How tPA and Other Treatments Can Cause a Hemorrhagic Conversion

Because tPA treatment can cause hemorrhagic conversion of ischemic strokes, it is important to understand what happens inside the brain during a typical ischemic stroke. But first, let's discuss stroke in general.

Older man clutching his forehead
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Stroke is a disease that affects the arteries leading to and within the brain. It is the No. 5 cause of death and a leading cause of disability in the United States. A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a clot or bursts (or ruptures). When that happens, part of the brain cannot get the blood (and oxygen) it needs, so it and brain cells die.


The brain is an extremely complex organ that controls various body functions. If a stroke occurs and blood flow can't reach the region that controls a particular body function, that part of the body won't work as it should.

Risk Factors

  • Age: The chance of having a stroke approximately doubles for each decade of life after age 55. While stroke is common among the elderly, a lot of people under 65 also have strokes.
  • Heredity (family history): Your stroke risk may be greater if a parent, grandparent, sister or brother has had a stroke. 
  • Race: African-Americans have a much higher risk of death from a stroke than Caucasians do. This is partly because blacks have higher risks of high blood pressure, diabetes, and obesity.
  • Sex (gender): Each year, women have more strokes than men, and stroke kills more women than men. Use of birth control pills, pregnancy, history of preeclampsia/eclampsia or gestational diabetes, oral contraceptive use, and smoking, and post-menopausal hormone therapy may pose special stroke risks for women. 
  • Prior stroke, TIA, or heart attack: The risk of stroke for someone who has already had one is many times that of a person who has not. Transient ischemic attacks are "warning strokes" that produce stroke-like symptoms but no lasting damage. TIAs are strong predictors of stroke. A person who's had one or more TIAs is almost 10 times more likely to have a stroke than someone of the same age and sex who hasn't. Recognizing and treating TIAs can reduce your risk of a major stroke. TIA should be considered a medical emergency and followed up immediately with a healthcare professional. If you've had a heart attack, you're at higher risk of having a stroke, too.

Hemorrhagic Conversion

A stroke is caused by the blockage of blood flow to a part of the brain, which causes a large area of tissue to become oxygen-hungry, and the cells that make up that area begin to die. Over time, fewer and fewer cells are left to be saved by stroke treatments, and after most of the cells have died, treating the stroke is no longer helpful and can actually turn the ischemic stroke into a hemorrhagic one. This event is known as a hemorrhagic conversion.

How is this possible? Most emergent treatments of ischemic stroke aim to return blood flow to the ischemic area by dissolving the stroke-causing blood clots. But just a few hours after an area of brain tissue has died, it loses its ability to retain blood inside of the arteries, increasing the risk that a large hemorrhage will occur if blood flow were to be returned. This type of bleeding into dead tissue is called a hemorrhagic conversion. Approximately 6 percent of all stroke cases treated with intravenous tPA, a powerful blood clot-busting medicine, experience a hemorrhagic conversion.

This prospect of hemorrhagic conversion is one of the main reasons why intravenous tPA and other similar stroke treatments can only be used within a certain time window after the onset of symptoms.

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