If studies show the accuracy of CT angiogram for detecting heart disease, why isn’t this tool used more often in chest pain ER cases?
Research have shown the efficacy of the CT angiogram in detecting heart disease in patients presenting to the ER with chest pain, so it makes absolutely no sense to me, the layperson, why this tool isn’t used in a standard way across the board in emergency room settings.
“Coronary computed tomographic angiography (CCTA) has been shown to have a high negative predictive value for the detection of coronary disease,” says Donna P. Denier, MD, of The Cardiology Center with the Appalachian Regional Healthcare System in NC.
“That is, it is very useful in ruling out the presence of coronary disease, even more than ruling it in,” continues Dr. Denier.
“The issues of its usefulness are cost, availability and safety. The majority of patients who present to an emergency department with chest pain can be categorized quickly into one of three groups based on a careful history, physical exam, evaluation of risk factors and review of EKG and troponin results.”
Troponin is an enzyme that leaks from the heart when there is cardiac muscle damage (heart attack).
Thus, as you may now be realizing, a troponin test detects a very recent or current heart attack, not blocked coronary arteries.
My mother’s troponin results were normal after I took her to the ER when she complained of shortness of breath and had vomited.
Three days later (after a second ER visit) she underwent quintuple bypass surgery!
Dr. Denier continues, “High risk patients are admitted and usually undergo cardiac catheterization (such as my mother) which makes a rapid conclusive diagnosis and allows for treatment at the same time.
“Low risk patients (e.g., athlete, under age 50, nonsmoker, healthy body weight/blood sugar/blood pressure) can be sent home and followed as outpatients for further testing.
“For low risk ambulatory patients, a stress test is the best test to rule out coronary disease because it gives functional information as well—how how far a patient can walk without developing symptoms.”
What about the moderate risk patient in the ER with chest pain? “It is the moderate risk patient who requires a test to safely rule out the presence of significant coronary disease,” says Dr. Denier.
“CT angio is clinically useful in this group. As this test is performed while the heart is beating, quality imaging is dependent upon slowing the heart rate enough to image between cycles.
“This limits some patients due to rapid or irregular heartbeats that cannot always be controlled with medication. Some patients cannot tolerate the medication that is used to slow the heart.
“Radiation exposure is another concern and although this has been reduced by newer technology, all centers do not have the latest equipment.
“Cost is definitely a limiting factor, and the test is not universally covered by insurance companies, as it is still considered a screening test.
“As technology evolves, cardiac CT will continue to be one of the techniques considered for the rapid and accurate evaluation of patients with chest pain.”