A saddle embolism is a clot that blocks both sides of an arterial branch. The classic example of a saddle embolism is a saddle pulmonary embolism that appears at the split of the pulmonary artery, blocking bloodflow to the lungs by effectively plugging both branches of the pulmonary artery. A saddle embolism can be a life threatening medical issue, depending on where in the body it is located.

In the case of a saddle pulmonary embolism, the blood clot commonly leads to death before it is even diagnosed and it is a common finding during necropsy of pulmonary embolism victims. Most commonly, the clot originates in the legs. Sometimes a saddle embolism can be caused by a clot of fat or another material. The saddle embolism can lead to death very rapidly because the blockage of the bloodflow to the lungs makes the patient highly unstable and if the embolus moves, it can completely cut off the supply of blood, leading to sudden death.

A saddle embolus can be caught before it causes death if a patient experiences a gradual onset of symptoms and goes to a hospital for treatment. The clot will be visible on a medical imaging study and immediate surgical treatment can be offered to clear the clot. Because the risks of pulmonary emboli are very serious, people with clotting disorders are given medications and carefully monitored for any signs of complications like saddle emboli. Likewise, people at risk for clots such as individuals sitting on long flights are encouraged to take steps to avoid clotting, such as periodically exercising to circulate the blood in the legs or wearing support stockings to reduce blood pooling.

Saddle emboli can strike in locations other than the pulmonary artery. There are a number of sites in the body where a large artery splits into two or more branches to bring a supply of blood to another area of the body. At any one of these points, an embolus can become lodged. The clot cannot successfully clear because the branches are much narrower, and it can snag in the branch. The bloodflow may be partially obstructed, moving sluggishly past the clot, or it can become completely blocked.

Treatments for emboli include catheterization procedures to pull the clot out, surgery, and medications to break up clots. Care providers must act quickly to identify and remove or break up clots to reduce the risk of severe complications for the patient.