Controversies in ACS Guidelines

Educational Objectives

After completing the activity, the clinician will be better able to detail some of the controversies relating to the clinical guidelines for managing patients with an acute coronary syndrome.

Summary

Interviewer: Roxana Mehran, MD, FACC

Take-home Messages:

• While guidelines in the United States and Europe support evidence-based care, a comparison of transatlantic guidelines reveals differences in their recommendations relating to the diagnosis and care of patients with acute coronary syndrome (ACS)
• Sometimes, there are legitimate reasons for differences between the U. S. and European guidelines, given the timing of the documents, the medications approved, and resources available
• However, there are also clear differences in either emphasis or interpretation that underscore the controversies related to ACS guidelines

There have been remarkable advances in the care of patients with ACS, which have been captured in practice guidelines, first articulated for myocardial infarction (MI) by the American College of Cardiology Foundation (ACCF)/American Heart Association (AHA) in 1990, then in Europe in 1996.

While guidelines in the United States and Europe support evidence-based care, differences in either emphasis or interpretation affect some areas. Occasionally, differences are due more to timing than to genuine differences in recommendations. For example, the 2013 full text version of the ACCF/AHA ST-segment elevation myocardial infarction (STEMI) guidelines¹ were published after release of the third universal definition of myocardial infarction.² Thus, it is not surprising that the U.S. guidelines differ in terms of electrocardiographic diagnosis of MI from the European guidelines, published before release of the new definition of MI.

Another explanation relates to differences in the approval for specific agents. Intravenous aspirin, for example, is only available in Europe, and hence is not included in the ACCF/AHA guidelines.

Definite Differences

On the other hand, there are definite differences, too. In a transatlantic comparison of STEMI guidelines, the authors noted that key differences relate to both the modes and timing of reperfusion for STEMI.³ The ACCF/AHA guidelines focus on primary percutaneous coronary intervention (PCI) as the leading and preferred mode of reperfusion in this setting. Fibrinolysis is endorsed only if unavoidable delays occur (>120 min). While the U.S. guidelines suggest that pre-hospital fibrinolysis may be useful in rural areas, the document notes that such areas have “neither the resources to train paramedics nor the funding for necessary equipment”

In contrast, the European Society of Cardiology (ESC) strongly sanctions pre-hospital logistics of care with a particular focus and Class I (Level of Evidence: B) recommendation for the use of pre-hospital care as a mode for reducing “system delay.”

Timing differs, too, especially as it relates to what is “preferable.” For patients presenting at a PCI-capable hospital in the United States, the recommended first medical contact (FMC)-to-device time is < 90 min. In the same setting in Europe, the recommendation is to achieve an FMC-to-device time < 90 min, but preferably within 60 min of presentation. The ESC further suggests a more stringent ≤ 60 min FMC-to-device time for high-risk cases, particularly those with large anterior infarcts, as well as early presenters (within 2 h) who are expected to derive greater myocardial salvage and incremental benefit from early reperfusion.

For patients presenting to non-PCI centers, the U.S. guidelines call for immediate transfer to a PCI facility for primary PCI with an FMC-to-device target time within 120 min. Overseas, they too suggest an FMC-to-device time within 120 min, but again state that within 90 min is preferable. For high-risk cases, the ESC recommends that FMC-to-device time should be within 60 min, but if even the standard 90-minute target cannot be achieved, then the ESC recommends fibrinolysis.

A similar comparison of guidelines concentrating on non-STEMI recommendations was published in JACC.⁴ Important differences include the use of a rapid rule-out protocol with high-sensitivity troponin assays, a preference for prasugrel/ticagrelor and fondaparinux for anticoagulation therapy, and a preference for radial artery access in the ESC guidelines compared with the AHA/ACC guidelines. As for the issue of arterial access, at ACC.18, Pinak Shah, MD (Brigham and Women’s Hospital, Boston), noted when discussing controversies in ACS guidelines, that “There exists sufficient evidence for U.S. guidelines to be stronger in favor of radial access for ACS.”

