Blood Clots and Anticoagulants

Blood clots can develop in the bloodstream when special proteins combine with blood cells called platelets. While they can help stop bleeding in response to an injury, some blood clots form without a good reason and don't dissolve on their own.

People with cancer have a higher risk for blood clots. It is estimated that up to 20% of patients with cancer develop venous thromboembolism (a condition that occurs when a blood clot forms in a vein) and 30% experience atrial fibrillation (an irregular and often very rapid heart rhythm that can lead to blood clots in the heart). The risk of a dangerous blood clot is often greatest for cancer patients during the first few months following a cancer diagnosis.

Surgery, hormone therapy, chemotherapy, tubes placed in veins to deliver treatments and certain cancer treatments that require hospital stay can also increase risk for blood clots. Left untreated, blood clots can be fatal and without treating atrial fibrillation the risk of stroke increases. Anticoagulant medications can help dissolve existing clots or prevent them from forming.

What are anticoagulants?

Anticoagulants or “blood thinning” medications are prescribed by doctors to prevent a blood clot from growing so your body can naturally break it down; they can also prevent new blood clots from forming. Anticoagulants are commonly part of treatment plans for cancer patients.

Doctors also give anticoagulants in lower doses to patients with certain high-risk cancers and after major cancer surgery to prevent blood clots from forming.

These medications come in a variety of forms, including oral, injections or IV infusions.

What conditions do anticoagulants treat?

One of the most common reasons patients take anticoagulation medication is venous thromboembolism (VTE). VTE is a medical condition that includes deep vein thrombosis and pulmonary embolism.

Deep vein thrombosis (DVT) is an abnormal blood clot that forms in a deep vein of the body. These blood clots most commonly occur in the legs. The blood clot can travel from the legs through the heart and into the lungs, causing a pulmonary embolism.

A pulmonary embolism (PE) occurs when a blood clot gets stuck in an artery in the lung, blocking blood flow.

Atrial fibrillation is another common condition that may require anticoagulation medication. This condition is an abnormal heart rhythm that can cause blood clots to form in the heart. Certain patients with this condition may need anticoagulant medications to help prevent a stroke.

What are the risk factors and warning signs of blood clots?

While blood clots can affect anyone, certain factors can increase risks. Common risk factors include:

• Surgery
• Immobility
• Previous VTE
• Trauma
• Cancer/chemotherapy
• Pregnancy
• Birth control medication containing estrogen
• Older age
• Obesity
• Smoking

Warning signs of deep vein thrombosis include swelling, redness, pain or tenderness, and skin that is warm to touch.

Warning signs of a pulmonary embolism include shortness of breath, chest pain, coughing or coughing up blood, and a fast heart rate.

Anticoagulant guidelines

If you are taking anticoagulants, call 911 or go to the nearest hospital emergency room if you experience any of the following:

• Signs of gastrointestinal bleeding (bright red blood in stool or dark, tarry stools)
• Signs of head bleeding (altered mental status, confusion, severe headache, drowsiness, slurred speech, sudden unexplained vomiting, numbness or weakness in a limb)
• Blood in the urine
• Coughing or vomiting blood
• Uncontrolled bleeding or extensive bruising
• A serious fall or hit on the head
• Chest pain or shortness of breath
• Redness, swelling, warmth or pain in a limb
• Other serious symptoms or changes in your health

There are several other guidelines for patients on anticoagulants:

• You must take your anticoagulation medicine as prescribed. Missed doses could result in blood clots or stroke.
• If you are taking a subcutaneous injectable anticoagulation medication, check your weight at least once a week and tell your health care team if you gain or lose more than 10 pounds.
• You may need to take this medicine for at least three months. Surgical patients are on a different schedule; after surgery, you may need to take anticoagulants for up to one month. You should not stop taking this medicine unless instructed by your provider or if there is a bleeding complication. Contact your provider for refills if needed.
• You may be told to stop taking this medicine before a medical procedure. If you have not been told to stop prior to a procedure, tell your health care team you are on an anticoagulant. You should also ask how to safely start taking the medicine again after the procedure.
• You should not take ibuprofen (Advil®, Motrin®), naproxen (Aleve®) or any other over-the-counter non-steroidal anti-inflammatory medicines unless approved by your health care provider.