5 Blood Clot Facts Doctors Want You to Know

Potentially fatal blood clots, known as venous thromboembolism (VTE), are more likely when you’re hospitalized or part of a high-risk group. Learn how to reduce your risk.

girl with dvt
Leg pain or swelling in the calf or leg are symptoms of deep vein thrombosis.Adobe Stock

Under normal circumstances, blood clotting can be helpful. For example, when you get hurt, your body forms a blood clot to stop the bleeding. After healing takes place, your body breaks down the clot and removes it. But sometimes this process goes wrong. Some people get too many blood clots, and other people have blood that clots in an unusual way. The result: venous thromboembolism (VTE), a disorder that affects up to 900,000 Americans each year, the Centers for Disease Control and Prevention (CDC) reports.

Without proper treatment, VTE can block blood flow in a vein carrying blood back to the heart or lungs. This can cause serious damage to your tissues and organs, or even death. The good news is that you can reduce your risk of VTE through lifestyle changes and medication when appropriate.

Here are five facts that doctors wish everyone knew about VTE.

1. Some Patient Populations Are at Higher Risk

“About 40 percent of all VTE occur in hospitals or shortly after discharge, and about 30 percent of all VTE occur in cancer patients,” says Mary Cushman, MD, a hematologist and the medical director of the thrombosis and hemostasis program at the University of Vermont Medical Center in Burlington. One strategy for reducing VTE in hospitalized patients is to use low dose blood thinning medication, notes Dr. Cushman. During a hospital stay, it’s important to have a VTE risk assessment by your healthcare team, the American Heart Association (AHA) advises. This will help determine the best prevention strategy for your situation.

People with cancer who are seen in outpatient settings may also benefit from low dose blood thinners, according to an article published in October 2021 in Cochrane. VTE risk is particularly high during chemotherapy treatment and after cancer-related surgery, notes the CDC. There are large ongoing clinical trials to help doctors determine how best to prescribe VTE prevention treatments for cancer patients. In the meantime, patients should ask their oncologists for a risk assessment and get educated about the symptoms and signs of blood clots.

Other populations at higher risk for VTE include people with chronic illnesses, such as heart disease and inflammatory bowel disease, as well as those with high estrogen because of pregnancy, oral contraceptives, or hormone replacement therapy, notes Cleveland Clinic. A personal history of stroke or a prior deep vein thrombosis also puts you at higher risk.

2. Signs and Symptoms of VTE Are Not Always Obvious

Deep vein thrombosis and pulmonary embolism are two forms of VTE. Deep vein thrombosis is when a blood clot forms in a deep vein, usually in the lower leg or thigh. A pulmonary embolism occurs when a clot breaks loose and travels through the bloodstream to the lungs.

If you have deep vein thrombosis, you may experience the following symptoms:

  • Swelling in legs or arms
  • Pain or tenderness
  • Increased warmth, cramps, or aching
  • Red or discolored skin

The symptoms of pulmonary embolism include:

3. There Is No Routine Screening Test for VTE

Routine screening tests are available for common conditions like diabetes and high cholesterol. But there aren’t any evidence-based screening tests to detect blood clots.

“The main ways that doctors assess your risk for VTE is by taking a good medical history and by evaluating your signs and symptoms,” says Ada Stewart, MD, a family physician with Cooperative Health in Columbia, South Carolina, and the board chair of the American Academy of Family Physicians. “Your doctor may also ask about any family history of blood clots and will review your current medication.”

Because there's no screening test for blood clots, it’s important to know the risk factors, such as:

  • Surgery
  • Sitting or being in bed for long periods of time
  • Age
  • Sex
  • Obesity
  • Hormone-based medication, like birth control
  • Pregnancy
  • Race and ethnicity

If your doctor suspects a blood clot, you may undergo a D-dimer test, a blood test that measures levels of a protein released by blood clots, per Mayo Clinic. Imaging tests like vascular ultrasound and magnetic resonance imaging (MRI) scans can also help a doctor diagnose VTE.

4. Behaviors and Lifestyle Factors Are Important for Preventing VTE

A sedentary lifestyle, obesity, and smoking all increase a person’s risk for blood clots, says Dr. Stewart.

Stewart notes that while many patients are aware that smoking is bad for cardiovascular disease and blood pressure, they don’t realize that smoking is also bad for blood clots.

You can’t change some risk factors, like age or family history, but behaviors are within your control. For example, if you have a job where you sit a lot, be sure to get up and move around periodically. If you smoke, quit. Maintain a healthy diet and get regular exercise.

5. There Are Effective Drugs to Help Treat VTE

Cushman says there’s been a “revolution of new drugs in the last 5 to 10 years that have simplified the treatment of VTE. These medicines, called direct oral anticoagulants (DOACs), are less cumbersome to use than the old standard warfarin treatment, which requires regular blood work for monitoring.”

If you’re concerned about taking anticoagulant medication, talk to your healthcare provider about the risks and benefits of each option. For example, bleeding is the main side effect of blood thinners and is a concern for some patients. This may be particularly true for those who are older and have other risk factors for bleeding.

If you’d prefer to try a more natural approach for lowering your risk of VTE, weight loss and other lifestyle changes are good options. Statins can also lower the likelihood of blood clots, according to a research review published in January 2017 in the Lancet Haematology. Still, it's not clear if these interventions will help prevent a recurrence once you’ve already had a blood clot. For these reasons, blood thinning drugs remain the cornerstone of treatment, notes Cushman.

Additional reporting by Ashley Welch