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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:
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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)
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
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
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) ST elevation or new LBBB, time > 12 hr
Risk factors: > 65 years BW < 70 Kg BP > 180/110 on anticoagulants Strokes no risks = 0.25% 3 risks = 2.5% Thrombolytics and Stroke
Contraindications to Thrombolytics • Absolute • Previous hemorrhagic stroke • CVA within past 1 year • Brain neoplasm • Active internal bleeding • Suspected aortic dissection
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 Contraindications to Thrombolytics
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
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 Cardiac Markers
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)