How Long Before a Pulmonary Embolism Turns Fatal

Timeline From Onset of Symptoms to Hospitalization

A pulmonary embolism (PE) results from a blood clot lodged in the lungs. This clot usually originates from breaking off another clot elsewhere in the body, typically the legs. With rapid treatment, most people affected by pulmonary embolism can recover.

However, a pulmonary embolism is considered a life-threatening emergency because the clot blocks blood flow into the lungs, causing pressure on the heart's right ventricle (chamber), eventually leading to excessive heart strain and death.

This article reviews blood clot fatality, the formation and travel time of clots to the lungs, symptoms and risk factors of pulmonary embolism, and when to seek medical care.

A woman hunched over holding her heart in pain.

Pornpak Khunatorn / Getty Images

Are Blood Clots Fatal?

Studies estimate the incidence of pulmonary embolism in the United States at 1 per 1,000 people per year, equating to 200,000 to 300,000 hospital admissions per year. It is estimated that as many as 30,000 to 50,000 Americans die yearly from PE.

Because of variations in the severity of the clot blockage to the lung's blood vessels and the pressure exerted on the heart's right ventricle, health outcomes vary. However, the pulmonary embolism's impact on the heart's right ventricle function is the most common cause of pulmonary embolism death. 

For people with pulmonary embolism but no associated decrease in right ventricle function, estimates place mortality (death) at around 2%. People with PE causing increased stress on the heart's right ventricle have a greater than 15% mortality rate.

Therefore, knowing the signs and symptoms of a pulmonary embolism and seeking rapid treatment is crucial to long-term survival.

Formation and Travel Time to Lungs

Pulmonary embolisms almost always begin as a distant clot in the arms or legs. Small pieces can break off and travel through the body's blood vessels as the distant clot grows. While smaller pieces might pass through the lungs without a problem, larger fragments of the clot can lodge in the lung's blood vessels and create a pulmonary embolism.

The size of the distant clot piece that lodges in the lung and how quickly that lodged piece starts to grow in the lung's blood vessels will affect how quickly pulmonary embolism forms.

Identifying the Signs of a Pulmonary Embolism 

People affected by pulmonary embolism can have different signs and symptoms. These may vary depending on the size of the PE, how much the lung is affected by lack of blood flow, and any underlying medical conditions, which can worsen PE formation.

The most common symptoms of pulmonary embolism are:

  • Shortness of breath
  • Chest pain that might worsen when breathing in
  • Cough
  • Leg or arm pain or swelling, which could be where the distant clot formed
  • Pain in the upper back
  • Excessive sweating
  • Light-headedness, dizziness, or passing out
  • A bluish tinge to lips or nails due to lack of properly oxygenated blood in the body's blood vessels

Risk Factors

Some risk factors associated with pulmonary embolism include:

  • Inactivity, such as during a long car or plane ride, can cause distant clots to form.
  • Other medical conditions, like cancer or heart disease, can elevate the risk for PE.
  • Smoking can cause blood vessel disease, leading to the formation of distant clots and elevating PE risk.
  • Obesity is linked to medical conditions like heart disease or blood vessel disease, which can elevate PE risk.
  • Supplemental estrogen from hormone replacement therapy or some birth control pills with higher estrogen levels is linked to a higher risk of blood clot formation and PE risk.
  • Pregnancy can cause clots due to the weight and pressure the baby puts on veins in the pelvis. This can slow blood flow in the legs and cause distant clot formation.
  • Inherited genetic conditions can elevate the risk of blood clot formation.

When to Seek Immediate Medical Attention

Identifying a distant clot before it turns into a pulmonary embolism offers the best option for optimal health and recovery. Symptoms of a distant clot in the arms or legs may include:

  • Pain
  • Swelling
  • Redness
  • Localized warmth, usually around the area of swelling or redness

If a clot has moved to the lungs, there are different signs and symptoms to be aware of. If you're experiencing any of the below signs or symptoms, you should seek immediate medical attention:

  • Chest pain
  • Shortness of breath
  • The feeling of a racing heart (an increase in heart rate)
  • Upper back pain
  • Coughing, including coughing up pink or blood-tinged secretions


A pulmonary embolism, or blood clot in the lungs, usually forms when a distant clot—usually from the arms or legs—breaks off and travels to the lungs. A PE is a medical emergency, but with quick identification and treatment, most people can recover without compromising overall health and wellness.

If you're experiencing symptoms of a pulmonary embolism, such as chest pain, difficulty breathing, or upper back pain, you should seek immediate medical attention to determine whether a PE is present and receive prompt treatment.

A Word From Verywell

A life-threatening diagnosis, such as a pulmonary embolism, can cause stress, anxiety, and worry. If you, or someone you know, has symptoms of PE, seek immediate medical care to ensure prompt treatment. You can recover from PE and lead a healthy life.

Frequently Asked Questions

  • Are all pulmonary embolisms fatal?

    When caught early, 98% of pulmonary embolisms can be successfully treated. Understanding the signs and symptoms of a pulmonary embolism, and seeking immediate medical attention, can ensure rapid treatment and resolution of a pulmonary embolism.

  • Does a pulmonary embolism happen suddenly or over time?

    The vast majority of pulmonary embolisms begin as a segment of a distant clot in a deep vein of the arms or legs that break off and lodge in the lung's blood vessels. Depending on the size and location of the pulmonary embolism and other risk factors, a pulmonary embolism usually develops over time.

  • How do pulmonary embolisms feel?

    A pulmonary embolism can feel similar to a heart attack with many of the same signs and symptoms. Anyone experiencing chest or upper back pain, difficulty breathing, a racing heart, or a cough with pink or blood-tinged secretions should seek immediate medical attention.

6 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. American Lung Association. Treating and managing pulmonary embolism.

  2. Gruber MP, Bull TM. Pulmonary embolism. Clin Resp Medicine, 3rd ed. 2008.

  3. Turetz M, Sideris AT, Friedman OA, et al. Epidemiology, pathophysiology, and natural history of pulmonary embolismSemin intervent Radiol. 2018;35(02):92-98. doi:10.1055/s-0038-1642036

  4. American Lung Association. Learn about pulmonary embolism.

  5. American Heart Association. Pulmonary embolism is common and can be deadly but few know the signs.

  6. American Lung Association. Pulmonary embolism symptoms and diagnosis.

By Pamela Assid, DNP, RN
Pamela Assid, DNP, RN, is a board-certified nursing specialist with over 25 years of expertise in emergency, pediatric, and leadership roles.