Deep vein thrombosis, pulmonary emboli explained

Deep vein thrombosis (DVT) occurs when blood in a vein becomes stagnant and then forms clot. This most often occurs in the lower extremities, but I have also seen it occur in the arms. There are two venous systems in the lower legs. One is the superficial system, which comprises the veins that you can see in your legs. If a clot forms in these veins, it generally does not move and causes redness and pain. The treatment is heat, elevation of the leg, and anti-inflammatory medications. The other is the deep system. The symptoms here can be swelling of the leg and pain, but I have seen patients who have no complaints until they develop blood clots in the lung.

DVT generally happens when there is a long period of lower leg inactivity. This can happen when a person is sitting for long periods of time, such as driving across the country or sitting in an airplane for a long flight. It is also common in people who are undergoing a surgical procedure that results in prolonged bed rest or orthopedic surgical procedures involving the lower extremities. This is why you hear physicians tell you to get up and walk around in the aisle on long airline flights or make frequent stops when you are driving. It is the reason why physicians place a post-operative surgical patient on “blood thinners” called anticoagulants. These medications affect the clotting cycle, making the blood take longer to clot.   

When a DVT goes untreated, some of the clotted blood can break loose, and it commonly travels to the lungs. This is called a pulmonary embolus (PE). This will result in shortness of breath and chest pain, but I have seen folks who just have a fever. In the worst case, the clot can be large and lodge in the main veins of the lung, resulting in death. So, the best thing here is prevention.  

If you have had DVT or PE, how do you gain back your medical certification? Both of these conditions are initially disqualifying. You should self-ground until you are cleared by the FAA with a special issuance. The first thing you should do is get better! Your physician is going to place you on one of several different anticoagulants. The classic one is called Warfarin (Coumadin). This medication works on the blood’s clotting mechanism to slow clot formation.   

The other anticoagulants are newer and also affect the clotting mechanism, but require no blood studies that allow your physician to show how “thin” your blood is. They are Pradaxa (Dabigatran), Xarelto (Rivaroxaban), and Eliquis (Apixaban). These are also acceptable to the FAA, but you will need to be on the medication for 30 days prior to presenting your case for consideration for special issuance.

What medical records/testing does the FAA want with these conditions? The FAA will need to see the records that explain how the DVT was discovered. You should provide the FAA with the X-ray studies that were used to make the diagnosis. They will need the results of a “hypercoagulable” profile. There are some people who have a hereditary condition that make them prone to developing blood clots. These people will need to remain on a blood thinner for the remainder of their lives. Those airmen who are taking Warfarin will need the results of the laboratory tests that are performed to determine how “thin” their blood is. This test is called the “international normalized ratio (INR)” and it is based on the common test result that is directly affected by the Warfarin. The airman will need to be at a therapeutic level of this test before he or she will be considered for special issuance. In general, a person who does not have a hypercoagulable state will be kept on the anticoagulant for about three months.

Those airman who have suffered pulmonary emboli will need to provide the following:

  • hospital admission and discharge summaries;
  • X-ray/scan studies that were performed to make the diagnosis;
  • results of a hypercoagulable profile;
  • INR levels, if the person is placed on Warfarin;
  • pulmonary function test (a test in which a person breathes into a machine that measures the air flowing in and out of the lungs).

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