Because large vessel coronary artery disease and small vessel disease have the same signs and symptoms, it's likely your doctor will check the main arteries in your heart first. If no problems are found, then your doctor might test for small vessel disease.

To diagnose small vessel disease, your doctor will also ask you about your medical history and family history of heart disease. During your exam your doctor will likely check for high cholesterol and diabetes.

The tests for small vessel disease are similar to those for other types of heart disease and include:

  • Stress test with imaging. You'll either exercise on a treadmill or a bike or take a medication that raises your heart rate to mimic the effect of exercise.

    Images will be taken of your heart using ultrasound images (echocardiogram) or with nuclear imaging scans to assess the blood flow to your heart muscle.

  • Coronary angiogram. This test helps doctors determine if the main arteries to your heart are blocked. A liquid dye is injected into the arteries of your heart through a catheter — a long, thin tube that's fed through an artery, usually in your groin, to arteries in your heart. As the dye fills your arteries, they become visible on X-ray and video.
  • Positron emission tomography (PET). This test, which uses a radioactive dye and medication, can show your heart's blood flow to other parts of your body. After the dye is injected, you lie in a doughnut-shaped machine to have images taken of your heart.
  • CT scan or CT angiography (CTA) scan. A CT scan combines a series of X-rays taken from different angles with computer processing to create detailed images. A CTA scan uses a contrast dye injected through a line in your arm or hand to assess your blood vessels.
  • MRI. In a cardiac MRI, you lie on a table inside a long tubelike machine that produces a magnetic field. MRI produces images of your heart that enables your doctor to see blockages.

If your doctor can't find blockages in your main arteries based on these tests, you might have an additional test to check for blockages in the smaller arteries of your heart:

  • Endothelial dysfunction test. The endothelium is a layer of cells that line all of your blood vessels. When the endothelium isn't functioning well, the blood vessels can't expand properly.

    To test endothelial function, a wire is threaded through a catheter inserted in one of your coronary arteries and a medication is injected into the artery that causes the small vessels in your heart to open. Then the blood flow through those vessels is measured.

    This invasive test is the surest way to detect small vessel disease. Researchers are looking at noninvasive methods of endothelial function.