Recurrent Low Risk Chest Pain: GRACE Guidelines
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Chest pain tends to give ED providers chest pain. The number of patients with clear symptoms and diagnostic findings of ACS is seemingly miniscule in comparison to a vast number of patients with ill-described chest discomfort and subtle EKG changes.
And yet in that vast majority we work through every day, there lurks danger, and few assurances, as we seek to ensure our patients are safe from major adverse cardiac events. Talk to any EM provider and you’ll get stories of patients with normal EKGs and stress tests who go on to have STEMIs or other poor outcomes almost immediately after these test return with normal results. These tales of dread tend lead to a (potentially healthy) fear and respect for the patient with otherwise reassuring chest pain. But they can also lead to repeat invasive testing for a cohort of patients with otherwise “low risk” chest pain.
When providers are early in their training, this tends to lead to questions of “how long is a negative stress test good for?” “What about a negative cath? - Is that good for 2 years, 4, years, 6?” “What about a negative CCTA?”
In the first (of many to come) GRACE guidelines (Guidelines for Reasonable and Appropriate Care in the Emergency Department), SAEM sought to tackle many of these questions as they looked at Recurrent, Low-risk Chest Pain in the Emergency Department. For these purposes low-risk is defined as either a HEART score < 4 or low risk by other measures (TIMI)
Of their 8 recommendations, we’ll focus on the ones that look at the evaluation of patients with negative functional and anatomic testing.
Recommendation 2: In adult patients with recurrent, low-risk chest pain, and a normal stress test within the previous 12 months, we do not recommend repeat routine stress testing as means to decrease rates of MACE at 30 days (Conditional, Against) [Low level of evidence]
As a common theme to many of these recommendations, there were no studies with direct evidence to answer the question as to whether or not repeat stress testing could result in a reduction in MACE for patients low-risk recurrent chest pain. Two randomized studies offered indirect evidence that stress testing did not reduce MACE at 30 days. Additionally, a retrospective cohort study looking at patients who completed outpatient stress testing vs those who did not complete outpatient stress testing did not demonstrate a benefit to stress testing in terms of reduction of MACE.
There are a number of factors to keep in mind when looking to apply this recommendation to your clinical practice. For starters, cardiac stress tests are imperfect studies and sensitivities and specificities of these studies vary based on the type of stress test performed (pharmacologic, exercise, echocardiographic, nuclear, treadmill only). Falsely negative stress tests can occur in the setting of multi vessel CAD (which can still be a very real entity even in patients who would otherwise seem to be “low risk” by their traditional risk factors for the development of coronary atherosclerosis). A careful reading of previous stress test results is warranted to ensure the study was adequate (achieved target heart rate) and truly negative (not having any areas of artifact or signs of myocardial dysfunction). When suspicion for a falsely negative stress test exist, the study authors point out that providers could consider a different modality of stress testing or anatomic evaluation through CCTA.
Shared decision making can be particularly helpful in this particular scenario and providers should weigh patient’s values carefully into their diagnostic evaluation. Not pointed out by the authors, but particularly applicable in some patient populations, providers should also carefully consider barriers to care and safe follow up when evaluating these patients. Barriers to care including a lack of outpatient follow up should be addressed by system level efforts to provide access to care. Providers should be familiar with their local resources to provide adequate follow up to patients they intend to discharge from the ED.
Recommendation 4:In adult patients with recurrent, low-risk chest pain and non-obstructive (< 50% stenosis) CAD on prior angiography within 5 years, we suggest referral for expedited outpatient testing as warranted rather than admission for inpatient evaluation. (Conditional, For) [Low level of evidence]
As noted by the authors, patient and physician preferences strongly impact the decision as to whether or not to perform this invasive test. This significantly limits the amount of evidence available to directly answer this question. A review of the available evidence (a meta-analysis and a few retrospective observational studies), did show a low incidence of all-cause mortality and AMI (1.32 cases expected for 100 patients followed for 1 year). Overall based on the available evidence, the likelihood of non-fatal MI or all-cause mortality within 5 years of a cardiac catheterization showing <50% stenosis is very low.
Recommendation 5 asks an identical question for patients with cardiac catheterization with no evidence of stenotic disease. Based on a similar evidence base, they come to the same conclusion. Those patient’s with a negative cardiac catheterization have a very low rate of MACE within 5 years of the study.
Recommendation 6: In adult patients with recurrent, low-risk chest pain and prior CCTA within the past two years with no coronary stenosis, we suggest no further diagnostic testing other than a single, high-sensitivity troponin below a validated threshold to exclude ACS within that two-year time frame. (Conditional, For) [Moderate level of evidence]
CCTA (Coronary CT Angiography) has some significant geographic and institutional variability in its use. At our institution, this study is used less often out of the Emergency Department than functional evaluation with traditional stress testing. There is however potential utility for this study as it is able to non-invasively answer the question “does this patient have coronary artery disease?” The authors found 18 studies offering indirect evidence of the prognostic value of CCTA. The CONFIRM registry referenced in the summary of evidence showed that patients with a negative CCTA had a rate of MACE of 0.6% at median of 2.1 years of follow-up. The PROMISE Trial similarly showed patients with a negative CCTA had a MACE rate of 0.3% at a median of 26 months follow-up. This cumulation of all the indirect evidence added up to a moderate level of evidence on which the panel was able to make their recommendation.
Summary
The GRACE guidelines for the evaluation of recurrent, low-risk chest pain offer an excellent summary of the available literature addressing a particularly challenging patient population we see in the ED. We approach these patients balancing concern for hidden disease, morbidity, and mortality against concern for harms from diagnostic evaluation and concerns for resource utilization. The amount of evidence available to directly answer the important questions posed by the panel is, at this time, disappointingly lacking. As with any research endeavor however, the asking of, framing of, and publication of these important questions could spur new research in the years to come. For now, we can evaluate these complex patients with a bit more clarity than before.
Post written by Jeff Hill, MD, MEd
Dr. Hill is creator and co-editor-in-chief of TamingtheSRU and an Assistant Program Director at the University of Cincinnati
Infographic and editing by Ryan laFollette, MD
Dr. LaFollette is co-editor-in-chief of TamingtheSRU and an Assistant Program Director at the University of Cincinnati
