US Chest Pain Guidelines Will Change Practice, Though Gaps Remain

With over a month to digest the long-awaited American College of Cardiology/American Heart Association (ACC/AHA) chest pain guidelines, physicians across the US are mostly happy to see a wide swath of modalities represented that could be used to look for underlying coronary disease, with an emphasis on a patient-centered approach. But they also have wish lists for future iterations.

As reported by TCTMD, the guidelines are the first in the US to make recommendations for the evaluation and diagnosis of acute or stable chest pain. Beset by delays and internal disagreement, the writing group ultimately pulled together advice that was endorsed by the American Society of Echocardiography (ASE), American College of Chest Physicians (CHEST), Society for Academic Emergency Medicine (SAEM), Society of Cardiovascular Computed Tomography (SCCT), and Society for Cardiovascular Magnetic Resonance (SCMR). The American Society of Nuclear Cardiology (ASNC), which also participated in its development, in the end decided not to endorse the document.

TCTMD reached out to a range of physicians who tried to sum up what the guidelines will—or should—mean for practice going forward.

“One of the most important things that these guidelines did . . . is really highlight a change in thinking,” Krishna Patel, MBBS (Icahn School of Medicine at Mount Sinai, New York, NY), told TCTMD. “Traditionally, there's always been this focus on diagnosis and identification of obstructive coronary artery disease and identifying who should go for invasive testing [and] who should be revascularized, and the guidelines really encourage us all to not think about that [but] think about recognizing and managing the overall cardiovascular risk of a patient.”

The guidelines really encourage us all to . . . think about recognizing and managing the overall cardiovascular risk of a patient. Krishna Patel

Because the guidelines carve out room for all testing modalities, Rohit Moudgil, MD (Cleveland Clinic, OH), told TCTMD, they have “empowered physicians as well as patients to make [the] decision” as to which test is best for the situation. “That's really, really good because that opens up physicians to have discussions with their patients, and I think that's really vitally important rather than just following algorithms,” he said.

Similarly, Renee Bullock-Palmer, MD (Deborah Heart and Lung Center, Browns Mills, NJ), a member of the ASCN board of directors who was part of the ACC/AHA writing committee, stressed to TCTMD that “there's no one test that fits all. You really have to look at the unique risks associated with the patient that you're seeing, their previous test results if they've had any available test reports, and more importantly if they've had a known history of CAD or not.”

For Deborah Diercks, MD (UT Southwestern Medical Center, Dallas, TX), who also served on the writing committee, the key message from the guidelines “is that we have been given the opportunity not to order secondary testing on everybody by using high-sensitivity troponin and looking at the incorporation of that into practice.” That, along with the warranty period suggested for different diagnostic modalities, “may actually decrease the resources that we spend on patients who present with recurrent chest pain,” she told TCTMD.

In many ways, said David L. Brown, MD (Washington University School of Medicine in St Louis, MO), the value of these guidelines is mostly for clinicians outside of the cardiology bubble. “When you think of the broader medical, clinical population that sees patients with chest pain, . . . they like algorithms, they like to be able to look stuff up,” he told TCTMD. “And to them, the most efficient, cost-effective approach is not necessarily at the top of their list of priorities; it's to get the diagnosis right and to do what the experts say they should do.”

New Tests and Options

While much of the discussion in the lead-up to the new guidelines was focused on how CT angiography might be incorporated, other tests also gained prominence.

Andrew Choi, MD (The George Washington University, Washington, DC), who served as a reviewer of the guidelines on behalf of SCCT, was excited to see cardiac computed tomography angiography (CCTA) get a stronger indication for use, across multiple settings, based on a range of recent studies. “It [now has] a class 1A indication in intermediate-risk acute chest pain and for intermediate- to high-risk stable cardiac chest pain,” he told TCTMD. “In many ways, this is not a change in many of our approaches, but it provides the evidence base . . . to help my colleagues that are outside of imaging, and even also downstream in emergency medicine and primary care, to understand what the best test is and what the evidence base is that supports these new class 1 recommendations.”

