Kaiser Permanente study suggests less need for referrals for follow-up non-invasive cardiac testing
When a patient arrives at the emergency department with chest pain, there is an urgent need to determine if they have had — or are at future risk of having — a heart attack. A new Kaiser Permanente study suggests that if a patient’s initial tests show no evidence of heart damage, their risk of experiencing a life-threatening heart problem or dying within the next 2 years is the same whether they are seen by a physician who is more likely or less likely to refer patients for follow-up stress testing or cardiac imaging.
“Within any hospital, there will be some emergency physicians who are more likely than others to refer patients for additional testing,” said lead author Dustin G. Mark, MD, an adjunct investigator with the Kaiser Permanente Division of Researchand an emergency medicine physician withThe Permanente Medical Group. “We were able to use this inherent difference to look at whether additional testing influenced patient outcomes. And what we saw was that the additional tests didn’t really have an effect.”
Until 2021, the American Heart Association/American College of Cardiology guidelines recommended that patients with chest pain have a stress test or heart imaging in the emergency department or within 72 hours of being discharged. But whether this additional testing improved outcomes for patients with a low- or moderate-risk of experiencing a life-threatening heart problem wasn’t clear.
The study, published in Circulation: Cardiovascular Quality and Outcomes, looked at 144,577 patients between ages 30 and 80 who came to a Kaiser Permanente Northern California emergency department between 2013 and 2019 with chest pain. All the patients had had a blood troponin test in the emergency department that found no sign their heart had experienced any stress.
Diagnostic Medical Sonography Program
The research team used a risk assessment tool, called HEART, to determine each patient’s future risk of having or dying from a heart-related problem based on their medical history and known risk factors for cardiovascular disease. Within the study group, 69,639 (48.2%) patients had a low-risk HEART score, 71,108 (49.2%) were assessed as moderate risk, and 3,830 (2.6%) were assessed as high risk.
Overall, 20% of the patients were referred by an emergency physician for additional non-invasive cardiac testing within 72 hours, and over 40% had an exercise stress test or coronary artery imaging within 30 days. Within 2 years of their emergency department visit, 4.8% of the patients experienced a heart attack, developed cardiac shock (when the heart can’t pump enough blood and oxygen to the brain or other vital organs), had a cardiac arrest (when the heart suddenly stops beating), or died from heart disease. An additional 2.9% of the patients died without first experiencing a heart-related problem.
A common problem
Every year, chest pain brings more than 7 million people in the U.S. to the emergency department. Chest pain can be a sign of a heart attack. But chest discomfort can also occur due to health problems that originate in areas such as the lungs, stomach, and esophagus.
“Chest pain is a concerning symptom that could be a sign of something very, very bad — but often it’s not,” said senior author Mary E. Reed, DrPH, a research scientist at the Division of Research.
“I think emergency physicians really struggle sometimes determining which patients are at serious risk of having a heart attack. This type of study can really help the emergency medicine physicians who have to make these decisions every day.”
An earlier study by the research team looked at 60-day outcomes among the same group of patients. That study also found that patients who were referred for additional testing were not less likely to experience a life-threatening heart problem.
The earlier study did find an association between being referred for testing and undergoing a coronary revascularization — a procedure to open narrowed arteries in the heart — within 60 days. But the new study showed that 2 years after the emergency department visit, the rate of revascularization procedures was about the same for those who were or were not originally referred for additional testing.
“The difference in these revascularization procedures that we saw in the earlier study wasn’t seen in our new study,” said Mark. “This is telling us that the patients who had more testing had their arteries opened sooner, while the patients that had less testing had the revascularization procedure later. But the timing of when they had revascularization did not affect overall outcomes.”
The researchers say their findings point to the need for evidence-based guidelines emergency medicine physicians can use to determine when referrals for non-invasive cardiac testing should be made.
“Overall, we’ve seen a decrease over the past decade in referrals for stress testing, both at KPNC and throughout the country,” said Mark. “We hope that our findings will contribute to new guidelines. We also hope they will reassure patients that chest pain is a symptom, but if initial blood troponin tests are normal it’s not always an indicator that they have a heart problem and need additional tests.”
This study was supported by Kaiser Permanente Northern California Community Health.
Co-authors include Jie Huang, PhD, Dustin W. Ballard, MD, MBE, David R. Vinson, MD, Jamal S. Rana, MD, PhD, Dana R. Sax, MD, MPH, and Adina S. Rauchwerger, MPH, for the Kaiser Permanente CREST Network Investigators.
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About the Kaiser Permanente Division of Research
The Kaiser Permanente Division of Research conducts, publishes and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and society at large. It seeks to understand the determinants of illness and well-being, and to improve the quality and cost-effectiveness of health care. Currently, DOR’s 600-plus staff is working on more than 450 epidemiological and health services research projects. For more information, visitdivisionofresearch.kaiserpermanente.orgor follow us @KPDOR.
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