CT Angiography Links Arterial Plaque With Diabetes, Blood Pressure, Cholesterol
Noncalcified arterial plaque is associated with diabetes, high systolic blood pressure, and elevated "bad" cholesterol levels in asymptomatic individuals, according to a new study published online in the journal Radiology.

Coronary artery disease (CAD) is the leading cause of death in both men and women worldwide, accounting for 17 million deaths annually. Current treatment strategies focus on cardiovascular risk and serum cholesterol levels rather than direct assessment of extent of disease in the coronary arteries.

Plaque that forms in the arterial walls can restrict blood flow and, in some cases, rupture, leading to potentially fatal heart attacks. There is considerable evidence that calcified, or stable, plaque is less prone to rupture than noncalcified, or soft, plaque. Intravascular ultrasound can quantify noncalcified and calcified coronary artery plaque, but it is invasive and unsuitable for screening purposes. Coronary artery calcium (CAC) scoring with CT, a common noninvasive option, measures how much calcified plaque a person has, but it does not measure noncalcified plaque, and that's the component that tends to be dangerous. Despite treatment for hypercholesterolemia (high levels of cholesterol in the blood), CAC scores often paradoxically increase. Thus, researchers have searched for other plaque measures that can identify treatment response.

"Most information to date about coronary artery disease and cardiovascular risk factors in asymptomatic individuals has been derived from calcium scoring," says the study's lead author, David A. Bluemke, MD, PhD, from the National Institutes of Health Clinical Center. "We hypothesized that risk factors for the presence of noncalcified plaque may differ from those for calcified plaque."

Coronary CT angiography (CCTA) has emerged as a viable screening option for plaque, including noncalcified plaque. CCTA can capture the full anatomic map of the coronary arteries in a single heartbeat with low radiation dose and provide a complete picture of the total amount of plaque throughout the arteries of the heart.

For the study, Bluemke and his colleagues used CCTA to assess the relationship between calcified and noncalcified coronary plaque burden in the coronary arteries and cardiovascular risk factors in low- to moderate-risk asymptomatic individuals.

The researchers recruited 202 asymptomatic men and women aged 55 or older who were eligible for statin therapy. CCTA was performed using a 320-detector row CT scanner and an IV contrast agent. Coronary wall thickness/plaque was evaluated, and analysis was performed to determine the relationship between risk factors and plaque.

Controlling for all risk factors, total coronary plaque index was greater in men than in women. Noncalcified plaque index was significantly associated with greater systolic blood pressure, diabetes, and elevated low-density lipoprotein cholesterol level.

"These results highlight the potential of CCTA in quantifying plaque burden to assess progression or regression of coronary artery disease in low- to moderate-risk individuals," Bluemke says.