cardiovascular disorders
Acute Myocardial Infarction (MI)
Treatment of Acute MI
Prehospital care: Oxygen,aspirin, nitrates, and triage to an appropriate medical center Drug treatment: Antiplatelet drugs, antianginal drugs, anticoagulants, and in some cases other drugs Reperfusion therapy: Fibrinolytics or angiography with percutaneous coronary intervention or coronary artery bypass surgery Post-discharge rehabilitation and chronic medical management of coronary artery disease Choice of Drugs for Acute Coronary Syndromes and choice of Oxygen Aspirin Nitrates Triage to appropriate medical center [325 mg], and pain management with nitrates) can reduce risk of mortality and complications. Early diagnostic data and response to treatment can help determine the need for and timing of Revascularization for Acute Coronary Syndromes . Risk-stratify patient and choose reperfusion strategy Drug therapy with antiplatelet drugs, anticoagulants and other drugs based on reperfusion strategy On arrival to the emergency department, the patient's diagnosis is confirmed. Drug therapy and timing of revascularization depend on the clinical picture and diagnosis. For STEMI, reperfusion strategy can include fibrinolytic therapy or immediate PCI. For patients with NSTEMI, angiography may be done within 24 to 48 hours of admission if the patient is clinically stable. If the patient is unstable (eg, ongoing symptoms, hypotension or sustained arrhythmias), then angiography must be done immediately (see figure Approach to myocardial infarction ). *Morphineshould be used judiciously (eg, ifnitroglycerinis contraindicated or if the patient has symptoms despitenitroglycerintherapy). Data suggest thatmorphineattenuates activity of some P2Y12 receptor inhibitors and may contribute to worse patient outcomes. † Complicated means that the hospital course was complicated by recurrent angina or infarction, heart failure, or sustained recurrent ventricular arrhythmias. Absence of any of these events is termed uncomplicated. ‡ CABG is generally preferred to PCI for patients with the following: Left main or left main equivalent disease Left ventricular dysfunction Diabetes Also, lesions that are long or near bifurcation points are often not amenable to PCI. CABG = coronary artery bypass grafting; GP = glycoprotein; LDL = low density lipoprotein; PCI = percutaneous intervention. All patients should be given Antiplatelet Drugs , Patients with acute myocardial infarction should be given the following (unless contraindicated): Antiplatelet Drugs : Anticoagulant Drugs : A Glycoprotein IIb/IIIa inhibitor when PCI is done Antianginal therapy usuallynitroglycerin Beta-blocker ACE inhibitor Statin All patients are givenaspirin160 to 325 mg (not enteric-coated), if not contraindicated, at presentation and 81 mg once a day indefinitely thereafter. Chewing the first dose before swallowing quickens absorption.Aspirinreduces short-term and long-term mortality risk. In patients undergoing PCI, a loading dose ofclopidogrel(300 to 600 mg orally once),prasugrel(60 mg orally once), orticagrelor(180 mg orally once) improves outcomes, particularly when administered 24 hours in advance. For urgent PCI,prasugrelandticagrelorare more rapid in onset and may be preferred. is more complicated to use because it requires frequent (every 6 hours) dosing adjustments to achieve target activated partial thromboplastin time (aPTT). The LMWHs have better bioavailability, are given by simple weight-based dose without monitoring aPTT and dose titration, and have lower risk of Heparin-induced thrombocytopenia . Duration of PCI in patients undergoing this procedure Duration of hospital stay (in patients on LMWH) or 48 hours (in patients on unfractionatedheparin) in all other cases Consider a glycoprotein IIb/IIIa inhibitor during PCI for high-risk lesions (high thrombus burden, no reflow).Abciximab,tirofiban, andeptifibatideappear to have equivalent efficacy, and the choice of drug should depend on other factors (eg, cost, availability, familiarity). This agent is continued for 6 to 24 hours. therapy). Nitrates is initially given sublingually, followed by continuous IV drip if needed. Standard therapy for all patients with unstable angina includes beta-blockers, ACE inhibitors, and statins. Beta-Blockers are recommended unless contraindicated (eg, by bradycardia, heart block, hypotension, or asthma), especially for high-risk patients. Beta-blockers reduce heart rate, arterial pressure, and contractility, thereby reducing cardiac workload and oxygen demand. For patients with STEMI: Immediate percutaneous coronary intervention or fibrinolytics For patients with NSTEMI: Immediate percutaneous coronary intervention for unstable patients or within 24 to 48 hours for stable patients 90 minutes) by an experienced operator ( Treatment references ). If there is likely to be a significant delay in availability of PCI, thrombolysis should be done for STEMI patients meeting criteria (see Unstable NSTEMI patients(ie, those with ongoing symptoms, hypotension, or sustained arrhythmias) should proceed directly to the cardiac catheterization laboratory to identify coronary lesions requiring PCI or coronary artery bypass grafting (CABG). Foruncomplicated NSTEMI patients,immediate reperfusion is not as urgent because a completely occluded infarct-related artery at presentation is uncommon. Such patients typically undergo angiography within the first 24 to 48 hours of hospitalization to identify coronary lesions requiring PCI or CABG. Fibrinolytics are not indicated for any NSTEMI patients. Risk outweighs potential benefit. Choice of reperfusion strategy is further discussed in Revascularization for Acute Coronary Syndromes . Functional evaluation Changes in lifestyle: Regular exercise, diet modification, weight loss, smoking cessation Drugs: Continuation of antiplatelet drugs, beta-blockers, ACE inhibitors, and statins 40% whether or not they received fibrinolytics usually should have stress testing of some sort before or shortly after discharge (see table Functional Evaluation After Myocardial Infarction ). Exercise Capacity Exercise Capacity If ECG Is Interpretable If ECG Is Interpretable If ECG Is Not Interpretable If ECG Is Not Interpretable Able to exercise Submaximal or symptom-limited stress ECG before or after discharge Exercise echocardiography or nuclear scanning Unable to exercise Pharmacologic stress testing (echocardiography or nuclear scanning) Pharmacologic stress testing (echocardiography or nuclear scanning) The acute illness and treatment of myocardial infarction should be used to strongly motivate the patient to modify risk factors. Evaluating the patient’s physical and emotional status and discussing them with the patient, advising about lifestyle (eg, smoking, diet, work and play habits, exercise), and aggressively managing risk factors may improve prognosis. On discharge, all patients should be on appropriate antiplatelet drugs, statins, antianginals, and other drugs based on comorbidities. 1.Meine TJ, Roe MT, Chen AY, et al: Association of intravenousmorphineuse and outcomes in acute coronary syndromes: results from the CRUSADE Quality Improvement Initiative.Am Heart J149(6):1043–1049, 2005. doi 10.1016/j.ahj.2005.02.010 2.Kubica J, Adamski P, Ostrowska M, et al:Morphinedelays and attenuatesticagrelorexposure and action in patients with myocardial infarction: the randomized, double-blind, placebo-controlled IMPRESSION trial.Eur Heart J37(3):245–252, 2016. doi: 10.1093/eurheartj/ehv547 3.Lawton JS, Tamis-Holland JE, Bangalore S, et al: 2021 ACC/AHA/SCAI guideline for coronary artery revascularization: a report of the ACC/AHA Joint Committee on Clinical Practice Guidelines.J Am Coll Cardiol79(2):e21–e129, 2022. doi: 10.1016/j.jacc.2021.09.006 