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Everything to Know About Blood Clots in Your Veins, Heart and Lungs

When you nick or cut yourself, your body jumps into action to stop the bleeding. Your blood cells clump together to prevent blood from leaking where it doesn’t belong. This is known as clotting. 

While clotting is a scary word for some, blood clots aren’t always a bad thing. They even help jumpstart the healing process. But sometimes clots can form where they shouldn’t. When this happens, blood clots can stop the flow of blood (a condition called thrombosis) and the results can be deadly.

“Thrombosis is dangerous because it can be life-threatening,” said Mohammad Zaidan, MD, an interventional cardiologist with Banner Health. “If a clot breaks loose and travels through the circulatory system, it can interrupt blood flow and affect the lungs, the heart or the brain.”

According to the Centers for Disease Control and Prevention (CDC), the precise number of people at risk of blood clots isn’t known, but it estimates that nearly 900,000 Americans could be affected each year. 

Read on to learn more about blood clots, their potential causes and what to do if you are at risk. 

What is a blood clot?

When a blood vessel is damaged, like from a cut, the damaged blood cells send a message to stop the bleeding. Platelets are the cells in our blood that respond to the message and get to work forming a clot.

The platelets turn from liquid to jelly-like blobs (clots). They begin to attach to one another and the blood vessel wall. Platelets grow long tentacles that look like a net to capture and trap red blood cells. This reaction usually stops when the injury is repaired and the body breaks down the clot. 

However, when a clot forms inside one of your veins and doesn’t dissolve, it can become a medical emergency.

The three types of blood clots that form in your blood vessels are called venous thromboembolism, pulmonary embolism and arterial thrombosis.

Venous thromboembolism (VTE)

This type of blood clot happens in the veins or arteries—most commonly in your leg, thigh or pelvis, as is the case with deep vein thrombosis (DVT). 

Pulmonary embolism (PE)

This type of blood clot happens when a clot breaks free and travels to the lungs, blocking some or all of the blood supply. For example, if a clot from your legs, such as DVT, travels to your lungs and blocks blood flow, your body cannot get the oxygen and nutrients it needs.

Arterial thrombosis

This type of blood clot occurs in the blood vessels or arteries of the heart or brain.

“The clot in the heart usually happens because of plaque buildup leading to a clot formation,” Dr. Zaidan said. “The clot may block blood flow to the heart, which can lead to a heart attack.”

When blood clots form in the cerebral arteries that feed the brain, it can cause a stroke. 

Who is at risk for blood clots?

Older adults over 60 are at higher risk for blood clots, but they can happen at any age. 

Risk factors include:

  • A history of blood clotting disorders
  • Diabetes
  • Hypertension (high blood pressure)
  • Injury to a deep vein
  • Having surgery or being in the hospital for an extended period
  • Cancer
  • Smoking
  • Obesity (being overweight)
  • Lack of physical activity or sitting for long periods of time
  • Being confined to a bed or a chair much of the time
  • Pregnant or six weeks postpartum
  • Hormone replacement or hormone-based birth controls
  • Have had a blood clot before

What are the symptoms of a clot?

For clots in the leg, like DVT, symptoms usually include swelling, pain and redness or warmth.

Symptoms of lung clots or pulmonary embolism include experiencing sudden shortness of breath, sharp chest pain, cough or pass out.

For coronary thrombosis, the common symptoms include severe pain and pressure in the chest and arm, shortness of breath and sweating.

How are blood clots treated?

“If we identify a blood clot in the leg or the lung, we typically prescribe blood-thinning medications, called anticoagulants, that prevent clots or, in special cases, we administer thrombolytics which are strong clot-busting medications,” Dr. Zaidan said. “In some cases, we use devices to remove the clot when it is causing life-threatening obstruction in the arteries of the lung and causing what is known as shock.”

For coronary thrombosis, a different type of blood thinner may be prescribed. In addition, stenting or surgery may be performed to treat the affected vessel and prevent a future heart attack.

Can I prevent blood clots?

There are not many things you can do to prevent a blood clot from occurring, but there are several things you can do to lower your risk of one. 

“The best thing you can do is to get regular checkups, stay active, maintain a healthy lifestyle – no smoking or sitting for long periods – and know if you have a family history of blood clots,” Dr. Zaidan said. 

Concerned about your risk for blood clots? Schedule an appointment with a primary care provider near you.

Other tips include:

  • For travel: If you know you’ll be sitting on a plane, train or in a car for a while, stand up often and stretch your legs. Make sure you wear loose clothing. Drink lots of water and avoid alcohol. Consider wearing compression stockings.
  • While pregnant: Ensure you stay hydrated, stay active and avoid long periods of sitting. In addition, elevate your legs to elevate any swelling in your feet and ankles.
  • After surgery: The risk of blood clots for those admitted to the hospital is higher than among the general population. To prevent blood clots, make sure you are fitted with an inflatable compression device after surgery and walk as soon as recommended to decrease your risk. You may also be given an anticoagulant medication as well.

When should I call 911?

Anytime you think you may need emergency care, call 911. 

For example, call if:

  • You have symptoms of a clot in your lungs
  • Sudden chest pain 
  • Trouble breathing, seeing or speaking
  • Coughing up blood


Blood clots can be beneficial for stopping bleeding, but they are also serious business. Whether in your heart, lungs, leg or arm, blood clots are something you want to be aware of and know the warning signs of. By being aware of blood clots, you can prevent them from becoming a significant problem. You may even be able to prevent them from happening altogether.

To learn more about your vascular health, take our free Artery Fit Test. Also interested in your learning more about your stroke risk? Take our free Stroke Risk Profiler

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