Blood Clotting

Last Updated 05/11/2020

Author:Jason M. Golbin, DO, MS, FCCP, and Aleksander Shalshin, MD, MS, FCCP

About Blood Clotting

Key facts about Blood Clotting
  • Clots can form within arteries, which carry blood from the heart, and veins, which carry blood to the heart.
  • Sometimes, blood clotting can be an abnormal condition.
  • Clots forming in the arteries can cause strokes and heart attacks. Clots that form in the veins cause a condition called deep venous thrombosis.

Blood clotting is a normal process. A clot—a clump of blood that turns from a liquid into a gel-like substance—forms around a cut blood vessel to stop the bleeding. When a clot forms without an injury to protect however, it can cause problems.

For example, when a clot forms in an artery—a blood vessel that carries oxygen-rich blood from the heart to the rest of the body—it can cause a stroke or a heart attack. Clots that form in a vein—a blood vessel that carries blood low in oxygen from the body back to the heart—cause a condition called deep venous thrombosis (DVT).

How serious is Blood Clotting?

Quick diagnosis of DVT or PE can save your life and prevent other complications associated with this potentially fatal condition.

When a DTV blood clot breaks away from its original location and travels to the heart or a lung, it forms what’s called a pulmonary embolism (PE).

DVT and PE are part of disorder called venous thromboembolism (VTE). The symptoms of DVT and PE can vary from person to person and range from mild shortness of breath to severe chest pain and sudden death.

Symptoms of Blood Clotting

You’re more likely to form blood clots if you’re not physically active—for example, if you’re in the hospital after surgery or a stroke.

The symptoms of DVT occur in your legs, with signs such as:

  • Swelling
  • Pain in one or both legs
  • Unusual redness
  • “Charlie horses,” or cramping or throbbing in the thigh or calf

Symptoms of PE include:

  • Shortness of breath
  • Chest pain
  • Dizziness
  • Anxiety
  • Rapid heartbeat

It’s easy to confuse the symptoms of PE for heart attack, pneumonia, and other conditions whose symptoms include cough, chest pain, and rapid heartbeat. Your health care provider may order a clinical diagnostic panel to arrive at a diagnosis.

What are the risk factors for Blood Clots?

Common risk factors for blood clot formation include:

  • Bone fractures
  • Major surgery
  • Being catheterized for a bladder condition
  • Birth control and pregnancy (because of the higher levels of the hormone estrogen)
  • Obesity
  • Cancer
  • Chemotherapy
  • Having had a blood clot in the past

Diagnosing Blood Clotting

During your appointment, your health care provider may:

  • Have you fill out a questionnaire
  • Take your medical history
  • Order blood tests
  • Order imaging studies, such as X-rays or an ultrasound
When should you see your health care provider?

Contact your provider if you have:

  • Sudden, unexplained shortness of breath
  • Swelling in one of your legs
  • Chest pain
  • A feeling that your heart is racing
  • A previous blood clot
  • A strong family history of DVT or PE

How is a Blood Clot diagnosed?

Your provider may order a special blood test called a D-dimer test. Elevated levels of D-dimer—a protein fragment commonly found with blood clots—are a good indication that you have a PE or DVT. If the blood test comes back normal, the chances that you have a blood clot are slim or none.

Your provider also relies on medical imaging studies, such as a computerized tomography, also known as CT or “CAT” scan, and a noninvasive scan called duplex or Doppler ultrasound.

CT is one of the most important tools for diagnosing PEs. During a CT scan of your chest, a contrast agent is injected into your vein to make it easier for the radiologist to search for a PE. Doppler ultrasound is an excellent test as well and doesn’t have side effects, but it can only diagnose DVTs, not PEs. Your provider will explain each test before you have it.

Important: If you’re allergic to contrast agents or iodine, your provider may order a ventilation/perfusion (V/Q) scan instead of a CT scan. A V/Q scan uses a radioactive isotope instead of iodine-based contrast to create a sharper image for the radiologist to check.