DAPT Debate

The ACCF/AHA guidelines advocate use of a bare-metal stent (BMS) if a high bleeding risk exists or if there are likely to be issues with dual antiplatelet therapy (DAPT) compliance, given the brief prescribed duration of DAPT in this setting (1 month for BMS, according to ACCF/AHA recommendations). Otherwise, DAPT is recommended for 1 year, given the benefits accrued in ACS. However, if a drug-eluting stent (DES) is placed, U.S. clinicians are encouraged to consider DAPT beyond 1 year.

The ESC prefers DES if no bleeding risk or compliance issues apply. Suggestions for 12 months of DAPT are similar for ACS; however, the ESC provides a strict minimum of 1 month for BMS and 6 months for DES.

In the same controversies session as Dr. Shah, Robert Yeh, MD (Beth Israel Deaconess Medical Center, Boston), discussed the issues surround DAPT duration. He noted that ACS patients derive significantly greater absolute benefit relative to harm compared with non-ACS patients. The majority of ACS patients have high DAPT scores and these patients have an even greater benefit with long-term DAPT. Therefore, he said, “most ACS patients deserve consideration for extended DAPT if they have not manifested bleeding.”

As for which agent, the updated U.S. DAPT guidelines state that in patients with ACS (STEMI or non-STEMI) treated with DAPT after coronary stent implantation, there is a Class IIa recommendation stating that it is reasonable to use ticagrelor or prasugrel in preference to clopidogrel for maintenance P2Y12 inhibitor therapy.5 The document also notes that prasugrel should not be administered to patients with a prior history of stroke or TIA.

(Editor’s Note: This interview features Glenn Levine, MD, who is Professor of Medicine at Baylor College of Medicine and Director of the Coronary Care Unit there at the Michael E. DeBakey Medical Center. Dr. Levine was first author of the 2016 ACC/AHA focused update to the guidelines on the duration of DAPT in patients with coronary artery disease⁵ and first author of the 2015 ACC/AHA/SCAI focused update on primary PCI for patients with STEMI.⁶)

Readings

1. O’Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2013;61:e78-e140. www.onlinejacc.org/content/61/4/e78
2. Thygesen K, Alpert JS, Jaffe AS, et al. Third universal definition of myocardial infarction. J Am Coll Cardiol 2012; 60:1581-98. www.onlinejacc.org/content/60/16/1581
3. Bainey KR, Armstrong PW. Transatlantic Comparison of ST-Segment Elevation Myocardial Infarction Guidelines: Insights From the United States and Europe. J Am Coll Cardiol 2016;67:216-29. www.onlinejacc.org/content/67/2/216
4. Rodriguez F, Mahaffey KW. Management of Patients With NSTE-ACS: A Comparison of the Recent AHA/ACC and ESC Guidelines. J Am Coll Cardiol 2016;68:313-21. www.onlinejacc.org/content/68/3/313
5. Levine GN, Bates ER, Bittl JA, et al. 2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol 2016;68:1082-115. www.onlinejacc.org/content/68/10/1082
6. Levine GN, Bates ER, Blankenship JC, et al. 2015 ACC/AHA/SCAI Focused Update on Primary Percutaneous Coronary Intervention for Patients With ST-Elevation Myocardial Infarction: An Update of the 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention and the 2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction. J Am Coll Cardiol 2016;67:1235-150. www.onlinejacc.org/content/67/10/1235

Disclosures

Glenn N. Levine, MD, FACC
This author has nothing to disclose.

Interviewer: Roxana Mehran, MD, FACC
Sanofi (C,G); Janssen Global Services LLC (C); Shanghai Bracco Sine Pharmaceutical Corp Ltd (C); Boston Scientific Corp (C); Johnson and Johnson Services Inc (C); Covidien Ltd (C); AstraZeneca plc (C); Abbott (C); Regado Biosciences (C); OrbusNeich (G); Merck & Co Inc (C); Bristol-Myers Squibb Co (C); Eli Lilly &Co/DSI (G); The Medicines Company (C); SCAI (O); Watermark Research Partners Inc (G)

Acknowledgements

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

AC500815

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.

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