Report from AHA: Vulnerable plaques factor into heart attack risk calculation

November 13, 2008

A combined diagnostic approach enhances clinical assessment of heart attack risk, according to a lecture at an American Heart Association conference this week. Such an approach would take into account vulnerable arterial plaques, traditional risk factors, and measures of atherosclerotic disease severity.

A combined diagnostic approach enhances clinical assessment of heart attack risk, according to a lecture at an American Heart Association conference this week. Such an approach would take into account vulnerable arterial plaques, traditional risk factors, and measures of atherosclerotic disease severity.

Dr. Morteza Naghavi, founder and chair of Screening for Heart Attack Prevention and Eradication (SHAPE), stressed the importance of vulnerable arterial plaque imaging as part of the diagnostic equation during an AHA plenary session in New Orleans.

"A combination of noninvasive structure and function assessment along with traditional risk-factor management -- not either alone -- is the way to go," Naghavi said.

The severity of disease can be determined with functional myocardial perfusion imaging and angiographic assessment of arterial structure.

Choices for anatomic imaging tests could include ultrasound to measure carotid intramedia thickness and plaque, MRI to detect aortic and carotid plaque, CT for coronary calcium scores and ankle-brachial index. Functional imaging tests could include ultrasound for brachial vasoreactivity, radial tonometry for vascular compliance. and fingertip tonometry for microvascular reactivity, he said.

These tests, while providing useful information in carefully selected patients, are expensive and have not been demonstrated to improve the outcomes of patients when used in undirected screening efforts, Naghavi said.

SHAPE has released guidelines that call for atherosclerosis screening in all apparently healthy men aged 45 to 75 years. Exceptions are patients with very low risk factors for plaque buildup in the heart and arteries. SHAPE asserts that this approach enhances identification and treatment of the "vulnerable patient" as a cost-effective, practical alternative to invasive modalities that screen for plaque. The AHA and American College of Cardiology have not endorsed the SHAPE guidelines, however.

The ACC/AHA Task Force on Practice Guidelines has approved a guideline for detection of atherosclerotic vascular disease in asymptomatic patients that will address how and whether a variety of new imaging tests and biomarkers might be integrated with traditional risk factors to evaluate cardiovascular risk. The guideline is expected to be published during the coming year.

For more information from the Diagnostic Imaging and SearchMedica archives:

Vessel imaging focus on plaque characterizationCT and MR gain ground in plaque detection