Blood Clots After Surgery

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Blood clots after surgery are a concerning complication. They can lead to deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT occurs when a blood clot forms in a deep vein, usually in your thigh or calf. A PE is a potentially fatal condition where the clot breaks free and travels through the veins to the lungs.

These complications are very serious and must be treated quickly to minimize the damage to your body. This article explains what causes blood clots to form and what puts you at risk of blood clots after surgery. It also discusses how to treat and spot blood clots after surgery and what you can do to prevent them.

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Common Causes & Risk Factors for Blood Clots

What Causes Blood Clots After Surgery?

A blood clot is more likely to form during or after surgery than it is during your routine day-to-day life. There are multiple reasons for this, but one major cause is inactivity.

During surgery, you lie still on the operating table for an extended time, which puts you at risk for clots.

Many people are also inactive after surgery because they’re in pain, sick, or unable to walk. That increases the risk of clot formation after the procedure. Inactivity makes it easier for blood to clot because muscle use typically squeezes blood out of your veins and keeps it from pooling. Pooling blood can lead to clots. Clots tend to form in your deep veins, leading to deep vein thrombosis (DVT).

Clots can break free and move from the legs to the lungs, causing a life-threatening condition called a pulmonary embolism (PE). A PE can be treated, but if left untreated, it can cause heart attack, shock, stroke, or death.

Your medical and social history may contribute to clot formation. For example, if you’re a smoker, you’re at higher risk for the formation of blood clots than the average person, even without having surgery.

Risk Factors for Blood Clots After Surgery

A wide range of medical conditions and other factors can increase your risk of post-surgical blood clots. These conditions include:

  • Age of 55 years or older
  • Cancer and cancer treatment
  • Pregnancy, as clotting speed increases in preparation for childbirth, and up to three months after the baby is born
  • Use of birth control methods that contain estrogen, such as the pill, patch, or ring
  • Use of hormone therapy with estrogen
  • History of blood clots
  • Family history of blood clots
  • Overweight
  • Smoking
  • Prolonged immobility
  • Long-term diseases, such as heart and lung conditions or diabetes

The type of surgery you are having can increase the risk of having blood clots after the procedure as well. If your surgery requires your arteries or veins to be cut or repaired, the risk of a blood clot is higher because your body works to stop bleeding by forming clots.

If you’re having surgery where your heart is stopped, typically a heart bypass surgery (CABG), your risk of a blood clot is also increased.

Talk to your healthcare provider about your risk of DVT and PE before you go into surgery, and ask about the type of prevention measures you may need.

Preventing Blood Clots After Surgery

After surgery, you'll want to be proactive in preventing blood clots. Here are things you can do at the hospital and at home to reduce your risk.

At the Hospital

Getting up and moving during your recovery from surgery is one of the best ways to prevent blood clots. Your healthcare provider will ask you to get up and move around as soon as possible after surgery.

If you can't walk around after surgery, you can prevent blood clots by flexing and stretching your feet. This improves blood flow in your calves, which prevents blood from pooling and clots from forming.

Before you head home, discuss your risk of blood clots with your healthcare provider. Blood clots after surgery can occur up to 90 days after the procedure.

Your healthcare provider may prescribe medication to prevent clots from forming. Injectable medications—such as Lovenox or Heparin—are very common during a hospital stay after surgery. This medication is given to prevent the formation of a blood clot. It is less commonly prescribed for use at home. 

At Home

When you get home, it's important to follow your healthcare provider's instructions to prevent DVT and PE. This includes taking medications as directed and getting up and walking around. If you can't walk around, have someone help you move your arms and legs.

Your healthcare provider may tell you to wear compression stockings to prevent blood clots after surgery. These snug stockings use pressure to improve blood flow and prevent clots.

Treating Blood Clots

The treatment for blood clots depends on their location. Blood thinners, like the drug Coumadin (warfarin), help the body remove a clot from the bloodstream. Heparin may also be given to prevent additional clots from forming or to prevent clots from getting bigger. You may be asked to take a blood thinner for at least three months or longer depending on your situation.

Typically, DVT is treated with medication, but if there’s a high risk of the clot moving to the lungs or you can’t safely take the medication, a device called an inferior vena cava filter may be placed. This device acts as a tiny basket, catching clots before they can lodge in the lungs and cause damage.

A healthcare provider places these filters through a small incision in the groin or neck, then threads the filter into place in the inferior vena cava (a large vein). The filter may be in place temporarily or permanently.

Treatment for a PE can include blood thinners or thrombolytics (medication that dissolves blood clots). Thrombolytics can cause complications like sudden bleeding so they are used only for serious and life-threatening PE. Sometimes a vena cava filter is placed or a flexible tube called a catheter is used to break up the clot or deliver medicine.

Signs of a Blood Clot

Not everyone with a blood clot will notice symptoms. In fact, about half of people with DVT don't show any signs at all. If you do have symptoms, they will show up in the affected part of the body, such as your leg. Common symptoms include:

  • Swelling
  • Pain
  • Tenderness
  • Redness of the skin

When to Call a Healthcare Provider

Contact a healthcare provider immediately if you notice any signs of a blood clot, such as pain or swelling in the affected body part. Your doctor will run special tests to diagnose DVT or PE. Both DVT and PE can be treated.

When to Call 911

Pulmonary embolism (PE) is a serious condition that requires immediate medical treatment. Seek medical help right away if you notice any of the following signs of symptoms of PE:

  • Difficulty breathing
  • Faster than normal or irregular heart beat
  • Chest pain or discomfort, which usually gets worse when you take a deep breath or cough
  • Coughing up blood
  • Very low blood pressure, lightheadedness, or fainting

Summary

Blood clots after surgery can be a very serious complication. If you experience unexplained pain, swelling, or a dramatic increase in pain after surgery, particularly in the legs, there could be an issue with blood clots, a condition known as deep vein thrombosis (DVT).

Understand your risks of developing blood clots after surgery. If you're taking certain medications and or have certain medical conditions, you may have an increased risk of DVT.

It’s far better to report the possibility of a blood clot to your healthcare provider than to ignore it and experience a life-threatening issue such as a pulmonary embolism (PE). Follow your healthcare provider's instructions to prevent blood clots after surgery, and get medical help right away if you notice any signs of DVT or PE.

Blood Clots Healthcare Provider Discussion Guide

Get our printable guide for your next healthcare provider’s appointment to help you ask the right questions.

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7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Heart Lung and Blood Institute. Venous thromboembolism.

  2. Stop The Clot, Spread The Word. Know your risk factors.

  3. Agency for Healthcare Research and Quality. Your guide to preventing and treating blood clots.

  4. Stop The Clot, Spread The Word. Hospitalization.

  5. MedlinePlus. Deep vein thrombosis.

  6. MedlinePlus. Pulmonary embolism.

  7. Centers for Disease Control and Prevention. What is venous thromboembolism?

By Jennifer Whitlock, RN, MSN, FN
Jennifer Whitlock, RN, MSN, FNP-C, is a board-certified family nurse practitioner. She has experience in primary care and hospital medicine.