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The Acute Coronary Syndromes, Including Acute MI. 2000 ACLS Text Consensus Guidelines. Acute Coronary Syndromes. Unstable angina Non-Q-wave MI Q-wave MI. Acute Coronary Syndromes. Are a continuum initiated by: - PowerPoint PPT Presentation
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The Acute Coronary Syndromes, Including Acute MI
2000 ACLS Text
Consensus Guidelines
Acute Coronary Syndromes
• Unstable angina
• Non-Q-wave MI
• Q-wave MI
Acute Coronary Syndromes
• Are a continuum initiated by:
• rupture of an unstable, lipid-rich atheromatous plaque in epicardial artery; activating platelet adhesion, fibrin clot formation and coronary thrombosis
Suspicious Chest Pains
• Classic angina - dull, pressure, substernal; arm or neck radiation; SOB, palpitations, sweating, nausea or vomiting
• Angina Equivalent - no pain but sudden ventricular failure or ventricular dysrhythmias
• Atypical chest pain - precordial area but with musculoskeletal, positional, or pleuritic features
CAD Risk Stratification
• High Risk ( 1 of the following features)≧– Prior MI, VT or VF or known CAD– Definite clinical angina– Dynamic ST changes– Marked anterior T-wave changes
CAD Risk Stratification
• Intermediate Risk (no high-risk features plus 1 of the following)– Definite angina (young age)– Probable angina (older age)– Possible angina (DM or 3 other risk factors)– ST depression 1 mm or T inversion 1 mm
CAD Risk Stratification
• Low Risk (no high- or intermediate-risk features plus 1 of the following)– Possible angina– One risk factor (not DM)– T-wave inversion < 1mm– Normal ECG
Short-Term Risk of Death
• High Risk ( 1 of the following)≧– Prolonged continuing pain not relieved by rest
(>20 min)
– Pulmonary edema, S3 or rales
– Hypotension with angina– Dynamic ST changes > 1 mm– Elevated serum troponin T or I
Short-Term Risk of Death
• Intermediate risk (no high-risk features plus 1 of the following)– Prolonged (> 20 min) but resolved or “stuttering”
angina– Rest angina > 20 min or relieved with NTG– Age > 65– Dynamic T-wave changes and angina– Q waves or ST depression < 1mm multiple-lead
groups
Short-Term Risk of Death
• Low Risk (no high- or intermediate-risk features plus 1 of the following)– Angina increased in frequency, severity, or
duration– Lower activity threshold before angina– 1 risk factor, no DM– New-onset angina > 2 wk to 2 mo– Normal or unchanged ECG
Primary goals of therapy for ACS
• Reduction of myocardial necrosis in patients with ongoing infarction
• Prevention of major adverse cardiac events – Death– Nonfatal MI– Need for urgent revascularization
• Rapid defibrillation when VF occurs
Out-of-Hospital Management
• Early defibrillation– Prehospital death: 52%– Primary VF: 4-18% of patients with MI– In-hospital VF: 5% – EMS system for immediate defibrillation is
mandatory– Early access to AED through out the community
Out-of-Hospital Management (cont’d)
• Delays in therapy– From onset of symptoms to patient recognition
• Median time 2 hrs
– During out-of-hospital transport: 5%– During in-hospital evaluation: door to data, to
decision and to drug (4 D’s): 25-33%
• Patient education is important to minimize the delay
Out-of-Hospital Management (cont’d)
• Out-of-hospital fibrinolysis– Appears to reduce mortality when transport times
are long– Recommended when a physician is present or
out-of-hospital transport time is 60min (Class IIa)
Out-of-Hospital Management (cont’d)
• Out-of-hospital ECGs– Increases the time spent at the scene by 0 to 4
min– Diagnosis of AMI can be made sooner– Recommended in urban and suburban
paramedic systems (Class I)
Out-of-Hospital Management (cont’d)
• Cardiogenic shock and out-of-hospital facility triage– Transfer patients at high risk (shock, HR > 100,
SBP < 100, age < 75) to facility capable of PCI or CABG (Class I)
– Transfer patients with contraindications to fibrinolytic therapy to interventional facilities (Class IIa)
ER Patient Care
Initial assessment (< 10 min)
• Measure vital signs
• Measure SpO2
• Obtain IV access• Obtain 12-lead ECG• Perform brief, targeted
history and PE)
• Obtain initial cardiac marker levels
• Evaluate initial electrolyte and coagulation studies
• Request, review portable chest x-ray (<30 min
ER patient care
• Initial general treatment (memory aid: “MONA” greets all patients– Morphine, 2-4 mg repeated q 5-10 min
– Oxygen, 4 L/min; continue if SaO2 < 90%
– NTG, SL or spray, followed by IV for persistent or recurrent discomfort
– Aspirin, 160 to 325 mg (chew and swallow)
Triage by ECG
• ST elevation or new LBBB– ST elevation 1 mm in 2 or more contiguous leads≧
