ED ACS Adult Guideline revision 2020

Guideline

Diagnosis and Management of Acute Coronary Syndrome (Adult)

Revision Date

2020

This is a sub-page of the page titled ACS (Acute Coronary Syndome) in the Emergency Department.

Target population

ACS (Acute Coronary Syndrome) is the term used to describe myocardial ischemia which results from the acute occlusion (either partial or complete) of a coronary artery.

This guideline is intended to expedite the diagnosis and management of ED patients presenting with signs/symptoms suggestive ACS. In this context, “suggestive” should be interpreted to mean that ACS is the most likely etiology; or, from a different perspective, the clinician feels that the probability of ACS is high enough that the condition is “ACS until proven otherwise.” Such patients are only a subset of those who present complaining of “chest pain” and thus this guideline is not intended to inform the management of all patients complaining of chest pain.

Type-2 cardiac ischemia (i.e. cardiac oxygen supply-demand imbalance not due to acute coronary occlusion) is not ACS. This guideline is not intended to guide the diagnosis and/or management of type-2 cardiac ischemia.

Impetus for guideline revision

• Last update was in 2011, and several interim events have occurred:
  • The Third Universal Definition of Myocardial Infarction was published in 2012; this changed the EKG criteria for diagnosis of STEMI.
  • For purposes of immediate management, 2014 and 2015 international ACS guidelines combined NSTEMI and unstable angina into the composite NSTE-ACS (Non-ST-Elevation ACS).
  • The Fourth Universal Definition of Myocardial Infarction was published in 2018; this introduced the terms "acute myocardial injury" and "chronic myocardial injury".
  • On November 12, 2019, the Yukon-Kuskokwim Delta Regional Hospital (YKDHR) switched cardiac troponin assay to the Roche Diagnostics Elecsys® Troponin T Gen 5 STAT. Details are available in the manufacturer's package insert.

Goals

1. The guideline should be quickly useful without having previously studied it.
2. All necessary medications and doses should be included in the guideline.
3. Major cautions and contraindications should be included in the guideline.
4. Clinicians with basic ED and/or Urgent Care skills who rarely diagnose and treat ACS should be able to use this guideline to correctly diagnose and manage most straightforward ACS cases (i.e. the majority of them) without external information sources. Unfortunately, some cases are not straightforward and can be challenging for even the most experienced experts; such cases are frequently not amenable to guideline-based management and early expert consultation may be warranted in order to individualize care.

Changes

Major

• This is a ground-up rewrite without significant inheritance.
• Utilization of high-sensitivity troponin-T test.
• New STEMI diagnostic criteria from the Third Universal Definition of Myocardial Infarction (2012). These EKG criteria are unchanged in the Fourth Universal Definition of Myocardial Infarction (2018).
• Use of the new term NSTE-ACS (Non-ST-Elevation Acute Coronary Syndrome).
• Oxygen is no longer mandatory, but rather titrated to achieve normoxemia.
• Enoxaparin dosing (in STEMI) is now adjusted for age and renal function.
• Morphine is no longer recommended (though neither is it recommended against).
• Fibrinolytic contraindications are on the fibrinolytic checklist and are not duplicated on the guideline.
• Inclusion of DAPT (Dual Anti-Platelet Therapy, which refers specifically to combining aspirin with a P2G12 inhibitor).
• Switch from alteplase to tenecteplase as the thrombolytic agent for STEMI reperfusion.

Minor

• For STEMI with age<75y, enoxaparin is started with an IV Bolus.

Rationale for Specific Recommendations

EKG prior to Immediate Interventions

YKDRH has limited inpatient capabilities in this context (no cardiologist, no telemetry). Dynamic ST/T changes are diagnostic for unstable angina and therefore an indication for MedEvac transfer to a higher level of care. Lack of EKG done while in pain (i.e. prior to NTG) can substantially delay diagnosis of unstable angina.

Enoxaparin for anticoagulation

- Time to angiography will be at least 6 hours and possibly up to 12-18 hours.

- Our ED has limited resources, and in this setting more complexity increases the likelihood of errors.

- Care will transition to a MedEvac crew; again, more complexity increases likelihood of errors.

Enoxaparin IV Bolus for STEMI with age < 75y

- recommended by the AHA/ACC 2013 STEMI guideline (see Secondary Information Sources below, pg e97, Table-1)

- recommended by the latest UpToDate.com article (see Primary Information Sources below)

- recommended by the South Central Alaska STEMI Committee's "Alaska Statewide STEMI Recommendations" (see Secondary Information Sources below)

Switch from alteplase to tenecteplase

1. Ease of administration
   • Tenecteplase is a single weight-based bolus pushed over five seconds (compared to three different alteplase infusions over ninety minutes).
   • The simplicity minimizes the risk of drug error.
2. Rapidity of administration
   • Standard-of-care is door-to-infusion time of <= 30 minutes.
   • Given our resource limitations, we are very unlikely to achieve this standard with alteplase infusions.
3. Efficiency
   • An IV lumen is not exclusively occupied for 90 minutes.
   • Nursing and MedEvac crews have more time to focus on other issues.
4. Standard of care
   • Per the UpToDate.com article Characteristics of fibrinolytic (thrombolytic) agents and clinical trials in acute ST elevation myocardial infarction, “Tenecteplase (TNK-tPA) is the fibrinolytic agent of choice within the United States, Canada, and many European countries.”

