Pulmonary Embolism

A pulmonary embolism occurs when a clot, or thickened mass of blood, breaks off from its point of origin in the body, travels through the bloodstream, and becomes lodged in a narrower vessel in a lung. This restricts blood flow to the affected lung, lowers oxygen levels in the lungs and increases blood pressure in that organ’s arteries. The most common cause of a pulmonary embolism is deep vein thrombosis, a clot that originates in a vein deep in the body, such as a leg.

Symptoms may include:

Symptoms vary, depending on the severity of the clot. Although most people with pulmonary embolisms experience symptoms, some will not. If you have any symptoms of pulmonary embolism, get medical attention immediately.

  • sudden shortness of breath (most common)
  • chest pain (usually worse with breathing)
  • a feeling of anxiety
  • a feeling of dizziness, lightheadedness, or fainting
  • irregular heartbeat
  • palpitations (heart racing)
  • coughing and/or coughing up blood
  • sweating
  • low blood pressure

You may also have symptoms of deep vein thrombosis (DVT), such as:

  • pain in the affected leg (may occur only when standing or walking)
  • swelling in the leg
  • soreness, tenderness, redness, and/or warmth in the leg(s)
  • redness and/or discolored skin

Your doctor will:

  • ask you or a family member about your risk factors, such as high blood pressure, smoking, heart disease, and a personal or family history of blood clots
  • ask about your signs and symptoms and when they began
  • conduct a physical examination

Your doctor may order one or more of the following tests:

  • Chest X-ray is an imaging test used to assess the lungs and heart. Chest X-rays show information about the size, shape, contour, and location of the heart, lungs, bronchi (large breathing tubes), aorta and pulmonary arteries, and mediastinum (area in the middle of the chest separating the lungs).
  • Ventilation-perfusion scan (V/Q scan) is a small amount of a radioactive substance used to help examine the lungs. A ventilation scan evaluates ventilation, or the movement of air into and out of the bronchi and bronchioles. A perfusion scan evaluates blood flow within the lungs.
  • Pulmonary angiogram is an X-ray image of the blood vessels is used to evaluate various conditions, such as aneurysm (bulging of a blood vessel), stenosis (narrowing of a blood vessel), or blockages. A dye (contrast) is injected through a thin flexible tube placed in an artery. This dye makes the blood vessels show up on X-ray.
  • Computed tomography (CT) scan is an imaging test uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. CT with contrast enhances the image of the blood vessels in the lungs. Contrast is a dye-like substance injected into a vein that causes the organ or tissue under study to show up more clearly on the scan.
  • Magnetic resonance imaging (MRI) is a test that uses a combination of a magnetic field, radiofrequencies, and a computer to make detailed images of organs and structures within the body.
  • Duplex ultrasound is a type of vascular ultrasound used to assess blood flow and the structure of the blood vessels in the legs. (Blood clots from the legs often dislodge and travel into the lung.) Ultrasound uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs.
  • Blood tests are used to check the blood’s clotting status, including a test called D-dimer level. Other blood work may include testing for genetic disorders that may contribute to abnormal clotting of the blood. Arterial blood gases may be checked to see how much oxygen is in the blood.
  • Electrocardiogram (EKG) is one of the simplest and fastest tests used to evaluate the heart. Electrodes (small, sticky patches) are placed at certain spots on the chest, arms, and legs. The electrodes are connected to an EKG machine by lead wires. The electrical activity of the heart is measured, interpreted, and printed out.


Treatment for this condition must always be discussed with your doctor
for a full discussion of options, risks, benefits, and other information.

Oral anticoagulants, also known as blood thinners, are the standard treatment for a pulmonary embolism. Your physician may prescribe the medication for a period of 3-6 months. While these do not dissolve existing clots, they prevent new clots from forming by reducing your body’s ability to clot. However, you may still feel the symptoms due to the existing clot. Ask your doctor about treatment options to dissolve/remove existing clot.

In some cases, the symptoms are severe (often accompanied by low blood pressure), and the blood clot needs to be removed as quickly as possible. In such cases, treatment is typically provided in a hospital interventional suite, after which your condition can be closely monitored. The length of your treatment and hospital stay will vary, depending on the severity of the clot.

Minimally-invasive endovascular procedures for the treatment of blood clots in the peripheral vasculature consist primarily of thrombolytic drug infusion, or mechanical removal.

In thrombolytic drug infusion, a clot-busting drug may be administered intravenously, and is circulated within the entire body. This is called systemic thrombolysis. Sometimes, drug therapy is delivered via a catheter inserted into the blocked or narrowed part of the vessel over a previously positioned guidewire that directs the catheter to the affected area. A thrombolytic drug, such as tissue plasminogen activator (tPA), is then infused at a set infusion rate for a period ranging from 6 to several hours, during which time, patients are closely monitored in an Intensive Care Unit (ICU) to ensure there are no complications associated with infusion of the drug.

A continuous vacuum using a mechanical pump can be used to aspirate a wide range of clot types as well. The pump delivers a high level of suction via a specially-designed catheter that can handle the vacuum pressure, and can be tracked easily to the clot’s location. This treatment is proving to be able to handle longer segments of clot, as well as a clot that has been in place for a longer period of time. Endovascular thrombectomy devices are increasingly used to remove clots from blood vessels because they offer a faster treatment option than thrombolytic infusion alone. Endovascular thrombectomy may sometimes be combined with thrombolytic infusion. The advantages of thrombectomy over thrombolytic drug administration alone can include rapid return to normal blood flow, reduced bleeding risk, decrease in procedural times, and potentially shorter hospital stays.