Patel agreed that “we all kind of saw it coming,” but still was happy to see CCTA put on par with functional testing in patients at intermediate risk. Going forward, she will likely not “reflexively order a functional test for everybody,” she said. “I wouldn't necessarily use it in all intermediate- to high-risk patient, but definitely in people who are at more of a low-to-intermediate-risk spectrum.”

Bullock-Palmer stressed, though, that other factors need to be considered before reflexively choosing one test over another. “I really have to look at the patient in front of me . . . you can't send them all for CT, you can't send them all for nuclear.” It’s about what’s available, too, she said. “If you cannot get a high-quality CT or you cannot get a good high-quality interpretation, then regardless, you should not be sending your patients for a CT.”

Also trained in nuclear cardiology, Patel highlighted that certain tests are now recognized as better than others if both are available, such cardiac PET over SPECT, “especially in certain situations where you're worried about microvascular disease” such as patients with long-standing hypertension, diabetes, and symptomatic chronic kidney disease.

The combination of the use of the high-sensitivity troponin and the guidelines will allow us to discharge more patients without any additional testing. Deborah Diercks

Diercks underscored the inclusion of high-sensitivity cardiac troponin (hs-cTn) assays, which she believes will be a game changer as they become available in more US hospitals. The new guidelines recommend that low-risk patients with hs-cTn levels below the limit of detection do not need additional testing. “That changes the paradigm where we tend to do risk stratification and order tests on that. And the combination of the use of the high-sensitivity troponin and the guidelines will allow us to discharge more patients without any additional testing,” she said.

Yader Sandoval, MD (Mayo Clinic, Rochester, MN), likewise, was happy to see the inclusion of hs-cTn testing in the guidelines as the “gold standard” for evaluating myocardial injury alongside structured risk assessment. “Many institutions around the country have adopted these assays following integration of the data from Europe and elsewhere,” he told TCTMD. “But really there was limited guidance.”

Changes to Practice and Processes

The novel guidelines, more generally, urge some key changes to how patients and disease are managed.

Diercks pointed to the change in recommended follow-up timing for unstable NSTEMI from 72 hours to 7 days, which will make it so that more patients are managed appropriately. “Although that seems kind of trite, it really is significant because we can usually get people followed up within a week who we're worried about,” she said. “It is impossible sometimes to get people followed up within 72 hours.”

In addition, “the statement in the guideline that is relatively strong about the incorporation of risk-stratification tools may also change practice,” Diercks said. “That formalized process of incorporating it into the evaluation will impact accreditation for chest pain, and it will ultimately result in better documentation of patients risk.”

[It’s] not just looking at the presence or absence of obstructive coronary artery disease, but looking at whether or not there's any coronary artery disease. Renee Bullock-Palmer

Choi told TCTMD he was excited to see priority placed on evaluation of nonobstructive coronary disease. “The traditional approach suggests an evaluation through stress testing focused on those that had advanced stage coronary disease,” he said. “With the inclusion of nonobstructive CAD and evaluation through CT angiography, that allows us to focus both on the symptoms but also on the prevention of heart attack through the identification of plaque and the addition of goal-directed medical therapy.”

That notion—addressing future risk—was important to the writing committee, Bullock-Palmer observed. The final document aims to focus on “not just looking at the presence or absence of obstructive coronary artery disease, but looking at whether or not there's any coronary artery disease,” she said, adding, “I think really looking at what's underneath the surface for these patients is important at preventing any future events.”

Bullock-Palmer drew attention to the fact that gender differences made it into the recommendations. “There's a myth,” she noted, “that women do not present with chest pain as often as men, but that is actually not true.”

Then there is advice for when not to act, Patel pointed out, saying she can now feel more comfortable in deferring or foregoing testing in patients “who have noncardiac chest pain or patients who are young and at a very low pre-test risk of having significant coronary artery disease.”

For Brown specifically, though, the guidelines won’t really affect his practice. This is “because they are focused on the outdated paradigm that's centered on finding obstructive coronary disease, and I don't really practice that paradigm anymore,” he said.

Missing Specifics

While most people who spoke with TCTMD took note of the document’s inclusivity, this in and of itself is a source of contention. Many would have liked to have seen choices ranked, based on evidence supporting their use in different scenarios.

