For Patients

What Is Ischemia of the Heart?

When a heart artery narrows, part of the heart may not receive enough blood to work normally. Doctors call this “ischemia.” The most common symptom of ischemia is chest pain (angina), but not everyone with ischemia has symptoms. Ischemia is associated with a higher risk of having a heart attack.

How Is Ischemia Treated?

Doctors use two standard ways to treat ischemia of the heart muscle.

  • One way (“medical therapy”) uses medicines and lifestyle changes to control symptoms and risk factors (such as smoking, high blood pressure, and high cholesterol).
  • Another way uses an invasive procedure called cardiac catheterization to see your heart arteries, and either stents are put in the narrowed arteries to restore blood flow or surgery is done to bypass the narrowed arteries and increase blood flow to the heart muscle.  Medicines and lifestyle changes are also recommended to control risk factors.

Which Treatment For Ischemia Is Better and Safer?

Although both treatments—medical therapy alone and medical therapy plus a procedure—are commonly used worldwide, doctors do not know which of these treatments is better and safer to use when a patient’s stress test shows ischemia.

What Is a Clinical Trial?

A clinical trial is a research study with volunteers that is designed to discover which treatment improves results for patients. Clinical trials usually compare different treatments like medications, procedures, or devices.

What is the ISCHEMIA Study?

The ISCHEMIA study is a clinical trial that compares two standard treatments for patients with ischemia of the heart to learn which one is better and safer:

  • Starting treatment with medicines and lifestyle changes alone, with a plan to use cardiac procedures only if they are needed, or
  • Starting treatment with invasive cardiac procedures (cardiac catheterization), and then stent placement or bypass surgery along with medicines and lifestyle changes


The U.S. National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH) is funding this clinical trial, which will include thousands of participants with ischemia. 

The results may have a lasting impact on the way patients with ischemia are treated.

If you are a patient and would like to learn more about the ISCHEMIA study, please e-mail