Transcript Acute Coronary Syndrome - LSU School of Medicine

Acute Coronary
Syndrome
Garland Anderson MD
September 29th 2014
Goals and Objectives
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Review the etiologies of Acute Coronary Syndrome (ACS)
Gain understanding of how to diagnose ACS
Understand the different types of ACS
Review the treatment of ACS
Understand risk stratification in patients with unstable angina
and non-ST segment elevation myocardial infarction
• Brief review of optimizing risk in secondary prevention after
myocardial infarction
Etiologies
• Atherosclerosis is a diffuse arterial disease
• Endothelial dysFx
• Formation of plaques
• Treatment of most risk factors reduces the dysfunction
• Progression of plaques
• Foam cells →fibrous cap
• Prone to Rupture
• Result ACS
Etiologies
• Rupture of Plaque
• Total Occlusion
• ST-segment elevation myocardial infarction (STEMI)
• Partial Occlusion-Spectrum of Disease
• Unstable Angina→
• non- ST-segment elevation myocardial infarction (NSTEMI)
• Acute Coronary Syndrome
• Imbalance between coronary blood flow and myocardial oxygen
demand
DDX Acute Chest Pain
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Anxiety/panic disorder
Aortic dissection
Costochondritis
Esophageal Conditions (spasm)
Gall bladder disease
Myocarditis/pericarditis
Peptic Ulcer Disease
Pneumonia
Pulmonary Embolus
Acute Coronary Syndrome
• Diagnosis
• History and Physical Exam
• EKG
• Cardiac Biomarkers
History
• Chest pain
• Present in less than half of patients over 85 years of age
• Typically poorly localized to anterior chest
• +/- Radiation ( Arms, neck, epigastrium, or back)
• Dyspnea
• Most common “atypical” symptom
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Weakness
Fatigue
Nausea/Vomiting
Diaphoresis
History
• Further define likelihood of ACS with chest pain
• Atherosclerotic risk factors
• Associated medical conditions (HTN/HLD)
• Age
• Smoking
• Similar pain with prior MI
• Chest pain characteristics not likely to represent ACS
• Worsens with
• Localized palpitation
• Deep breathing
• Movement of the affected area
Electrocardiogram
• Should be obtained within 10 minutes of presentation to the
emergency department
• ST-segment elevation of 0.1 mV or more in at least 2
contiguous ECG leads
• Diagnostic of STEMI
• Degree of ST-segment elevation correlates with the amount of
myocardium experiencing injury
• ST-segment depression and/or T-wave inversion can indicate
ischemia
• Suggestive of, but not specific for, the diagnosis of unstable
angina or NSTEMI
Electrocardiogram
• ECG results can be initially normal in up to 20% of patients
experiencing ACS.
• Might not be helpful If patient’s baseline ECG is abnormal
• Preexisting ST-segment or T-wave changes
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Left bundle-branch block
Left ventricular hypertrophy
Left ventricular aneurysm
Myocarditis
Electrolyte abnormality
Preexcitation syndrome
Ventricular pacemaker rhythm
Electrocardiogram
Electrocardiogram
Electrocardiogram
Electrocardiogram
Electrocardiogram
Electrocardiogram
Cardiac Biomarkers
• Troponins
• Highly sensitive and specific markers of myocardial damage
• Elevated in patients with NSTEMI and STEMI but are normal in
patients with unstable angina
• Typically do not increase until approximately 6 hours after onset
of chest pain.
• ECG results consistent with ischemia, normal cardiac troponin levels
should not be used in the decision to discharge a patient
• Serial levels should be measured at 8-hour intervals on the first day
• When levels are elevated, they can remain elevated for up to 10
days
Cardiac Biomarkers
• In ACS, the amount of troponin elevation is directly related to
infarct size
• Normal serial troponin levels rule out an acute MI with a high
negative predictive value
• Multiple nonischemic etiologies of elevated troponin
Acute Coronary Syndrome
Treatment
• Critical to initiate therapy promptly to limit ongoing
myocardial damage
• Must be tailored to the type of ACS and specific patient
characteristics
Treatment
• Oxygen
• Supplemental oxygen is usually administered to all patients
• Recommended in patients with:
• Arterial oxygen saturation level less than 90%
• Respiratory distress
• Incipient heart failure
Treatment
• Relief of Anginal Pain
• Nitroglycerin (NTG)
• 0.4 mg should be administered sublingually every 5 minutes for up to
3 doses or until the pain resolves
• Patient should be in the seated or recumbent position when
administered to optimize benefit and prevent systemic hypotension
• Ischemic chest pain continues or recurs, intravenous NTG is indicated
• Contraindicated in patients who have taken phosphodiesterase
inhibitors (eg, sildenafil, tadalafil) within the previous 24 hours
• Use with caution in patients with right ventricular infarction or
diastolic dysfunction to prevent systemic hypotension
Treatment
• Relief of Anginal Pain
• Morphine sulfate (2 to 5 mg)
• Major role in analgesia.
