(Press-News.org) OAK BROOK, Ill. – Imaging of the coronary arteries with computed tomography (CT) angiography provides an accurate assessment of arterial plaque and could have a dramatic impact on the management of diabetic patients who face a high risk of heart attacks and other cardiovascular events, according to a new multicenter study published online in the journal Radiology.
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 non-calcified, or soft, plaque. Intravascular ultrasound can quantify non-calcified and calcified coronary artery plaque, but it is invasive and unsuitable for screening purposes, and coronary artery calcium (CAC) scoring with CT, a common noninvasive option, has limitations.
"Calcium scoring measures how much calcified plaque a person has, but it doesn't measure the component that's not calcified, and that's the component that tends to be dangerous," said João A. C. Lima, M.D., from the cardiology division at Johns Hopkins University in Baltimore, Md.
Quantitative plaque analysis with coronary computed tomography angiography (CCTA) has emerged as a viable screening option. CCTA can capture the full anatomic map of the coronary arteries in a single heartbeat with low radiation dose. CCTA can provide a picture of the total amount of plaque throughout the arteries of the heart.
Researchers from three centers—the National Institutes of Health (NIH) in Bethesda, Md., Johns Hopkins, and the Intermountain Medical Center Heart Institute in Salt Lake City—recently collaborated to evaluate CCTA in 224 asymptomatic diabetic patients. Obese people with diabetes have a propensity for extensive and premature development of coronary artery plaque, making them an ideal study group for plaque assessment.
The researchers used measurements of coronary artery wall volume and length to determine a coronary plaque volume index (PVI) for each patient. The technique provided information well beyond the presence or absence of coronary stenosis, or narrowing. PVI was related to age, male gender, body mass index (BMI) and duration of diabetes. Younger individuals with a shorter duration of diabetes had a greater percentage of soft plaque.
"Coronary plaque volume index by CCTA is not only clinically feasible and reproducible in patients with diabetes," said David A. Bluemke, M.D., Ph.D., from the NIH Clinical Center. "It provides a more complete picture of the coronary arteries that could be routinely applied in at-risk patients."
"These findings represent a very important step in the ability to quantify plaque, particularly non-calcified plaque," added Dr. Lima.
BMI, a measure of body fat based on weight and height, was the primary modifiable risk factor associated with total and soft coronary plaque as assessed by CCTA.
"The results reinforce how important it is to evaluate BMI as a potential driver of overall diabetes," Dr. Bluemke said. "As the only modifiable risk factor, obesity is an important target for managing diabetic patients."
Only about one-third of the coronary plaque in patients showed calcification, underscoring the widespread presence of non-calcified plaque. The ability to distinguish between calcified and non-calcified plaque is important because treatment may vary based on plaque composition.
"People with soft plaque respond better to interventions, particularly medical therapy like statins," Dr. Lima said.
The researchers will continue monitoring the patients from the study to better understand the value of coronary artery plaque assessment in predicting future cardiovascular events and to further define the role of plaque volume index versus CAC score. A clinical trial would be necessary to determine if risk factor reduction would result in reduced PVI.
"Now that we have baseline indices of plaque in the study patients, we can look for people who, despite optimal management, experience a cardiovascular disease event like a heart attack," Dr. Bluemke noted.
CCTA is likely to be valuable for other groups of patients at high risk for cardiovascular events, the researchers said, and may one day enable physicians to predict plaque development and treat it aggressively before PVI increases significantly.
INFORMATION:
"Coronary Artery Plaque Volume and Obesity in Patients with Diabetes: The Factor-64 Study." Collaborating with Drs. Lima and Bluemke were Alan C. Kwan, B.A., Heidi T. May, Ph.D., George Cater, M.D., Christopher T. Sibley, M.D., Boaz D. Rosen, M.D., Karen Rodriguez, B.S., Donald L. Lappe, M.D., Joseph B. Muhlestein, M.D., and Jeffrey L. Anderson, M.D.
Radiology is edited by Herbert Y. Kressel, M.D., Harvard Medical School, Boston, Mass., and owned and published by the Radiological Society of North America, Inc.
RSNA is an association of more than 53,000 radiologists, radiation oncologists, medical physicists and related scientists promoting excellence in patient care and health care delivery through education, research and technologic innovation. The Society is based in Oak Brook, Ill.
For patient-friendly information on CCTA, visit RadiologyInfo.org.
CT measures potentially dangerous arterial plaque in diabetic patients
2014-04-22
ELSE PRESS RELEASES FROM THIS DATE:
Acute respiratory distress syndrome: Study IDs surgical patients at risk
2014-04-22
ROCHESTER, Minn. — Acute respiratory distress syndrome is a leading cause of respiratory failure after surgery. Patients who develop the lung disorder postoperatively are at higher risk of dying in the hospital, and those who survive the syndrome may still bear its physical effects years later. A Mayo Clinic-led study is helping physicians better identify patients most at risk, the first step toward preventing this dangerous and costly surgical complication. They found nine independent risk factors, including sepsis, high-risk aortic vascular surgery, high-risk cardiac ...
