Intraplaque Composition Combined with Stress Echo for Cardiac Risk Stratification

The root cause of heart attacks and strokes is atherosclerosis, the hardening and thickening of blood vessels due to the presence of "plaque" which is a build-up of fat and cholesterol in the walls of vessels. To diagnose heart disease, patients receive a stress test to find out if they require a procedure known as an angiogram. Up to 52% of patients receiving an angiogram are found to have no significant heart disease. On the other hand, a stress test can also miss patients that should be referred for an angiogram (false negative). In Ontario alone, 90% of stress tests are found to be normal and these patients are sent home with little follow-up. Of these 3-5% (~4,000 patients/year) will have a major cardiovascular event (heart attack, surgery, or death) within 3 years. Thus we need to improve the accuracy of stress testing to better decide who needs procedures, and to better identify which patients are at risk of heart disease earlier. We propose improving this by using ultrasound at the time of stress testing to look for plaque blockages within the neck arteries of patients. If the ultrasound shows that these plaques have additional leaky blood vessels within them, then this could indicate that the patients are at higher risk of having a major cardiovascular event in the future, even if the stress test does not show an abnormal result. To prove this, we propose a study looking at the combination of stress testing and the neck ultrasound (to assess plaque composition), to identify patients at risk for cardiovascular events (heart attacks and death). It is easy to combine these tests because they use the same ultrasound technology and so additional important information can be obtained during the same test to help better identify patients that may be at risk of disease in the future, and would benefit from earlier prevention.