Advanced CT imaging proves as accurate as invasive tests to assess heart blockages, study shows

November 19, 2013

An ultrafast, 320-detector computed tomography (CT) scanner that shows both anatomy within coronary arteries and blood flowcan accurately sort out which people need - or don't need - an invasive procedure to identify coronary blockages, according to an international study. The researchers say their findings could potentially save millions of people worldwide from having an unnecessary cardiac catheterization.

The study, known as CORE 320, involved 381 patients at 16 hospitals in eight countries. An article on the results was published online by the European Heart Journal on Nov. 19, 2013.

In the study, participants were evaluated with a 320-detector CT and conventional tests that are widely used today. The researchers say 91 percent of those in whom the CT scan ruled out blockages would not have required invasive treatment such as stenting or bypass surgery. So those patients, none of whom had a history of coronary artery disease, could have avoided invasive tests because for them the CT scan was just as accurate in determining who would be a good candidate for revascularization as the conventional tests.

"Ours is the first prospective, multicenter study to examine the diagnostic accuracy of CT for assessing blockages in blood vessels and determining which of those blockages may be preventing the heart from getting adequate blood flow," says Joao A. C. Lima, M.D., senior author of the study and a professor of medicine and radiology at the Johns Hopkins University School of Medicine. "We found an excellent correlation in results when we compared the 320-detector CT testing with the traditional means of assessment using a stress test with imaging and cardiac catheterization."

The study findings, says Lima, would apply to people who have chest pain but not a heart attack based on EKG and other evidence. Many people in that situation are sent to a cardiac catheterization laboratory for further evaluation with angiography, an invasive test to look for blockages in the coronary arteries using dye and special X-rays. About 30 percent of people who have such catheterization are found to have minimal disease or no blockage requiring an intervention to open the vessel with a stent or bypass the vessel through surgery, says Lima.

The 381 patients who completed the study had traditional single-photon emission computed tomorgraphy (SPECT) tests and invasive angiography. Lima says SPECT, a stress test with imaging, shows reduced blood flow to the heart without indicating the number or specific location of blockages.

Study participants also had two types of tests with a noninvasive 320-detector CT scanner. In the first CT test, the scanner was used to see the anatomy of vessels to assess whether and where there were blockages. That test is known as CTA, in which the "A" stands for angiography. Then, in a second CT test with the same machine, patients were given a medication that dilates blood vessels and increases blood flow to the heart in ways similar to what happens during a stress test. The second test is called CTP, with the "P" standing for perfusion.

"We found that the 320-detector CT scanner allowed us to see the anatomy of the blockages and determine whether the blockages were causing a lack of perfusion to the heart," sayslead author Carlos E. Rochitte, M.D., a cardiologist at the Heart Institute (InCor), University of São Paulo Medical School, in Brazil, "We were therefore able to correctly identify the patients who needed revascularization within 30 days of their evaluation."

"Many patients are sent for an angioplasty when they may not need it. Our ultimate goal is to have more certainty about which patients having chest pain - without evidence of a heart attack - need an invasive procedure to open an arterial blockage," says cardiologist Richard George, M.D., an associate professor of medicine at the Johns Hopkins University School of Medicine and a co-author of the study.

"The CTP test added significant information about the patients'conditions and boosted our ability to identify those whose blockages were severe enough to reduce blood flow to the heart," adds George, who developed the CTP method with Lima.

The 320-detector CT provides a complete picture of the heart by making just one revolution around the body. The researchers say the two tests combined - CTA and CTP - still produce less radiation than a scan with the 64-detector CT scanner in widespread use today.

"In our study, the amount of radiation exposure to patients from the two 320-detector CT tests was half the amount they received as a result of the traditional evaluation methods - the angiogram and nuclear medicine stress test combined," says Lima.

