Diagnostic Tests for Obstructive Coronary Artery Disease

Our doctors quickly assess the urgency of your symptoms, using the latest diagnostic tests when needed. When we suspect obstructed coronary artery disease, we look for narrowed or blocked arteries using a series of tests. 

We perform a full range of diagnostic tests using cardiac catheterization, which can also deliver immediate treatment in urgent situations.. These minimally invasive tests, some of which are not widely available, include:

• Coronary angiogram or angiography: The most common catheterization test looks for the blocked arteries typically associated with heart disease. A cardiologist injects a special contrast dye that shows up on low-dose X-rays and tracks the flow of blood. The cardiologist can pinpoint blocked or narrowed arteries, assess the severity of the condition, and determine what type of treatment, if any, is needed.
• Fractional flow reserve (FFR): This test can help clarify the need for treatment, if a standard angiogram shows that an artery is only modestly narrowed. We thread a wire with a pressure sensor past the spot in question, to compare blood flow and pressure on each side. We can determine when you need a stent and when medication alone is enough. Our doctors continue to study this technique and participate in clinical trials, leading many of them. They have pioneered techniques to perform the tests, as well as the methods for interpreting and applying the results.
• Intravascular ultrasound (IVUS): We attach an ultrasound probe to the end of a catheter to see inside arteries and make measurements if the vessels are narrowed or blocked. This technique often provides more information than a standard angiogram and can help plan the most appropriate treatment. We can also evaluate suspected bridging, when an artery sits under heart muscle rather than on top. Stanford researchers pioneered IVUS, and it remains a highly precise tool for detecting and evaluating coronary artery disease.
• Optical coherence tomography (OCT): Like intravascular ultrasound, OCT uses a probe, but one that emits light waves instead of sound waves. OCT offers much greater resolution than IVUS, with the ability to see tiny details inside an artery. Our doctors continue to study the best way this technology can improve patient care.
• Vascular function testing: If you feel chest pain but your coronary arteries look clear on a standard angiogram, we may perform further, highly specialized testing:
  • Endothelial function testing: This test examines the endothelial cells that line your coronary arteries, controlling when they contract and relax. A cardiologist injects a drug to see how the vessels react and to analyze whether they work properly. Those that do not may play a role in heart attack, as well as the thickening and hardening of arteries called atherosclerosis. We are among the few programs in the country offering this testing.  
  • Index of microcirculatory resistance: The index is the most accurate method for measuring the health of the tiny branches (microvasculature) of the coronary arteries, a challenging evaluation. The branches play a crucial role in delivering oxygen-rich blood but are too small to appear on an angiogram. Created by one of our doctors, the index is calculated by gauging blood pressure and flow after injecting a special drug. We use the latest, specialized wires to take those measurements.

In addition to a physical exam and complete medical history, evaluation for obstructive coronary artery disease can also include:

• Blood tests
• Electrocardiogram (ECG)
• Stress echocardiogram (echo)
• Myocardial perfusion (nuclear) scan
• Cardiac MRI
• CT coronary angiogram