Date: June 30th, 2022

Reference: McGinnis et al. Major adverse cardiac event rates in moderate-risk patients: Does prior coronary disease matter? AEM June 2022.

Guest Skeptic: Dr. Corey Heitz is an emergency physician in Roanoke, Virginia. He is also the CME editor for Academic Emergency Medicine.

Case: You are working a shift in your local community emergency department (ED) when a 47-year-old male presents with chest pain. His symptoms are moderately suspicious, he has a normal EKG, and a history of hypertension. His father had a minor heart attack at the age of 63. With a negative initial troponin, this gives him a HEART score of 4. He has no history of coronary artery disease. You have been reading about the overuse of objective cardiac testing (OCT) and wonder if this patient really needs admission to the hospital.

Background: Chest pain is one of the most common presentations to the ED. Much ink has been spilled over the years on trying to find a way to safely rule-out acute coronary syndrome in these patients. Multiple clinical decision instruments have been created to risk stratify patients and guide clinicians (TIMI, GRACE, MAC, T-MAC, HE-MAC, ADAPT, VCPR, EDACS, etc).

The HEART score was originally developed in 122 patients in the Netherlands and published in 2008. Backus and colleagues published their multi-centre validation of the HEART score in 2010. Since then, there have been several studies looking at this clinical decision instrument.

We looked at a HEART Score Pathway that included a HEART Score and 0 and 3 hour cardiac troponin testing on SGEM#151 with our friend Salim Rezaie. The bottom line from that episode was that the HEART Pathway appears to have the potential to safely decrease objective cardiac testing, increase early discharge rates and cut median length of stay in low-risk chest pain patients presenting to the ED with suspicion of ACS.

In prior decades nearly all patients presenting to EDs with chest pain were admitted to hospital. If we thought about ACS, we brought them in. This would be for objective cardiac testing including stress test, CT-angiography, and/or invasive angiography. However, all this recent research into clinical decision tools and pathways to risk-stratify these patients is reducing admissions and therefore ED and hospital overcrowding [1-5].

Many patients risk stratified as “non-low” risk are admitted, but the benefit of objective cardiac testing in this cohort is unclear in the absence of elevated troponins or abnormal EKGs [6-9]. The study we will be reviewing today seeks asks if the presence of known coronary artery disease is predictive of major adverse cardiac events (MACE) in a previously identified non-low risk group of patients.

Clinical Question: What is the 30-day incidence of MACE in patients who are non-low risk but have known coronary artery disease?

Reference: McGinnis et al. Major adverse cardiac event rates in moderate-risk patients: Does prior coronary disease matter? AEM June 2022.

  • Population: Adult patients (age >21 years) with chest pain or suspected ACS, HEAR >4, elevated troponin, ischemic EKG or prior CAD
    • Exclusions: Patients with evidence of an ST-segment elevated myocardial infarction and patients who were identified as low risk (HEAR < 4) by the HEART Pathway
  • Intervention: Assessment of moderate-risk patients as described in the inclusion/exclusion criteria
  • Comparison: None
  • Outcome:
    • Primary Outcome: 30-day MACE defined as the composite of all-cause death, MI, or coronary revascularization.
    • Secondary Outcomes: Individual components of the MACE composite at the index visit
  • Study Design: A preplanned subgroup analysis of non–low-risk patients in the HEART Pathway Implementation Study was conducted. The original study was a prospective interrupted time-series of accrued adults with possible ACS from three US sites (November 2013–January 2016).

Dr. Henderson McGinnis

This is an SGEMHOP episode, which means we have the lead author on the show. Dr. Henderson McGinnis is a Professor in the Dept of Emergency Medicine at Atrium Health Wake Forest Baptist.

Henderson is the Medical Director for AirCare, the system’s critical care air and ground transport service. He is also the fellowship director of the Wilderness Medicine Fellowship at the Wake Forest EM Program.

Authors’ Conclusions: MACE rates at 30 days were low among moderate-risk patients but were significantly higher among those with prior CAD.”

Quality Checklist for Clinical Decision Tools:

  1. The study population included or focused on those in the ED.  Yes
  2. The patients were representative of those with the problem. Yes
  3. All important predictor variables and outcomes were explicitly specified. Unsure
  4. This is a prospective, multicenter study including a broad spectrum of patients and clinicians (level II). No
  5. Clinicians interpret individual predictor variables and score the clinical decision rule reliably and accurately. Yes
  6. This is an impact analysis of a previously validated CDR (level I). No
    7. For Level I studies, impact on clinician behavior and patient-centric outcomes is reported. N/A
  7. The follow-up was sufficiently long and complete. Yes
    9. The effect was large enough and precise enough to be clinically significant. Yes

Results: Out of the original cohort of patients, 37.7% (1,715/4,550) were classified as moderate risk with non-ischemic EKGs and negative serial troponins. Mean age was 61 years, 55% were women, and 29.6% had known coronary artery disease.