Cow manure harbors diverse new antibiotic resistance genes
2014-04-22
Manure from dairy cows, which is commonly used as a farm soil fertilizer, contains a surprising number of newly identified antibiotic resistance genes from the cows' gut bacteria. The findings, reported in mBio® the online open-access journal of the American Society for Microbiology, hints that cow manure is a potential source of new types of antibiotic resistance genes that transfer to bacteria in the soils where food is grown.
Thousands of antibiotic resistance (AR) genes have already been identified, but the vast majority of them don't pose a problem when found in ...
Annals of Internal Medicine tip sheet for April 22, 2014
2014-04-22
1. Health care leaders and advocates call for patient-centered 'revolution' in medical education
Patients and families should be included in the training environment not only as the recipients of care, but also as teachers and evaluators of residents and students, according to a new commentary being published in Annals of Internal Medicine. “Patients and families can provide invaluable insights and perspectives for changing and improving physician training programs,” says lead author Steven E. Weinberger, MD, FACP, executive vice president and chief executive officer ...
Narrowing of neck artery without warning may signal memory and thinking decline
2014-04-21
PHILADELPHIA – For the first time, researchers have demonstrated that narrowing of the carotid artery in the neck without any symptoms may be linked to problems in learning, memory, thinking and decision-making, compared to people with similar risk factors but no narrowing in the neck artery, according to a study released today that will be presented at the American Academy of Neurology's 66th Annual Meeting in Philadelphia, April 26 to May 3, 2014.
"To date, the focus of diagnosis and management of carotid artery blockages has been prevention of stroke since that was ...
Study examines patient care patterns in Medicare accountable care organizations
2014-04-21
Bottom Line: A third of Medicare beneficiaries assigned to accountable care organizations (ACOs) in 2010 or 2011 were not assigned to the same ACO in both years and much of the specialty care received was provided outside the patients' assigned ACO, suggesting challenges to achieving organizational accountability in Medicare.
Author: J. Michael McWilliams, M.D., Ph.D., of Harvard Medical School and Brigham and Women's Hospital, Boston, and colleagues.
Background: ACOs are intended to foster greater accountability in the traditional fee-for-service Medicare program by ...
False-positive mammograms associated with anxiety, willingness for future screening
2014-04-21
Bottom Line: Mammograms with false-positive results were associated with increased short-term anxiety for women, and more women with false-positive results reported that they were more likely to undergo future breast cancer screening.
Author: Anna N.A. Tosteson, Sc.D., of the Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, N.H., and colleagues.
Background: A portion of women who undergo routine mammogram screening will experience false-positive results and require further evaluation to rule out breast cancer.
How the Study Was Conducted: The ...
Increased prevalence of celiac disease in children with irritable bowel syndrome
2014-04-21
There appears to be an increased prevalence of celiac disease among children with irritable bowel syndrome (IBS).
Recurrent abdominal pain affects 10 percent to 15 percent of school-aged children. The prevalence of celiac disease is as high as 1 percent in European countries and patients can present with a wide spectrum of symptoms, including abdominal pain, although the disease is often asymptomatic.
The authors assessed the prevalence of celiac disease in 992 children with abdominal pain-related disorders: IBS, functional dyspepsia (indigestion) and functional abdominal ...
Today's Antarctic region once as hot as California, Florida
2014-04-21
Parts of ancient Antarctica were as warm as today's California coast, and polar regions of the southern Pacific Ocean registered 21st-century Florida heat, according to scientists using a new way to measure past temperatures.
The findings, published the week of April 21 in the Proceedings of the National Academy of Sciences, underscore the potential for increased warmth at Earth's poles and the associated risk of melting polar ice and rising sea levels, the researchers said.
Led by scientists at Yale, the study focused on Antarctica during the Eocene epoch, 40-50 million ...
Penn researchers find link between sleep and immune function in fruit flies
2014-04-21
PHILADELPHIA - When we get sick it feels natural to try to hasten our recovery by getting some extra shuteye. Researchers from the Perelman School of Medicine at the University of Pennsylvania found that this response has a definite purpose, in fruitflies: enhancing immune system response and recovery to infection. Their findings appear online in two related papers in the journal Sleep, in advance of print editions in May and June.
"It's an intuitive response to want to sleep when you get sick," notes Center for Sleep and Circadian Neurobiology research associate Julie ...
'Upside-down planet' reveals new method for studying binary star systems
2014-04-21
What looked at first like a sort of upside-down planet has instead revealed a new method for studying binary star systems, discovered by a University of Washington student astronomer.
Working with UW astronomer Eric Agol, doctoral student Ethan Kruse has confirmed the first "self-lensing" binary star system — one in which the mass of the closer star can be measured by how powerfully it magnifies light from its more distant companion star. Though our sun stands alone, about 40 percent of similar stars are in binary (two-star) or multi-star systems, orbiting their companions ...