Researchers in the study focused on a condition known as acute coronary syndrome, which includes heart attacks and unstable angina (chest pain), a condition that often progresses to a heart attack. This syndrome occurs when narrowed or blocked coronary arteries prevent oxygen-rich blood from reaching the heart muscle. Since chest pain has many causes, patients are often unnecessarily admitted to the hospital before it is determined that their chest pain is not due to acute coronary syndrome or other serious conditions.
CT angiography is a type of heart X-ray exam using a device that creates pictures of the coronary arteries, allowing physicians to see whether arteries have major blockages.
“Quickly distinguishing emergency room patients who are experiencing acute coronary syndrome from patients with pain of non-cardiac origin is a significant challenge for U.S. hospitals,” said Susan B. Shurin, M.D., acting director of the NHLBI. “This study provides important information to inform decisions about allocation of resources in our health care system.”
The study results suggest that CT scans allow hospitals to send many patients with chest pain home sooner without compromising their safety. The average length of hospital stay was 23.2 hours for those who underwent CT scans, compared to 30.7 hours for those who underwent standard screening procedures alone. Half of the patients who received a CT scan were discharged in 8.6 hours or less. In contrast, half of the patients in the standard evaluation group were sent home in 26.7 hours or less.
Even with shorter hospital stays in the group that received CT scans, the researchers did not miss any cases of acute coronary syndrome among those participants. After 28 days of follow-up, there was no significant difference in serious cardiovascular events between the two groups.
The study, which appears in the July 26 New England Journal of Medicine, was part of an NHLBI-funded program called Rule Out Myocardial Infarction/Ischemia Using Computer-Assisted Tomography (ROMICAT-II).
Led by investigators at Massachusetts General Hospital in Boston, the researchers randomized participants with suspected acute coronary syndrome to receive standard emergency room screening evaluations alone or to standard evaluations plus cardiac CT angiography.
The researchers studied 1,000 participants between 40 and 74 years old in nine U.S. hospitals. Participants were eligible to enroll in the trial if they showed symptoms suggestive of acute coronary syndrome but no prior history of heart disease or evidence of heart damage on their electrocardiogram (ECG) tests or blood tests.
“The results from this study should help health care providers and patients make better informed decisions by knowing the risks and potential benefits of using CT scans to more quickly diagnose acute coronary syndrome,” said Udo Hoffmann, M.D., M.P.H., the study’s principal investigator at Massachusetts General Hospital and Harvard Medical School, Boston. “It can be a relief to patients with chest pain to quickly know they are not having a heart attack and that they can spend the night at home, instead of in a hospital bed.”
Participants in the CT group were exposed to more radiation than those in the standard screening group, though the study authors suggested that future CT scans could be done using less radiation, which could help lower exposure without sacrificing accuracy.
Overall costs were similar in the two treatment groups.
The NHLBI funded ROMICAT-II through the following grants: HL092040, HL092022, HL098370, and HL093896. Learn more about this clinical trial (NCT01084239) at: http://clinicaltrials.gov/ct2/show/NCT01084239
For more information or to schedule an interview, contact the NHLBI Communications Office at 301-496-4236.
Part of the National Institutes of Health, the National Heart, Lung, and Blood Institute (NHLBI) plans, conducts, and supports research related to the causes, prevention, diagnosis, and treatment of heart, blood vessel, lung, and blood diseases; and sleep disorders. The Institute also administers national health education campaigns on women and heart disease, healthy weight for children, and other topics. NHLBI press releases and other materials are available online at http://www.nhlbi.nih.gov
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Coronary heart disease: http://www.nhlbi.nih.gov/health/health-topics/topics/cad/
Chest CT scan: http://www.nhlbi.nih.gov/health/health-topics/topics/cct/
Note: On Thursday, July 26, 2012, the 4th paragraph was updated to the correct quote from Dr. Shurin.
NHLBI Communications Office