Acute Coronary Syndrome

Objectives

• The healthcare professional will have the ability to list the three classes of Acute Coronary Syndrome.

• The healthcare professional will have the ability to list the appropriate acute interventions needed for a patient symptomatic for Acute Coronary Syndrome.

• The healthcare professional will have the ability to list at least three differential diagnosis’ of chest pain.

• The healthcare professional will be able to list four diagnostic tests needed for a patient symptomatic for Acute Coronary Syndrome.

Acute Coronary Syndrome includes the following

diagnoses:

• ST elevation MI (STEMI)

• Non ST elevation MI (NSTEMI)

• Unstable Angina (UA)

Stable Angina

Stable Angina is not included in ACS• It is predictable

• Is associated with activities such as physical activity, cold and even eating

• Usually last for 1-5 minutes and is relieved by rest

• Transient ST depression may be visible but disappears with pain relief

Unstable Angina

Considered to be unstable if presented in any of the following three ways:

• Angina at rest lasting for more than 20 minutes • New onset angina that markedly limits

physical activity

• Increasing angina that is more frequent, lasts longer, or occurs with less exertion than previous angina

Symptoms of unstable angina

• Substernal pain/pressure radiating to the jaws and down arms

• Nausea• Dyspnea• Diaphoresis• Nitroglycerin may not give total relief of

symptoms

NSTEMI vs. UA• NSTEMI and UA can at times only be

discernible by the presence of positive serum biomarkers such as cpk-mb and Troponin.

• Consider data from 12 lead

• Diagnosis of NSTEMI versus UA until proven otherwise

• Disposition of UA and NSTEMI may be determined by their TIMI score.

Time Course for cardiac enzymes

Test Onset Peak Duration

CPK-MB 3-12 hours 18-24 hours

36-48 hours

Troponin 3-12 hours 18-24 hours

Up to 10 days

NSTEMI and UA

• Ischemic ST-segment depression > 0.5mm

• Dynamic T-wave inversion with pain or discomfort

• Nonpersistent or transient ST-segment elevation > 0.5 mm for < 20 minutes

TIMI

• Early risk stratification for UA and NSTEMI

• TIMI 11B and ESSENCE trials

• Seven variables predictive of outcomes

A TIMI score is determined by a list of 7 risk factors.

• Age>65• Three or more cardiac risk factors• Aspirin use in the last 7 days• Two or more episodes of chest pain in the last

24 hr• ST-segment deviation on presenting EKG• Increased biomarkers

• Prior coronary artery stenosis > 50%

High risk patients have a TIMI score >5

• Typically admitted to the ICU or telemetry depending on their hemodynamic state

• Patients with hemodynamic compromise or continued chest pain should undergo PCI.

Moderate Risk

• TIMI score of 3-4

• Can be admitted to the chest pain center or telemetry for further evaluation.

Low Risk TIMI

• TIMI score of <2 and no other concerning features of their presentation can be considered for an abbreviated evaluation protocol

• Serial serum biomarkers

• Discharge with outpatient stress testing within 72 hours

• Serial EKGs

ST segment elevation Myocardial Infarction (STEMI)

• The AHA classifies a STEMI as ST-segment elevation or presumed new Left Bundle Branch Block (LBBB)

• STEMI is characterized by ST-segment

elevation >1mm in 2 or more contiguous precordial leads or 2 or more adjacent limb leads

Contiguous Leads

Area of infarction Leads Associated Vessels InvolvedInferior II, III, & AVF; ST elevation Right coronary artery, Left

circumflex

Posterior V1, V2, V3 ST depression; Large R waves

Proximal Right Coronary artery, Left circumflex

Anterior V1, V2, V3, V4;ST elevation Left Anterior descending

Lateral V1, AVL, V5, V6;ST elevation

Left Circumflex

Right Ventricular Elevation II < III, AVF,V1;Large R V4

Proximal right coronary artery

Physical signs of STEMI

• Severe chest discomfort but may include discomfort in other areas of the upper body

• Shortness of breath

• Sweating

• Dizziness

• Usually intense lasting for more then 15 minutes

Treatment of Patients with Acute Coronary Syndrome

• Should be rapid

• STEMI should be the presumed diagnosis until proven other wise with serial EKG’s and cardiac markers.

Initial treatment should include

• ABCs

• Maintain a saturation above 90%

• Administer O2 to all patients with chest pain for the first 6 hours

• 12 lead EKG

12 Leads

• First 10 minutes of the patients’ presentation and presented to an experienced physician

• If the first ECG is not clearly diagnostic and patient is still symptomatic a 12-lead should be repeated

Inferior wall MI

• Affecting the RV

• Sensitive to nitrates

• Susceptible to hypotension

• Elevations in leads II, III and AVF

• Consider a right sided EKG

Right Sided EKG

• Move the V3, V4, V5 and V6 leads to the mirrored right sided position of the chest

• Be certain to label this EKG as right sided.