• ST depression or dynamic T-wave inversion– ST depression > 1 mm– Marked symmetrical T-wave inversion in multiple
precordial leads– Dynamic ST-T changes with pain
• Nondiagnostic ECG or normal ECG
ST elevation or new LBBB
Start adjunctive treatment
• If time < 12 hr– Select a reperfusion strategy based on local
resources
• If time > 12 hr– Assess clinical status, either high-risk or clinically
stable
ST elevation or new LBBB
Adjunctive treatments– β-blockers– NTG IV– Heparin IV– ACE inhibitors (after 6 hours or when stable)
ST elevation or new LBBB, time < 12 hr
Reperfusion strategy based on local resources– Thrombolytics (< 30 min)
• TPA 15 mg bolus + 0.75 mg/Kg over 30 min + 0.5 mg/Kg over 60 min or
• SK 1.5 million IU over 1 h
– Primary percutaneous coronary intervention (PCI, angioplasty ± stent) (90 30 min)
– Cardiothoracic surgery backup
ST elevation or new LBBB, time > 12 hr
• Perform cardiac catheterization for high-risk patients– Persistent symptoms– Depressed LV function– Widespread ECG
changes– Prior AMI, PCI, CABG
• Admit to CCU/ monitored bed if clinically stable– Continue or start
adjunctive treatments– Serial serum markers– Serial ECG– Consider imaging study
(2D echocardiography or radionuclide)
Benefit of Thrombolytics
Time Lives saved/1000 < 1h 65 1-2 h 37 2-3 h 29 3-6 h 26 6-12 18
12-24 9
Thrombolytics and Stroke
• Risk factors:– > 65 years
– BW < 70 Kg
– BP > 180/110
– on anticoagulants
• Strokes– no risks = 0.25%
– 3 risks = 2.5%
Contraindications to Thrombolytics
• Absolute–Previous hemorrhagic stroke
–CVA within past 1 year
–Brain neoplasm
–Active internal bleeding
–Suspected aortic dissection
Contraindications to Thrombolytics
• Relative:– BP > 180/110 or
chronic severe hypertension
– On anticoagulants– Trauma or internal
bleeding < 2-4 wks
– Traumatic CPR (>10 min)– Major surgery < 3 wks– Previous SK– Active ulcer– Pregnancy – Hidden puncture
ST depression or dynamic T-wave inversion
• Thrombolytics contraindicated• Adjunctive therapy:
– Heparin (UFH/LMWH)– Aspirin 160-325 mg qd– Glycoprotein IIb/IIIa receptor inhibitors– NTG IV -blockers
• Cardiac catheterization for high-risk patients or monitoring for clinically stable patients
Glycoprotein IIb/IIIa receptor inhibitors
• Inhibits the GP IIb/IIIa receptor in the membrane of platelets
• Inhibits final common pathway activation of platelet aggregation
• Available approved agents– Abciximab (ReoPro)– Eptifibitide (Integrilin)– Tirofiban (Aggrastat)
Low Molecular Weight Heparin
• Not neutralized by heparin-binding proteins• More predictable effects• Measurement of aPTT not required• Administered subcutaneously, avoiding
difficulty with continuous IV administration• Available agents
– Enoxaparin (Loxinox), dalteparin (Fragmin), nadroparin (Fraxiparine)
Low Molecular Weight Heparin
• Inhibits thrombin indirectly through complex, with antithrombin III
• Compared with unfractionated heparin, has more inhibition of factor Xa
• Each molecule of Xa inhibited have led to many molecules of thrombin
Lower dose of heparin
To reduce the incidence of ICH• Bolus dose: 60 U/kg (maximum 4000U)
• Maintenance dose: 12 U/kg/hr (maximum 1000 U/hr for patients weighing < 70 kg)
• Optimal aPTT: 50-70 sec
Nondiagnostic ECG or normal ECG
• Meets criteria for unstable or new-onset angina? Or troponin positive?– Yes, start adjunctive treatments and assess
clinical status• Cardiac catheterization for high-risk patients or
monitoring for clinically stable patients
– No, admit to ER chest pain unit for monitoring• If no evidence of ischemia or infarction
– Discharge and arrange follow-up
Cardiac Markers
• Myoglobin– Nonspecific– Rapid-release kinetics– Useful for its negative
predictive accuracy in the early hours after symptom onset
– Useful marker for reperfusion
• Inflammatory Markers– Can indicate plaque or
systemic inflammation associated with ACS
– CRP identifies a subgroup of patients with unstable angina at high risk for adverse cardiac events
Cardiac Markers
• CK-MB Isoforms– Improved sensitivity
compared with CK-MB– Only one form in the
myocardium
– CK-MB2 > 1U/L or CK-MB2/CK-MB1 > 1.5
• Troponins– Troponin I/Troponin T – Increased sensitivity
compared with CK-MB– Detect minimal
myocardial damage– Useful in risk
stratification– Biphasic release kinetics
Acute stroke
• Major guidelines changes– IV administration of tPA for ischemic stroke
• within 3 hrs of onset of stroke symptoms (Class I)• Between 3-6 hrs of onset of stoke symptoms (class
indeterminate)
– IA fibrinolysis within 3-6 hrs may be beneficial in patients with occlusion of MCA (Class IIb)