Every day, patients present to EDs across the country complaining of chest pain. But, until recently, there has been precious little guidance regarding what type of imaging tests would be most useful in discerning the root cause of the pain in this diverse group of patients. However, new recommendations from the American College of Cardiology and the American College of Radiology attempt to fill this gap by assessing what specific imaging tests should be used in 20 fundamental clinical scenarios.1
“Before this document, there was no single publication that addressed appropriate imaging choices for chest pain patients who are seen by emergency medicine physicians,” observes Frank Rybicki, MD, PhD, a co-chair of the writing panel for the recommendations, professor and chair of the department of radiology at the University of Ottawa, and the head of medical imaging at Ottawa Hospital in Ottawa, Canada. “However, this is a highly important patient population with acute imaging needs and there are serious consequences to imaging results and costs.”
PHYSICIANS RATE IMAGING TESTS
The 20 clinical scenarios analyzed in the document are broken down into three critical diagnoses, including acute coronary syndrome, pulmonary embolism, and acute aortic syndrome. In addition, there is a fourth category for patients for whom a leading diagnosis is not possible or is problematic.
For each clinical scenario, an expert panel rated whether a specific imaging test is rarely appropriate (R), may be appropriate (M), or appropriate (A). When at least 60% of the rating panel members agreed on the appropriateness of a specific imaging test, consensus was reached, and the finding is indicated in the recommendations. In cases where the group did not reach consensus, the recommendations reflect this finding with an M plus an asterisk (M*), suggesting the imaging test may be appropriate.
While the document is clearly designed for use by emergency providers, development of the recommendations was a multidisciplinary exercise, including physicians from emergency medicine, radiology, and cardiology.
“Everyone was at the table for the rating panel,” Rybicki notes. “It was a live meeting. It wasn’t virtual; it wasn’t a call in. Everyone could see everyone, everyone could talk to everyone, and then they got on a plane, went home, and made their ratings.”
In addition to the rating group, there was a writing group and a review group, although none of the panels were in communication with each other as they performed their work, Rybicki explains.
W. Frank Peacock, MD, FACEP, a co-chair of the writing panel, professor of emergency medicine, and associate chair and research director of the Baylor College of Medicine in Houston, acknowledges each specialty brought a different perspective to the exercise.
“Everyone clearly has a different mission. Emergency doctors are on the front lines and have a huge population of patients who are undifferentiated,” he observes. “If you think about a heart failure specialist and the next patient he or she sees, chances are about 80% it will involve heart failure. For me, the chance that it will be heart failure is about 1%, so we all have different perspectives and different missions, but we all work on the same constellation of patients eventually.”
Peacock, a cardiology researcher, adds that many of the non-emergency specialists involved in this exercise were engaged in research or work that involves emergency or acute care medicine.
“I was actually very pleased with how collaborative this was,” he says. “Some of it is just the realities of medicine. We are all a big team today, but … there was also a lot of cross-pollination going on.”
What is most important about these guidelines for emergency providers? Peacock observes that developers attempted to craft guidelines as close to real life as possible.
“When a patient arrives, there is a group of diagnoses that you always entertain, but the reality is that there is no one test that takes care of that, so you have to pick the test,” he explains. “So we tried to construct [these guidelines] in a fashion where the doctor’s opinion of what he or she thinks most likely carries a lot of weight.”
For instance, when physicians examine chest pain, they typically consider a myocardial infarction (MI) or acute coronary syndrome, chest pain of pulmonary origin, such as a blood clot, or pain stemming from the aorta such as a dissection, and assess which is most likely based on the assessment and the patient’s story, Peacock explains.
“We try to give the physician that credit ... and go down that road. That is what we do every day,” he says. “We tried to make this practice consistent. When you see a patient and they say they have crushing chest pain that has been there for 20 minutes, and it sounds like a heart attack, then what tests fit with heart attack?”
Generally, when an imaging test receives a rating of R for a particular scenario, that means you probably shouldn’t perform that test, Peacock offers.
“Physicians can take that as pretty good guidance. It doesn’t say you should never do the test, but just rarely,” he says. “There are a lot of appropriate tests, and the reason there may be multiple appropriate tests for the same situation is because in that scenario, a test may not be available in your hospital, so you have a selection of tests with reasonable results for that scenario.”
While the document may seem long, the recommendations themselves exist within tables so that the important information is condensed and easy to access.
“The tables are designed so that you can actually put them on a note card ... and use them,” Rybicki observes. “Similarly, it is very easy to make an app on your phone that will show the guidelines for the 20 clinical scenarios so that they are readily useful.”
While developers could not reasonably address every clinical scenario emergency physicians face when they are dealing with chest pain, they did their best to strike a balance between scenarios that were so granular that they wouldn’t apply to very many patients and, on the other extreme, scenarios without enough discriminating factors to make them useful, Rybicki explains.
“Presentations to the ED with chest pain really don’t change,” he says. “Testing changes and data change, but how patients get sick typically does not change.”
NEW BLOOD TESTS OFFER DIVIDENDS
While there may be a general perception that imaging tests are overused in the ED, that is not an issue that developers attempted to address in this exercise, Peacock notes.
“It is easy when you are sitting in an office and a patient has a negative test three days later to say, ‘you didn’t need that test,’” he says. “That is a different perspective than when you are in the ED and the patient is moaning about how bad his chest hurts, and he is 60 years old. Until you have that negative test you honestly don’t know if it was needed or not.”
While that is a different question than what developers were charged with addressing in this case, Peacock suggests that the whole issue of testing for chest pain will need to be reassessed once the FDA approves high-sensitivity troponin tests, which are already in use in Europe and other parts of the world.
“We are easily five to seven years behind the rest of the world on this. When [high sensitivity troponin tests] are approved here, we are going to have to rewrite all these recommendations. A negative high-sensitivity troponin [test] has a different implication than a negative low-sensitivity troponin, where more testing is required,” he explains.
When high-sensitivity troponin tests are available to emergency physicians, it is quite possible that there could be less overall testing required, Peacock suggests.
“I hope we get this next generation of tests in soon because the beauty of a blood test is that it takes an hour, costs $50, and there is no radiation exposure,” he says. “It is not like a CT angiogram where you have to put the patient in a tube, inject dye that might hurt their kidneys, and certainly give them a significant radiation dose.”
Peacock observes that the newer-generation blood tests offer a huge opportunity to actually reduce exposure to radiation, dye, and unnecessary testing.
“[The tests] currently exist, just not in our part of the globe,” he says.
REFERENCE
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Rybicki F, et al. Appropriate utilization of cardiovascular imaging in emergency department patients with chest pain: A joint document of the American College of Radiology Appropriateness Criteria Committee and the American College of Cardiology Appropriate Use Criteria Task Force. J Am Coll Cardiol 2016;67:853-879.
SOURCES
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W. Frank Peacock, MD, FACEP, Professor of Emergency Medicine, Associate Chair and Research Director, Baylor College of Medicine, Houston. Email: [email protected].
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Frank Rybicki, MD, PhD, Professor and Chair, Department of Radiology, University of Ottawa; Head of Medical Imaging, Ottawa Hospital, Ottawa, Canada. Email: [email protected].