• Safety concerns have been raised about the use of morphine
• Some studies have found a higher likelihood of mortality in patients
receiving morphine
Treatment
• Initial Antiplatelet Therapy
• Aspirin
• 162 to 325 mg should be started over the telephone or at the initial
medical encounter, even if a dose was taken earlier that day.
• Administered to patients with STEMI whether or not they will receive
fibrinolytic therapy.
• Chewed, rather than swallowed whole.
• 75 to 162 mg should then be continued indefinitely because it results
in a significant reduction in mortality and MI.
Treatment
• Initial Antiplatelet Therapy
• Clopidogrel (Plavix)
• Patients who are intolerant of ASA because of allergy or major
gastrointestinal disease.
• Loading dose of 300 mg
• 75 mg/day maintenance dosage
Treatment
Treatment
• Cardioprotective Drugs
• Beta blockers
• Should be administered within the first 24 hours unless
contraindicated.
• Marked first-degree atrioventricular (AV) block
• PR interval more than 240 ms
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Second- or third-degree AV block
Acute heart failure
Low cardiac-output states
Active bronchospasm.
Treatment
• Cardioprotective Drugs
• Beta blockers
• Initial dose should be based on the heart rate and blood pressure.
• Reduce oxygen demand, ventricular fibrillation risk, cardiac
remodeling, and progression of coronary disease.
• Help control heart rate and hypertension
Treatment
• Cardioprotective Drugs
• Angiotensin-converting enzyme (ACE) inhibitors
• Should be administered at a low dose within the first 24 hours of
hospitalization.
• Reduce mortality and morbidity rates, prevent cardiac remodeling,
and are of extra benefit in the presence of anterior wall infarctions,
hypertension, and systolic dysfunction.
• Prevents approximately 1 mortality per 200 treated patients.
• Angiotensin receptor blockers can be substituted if the patient is
intolerant of ACE inhibitors
Treatment
• Cardioprotective Drugs
• Statins
• Shown to be of long-term benefit in patients with ACS.
• Patients already taking a statin when presenting with ACS are less
likely to have STEMI or acute in-hospital arrhythmias.
• Should be started in all patients with ACS during hospital admission,
regardless of the LDL level.
• Plaque stabilization, reversal of endothelial dysfunction, decreased
thrombogenicity, reduced inflammation independent of the longterm cholesterol level-lowering benefit.
• Early regression of coronary atherosclerosis, decrease in mortality
rates, and significant reduction in the rate of major cardiovascular
end points
Treatment
• Management of STEMI
• Percutaneous Coronary Intervention (PCI)
• Coronary angiography and angioplasty with stent placement are the
reperfusion therapies of choice in patients presenting with
• Acute STEMI
• ACS with a new (or presumed new) left bundle-branch block
• Posterior wall myocardial infarction (MI)
• Therapies of choice if they present
• Within 12 hours of symptom onset
• Hospital with PCI capability
• PCI can be performed within 90 minutes of first medical contact
• door-to-balloon time
Treatment
• Management of STEMI
• Special situations
• Hospitals Without PCI Capability. These patients with STEMI should
be transferred to a PCI center if the PCI can be performed within 90
minutes of first medical contact.
• Lack of Onsite Surgical Backup. Clinical studies indicate that patients
at hospitals with PCI and stent capabilities but without onsite
surgical backup can experience outcomes that are better than those
associated with coronary fibrinolysis, if PCI is performed in a highvolume center by expert operators.
• Cocaine Users.
• Beta blocker use should always be avoided in cocaine users to prevent the
vasoconstriction that can occur when beta blockers leave alpha
stimulation unopposed
• Bare-metal stent should be considered because of the possibility of poor
long-term adherence to antiplatelet drug
Treatment
• Management of STEMI
• Fibrinolysis
• Patients who cannot be transferred to a PCI center within 90 minutes
should undergo urgent intravenous fibrinolysis.
• Most effective when administered within the first 4 hours, and
especially within the first 30 to 60 minutes.
• Still beneficial up to 12 hours after symptom onset.