Right Sided EKG

Posterior MI

• If depression is noted in leads V1, V2, and V3 with large R waves a posterior EKG is recommended to diagnose a posterior MI

• V4 is placed at the left posterior axillary line, V5 is on the border of the left scapula and V6 is near the spine

• Re-label the EKG V7, V8 and V9 posterior view

Don’t forget

• Resuscitation equipment

• Two large bore IVs • Bedside monitor

Initial Testing

• CBC • Differential • CPK-MB • Troponin • PT • PTT • Comprehensive metabolic profile • CXR

Remember MONA

• Oxygen

• Aspirin

• Nitroglycerin

• Morphine

Aspirin

• Dose 4--81mg baby aspirin

• Contraindication could include allergy or suspect for AAA

• Clarify a documented allergy to aspirin as true allergy or sided effect and discuss with physician

Nitroglycerin

• Effective treatment for the pain associated with ischemic chest pain

• Dilation of coronary arteries • 0.4 mg every 5 minutes until pain free or

a total of three

Use Nitrates with caution

• Do not use if blood pressure is less than 90 systolic

• Systolic blood pressure is < 30 of baseline

• Caution with bradycardia and hypotension • Inferior wall MI –may have inadequate preload

use with caution

Avoid nitrates in patients who take medicines for erectile

dysfunction Phosphodiesterase-5 inhibitors are:• Viagra (sildenafil)

• Levitra (vardenafil)

• Cialis (tadalafil)

– May lead to severe hypotension

– Patients may be reluctant to include with medication reconciliation

Morphine

• For patients with ACS that are unresponsive to nitrates

• 2-4mg increments

• Analgesic for pain

• Reduce pulmonary congestion

• Vasodilator that reduces oxygen requirements

• Reduces preload

Clopidogrel (Plavix)

• Reduces platelet aggregation through a different mechanism than aspirin

• Initial loading dose of 600mg for patients requiring primary PCI and stenting

• Ideally primary PCI should be done within 90 minutes of dosing

Heparin

• Indirect inhibitor of thrombin

Disadvantages: • Frequent need for monitoring of PTT• Unpredictable anticoagulation• Need for IV administration• Possibility of HIT (heparin induced

thrombocytopenia)

LMW Heparins

• Better outcomes than heparin in patient survival rates and frequency of ischemic complications

• LMWH such as enoxaparin (Lovenox) is recommended for patients <75 years of age

• Creatinine levels should be monitored

Beta Blockers

• Recommended for most patients with ST elevation MI

• Watch for signs of inadequate perfusion • Beta blockers reduce the size of the infarct,

reduce likelihood of cardiac rupture and reduce mortality

• They also reduce the incidence of VT and Vfib

Contraindications for Beta Blockers

• Severe LV failure with pulmonary edema,

• HR <60bpm, SBP <100, • Signs of poor peripheral perfusion • 2nd degree heart block• 3rd degree heart block • Reactive airway disease• Cocaine use

History and physical

• Presenting symptoms

• Characteristic of pain associated with symptoms

• Past medical history

• Significant family history

Differential Diagnoses

• AAA

• PE

• Tension pneumothorax

• Perforated peptic ulcer

• Esophageal rupture

Reperfusion Therapy

• Percutaneous Coronary Intervention has been shown to be superior to fibrinolysis

• Considered if less than 12 hours has elapsed from the onset of symptoms

• The goal for PCI is less then 90 minutes from the time the patient seeks medical attention

Mortality rates for patients with AMI treated with PCI

• Lower then those treated with fibrinolysis

• Mortality rate at 6 months was significantly lower for patients with early PCI (50% vs. 63%)

• In the subgroup <75 years old early PCI had a 15% reduction in the 30 day mortality rate and improvement in the one year survival rate

Further Diagnostic Studies

Patients with persistent chest pain, a non-definitive 12 lead and negative cardiac enzymes may be a candidate for more definitive testing.

Resting Myocardium Perfusion Imaging

• Injected thallium-201 and technetium-99m accumulates in myocardial tissue

• Ischemia will demonstrate a decreased radioactive count

Limitations of Resting Stress

• Preexisting myocardial damage

• May be falsely negative if pain has resolved for more than three hours

• The acute rest imaging must be readily available.

References

• Advanced Cardiovascular Life Support, American Heart Association, 2006

• “The Role of Invasive Therapy of Acute Myocardial Infarction after TIMI 11 B.”

Journal of Interventional Cardiology; Vol 2 Issue 1; pages 1-3; June 2007

Echocardiography

• Exclude other potential diagnosis

– Aortic dissection

– PE

– Pericarditis with pericardial effusion

DC planning Per facility

• Life style modifications• Future risk education• Aspirin prescribed at discharge• Beta Blockers prescribed at discharge• Dietary consult for education • Smoking Cessation