnose a blood clot
Treatment of venous or arterial thromboembolism can vary depending on the location of the embolus and the degree of obstruction. Medicines are at the heart of any plan.
Options for Venous Thromboembolism
Anticoagulants (“blood thinners”) are the first-line treatment for venous thromboembolism. These medicines keep the clot from getting bigger while the body slowly reabsorbs it.
There are injectable anticoagulants, such as heparin and Arixtra (fondaparinux), and oral anticoagulants, such as Coumadin (warfarin), Eliquis (apixaban), and Xarelto (rivaroxaban).
If the anticoagulant isn’t enough, a special filtering device can be inserted into the inferior vena cava (the large vein that carries blood back to the heart) to catch the clot before it reaches the lungs.
Medications called thrombolytics (“clot busters”) are only used in severe cases because they can cause bleeding. Options include Eminase (anistreplase), Retavase (reteplase), Streptase (streptokinase), and more. 14
If needed, surgery can be done to remove the clot that causes DVT (called thrombectomy) or to remove the clot that causes PE (called embolectomy).
How to Treat Pulmonary Embolism
Options for Arterial Thromboembolism
Many of the same drugs used to treat venous thromboembolism are also used to treat arterial thromboembolism. This includes the use of anticoagulants and thrombolytics, as well as antiplatelet drugs such as Plavix (clopidogrel), which prevent platelets from clumping together.
Some people may need surgery if the blockage is severe. This may involve:
- embolectomy (removal of a clot)
- Arterial bypass surgery (rearrangement of blood supply)
- Angioplasty (increasing blood flow): This is done with a balloon catheter, a device that widens a blood vessel. A stent, a device that stays in place to keep a blood vessel open, may or may not be in place.
Anticoagulants (blood thinners) play a central role in the treatment of thromboembolism. In severe cases, a surgical procedure called an embolectomy may be necessary to remove the clot. Bypass surgery or angioplasty may also be needed to treat or repair blocked arteries.
Thromboembolism is the blocking of a blood vessel by a blood clot that has dislodged from another site in the circulatory system. There are venous thromboembolism (in which a vein is blocked) and arterial thromboembolism (in which an artery is blocked).
Symptoms of thromboembolism vary depending on the location of the blockage. Venous thromboembolism often occurs in the legs and lungs, leading to deep vein thrombosis and pulmonary embolism, respectively. Arterial embolism can block blood flow to the brain or heart, triggering a stroke or heart attack.
Thromboembolism can usually be diagnosed with blood tests and imaging tests. Treatment usually involves blood thinners and other medications, although surgery may be needed to clear blockages or alter blood flow.
Thromboembolism is almost always serious and requires immediate medical attention. Arguably the biggest challenge is identifying the signs and acting quickly.
It helps identify risk factors for conditions like DVT, heart attack, and stroke, and do everything you can to minimize your risk.
For example, if you have a heart condition and are flying long distances, be sure to wear a pair of compression stockings, keep your legs uncrossed, and get up and move frequently. If you are at risk for a heart attack or stroke, controlling cholesterol and high blood pressure (and quitting smoking) can greatly reduce your risk.
COVID-19 and severe blood clotting problems