Clopidrogel 600mg loading dose for "STEMI > 12h" and NSTE-ACS

- the pharmacologic properties differentiating the different P2Y12 inhibitors are:

• Mechanism of action (direct versus indirect).
• Potency (with regards to both effectiveness and adverse effects)
• Onset time
• Recovery time
• Resistance

- Recommendations from UpToDate reviews and national guidelines attempt to balance these effects for the different ACS scenarios.

• The "STEMI < 12h" category assumes the patient is receiving fibrinolytic therapy. In this setting, the risk of bleeding is much higher, so a relatively weak anti-platelet effect is desired.
• The two other ACS categories ("STEMI > 12h" and NSTE-ACS) will not receive fibrinolytics, therefore a much more potent anti-platelet effect is achievable without a substantial increased bleeding risk. This is why these patients receive a loading dose of a more potent agent (prasugrel or ticagrelor) or the very large loading dose of clopidrogel.

Issues intentionally NOT addressed in this revision

1. Diagnosis and management of “chest pain” which is not suggestive of acute myocardial ischemia.
2. Diagnosis/Management of type-2 MI’s.
3. HS-troponin diagnostic algorithms other than the FDA-approved cutoffs.
4. Use of the terminology “acute cardiac injury” and “chronic cardiac injury”.
5. Diagnosis/management of suspected ACS in a village clinic.
6. Different f/u strategies based upon risk stratification (i.e. when ACS has been ruled-out).

Future Directions (i.e. for future revisions)

• Review/update this guideline every two years. Given the importance of the topic and the vast amount of active research, frequent updates are indicated.
• Evidence-based troponin algorithm/cutoffs.

- Based upon institutional data or published data?

• Evidence-based use of anticoagulation.

A cochrane review of RCT's found that anticoagulation (i.e. heparins, both unfractionated and low-molecular-weight) for ACS yielded no effect on patient-important outcomes, a possible small decrease in subsequent nonfatal-MI, and increased bleeding. Yet other respected evidence-based reviews have criticized that conclusion as optimistic and concluded harm without meaningful benefit.,, However, anticoagulation persists in most guidelines, apparently due to an unhealthy combination of tradition and liability concerns. We should consider reviewing this topic and developing the clinical courage to remove heparin from the ACS guideline.

• Develop a similar guideline for suspected ACS in a village clinic.

- It differs enough to warrant being a standalone guideline; incorporating it into the ED guideline risks making the ED guideline too unwieldy to be quickly usable.

Primary Information Sources for Guideline Revision

ACS

Barstow C, Rice M, McDivitt JD. Acute Coronary Syndrome: Diagnostic Evaluation. Am Fam Physician. 2017;95(3):170-177. (Archived)

Myocardial Infarction Definition

Fourth Universal Definition of Myocardial Infarction, 2018 (Consensus statement by the ACC, ESC, AHA)

STEMI

UpToDate: Overview of the acute management of ST-elevation myocardial infarction (Current: Dec 2019, Updated: 01-28-2019)

UpToDate: Antiplatelet agents in acute ST-elevation myocardial infarction (Current: Dec 2019, Updated: 09-17-2019)

UpToDate: Anticoagulant therapy in acute ST-elevation myocardial infarction (Current: Dec 2019, Updated: 02-20-2019)

NSTE-ACS

UpToDate: Overview of the acute management of non-ST elevation acute coronary syndromes (Current: Dec 2019, Updated: 12-13-2018)

UpToDate: Antiplatelet agents in acute non-ST elevation acute coronary syndromes (Current: Dec 2019, Updated: 09-17-2018)

UpToDate: Anticoagulant therapy in non-ST elevation acute coronary syndromes (Current: Dec 2019, Updated: 02-02-2019)

Secondary Information Sources for Guideline Revision

ACS

Group GW and TN. Beta Blockers for Heart Attack. TheNNT. https://www.thennt.com/nnt/beta-blockers-for-heart-attack/. Accessed February 18, 2020. (Archived)

STEMI

2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction (Archived)

UpToDate: Characteristics of fibrinolytic (thrombolytic) agents and clinical trials in acute ST elevation myocardial infarction

Group GW and TN. Thrombolytics for Major Heart Attack (STEMI). TheNNT. https://www.thennt.com/nnt/thrombolytics-for-major-heart-attack/. Accessed February 18, 2020. (Archived)

Alaska Heart Institute: Alaska Statewide STEMI Recommendations (updated May 2017) (Archived)

NSTE-ACS

2014 AHA/ACC Guideline for the Management of Patients With Non–ST-Elevation Acute Coronary Syndromes: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Archived)

Additional Resources

High-sensitivity Troponin-T Interpretation

High-sensitivity Troponin-T

ECG Interpretation

UpToDate: Electrocardiogram in the diagnosis of myocardial ischemia and infarction

Fibrinolytics

UpToDate: Management of post-thrombolytic intracerebral hemorrhage

RV Infarct

UpToDate: Right ventricular myocardial infarction

Credits

Lead Author[s]

Andrew W. Swartz, MD

Reviewer[s]

Ann Marie Garritano, MD