Deep Vein Thrombosis and Pulmonary Embolism

When a blood clot forms in your arm or leg vein, we call it deep vein thrombosis (DVT). If left untreated, the clot may become larger and cause significant swelling or pain in your arm or legs. An embolism can also break off and travel to your lungs, causing breathing difficulty, chest pain, and putting stress on your heart. We call this condition pulmonary embolism (PE). The bigger the clot, the more dangerous this becomes.

Generally, DVT stems from a combination of factors, including an injury (e.g., surgery, motor vehicle accident), inactivity (due, perhaps, to a long plane ride, hospitalization, or recuperation from surgery), and a condition that makes you more likely to experience clotting (such as pregnancy, cancer, or genetics). Using tobacco or contraceptives also increases your risk of a blood clot.

If you don’t have any of these factors, we consider the DVT to be "unprovoked." It is important to determine whether your blood clot is provoked or not, as it affects treatment and prognosis. Certain conditions can increase your risk of blood clots, including:

  • May-Thurner syndrome occurs when the main vein in your left leg (common iliac vein) gets compressed between your right leg artery and the spine. This may cause scarring and increase your risk of a blood clot in the left pelvis and thigh.
  • Thoracic outlet syndrome (TOS) happens when your large arm vein is compressed between the first rib and collar bone (clavicle). This can form scar tissue, which leaves you vulnerable to DVT. If you suddenly develop DVT in your arm, usually when you’re involved with some sports activity such as swimming, we call it effort thrombosis or Paget-Schroetter's syndrome.

If you have DVT, you may have a number of symptoms including sudden swelling and/or pain in the affected arm or leg, reddish skin, and dilated veins on the surface of the arm or leg.

If you develop PE, you might have sudden shortness of breath and chest pain.. You could also experience dizziness, fast or irregular heart rate, low blood pressure, low oxygen level, or fainting (syncope). If you have these signs, please go to the nearest emergency room.  

The best way to prevent DVT and PE is by reducing the risk factors that can lead to these conditions. It can help to exercise regularly, elevate your legs, avoid prolonged standing, and stop smoking. If you are going to be immobile due to surgery or hospitalization, we may prescribe blood thinning medication in advance.

Diagnosis and Treatment

To diagnose DVT, we start with a physical exam, an electrocardiogram or EKG, and assess your symptoms. We may also need to do blood work and imaging. We typically use one or more of these imaging tests:

  • Arm or leg ultrasounds are sonograms that check your veins for a blood clot. This test is highly accurate and non-invasive.
  • Computed tomography angiography (CTA) uses X-ray technology and contrast material to generate 3D pictures of the arteries of the lung. This quick exam is the gold standard for diagnosis of PE.
  • Ventilation/perfusion scan (VQ scan) is less common than the CTA though it is more accurate. This nuclear medicine exam compares the parts of the lung that are receiving blood to those that are receiving air. If there are areas that don’t match up, it indicates a blocked artery caused by PE.

If you have urgent PE symptoms, such as low blood pressure, fainting, heart strain, or low oxygen level, we may start some treatment immediately.

We may start by doing blood work, to see whether we need to do an imaging test. We often start with the D-timer test, which measures blood clotting and can help us rule out a DVT or PE.

If we diagnose PE, we may conduct additional testing to evaluate the strain on your heart and the extent of blood clotting in the legs. We may do ultrasounds of your heart (transthoracic echocardiogram) and both legs.

Mount Sinai vascular specialists are experts in the treatment and long-term management of VTE. We often use blood thinning medication to stabilize the blood clot and prevent further PE. Blood thinners do not break down an existing blood clot, but they stop it from growing and progressing to PE. We tend to use one of these blood thinners:

  • Heparin agents (enoxaparin) are injectable medications that you take twice a day or as continuous infusions (unfractionated heparin) that we administer only in the hospital.
  • Warfarin is an oral blood thinning agent. We adjust your dose to meet your specific needs, which can take anywhere from a few days to a few weeks to establish the proper dosage for you. During this time, we may give you heparin to protect you from blood clots. Taking other medications and a number of common foods can make you vulnerable to bleeding or blood clots while on this medication. Our doctors will discuss these considerations with you before starting a prescription plan.
  • Novel oral anticoagulants act by blocking blood factors involved with clotting. Dosing varies: you take dabigatran and apixaban twice a day and rivaroxaban and edoxaban once daily. These medications help you achieve the appropriate level of blood thinning without having to adjust the dose or monitor your blood.

For those very rare occasions when blood thinning medication is not an option, we may use a device called an inferior vena cava (IVC) filter to protect you from PE. We implant the filter in your groin or neck vein through a minimally invasive procedure, then deploy it into your abdomen.  We use both temporary filters (for a few months) and permanent ones.

We may use a clot-busting medication if you have a life-threatening PE. The medicine will break down the blood clot in the lung immediately, a process called thrombolysis. We deliver this medication either by injection in the vein (systemic thrombolysis) or through a small tube (catheter) in the groin area, a procedure called mechanical and catheter-directed thrombolysis. In rare cases, we remove the blood clot surgically.

If you have May-Thurner or thoracic outlet syndrome, we may also need to remove the clot from your blood vessel. We can do this by mechanical and catheter-directed thrombolysis, performing surgery to remove the first rib, or implanting a mesh tube (stent) inside your vein to keep it open long-term.

You might experience long-term effects of DVT and PE. The major effects may be:

  • Venous insufficiency or "leaky veins" and post-thrombotic syndrome (PTS) affects about half of everyone who’s experienced DVT. It happens when blood pools in the legs because the veins are not functioning properly. Symptoms include leg swelling, redness, varicose veins, dark-stained skin, and, in severe cases, non-healing ulcers. The best treatment is prevention; we recommend wearing compression stockings (prescription grade) to prevent PTS.
  • Chronic thromboembolic pulmonary hypertension (CTEPH) results from an old or recurrent PE that causes high blood pressure in the lungs and heart strain over time. While this doesn’t happen often, symptoms include shortness of breath, limited ability to exercise, dizziness, leg swelling, chest pain, and palpitations. Our vascular surgeons work together with a cardiologist to manage these cases.