For patients who visit an emergency room with chest pains, but who don’t have an abnormal EKG or elevated troponin levels, a CT scan can send them home earlier than conventional diagnostic procedures, doctors reported Wednesday. The patients are exposed to higher levels of radiation and the cost is slightly higher, but those effects are offset somewhat by the increased peace of mind associated with leaving the hospital sooner, the team reported in the New England Journal of Medicine.
An estimated 6 million Americans report to ERs each year with chest pains. One of the first things physicians do is perform an electrocardiogram or EKG to check for abnormal heart activity and check blood for elevated levels of troponin. Troponins are proteins released by heart muscles when they die and elevated levels suggest that a heart attack has occurred. If those tests are negative and physicians cannot find any other physiological cause for the pain, the patient will frequently be admitted for observation and may be subjected to a stress test to further check for irregular activity of the heart.
Previous small studies at Massachusetts General Hospital in Boston have shown that using coronary computed tomography angiography (CCTA) in the ER can help rule out (or rule in) heart attacks faster. In CCTA, a contrast agent is injected into the bloodstream and the blood vessels around the heart are imaged to look for blockages to blood flow.
In the new study, a team led by Dr. Udo Hoffman of Mass General extended the study to 1,000 patients at nine major hospital centers. The patients were randomly assigned to receive either conventional care by ER doctors or to receive the imaging, the results of which were immediately reported back to the patients’ physicians. The physicians were then free to treat the patients as they saw fit.
The team reported that half of the patients receiving CCTA were released from the hospital within 8.6 hours, compared to only 10% of those in the control group. The average length of the hospital stay was 23.2 hours for those who underwent CT scans, compared to 30.7 hours for those who underwent standard screening. There was no significant difference in coronary events in the two groups. Average costs for the CCTA group were $4,289, compared to $4,060 for the conventional care group. “We found that the use of CCTA in emergency department evaluation of acute chest pain very effectively identified which patients did or did not have coronary artery obstruction, allowing clinicians to focus the use of resources on patients with heart disease,” Hoffman said.
In an editorial accompanying the report, Dr. Rita F. Redberg, a cardiologist at UC San Francisco, agreed that CCTA was useful in speeding up release from the hospital. But, she noted, because less than 1% of the patients in either group suffered a heart attack and none died, it is impossible to know whether patients in either group actually benefited from the testing they received.
The study was sponsored by the National Heart, Lung and Blood Institute.