How Pulmonary Embolism Is Treated

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When a person is found to have had an acute pulmonary embolus, the appropriate treatment depends on whether their cardiovascular status is stable or unstable.

For Relatively Stable People

Most people diagnosed with a pulmonary embolus are reasonably stable from a cardiovascular standpoint. That is, they are conscious and alert, and their blood pressure is not dangerously low.

For these people, treatment with anticoagulant drugs (blood thinners) is usually begun right away. Early treatment greatly reduces their risk of dying from a recurrent pulmonary embolus.

First 10 Days

For the first 10 days after the pulmonary embolus has occurred, treatment consists of one of the following anticoagulant drugs:

  • Low molecular weight (LMW) heparin, such as Lovenox or Fragmin. These are purified derivatives of heparin that can be given by skin injection instead of intravenously.
  • Fondaparinux, another subcutaneously administered heparin-like drug.
  • Unfractionated heparin, “old-fashioned” heparin that is given intravenously.
  • Rivaroxiban (Xarelto) or apixaban (Eliquis), two of the  “new oral anticoagulant drugs” (NOAC) that are an oral substitute for Coumadin. These two NOAC drugs are the only ones currently approved for the acute treatment of a pulmonary embolus.

All of these drugs work by inhibiting the clotting factors, proteins in the blood that promote thrombosis. Today, most doctors will use either rivaroxiban or apixaban during the first 10 days of therapy in people who are able to take oral medication. Otherwise, LMW heparin is most commonly used.

10 Days to 3 Months

After the initial 10 days of therapy, treatment is selected for longer-term therapy. In most cases, this long-term therapy is continued for at least three months and in some cases for up to a year.

This longer-term treatment almost always consists of either of one of the NOAC drugs. For this phase of treatment (that is, after the first 10 days), the NOAC drugs dabigatran (Pradaxa) and edoxaban (Savaysa) are also approved for use, in addition to rivaroxiban and apixaban. In addition, Coumadin remains an option for this long-term treatment.

Indefinite Treatment

In some people, long-term anticoagulation therapy should be used indefinitely after a pulmonary embolus, possibly for the rest of their lives. Generally, these are people fall into one of two categories:

  • People who have had a pulmonary embolus or a severe deep vein thrombosis without any identifiable provoking cause.
  • People in whom the provoking cause is likely to be chronic, such as active cancer, or a genetic predisposition to abnormal blood clotting.

If Anticoagulant Drugs Cannot Be Used

In some people, anticoagulant drugs are not an option. This may be because the risk of excess bleeding is too high or they may have had recurrent pulmonary embolus despite adequate anticoagulation therapy.

In these people, a vena cava filter should be used. A vena cava filter is a device that is placed in the inferior vena cava (the major vein that collects blood from the lower extremities and delivers it to the heart) by a catheterization procedure. These filters “trap” blood clots that have broken loose and prevent them from reaching the pulmonary circulation.

Vena cava filters can be quite effective, but they are not preferred to anticoagulant drugs because of the risks involved with their use. These include thrombosis at the site of the filter (which may lead to recurrent pulmonary embolism), bleeding, migration of the filter to the heart, and erosion of the filter.

Many modern vena cava filters can be retrieved from the body by a second catheterization procedure if they are no longer needed.

For Unstable People

For some people, a pulmonary embolus is a cardiovascular catastrophe. In these people, the embolus is large enough to cause a major obstruction of blood flow to the lungs, which leads to cardiovascular collapse. These people usually display extreme tachycardia (rapid heart rate) and low blood pressure, pale sweaty skin, and altered consciousness.

In these cases, simple anticoagulation therapy—which primarily works by stabilizing blood clots and preventing further clotting—is not enough. Instead, something must be done to break up the embolus that has already occurred, and restore the pulmonary circulation.

Thrombolytic Therapy (“Clot Busters”)

With thrombolytic therapy, intravenous drugs are administered that “lyse” (break up) clots that have already formed. By breaking up a large blood clot (or clots) in the pulmonary artery, they can restore a person’s circulation.

These drugs (also known as fibrinolytic drugs because they work by disrupting fibrin in clots) carry a substantial risk of bleeding complications so they are used only when a pulmonary embolus is immediately life-threatening. The thrombolytic agents most often used for severe pulmonary embolism are alteplase, streptokinase, and urokinase.

Embolectomy

If thrombolytic therapy cannot be used because the risk of excessive bleeding is deemed to be too high, an attempt can be made at embolectomy. An embolectomy procedure attempts to mechanically break up a large clot in the pulmonary artery, either by surgery or by a catheter procedure.

The choice between catheter-based or surgical embolectomy usually depends on the availability of doctors who have experience with either of these procedures, but in general catheter-based embolectomy is preferred because usually it can be done more quickly.

However, an embolectomy procedure of either type always carries major risks—including rupture of the pulmonary artery, with cardiac tamponade and life-threatening hemoptysis (bleeding into the airways). So, embolectomy is usually only performed in people judged to be extremely unstable and who have a very high risk of death without immediate effective treatment.

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