Diercks pointed out that the lack of graded recommendations, putting one test ahead of another, was “intentional” and speaks to the need for consensus. As an emergency department physician, she “would have liked more directed guidance for imaging. . . . I think that the intent, the hope, would have been more specific, but we couldn't get there,” Diercks continued, citing “disagreement amongst the experts” over earlier iterations of the guidelines that included more-specific algorithms.

While choice of test will always vary according to availability, expertise, and individual patient characteristics, “it would be nice to have had some more specific examples of when you would choose one test over another,” Patel agreed. “If you're thinking PET or SPECT or stress echo, when would you chose that over, let's say, a coronary CTA?”

Patel said she understands why the writing committee kept things vague. However, “when you give so many options to a referring physician, some of them like general medicine doctors who don't really necessarily know the nuances between these tests, it could be hard for them to choose one versus another and that can make a difference,” she commented.

Moudgil noted that more-concrete recommendations spelling out the benefits of one modality over another would be particularly helpful for noncardiologists. “Although they categorize everything as ‘stress testing,’ they should be a little bit more delineated,” he said, giving the example of a patient with a conduction abnormality. In that situation, he said, dobutamine echo would not be recommended, though that’s not spelled out.

Sandoval mentioned another missing piece, noting that there were “no clear recommendations” about sex-specific thresholds recommended for hs-cTn assays, although the guidelines acknowledged the potential for underdiagnosis in women. “That was an important gap in the document,” he said.

Flak Over FFR-CT

A major flash point in the guideline’s creation was the inclusion of FFR-CT, which is what led the ASNC not to endorse them. In a letter published by the ASNC’s board of directors, they say “FFR-CT was given an inappropriately large role.” Its inclusion is particularly contentious because only a single company, HeartFlow, offers this technology to estimate the functional significance of a coronary lesion.

[FFR-CT would be] out of the scope of major universities and academic centers, and for sure out of the hands of community [physicians] as well as the private practices. Rohit Moudgil

Moudgil called the inclusion of FFR-CT “premature,” particularly since it is so broadly unavailable to most practicing physicians. FFR-CT, he said, would be “out of the scope of major universities and academic centers, and for sure out of the hands of community [physicians] as well as the private practices,” he said. “It should be recommended but with a grain of salt.”

The guidelines stipulate that if you’re doing CCTA, then FFR-CT or a stress test could follow. “I would have preferred stress testing [to be] more prominent than FFR-CT,” Moudgil added.

Brown also is of the opinion that FFR-CT should not have been recommended, but his argument is based on the thought that fractional flow reserve testing, more broadly, has not been proven beneficial in stable CAD. “I thought we learned from the ISCHEMIA trial that ischemia is a marker for adverse outcomes but revascularization as a response to ischemia doesn't help patients,” he said. “So I'm not sure why there's such an emphasis on stress testing, on the one hand, and I guess the surrogate for stress testing—which is very unproven—the FFR-CT: why those things have such a central role and why, if those tests are abnormal, the guidelines shunt you right to invasive coronary angiography.”

Choi disagreed. “I applaud the guideline authors, because they followed the evidence. There are a lot of studies and randomized controlled trials as well as the ADVANCE Registry that support the use of FFR-CT, and I think that the inclusion reflects that evidence.” Importantly, he noted, not every patient needs an FFR-CT or a stress test. “It's meant to be for selected patients and only if it will change the management.”

Reimbursement Questions

As for how the new guidelines may affect reimbursement, time will tell.

“Reimbursement is in part guided by these kind of guidelines,” Choi said. “It's guided by the evidence, and it's guided by the individual payers. Many of the private payers based on the evidence had already shifted to an approach that applies this guideline that has an anatomic approach or a CT angiography approach first, and I think that the guideline will continue to accelerate that trend.”

Patel said she hopes the guidelines will “make it easier” to get reimbursement and decrease the need for prior authorization, especially for coronary CTA, stress PET, and stress CMR.

While Moudgil said that CCTA “will start getting more reimbursement after these guidelines,” for other tests reimbursement will “become difficult,” most notably for lower-risk patients where payers may argue against the need for testing. 