Key Result: Moderate risk patients with known CAD had a higher risk of MACE than those without CAD.

  • Primary Outcome: 30-day MACE defined as the composite of all-cause death, MI, or coronary revascularization.
    • Moderate risk patients with known CAD: 7.1% (36/508)
    • Moderate risk patients without CAD: 1.4% (17/1,207)
    • LR- for 30-day MACE among moderate-risk patients without prior CAD was 0.08 (95% CI; 0.05 to 0.12).
  • Secondary Outcomes: Individual components of the MACE composite at the index visit and 30-day

Listen to the podcast to hear Henderson answer our 10 nerdy questions.

1. Secondary Analysis of a Subgroup – The biggest limitation which you identify up front is that this study is a secondary analysis of a subgroup of patients from the HEART Pathway Implementation Study. How cautious should we be in interpreting these results until a prospective study is done specifically looking at the patient population that could potentially be discharged home from the ED?

2. Prior Coronary Artery Disease (CAD): This study hinges in part on whether the patient had known CAD. In the methods section, there is no definition of prior known CAD. What entities does this encompass?

3. Objective Cardiac Testing (OCT): Often people were admitted to hospital for OCT (stress testing, coronary computed tomography angiography, or invasive coronary angiography). Our friend Dr. Morgenstern at First10EM has written multiple blog posts on why he does not order stress tests. What OCT are you doing at your centre and on whom?

4. HEAR Score: A lot of your discussion centers around what you term the “HEAR” score, or HEART without the “T“. Can you discuss this concept for our listeners, and if and how you suggest using it clinically?

5. Not HS-Troponin: Since we are talking about the “T” in the HEART score this study did not use hs-sensitivity troponins. Many places are now switching over to this assay. What impact do you think it will have on managing these patients with moderate risk?

6. Pre/Post and Wash-In: In the method section you discuss the different phases of the study such as pre-implementation, post-implementation, and a wash-in period. You also excluded patients with another chest pain visit within a year. Can you explain how this influences the study population?

7. Two Percent Threshold: This gets back to my previous question about OCT. Moderate risk patients with no CAD has a 30-day MACE of 1.4%. This is below the pretest threshold of 2% which has been determined to be a reasonable cut off for getting OCT.

8. Primary Outcome: While the 30-day MACE of 1.4% is below 2% for OCT, it is still above the what most physicians consider acceptable [10-12].

9. MACE Events: There were 17 MACE events that made up the 1.4% in the moderate-risk patients without known CAD. Included four deaths of which at least two were apparently due to noncardiac causes. In addition, two of the three missed MIs were due to serial troponin protocol violations. Recategorizing those patients would result in 12/1,207 (0.99%) that would be below both the 2% and 1% threshold.

10. Anything Else: Is there any other aspect of the trial that you would like to highlight or discuss in this talk nerdy section?

Comment on Authors’ Conclusion Compared to SGEM Conclusion: We agree with the authors’ conclusion.

SGEM Bottom Line: It may be reasonable, in patients who are moderate risk by the HEART score but do not have existing known CAD, to pursue outpatient follow up instead of urgent inpatient workup.

Case Resolution: You discuss the situation with your patient, and offer him the option of pursuing admission, or close outpatient follow up. He elects discharge after serial troponins and will call his physician in the morning.

Dr. Corey Heitz

Clinical Application: The HEART Pathway Implementation Study is a well-designed study, of which this is a well-done subgroup analysis. The results are somewhat limited by the mis categorizations of the initial HEAR(T) score, but correct categorization would likely have further decreased the incidence of MACE for moderate risk patients without CAD. The LR- for moderate risk patients without CAD, compared to those with CAD and high-risk patients, was 0.08. This means it may be possible to further identify a group of low-risk patients even among those who are initially categorized as moderate risk.

What Do I Tell the Patient? Based on your age, the features of your symptoms, and other risk factors, you are in a group that we consider “moderate” risk for negative outcomes in the coming weeks. However, the fact that you have no prior CAD may allow us to consider you low risk and discharge you home with outpatient follow up.

Keener Kontest: Last weeks’ winner was Douwe Rijpsma from the Netherlands.  They knew Riff was the name of the character in West Side Story who is fatally stabbed by Bernardo.

Listen to the podcast to hear this weeks’ kenner question. The first person to email me at the correct answer will receive a cool skeptical prize. Remember to use “keener” in the subject line.

SGEMHOP: Now it is your turn SGEMers. What do you think of this episode on discharging moderate risk CP patients who do not have a history of CAD? Tweet your comments using #SGEMHOP.  What questions do you have for the Henderson and his team? Ask them on the SGEM blog. The best social media feedback will be published in AEM.

Also, don’t forget those of you who are subscribers to Academic Emergency Medicine can head over to the AEM home page to get CME credit for this podcast and article.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics Guide to Emergency Medicine.


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