• Results in normal coronary perfusion in 55% of patients
Treatment
• Management of STEMI
• Coronary Artery Bypass Graft Surgery
• Associated with low rates of recurrent ischemia, complete
revascularization, and few revascularization
• Preferred therapy for
• Left main coronary disease,
• Left main equivalent disease (ie, high-grade proximal stenosis of the left
anterior descending and circumflex arteries)
• Diffuse 3-vessel disease
• Surgical mortality rates after CABG for patients with STEMI are higher
in the first week after MI.
• when possible, surgery should be postponed for at least 1 week in patients
in stable condition.
Treatment
• Management of STEMI
• Anticoagulants
• Recommended for all patients with STEMI.
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Unfractionated heparin (UFH)
Low-molecular-weight heparin (LMWH)
Synthetic heparin (fondaparinux [Arixtra])
Direct thrombin inhibitors (bivalirudin)
• Should be administered before invasive procedures are started.
• Choice of anticoagulant be guided by the reperfusion therapy
planned and the individual’s risk of bleeding.
• PCI = UFH plus a glycoprotein inhibitor IIb/IIIa, or bivalirudin alone
• Fibrinolysis = UFH, LMWH, or fondaparinux If bleeding is a concern,
• LMWH is associated with a lower rate of reinfarction at 30 days than UFH,
but it is also associated with more major bleeding.
Treatment
• Management of STEMI
• Antiplatelets
• ASA is indicated for all patients with STEMI whether they receive
reperfusion therapy with PCI, fibrinolysis, or bypass surgery.
• Thienopyridines. If PCI is to be performed, clopidogrel should be
administered in addition to ASA before the procedure (loading dose
of 300 to 600 mg, followed by 75 mg/day). These drugs are indicated
even when patients receive anticoagulants.
• Glycoprotein IIb/IIIa inhibitors (eg, abciximab [Reopro], eptifibatide
[Integrilin], tirofiban [Aggrastat])
• Not recommended for STEMI patients already receiving dual antiplatelet
therapy plus an anticoagulant.
• Might have a role in the catheterization laboratory in select patients with
large thrombi or those who have not received adequate pre-procedure
thienopyridine therapy.
• More potent than clopidogrel, faster in onset, and more consistent in
platelet inhibition.
Treatment
• Management of NSTEMI/UA
• Anti-Ischemic, Antiplatelet, and Anticoagulant therapy
• Identical to management of STEMI
• Non-ST-segment elevation MIs occur more frequently than
STEMIs, but are associated with similar long-term outcomes.
• In contrast to STEMIs, for which urgent revascularization is
required because of complete or near-complete vessel occlusion,
urgent intervention is less often required for NSTEMIs because
the involved vessel is partially patent in 60% to 85% of patients.
Treatment
• Predicting Mortality Risk
• The Thrombolysis in Myocardial Infarction (TIMI) risk score helps
determine the risk of mortality within the first 30 days of
presentation.
• High-Risk Clinical Presentations
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Cardiogenic Shock
Hemodynamic Instability
Clinical Heart Failure
Severe Systolic Dysfunction (EF < 40%)
Persistent or Recurrent Ischemia
Sustained Ventricular Tachycardia
High-risk Thombolysis in Myocardial Infarction (TIMI) score
Treatment
TIMI Risk Score for UA/NSTEMI
Calculation of Risk Score
Characteristic
Application of Risk Score
Point
Historical
Score
Death/MI/Urgent
Revascularization
(14 d)
0-1
5%
Age ≥ 65 y
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2
8%
≥3 Risk factors for CAD
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13%
Known CAD (stenosis ≥50%)
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4
20%
Aspirin use in past 7 days
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5
26%
6-7
41%
Presentation
Severe angina (≥ 2 episodes w/in 24h)
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ST deviation > 0.5 mm
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+ cardiac markers (Troponin, CK-MB)
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RISK SCORE = Total points
(0-7)
Treatment
Treatment
• Secondary Risk Factor Prevention
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Blood Pressure
Lipid Management
Physical Activity
Smoking Cessation
Weight Management
Other Considerations
• Diabetes Management
• Metabolic Syndrome
• Influenza Immunization
Summary
• Acute coronary syndrome requires prompt diagnosis
• Early medical management is needed to reduce risk to
myocardial tissue
• The type of ACS guides the choice of treatment modalities
• Risk stratification/TIMI scores show what patients with
NSTEMI/UA could benefit from early PCI
• Risk factor modification is important in secondary prevention
of myocardial infarctions
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