“I’m hopeful that that should not happen because it should not be a test-first a strategy; it really has to be a patient-first strategy,” Bullock-Palmer said. “No one knows the patient more than, one, the patient and, two, the provider taking care of the patient. To really have someone outside tell you that ‘No, you can't order this test’ because they are only going to cover another test I think is really inappropriate. . . . Hopefully the insurance will not use that as armamentarium to deny patients from having quality care.”

Meaningful, Measurable Change

Moving forward, education and training will be key to choosing and using the best imaging modalities in any given clinical situation.

“We have a lot of important work to do around education for the guideline and seeing it implemented not only in the imaging community but in the general cardiology community, in the primary care community, and in the emergency medicine community,” Choi said. “There are 10 million imaging tests that are performed yearly in the United States. About 80-90% are stress testing and about 10-20% are coronary CT based imaging, and I think the guideline will cause this to shift in a positive way.”

Additionally, Choi anticipates a reduction in “layered testing,” which is when multiple tests are ordered at the same time. “What I personally also hope we'll see is that through the incorporation of nonobstructive CAD that we'll start to impact and see a reduction in heart attacks and cardiac events over the next 10 years by incorporating these principles,” Choi said.

Diercks said she hopes any changes to practice are tracked and assessed. “It would be useful to know if any advances were made from these and how they are adopted. I think a pragmatic study looking at the incorporation of some of these guidelines into actual care, and whether it changes or not, would be very useful,” said Diercks.

Training and access, said Patel, will be key. She called for a push to train more physicians and imagers “who can read and report these tests properly, and we also need to focus on ensuring that all different test options are available across different settings.”

Another area that “would be ripe to look at,” said Bullock-Palmer, is how high-sensitivity troponin assays will impact emergency room care and length of stay. “I think moving forward it would be interesting to see how these guidelines impact primary prevention and even secondary prevention of heart disease, especially with a focus on preventative care,” she said.

For clinicians seeking to incorporate these guidelines into their practice today, Bullock-Palmer advised having a patient-first strategy as well as remembering the importance of prevention. “Even if a patient does not have nonobstructive disease but does have some clinical disease, those patients should be on appropriate guideline-directed medical therapy,” she said.

The protracted debate that went into inking these guidelines will ultimately need to be repeated again and again—ideally with less friction as the years go by and patterns shift.

Diercks hinted that more-concrete advice is already in the offing: “There will be some other recommendations coming out that aren't based on the guidelines that may be a little bit more direct.”

I would like us to move into the 21st century and pay less attention to ischemia and more attention to other causes of chest pain, meaning microvascular dysfunction and spasm. David L. Brown

Brown, for one, believes there’s room to both broaden and streamline the document. “I would like us to move into the 21st century and pay less attention to ischemia and more attention to other causes of chest pain, meaning microvascular dysfunction and spasm, and not focus on revascularization when you do find an obstructive CAD unless the patient has refractory symptoms,” he said, adding, “I would love to have an eraser and just be able to go through these decision pathways and just simplify them by getting rid of the stress testing, getting rid of the FFR-CT, and making these pathways much more simple and at the same time not losing anything in terms of worsening patient outcomes.”

As everyone involved keeps pointing out: these guidelines are the first of their kind, but they won’t be the last. Whether the next iteration will take as long to publish, or be as beset by controversy, remains anyone’s guess. According to the ACC, “there is currently no scheduled update to the chest pain guideline,” though any future scheduled updates will be posted to ACC.org. Additionally, the AHA said that while “guideline updates are done usually every 4-5 years” as determined by the AHA/ACC joint task force, “if something significant changes in the interim, we sometimes do focused updates.”

To TCTMD, Martha Gulati, MD, chair of the guideline-writing committee, confirmed that the time line for when these guidelines might be updated will be dictated by the ACC and AHA. However, in an ideal world, she would love to see a “more nimble” approach for updating all kinds of guidelines, wherein writing committee members convene every year to at least review any new data and then potentially decide whether to issue an update. “It seems to me it would be easy to allow us to do that and still get a review process in place where people review it and quickly give feedback,” she said. “That might be naive of me to say that, but I feel like that's the way we need to go so that we keep our guidelines up to date.”

Not everything would need to be completely rewritten in this case, Gulati added, “but if there's a section that needs to be updated, let's keep them timely and relevant so that our practice is up to date with literature.”