Tests and diagnosisBy Mayo Clinic staff
Because large vessel coronary artery disease and small vessel disease have the same signs and symptoms, it's likely you'll be tested for large vessel coronary artery disease by checking the main arteries in your heart first. If no problems are found, then your doctor may do additional tests for small vessel disease.
To diagnose small vessel disease, you'll need a physical exam. Your doctor will also ask you about your medical history and any family history of heart disease. Your doctor will likely check your cholesterol levels to see if high cholesterol could be clogging your arteries and causing chest pain.
The tests for small vessel disease are similar to those for other types of heart disease and include:
- Stress test with imaging. Your doctor may perform an exercise stress test when checking for coronary artery disease, but without any images of the heart, it's usually not enough to diagnose small vessel disease. For this type of stress test, 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. Then your doctor will take images of your heart using ultrasound images (echocardiogram) or with nuclear imaging scans to check your heart's function and assess the blood flow to your heart muscle.
- Positron emission tomography (PET). This test can show your heart's blood flow to other parts of your body. In this test, you'll have a radioactive dye injected so that your heart will show on the scan. Then you'll lie in a doughnut-shaped machine to have images taken of your heart, which will be sent to a computer monitor for your doctor to see. PET scans may help your doctor diagnose small vessel disease, but the test is expensive and not widely used.
- Magnetic resonance imaging (MRI). In a cardiac MRI, you lie on a table inside a long tube-like machine that produces a magnetic field. The magnetic field aligns atomic particles in some of your cells. When radio waves are broadcast toward these aligned particles, they produce signals that vary according to the type of tissue they are. Images of your heart are created from these signals, which your doctor will look at to determine if the main arteries in your heart are blocked.
- Endothelial function 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. This noninvasive test uses a blood pressure cuff and finger probes to give your doctor information about your endothelial function. This test can't definitively diagnose small vessel coronary artery disease, but it can provide additional information about your heart health.
- Coronary angiogram. This test helps doctors determine if the main arteries to your heart are narrowed or 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.
If your doctor can't find any blockages in your main arteries based on these tests, you'll have an additional test to check for blockages in the smaller arteries of your heart:
- Endothelial dysfunction test. In this test, a wire will be threaded through a catheter inserted in one of your coronary arteries. Your doctor will then inject a medication into the artery that causes the small vessels in your heart to open and let blood rush through, and then the blood flow through those vessels is measured. Although this test is invasive, it's a good way to detect small vessel disease.
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