The researchers say they will continue to follow the patients in the study for five years, looking for any heart-related events such as heart attacks, as well as hospital admissions, procedures or operations.
-end-
The Johns Hopkins Hospital is among the hospitals in the United States that participated in the CORE 320 study, along with hospitals in Germany, Canada, Brazil, the Netherlands, Denmark, Japan and Singapore. Images obtained during the study were evaluated in core laboratories at Johns Hopkins and at the Brigham and Women's Hospital in Boston.

The study was sponsored by Toshiba Medical Systems Corporation. The company was not involved in the study design, data acquisition, data analysis or manuscript preparation.

Johns Hopkins Medicine (JHM), headquartered in Baltimore, Maryland, is a $6.7 billion integrated global health enterprise and one of the leading academic health care systems in the United States. JHM unites physicians and scientists of the Johns Hopkins University School of Medicine with the organizations, health professionals and facilities of The Johns Hopkins Hospital and Health System. JHM's vision, "Together, we will deliver the promise of medicine," is supported by its mission to improve the health of the community and the world by setting the standard of excellence in medical education, research and clinical care. Diverse and inclusive, JHM educates medical students, scientists, health care professionals and the public; conducts biomedical research; and provides patient-centered medicine to prevent, diagnose and treat human illness. JHM operates six academic and community hospitals, four suburban health care and surgery centers, and more than 35 Johns Hopkins Community Physicians sites. The Johns Hopkins Hospital, opened in 1889, was ranked number one in the nation for 21 years in a row by U.S. News & World Report. For more information about Johns Hopkins Medicine, its research, education and clinical programs, and for the latest health, science and research news, visit http://www.hopkinsmedicine.org.

Johns Hopkins Medicine
Media Relations and Public Affairs

Media Contacts:


Ellen Beth Levitt
eblevitt@jhmi.edu
410-955-5307

Helen Jones
hjones49@jhmi.edu
410-502-9422

Johns Hopkins Medicine

Related Heart Attack Articles from Brightsurf:

Top Science Tip Sheet on heart failure, heart muscle cells, heart attack and atrial fibrillation results
Newly discovered pathway may have potential for treating heart failure - New research model helps predict heart muscle cells' impact on heart function after injury - New mass spectrometry approach generates libraries of glycans in human heart tissue - Understanding heart damage after heart attack and treatment may provide clues for prevention - Understanding atrial fibrillation's effects on heart cells may help find treatments - New research may lead to therapy for heart failure caused by ICI cancer medication

Molecular imaging identifies link between heart and kidney inflammation after heart attack
Whole body positron emission tomography (PET) has, for the first time, illustrated the existence of inter-organ communication between the heart and kidneys via the immune system following acute myocardial infarction.

Muscle protein abundant in the heart plays key role in blood clotting during heart attack
A prevalent heart protein known as cardiac myosin, which is released into the body when a person suffers a heart attack, can cause blood to thicken or clot--worsening damage to heart tissue, a new study shows.

New target identified for repairing the heart after heart attack
An immune cell is shown for the first time to be involved in creating the scar that repairs the heart after damage.

Heart cells respond to heart attack and increase the chance of survival
The heart of humans and mice does not completely recover after a heart attack.

A simple method to improve heart-attack repair using stem cell-derived heart muscle cells
The heart cannot regenerate muscle after a heart attack, and this can lead to lethal heart failure.

Mount Sinai discovers placental stem cells that can regenerate heart after heart attack
Study identifies new stem cell type that can significantly improve cardiac function.

Fixing a broken heart: Exploring new ways to heal damage after a heart attack
The days immediately following a heart attack are critical for survivors' longevity and long-term healing of tissue.

Heart patch could limit muscle damage in heart attack aftermath
Guided by computer simulations, an international team of researchers has developed an adhesive patch that can provide support for damaged heart tissue, potentially reducing the stretching of heart muscle that's common after a heart attack.

How the heart sends an SOS signal to bone marrow cells after a heart attack
Exosomes are key to the SOS signal that the heart muscle sends out after a heart attack.

Read More: Heart Attack News and Heart Attack Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.