Pulmonary embolism (PE) is a medical condition in which a thrombus obstructs a pulmonary artery leading to downstream symptoms. ¬1 The most common cause of a PE, is deep vein thrombosis (DVT). 2 It is a serious condition that can lead to a medical emergency. Although the exact number of people affected by PE is unknown, it is estimated to affect 900,000 new Americans each year. 3 About 10-30% of newly diagnosed individuals will die within the first month; adding to a total death rate of 60-100k each year. 3 It is very important to diagnose and treat PE right away, because one-third of undiagnosed/untreated PE patients do not survive.
PE can result in low oxygen levels in blood, damage to organs from low oxygen levels, and irreversible damage to the pulmonary tract. 2 One of the most important complications to watch out for in pulmonary embolism is pulmonary hypertension. Pulmonary hypertension causes high blood pressure in the lungs and right side of the heart, which can result in right sided heart failure because of the resistance the heart has to work against. 1 There are many different causes of pulmonary embolism, the biggest of them is DVT. DVT is a blood clot in the deep veins of your legs.
An embolus is formed when a portion of the thrombus breaks off and travels through your blood to your lungs, where it gets stuck in a pulmonary artery. 2 This leads to a decrease in blood supply to your lungs. Another cause of PE, can be as a result of trauma. Trauma to a bone can lead to release of fat from the marrow, which can also travel to your pulmonary arteries. 2 Other less common causes of pulmonary embolism include breakage of a tumor and air bubbles. 2 There are many risk factors for the development of PE, most of them are similar to those for the development of DVT.
Risk factors include: immobility, family history, pregnancy, oral contraceptive use, surgery, injury, obesity, smoking, cancer, and heart failure. 1 The risk for PE is equal among men and women, but doubles for every 10 years past the age of 60. 2 Although pulmonary embolism is a serious medical condition, over half the people with PE do not experience any symptoms. 2 Symptoms are mostly commonly a result of multiple pulmonary artery blockages. 2 Shortness of breath, chest pain, arrhythmia (irregular heartbeat), and hemoptysis (coughing up blood) are the most common symptoms of PE. Other less common symptoms include sweating, increased heart rate, anxiety, light-headedness, and fainting. 2
Because blood clots are the most common cause of PE, it is also important to watch for symptoms of those. Symptoms of blood clots include pain, warmth, tenderness, redness, and swelling of the legs. 1 Our patient was enduring many symptoms of DVT. He was experiencing swelling, pain and warmth in his right calf, but he was not enduring any of the major symptoms of PE besides chest pain. This is a good sign that his DVT had not yet progressed to a pulmonary embolism.
Diagnosis of PE is a comprehensive process which involves looking at the patient’s medical history, physical exam, and using diagnostic test. 1 Some of the most useful test for diagnosis of PE include ultrasound, computer tomography scans, lung ventilation/perfusion scan, pulmonary angiography, and blood test. 2 Other test that your doctor may conduct to rule out other causes include chest x-ray, magnetic resonance imaging, electrocardiogram, and echocardiograph. 2 Ultrasounds use sound waves used to follow blood though your veins, CT scans use dye, and lung V/P scans use radioactive substances.
One important diagnostic test that is comparatively cheaper is the blood test. We measure for the value of d-dimer, which tells us the amount of fibrin degradation products in the blood. D-dimer is not a very specific test for PE, but can implicate problems with blood clotting. 2 A higher value indicates more blood clotting, which is an important risk factor in PE. As for our case, E. P. was ordered a d-dimer blood test, which came back as abnormal. This indicated excess fibrin degradation products in the blood which supported the doctor’s diagnosis of DVT.
The goal of therapy for PE is to reduce blood clotting or break apart existing blood clots. 1 The most common drugs used for PE are anticoagulants/antiplatelet agents. All of these drugs through their various mechanisms work by inhibiting your bloods ability to clot. The most important thing to note for these drugs is that they do not break apart existing clots.
The most common side effect with these drugs is bleeding, which is a result of too much blood thinning. 1 Thrombolytics are drugs that are used to break apart existing clots; their use in PE is limited to serious situations. Rarely surgery may also be required for the removal of a clot. There are some non-pharmacological options for prevention of PE; these involve weight loss, smoking cessation, and exercise. 1
Another preventive measure some doctor may suggest is placement of a vena cava filter, which is used to break apart any embolus traveling to the lungs. 2 Direct oral anticoagulants have increased treatment options for many blood coagulation disorders. It is suggested that direct oral anticoagulant users monitor therapy if using combined with p-gp and/or CYP3A4 inducers/inhibitors. Also use of aspirin with direct oral anticoagulants is prohibited unless benefits clearly outweigh risk. 4 E. P. is currently on aspirin, if he is placed on a direct oral anticoagulant, we suggest discontinuation of the aspirin.
According to a guidance article published in Journal of Thrombosis and Thrombolysis, when switching from heparin to a direct oral anticoagulant, it is suggested to begin the direct oral anticoagulant at the time of heparin discontinuation. Our patient was diagnosed with deep vein thrombosis, putting him at a much greater risk for PE. Other risk factors that E. P. ad for the development PE include age over 60, immobility, and hypertension. We suggested E. P. be placed on Coumadin or Pradaxa based on his preference and insurance.
These drugs will help E. P with his DVT and help protect him against PE. It is also important to counsel our patient to get some exercise, wear his compression stockings, stay hydrated, and if he is placed on warfarin to watch his vitamin k intake, avoid alcohol, and monitor for signs/symptoms of bleeding. As for Pradaxa, it is important to discontinue aspirin, start at same time as heparin discontinuation, and monitor for CYP3A4 and p-gp interactions.