After more than 200 years since it was first described, and more than 150 years since its association with leg clots was recognised, the pulmonary embolism remains one of the most underdiagnosed and potentially preventable causes of death.

It occurs when a blood clot dislodges from a vein, travels through the body, and lodges in the lung. Most clots originally form in one of the deep veins of the legs, thighs or pelvis; this condition is known as deep vein thrombosis (DVT). The clot then travels and blocks blood flow to parts of the lung, preventing oxygen from reaching the body — PE.

In the USA, it is estimated that between 50,000 and 75,000 people die yearly as a result of a PE. In fact, studies have shown that every year, more people die from DVT and PE than from breast cancer, Aids and motor vehicle accidents combined.

Pulmonary embolism symptoms vary from one person to another and could include:

• Shortness of breath

• Sharp chest pain while taking a deep breath

• Cough

• A rapid heart rate

Pulmonary embolism risk factors:

• Thrombophilia refers to the blood tendency to clot more easily than normal. Various genetic and acquired factors in the blood-clotting process may be involved. If a person is found to have a PE and there is no known medical condition or a recent surgery that could have caused it, a thrombophilia condition should be suspected. In addition, it is suspected in people who have more than one PE or if a family member has also experienced a PE.

• Surgery, especially when involving the hip, pelvis or knee, increases a person’s risk of developing a blood clot. During the recovery period, this risk often continues because the person is less active.

• Travel. Inactivity during long trips can increase one’s risk of developing a DVT/PE.

• Medical conditions The following can increase a person’s risk of developing a blood clot: pregnancy, birth control pills or hormone replacement therapy for menopause; obesity; smoking; cancer; heart failure and kidney problems such as nephrotic syndrome.

Pulmonary embolism diagnosis:

If a person’s condition suggests a PE, some tests — mainly a CT scan of the pulmonary vessels — are needed to confirm the diagnosis. Some patients with a suspected PE will also undergo testing to determine if DVT exists.

Pulmonary embolism treatment:

• Thrombolysis or “clot-busting” is used with patients who have serious complications related to PE or DVT and/or patients with large blood clots in the legs or lung. The best chance of responding to thrombocytic therapy is when there is a short time between the diagnosis of DVT/PE and the start of treatment.

• Embolectomy is the medical term for removal of PE from the lung. It may be performed using catheters or with a surgical procedure similar to open-heart surgery. It may be considered if a person is in serious condition as a result of PE, (eg persistently low blood pressure), and/or did not respond well to a thrombocytic or could not receive one.

• Anticoagulants or blood thinners. Patients are usually treated first with an injectable anticoagulant (heparin or one of its derivatives) then an oral pill (Warfarin, Xarelto, Pradaxa, Eliquis or Savaysa). Duration of treatment can vary from a minimum of three months to lifelong therapy.

• Inferior vena cava (IVC) filter is a device that blocks the circulation of clots in the bloodstream. It is placed, via a catheter, in the inferior vena cava (the large vein leading from the lower body to the heart). An IVC filter is often recommended in patients with PE who cannot use anticoagulants or who develop recurrent PEs despite anticoagulation.

Pulmonary embolism prevention:

• Surgical patients may be given blood thinners to decrease their risk of developing a clot. Anticoagulants may also be given to women at high DVT- or PE-risk during and after pregnancy.

• Extended travel confers a two- to fourfold increase in clot risk. A few tips that may be of benefit:

1. Stand up every two hours.

2. Flex and extend the ankles and knees periodically, avoid crossing the legs and change positions frequently.

3. Consider wearing knee-high compression stockings.

4. Avoid medications (like sleeping pills) or alcohol, that could impair your ability to get up and move.

• Joe Yammine is a cardiologist at Bermuda Hospitals Board. He trained at the State University of New York, Brown University and Brigham and Women’s Hospital. He holds five American Board certifications. He was in academic practice between 2007 and 2014, when he joined BHB. During his career in the US, he was awarded multiple teaching and patients’ care recognition awards. The information herein is not intended as medical advice nor as a substitute for professional medical opinion. Always seek the advice of your physician. You should never delay seeking medical advice, disregard medical advice or discontinue treatment because of any information in this article.