Treating Blood Clotting

The most common treatment for DVT and PE is a course of blood thinners, called anticoagulants, that you either inject or take in pill form. Many blood-thinning agents are on the market, and they range from convenient, once-a-day dosing for novel oral anticoagulants to traditional medications like warfarin. Hospitals typically use injectable anticoagulants like enoxaparin or heparin while you’re an inpatient, then move you to pills when you’re discharged. Your health care team will work with you to find the best option for your condition.

Living with Blood Clots

DVT and PE can be life threatening, but patients usually survive the initial event. If you’ve had a DVT or PE, you’ll need to learn how to live with your condition. Anticoagulants are the mainstay of therapy for VTE. Your health care provider will prescribe this medication for as little as 3 months or as long as your lifetime: the duration depends on what has caused your VTE. As long as you’re taking anticoagulants, you must take extra care because these medications increase your risk of bleeding. Your provider will monitor you and your dose and may order regular blood tests.

What to expect

People who have had DVT or PE have a higher likelihood of getting a condition called post-thrombotic syndrome (PTS). PTS can occur in some patients after DVT. Often, the more severe the DVT, the greater the likelihood of developing PTS. Symptoms of PTS include:

  • Swelling
  • Pain
  • Aching
  • Heaviness
  • Cramping

Your health care provider may prescribe compression stockings to help decrease swelling and prevent PTS. Your provider may also tell you to keep your feet elevated whenever possible.

  • Pulmonary hypertension. Most people who have had a PE recover over time. In rare cases, however, the PE leads to an increase in the blood pressure in your pulmonary artery—the main blood vessel that carries blood from your heart to your lungs, which then fill the blood with oxygen again. If you continue to have shortness of breath even while you’re taking anticoagulants, your provider may order an echocardiogram, a noninvasive test that measures the pressure in your pulmonary artery.

Managing VTE

What is an IVC filter?

If you’re one of the rare people who can’t take anticoagulants, your provider may suggest an inferior vena cava (IVC) filter—a small filter placed in your body during a minimally invasive surgical procedure that captures blood clots before they can travel to your heart, brain, or lungs. IVC filters have their pros and cons, so if your provider suggests that one may be right for you, be sure to have an in-depth discussion so that you fully understand the risks and benefits.

If you’ve been diagnosed with DVT or PE, your provider may complete a “hypercoagulability” workup. This workup typically includes several blood tests to see whether there may be a genetic cause for your VTE, especially if there’s no other clear explanation for why you developed the blood clot (such as surgery or a broken bone). Unfortunately, we have no way of knowing whether your VTE will recur.

After a VTE, especially if you had no risk factors, your provider may order tests to search for hidden cancer. Data indicate that up to 10% of patients will be diagnosed with cancer within 1 year of being diagnosed with VTE. That said, no data currently exist to support screening every patient who has had a DVT or PE for cancer.


Questions to ask your health care provider

What resources are available online?

Many resources are available to patients online, including

What happens if I develop a Blood Clot during pregnancy?

Women who are pregnant are at increased risk for DVT or PE, and this risk persists for weeks after delivery. If you have risk factors that increase your risk for VTE during pregnancy (such as a previous DVT), your provider may send you to a specialist who has expertise on this topic. Professional societies such as the American College of Chest Physicians and the American College of Obstetrics and Gynecology have recommendations to help these specialists prevent and treat VTE in pregnant women.

What can I do to reduce my risk for developing DVT during prolonged travel?

Data suggest that each 2-hour increase in travel time increases your risk for developing DVT by about 20%. Some people may benefit from wearing compression stockings while they travel. In addition, while you’re traveling, make sure that you:

  • Take frequent walks
  • Stay hydrated
  • Sit in an aisle seat if you’re traveling by air

When are clot-busting medications (Thrombolytics) used?

Thrombolytics, often called “clot busters,” are used occasionally in the hospital but only for the sickest patients. If your provider recommends treatment with a thrombolytic, make sure you talk to him or her about the risks and benefits.

What can hospitals do to prevent VTE in their patients?

All hospitals have protocols in place to prevent DVT and PE in their patients. For information and statistic on Medicare patients who developed blood clots while in the hospital, see the Centers for Medicare & Medicaid Services’ Hospital Compare website.