Blood Clots and Pulmonary Embolism

A young woman attended the emergency department with chest pains several weeks after being prescribed a birth control pill. Her X-ray was mistakenly read by the emergency room physician as negative. She was diagnosed with chest wall muscle pain and was discharged with pain pills. Three days later, she attended the family doctor who was told that the X-ray was normal − even though the X-ray report had been corrected by the radiologist as abnormal − and more pain pills were prescribed. Later that day she suddenly died, the autopsy showing that she had a pulmonary embolism. That same year, a 36-year-old healthy male who had had a fractured tibia repaired and casted for two weeks was standing waiting for his bus when he suddenly collapsed and died. Autopsy showed a pulmonary embolism arising from a clot in the casted lower leg. These were but two cases of death from pulmonary embolism that I investigated when serving as regional supervising coroner for eastern Ontario.

A pulmonary embolism is a blockage in one of the arteries of the lung blocking blood flow to part of the lung, and is caused by a blood clot that travels to the lung from a deep vein in a leg or, occasionally, from other sites including the arms. Veins return the blood to the heart to be pumped out by the right side of the heart through the pulmonary artery to the lungs. (After the blood is re-oxygenated in the lungs, it travels back to the left side of the heart to be pumped out via arteries to the whole body.) When a clot released from the leg vein enters the pulmonary arteries it will eventually stop, obstructing further blood flow to that part of the lung. There may be earlier symptoms of pain and or swelling in a leg suggestive of a clot (phlebitis or deep-vein thrombosis) or no prior symptoms at all, as in the cases above.

The incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) in Canada is about 1-2 cases in 1,000 adults per year and is the third most common cardiovascular disease after heart attack and stroke. This information is important, as the risk is higher in seniors and there are certain preventive measures which you should know about, especially as snowbirds. Other risk factors for DVT and PE include those who have had recent surgery with resultant immobility, casting of lower legs, cancer treatment, immobility, obesity, taking certain birth control medications, genetic predisposition, past history of DVT or PE and those suffering from Covid-19.

Symptoms of DVT usually affect the lower legs with possible swelling, pain, tenderness and redness of the skin. If any of the above risk factors are present, suspicion should be high. Urgent medical assessment is indicated − not only to diagnose and treat the clots and inflammation, but also to initiate treatment to reduce the threat of embolism.

Diagnosis of DVT is made by a careful history and physical examination, along with ultrasound examination of the affected area to detect any blockage of blood flow in the deep veins. If any suspicion of a pulmonary embolism exists, further tests to examine the lungs would be indicated.

Treatment for DVT is the administration of anticoagulants (often called “blood thinners”), which don’t actually thin the blood but reduce the ability of the blood to clot, thereby preventing further clotting as well as allowing time to let the body reabsorb the existing clot(s). The anticoagulants may be administered initially by injection (heparin), followed by the carefully monitored use of oral anticoagulants, most commonly Coumadin (warfarin), Xarelto (rivaroxaban) or Eliquis (apixaban).

Because bleeding time is prolonged with the use of these drugs, careful dosing is necessary involving frequent regular blood testing (INR) for those on Coumadin. Bleeding is the most common side-effect and requires immediate attention. Snowbirds requiring this test must continue to take the test even during their winter vacation in order to reduce the risk of a sudden bleeding episode. Xarelto and Eliquis do not require routine blood testing.

Symptoms of PE most commonly include chest pain, shortness of breath and cough. Usually, the chest pain comes on suddenly and may seem like a heart attack. It may or may not be associated with leg symptoms suggesting a deep vein thrombosis. The shortness of breath is usually worse with exertion and the cough may produce bloody sputum. In some cases, the individual will feel faint and may experience a rapid heart rate. If any of these symptoms occur, emergency attention is indicated to confirm the diagnosis and allow for the urgent administration of medical treatment.

The history is important to the physician, as one or more of the above risk factors may create suspicion that a pulmonary embolism is causing the chest complaint(s). It is especially necessary, as physical examination and even a plain X-ray of the chest may reveal no abnormalities. Suspicion is the key element in this situation in order that the proper special tests are performed in diagnosing embolism. Physical examination may or may not reveal faster respiratory and heart rates, and certain abnormal sounds may be heard on listening by auscultation to the lungs. Examination of the legs is important to detect any sign of a DVT. An electrocardiogram should be done and, if diagnosis is still uncertain, there are several advanced imaging tests of the lungs and legs which may aid in determining whether or not a pulmonary embolism is present.

When a diagnosis of pulmonary embolism is made, emergency admission to the hospital is indicated to initiate anticoagulation drugs to prevent extension or further clots, as well as other complications. Once appropriate bleeding times are achieved, oral anticoagulants will be started as the patient’s progress is being monitored. Occasionally, “clot busting” drugs (thrombolytics) may be used in life-threatening cases. In rare severe cases, catheter or surgical removal of a large lung clot may be necessary. In cases where anticoagulants can’t be used or when recurrent release of clots is noted, insertion of a filter into the main vein returning blood to the heart (inferior vena cava) may prevent further clots from travelling to the heart and lungs. Upon discharge from hospital, careful ongoing administration and monitoring of anticoagulants will be necessary − sometimes for years.

Snowbirds should be aware of steps which they can take to reduce the risk of DVT and PE. If you travel by plane, maintain some movement of your legs and get up and move about for short periods every hour or so. If travelling by car, stop for some exercise at least every two hours. Keep any other health conditions such as heart disease and diabetes as stable as possible. Lose weight if necessary and keep fit. Walking or other regular exercise most days of the week is important and, if at home in the winter, invest in a treadmill. If you have a problem with swollen lower legs or ankles, consult a physician; but the use of compression stockings and frequent elevation of your legs when resting are generally indicated. If you have any of the known risk factors, be sure to tell your doctor if suffering from new leg pain or chest symptoms.

If you are on anticoagulants while out of Canada and require regular blood testing, it is necessary to continue testing, usually monthly. Take a note from your home doctor indicating your diagnosis, the dose of anticoagulant that you take, the need for regular testing and your doctor’s fax or e-mail address. Find a local lab which will co-operate. A telephone call to your doctor a couple of days later may give you needed advice regarding any required dosage change. If this doesn’t work, you will have to get the service from a local physician but, as it is not a sudden and unexpected need, most travel insurance policies will not cover these expenses.

Although the chances of getting either of these conditions is low, your knowledge of some of the basic symptoms and facts about DVT and PE may help you recognize these serious conditions − should they occur with you or a loved one − and may result in a more favourable outcome.

by Dr. Robert MacMillan MD