Coronary artery disease results in the formation of atherosclerotic plaques in the coronary arteries, which supply blood to the heart muscle. These plaques can accumulate enough to narrow the vessel, decreasing the flow of blood to the muscle. Chest pain, or angina is the result of such decreased flow. More importantly, plaque can rupture or erode, causing a cascade of events that result in a myocardial infarction, or heart attack. Unfortunately, in up to 50% of patients their first sign of coronary artery disease is a heart attack or sudden death.

Stress testing looks for coronary artery disease in an indirect fashion. It looks for signs of decreased blood flow to the heart muscle. This often requires approximately 70% narrowing of the vessel to be picked up on a nuclear stress test or ECHO exam. Even extensive atherosclerotic plaque may not cause this degree of narrowing. Because of this, stress tests are frequently “normal” even though coronary artery disease is present.

Interestingly, many of the plaques that lead to heart attacks do not cause severe narrowing of the coronary blood vessels. The plaques which are most worrisome are called “vulnerable” plaques, usually soft or fatty rather than hard or calcified.

Coronary CTA is unique in that it looks at the vessel lumen (inside) to assess the degree plaques build up. Additionally, however, CCTA can see the wall of the vessel and directly visualize and differentiate the type of plaques. Our radiologists identify plaques, the vessels they are in, the degree of narrowing and the type of plaques—calcified or soft. Additionally, we evaluate surrounding tissue and organs, often identifying non-cardiac causes of chest pain.

Coronary CTA has been shown to have high sensitivity for detecting coronary artery disease. It also has phenomenal negative predictive value, almost 100%, meaning a normal CCTA insures you do not have coronary artery disease as the cause of your chest pain or other symptoms. No other test, short of an invasive cardiac cath, comes even close to this combination of sensitivity and negative predictive value.

Which is why we believe CCTA is “better than a stress test.”

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