Pulmonary Embolism

What is Pulmonary Embolism?

Pulmonary Embolism (“PE”) is a medical condition wherein a lung artery (or arteries) develops a blockage from a substance that traveled through the bloodstream to the lung. Venous thromboembolism (“VTE”) is a common medical term for pulmonary embolism and DVT. Click here to see a video animation of DVT and PE.

What causes PE?

The most common cause (over 90% of cases) is from a blood clot (“thrombus”) from a deep vein, usually in the leg (“deep venous thrombosis” or “DVT”). If the blood flow in the legs becomes slowed, clots may form. This can happen during periods of immobility, such as after a surgery, during long car or airplane trips, or because you are bedridden. Damaged veins, such as from an injury or previous surgery are more prone to forming blood clots.

Other lesser common causes of PE are air (such as from an air bubble in an IV catheter), fat (such as from fat in the bone marrow during a leg fracture), tumor (such as from cells of a cancer breaking off into the bloodstream), infected material (such as from IV drug abuse), or amniotic fluid (such as during a delivery).

What are the symptoms or signs of PE?

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Unexplained shortness of breath, chest pain, cough, and hemoptysis (coughing up blood) are some of the most common features of PE. The chest pain is often “pleuritic” or more painful with breathing. Patients may also experience arrhythmia (abnormal heartbeat), especially rapid or irregular heartbeats. Other symptoms or signs may include feeling of dread or anxiety, severe sweating, low grade fever, lightheadedness, rapid breathing, fainting, and cyanosis (bluish discoloration of the lips and finger tips). Multiple and smaller clots may lead to pulmonary hypertension. Not all persons with PE have these signs/symptoms, and some have none. In about 5% of cases, PE can also present with circulatory collapse and “sudden death”.

Sometimes the only signs and symptoms come from the clot in the leg (DVT). DVT can cause swelling, warmth, redness, and pain of the affected leg.

It is important to see your doctor immediately if you have signs or symptoms of VTE.

How is VTE diagnosed?

First, your doctor will take your medical history and examine you to look for risk factors for VTE, look for signs of DVT or PE, look for other causes to explain your signs/symptoms, and to decide the likelihood that you might have VTE.

Next, your doctor will do testing to help diagnose or exclude VTE. There are a number of available tests. Your doctor will decide how to evaluate you depending upon your condition, other health problems, how likely it is that the doctor thinks you have VTE, and local testing preferences/availability.

Some of the diagnostic options include:

  1. Ventilation/Perfusion Lung Scan
  2. CT Angio with PE protocol
  3. Pulmonary Angiogram
  4. Ultrasound/Doppler of the legs
  5. D-Dimer blood test

In addition, your doctor may obtain a regular chest x-ray, EKG, Echocardiogram, complete blood count (CBC), tests of clotting status (PT/PTT), other blood tests (such as kidney function, liver enzymes, electrolytes, and sedimentation rate), and arterial blood gases.

Who is at risk for VTE?

VTE affects both men and women equally. The risk increases with increasing age, doubling with each ten years after age 60.

Known risk factors include:

  • Immobility- this can occur in just hours, such as sitting still on an airplane or long car ride.
  • History of previous DVT or PE.
  • Persons with congestive heart failure
  • Patients with cancer or recently treated for cancer.
  • Estrogen-containing hormones (including oral contraceptives)
  • Those with certain inherited conditions (such as Factor V Leiden, Protein C or S deficiency, antithrombin deficiency, and others)
  • Being overweight or obese
  • Pregnancy or just after pregnancy
  • Cigarette smoking
  • Recent major surgery
  • Previous deep vein injury or those with central venous IV catheter
  • Bedridden persons
  • Burn victims
  • Older persons, especially over the age of 60
  • Injury to the pelvis, hip, or leg

How is Pulmonary Embolism treated?

In most cases, the treatment consists of medicines aimed at stopping the clot from growing and preventing new clots from forming. These medicines are called anticoagulants (“blood thinners”).

Blood thinners come in pills, IV injections, and shots under the skin. The pill is called warfarin (trade named “Coumadin”). The injections include heparin and enoxaparin (“Lovenox”). Often, your doctor will start the injectable treatments (which are faster acting) at the same time as the pill, which can take several days or more to reach a satisfactory level in your blood. Once the Coumadin is working, the injections are stopped and you can go home on Coumadin. Coumadin is taken once a day. In some patients (such as pregnant women), the treatment is only injections.

Your doctor will monitor your Coumadin treatment by a blood test (“protime” or “PT” and “International Normalized Ratio” or “INR”). Initially, you may have this test daily, but eventually only weekly or biweekly. The ideal is an INR of 2-3. Coumadin is inhibited by Vitamin K, so you should not eat foods rich in this substance (such as certain leafy green vegetables, broccoli, Brussels sprouts, okra, sauerkraut, asparagus, certain onions, and cabbage).

Anticoagulants do not break up the clots already formed. Over time, the body dissolves most clots. If your symptoms are life-threatening, you might need treatment with medicine to quickly dissolve the clot (“thrombolytic”), or rarely, surgery to remove it. These have added risks and are not used unless absolutely necessary.

Treatment for VTE typically continues for 2-6 months, depending upon the cause and circumstances. If you’ve had clots before or if you have cancer, you may require longer treatment. Some patients require treatment indefinitely.

In some people, the medicines don’t work or they cannot take the medicines. In those cases, the doctor may have a device (or “filter”) inserted into the large vein below your lungs (“vena cava”), to interrupt the passage of further clots passing from the legs to the lungs. These vena cava filters do not stop clots from forming and may not entirely prevent clots from reaching the lungs.

Treatment of pulmonary embolism also includes treating the symptoms. Oxygen is administered. Analgesics are given to relieve pain. Intravenous fluids are given, and sometimes drugs that increase blood pressure, if the blood pressure is low. Mechanical ventilation (“breathing machine”) may be necessary if respiratory failure develops.

What is the prognosis?

In general, the prognosis depends upon how much lung is damaged by clots, and the existence of other medical problems (especially of the heart or lungs). At least 100,000 cases of PE occur each year in the US and if left untreated, about 25-30% of patients who have PE will die. In the US, PE is the third most common cause of death in hospitalized patients.

What can be done to prevent VTE?

The main goal is to prevent the development of DVT. Steps you can take include:

  • Get out of bed and move around as soon as possible after surgery
  • Exercise your legs or walk around if you are on a long car trip or airplane
  • Don’t smoke, especially if you have other risk factors, such as estrogen supplements
  • Take medicines (if prescribed by your doctor) before/after surgery
  • Wear specialized stockings if recommended by your doctor (especially for those with a history of DVT)

Living with VTE

  • Most importantly, take your medicines exactly as prescribed. Taking too little does not protect you and taking too much can cause bleeding.
  • Ask your doctor about your diet, because certain foods can inhibit the function of Coumadin. It is best to maintain a balanced and regular diet.
  • Check with your doctor about drug interactions, including antibiotics and certain over-the-counter drugs.
  • Take the blood tests as ordered by your doctor and make sure you thoroughly understand any directions for changing the dose.
  • Call your doctor immediately if you experience any bleeding from the skin or nose that will not stop in 10 minutes after you apply pressure, any bleeding from the digestive tract (such as vomiting blood or vomit that looks like coffee grounds, bloody stools or black tarry stools, or abdominal pain), any sudden neurological problems (such as severe headache, sudden loss of vision, sudden loss of movement in your arms or legs, or confusion).
  • Call your doctor if you symptoms recur after they had resolved

Where can I learn more?

NIH/MedlinePlus
American Medical Association
NHLBI
ATS 2009 Reading List