myocardial%20infarction%20w_%20st-segment%20elevation
MYOCARDIAL INFARCTION W/ ST-SEGMENT ELEVATION
Myocardial infarction is death of cardiac myocytes (necrosis) caused by prolonged ischemia. The term acute "usually" refers to the time 6 hours to 7 days following pathologic appearance of the infarct.
The patient may experience ischemic-type chest discomfort with accompanying symptoms of nausea, vomiting, dyspnea, diaphoresis, lightheadedness, dizziness, syncope, fatigue and weakness.
Rapid diagnosis and risk stratification of chest pain in patients are important to identify acute myocardial infarction patients who will benefit from reperfusion therapy.

Myocardial%20infarction%20w_%20st-segment%20elevation Management

Prevention

Secondary Prevention

Antiplatelet Therapy

  • Aspirin
    • Standard 1st-line antiplatelet therapy; daily administration should continue indefinitely in all patients unless contraindicated
    • Results in a significant reduction in mortality and nonfatal reinfarction and nonfatal stroke
    • The addition of a second antithrombotic agent to Aspirin for long-term secondary prevention in patients without high bleeding risk should be considered in those whose risk of ischemic events is high and may be considered in those whose risk of ischemic events is at least moderately increased
    • Ticlopidine may be considered as an alternative agent to Aspirin-intolerant patients 
  • Clopidogrel or Prasugrel
    • In conjunction with Aspirin, should be given for at least 12 months in patients receiving a stent (BMS or DES) during percutaneous coronary intervention (PCI)
    • If the risk of bleeding outweighs benefit, earlier discontinuation of either Clopidogrel or Prasugrel should be considered
    • Clopidogrel may be a useful substitute for Aspirin in patients who cannot tolerate Aspirin
  • Ticagrelor
    • In conjunction with Aspirin, it may be given for 12 months to patients who underwent stent implantation to prevent thromboembolic events and >12 months (may consider for up to 3 years) to high-risk post-MI patients who have tolerated DAPT for 12 months without bleeding complication  
  • Vorapaxar
    • Newly approved protease activated receptor-1 (PAR-1) antagonist that inhibits platelet activation
    • Studies showed that Vorapaxar, when given with other antiplatelet agents, significantly reduced incidences of MI, stroke, and death caused by cardiovascular disease

Anticoagulants (Oral)

  • Eg Vitamin K antagonists (Warfarin) and non-vitamin K antagonists/direct oral anticoagulants  
  • Given to patients with atrial fibrillation or LV thrombus
  • Warfarin
    • Patients with left ventricular thrombus may be treated for 3-6 months then reassessed
    • Use of Warfarin with antiplatelet agents is associated with increased risk of bleeding and should be closely monitored
  • Rivaroxaban
    • May be given, in conjunction with Aspirin, to high-risk post-MI patients >12 months (and up to 2 years) or those with multivessel CAD

Beta-Blockers

  • Continue indefinitely in all post-MI patients for at least a year unless contraindicated
  • Recommended in patients with systolic HF or LV dysfunction
    • May be given for >1 year in patients with LVEF ≤40%
  • Has been shown to reduce mortality from a reduction in sudden and non-sudden cardiac death
  • Consider to give in patients who continue to experience angina after revascularization

ACE Inhibitors

  • ACE inhibitors should be continued indefinitely in patients with LV dysfunction
    • May be given for >1 year in patients with LVEF ≤40%, anterior infarct or diabetes 
  • If patient has no evidence of symptomatic or asymptomatic LV dysfunction, ACE inhibitors may be stopped in 4-6 weeks
    • There may be a benefit to administering ACE inhibitors for at least 4-5 years even if a patient does not suffer from ventricular dysfunction if the drug is tolerated
    • This benefit may be even greater in DM patients after MI
  • Decrease in mortality has been shown when ACE inhibitors were started soon after MI
    • Patients with LVEF <40%, HF in the acute event, or wall motion index of ≤1.2 have seen the greatest benefit

Angiotensin II Antagonists

  • Continue in any patients intolerant of ACE inhibitors and with clinical or radiological signs of heart failure or LVEF <40%

Aldosterone Antagonist (Mineralocorticoid Receptor Antagonist)

  • May be considered in post STEMI patients with LVEF <40% and HF or diabetes, provided that creatinine is <2.5 mg/dL (221 mmol/L) in men and <2.0 mg/dL (177 mmol/l) in women and potassium is ≤5.0 mEq/L
  • Monitor serum potassium and watch out for hyperkalemia

Nitrates

  • Prophylactic sublingual GTN (tablet or spray) may be given to patients with continuous angina prior to engaging in activities that will precipitate angina

Calcium Antagonists

  • Consider to give in patients who continue to experience angina after revascularization 
  • May be considered in patients with contraindications to beta-blockers and do not suffer heart failure or left ventricular dysfunction
  • A randomized controlled trial in the chronic phase of STEMI showed reduction in the risk of reinfarction and death with Verapamil in those not on beta-blockers 
  • Evidence of benefit is not as strong as for beta-blockers

Aggressive Lipid Lowering

  • All post-STEMI patients should be started on high-intensity statin therapy, if without contraindications, to achieve the following recommended treatment goals for LDL-C:
    • High risk: <70 mg/dL (<1.8 mmol/L)
    • Very-high risk: <55 mg/dL (<1.4 mmol/L)
  • Consider adding other non-statin therapy (eg Ezetimibe, PCSK-9 inhibitors) if target LDL-C levels are not achieved  
  • On discharge, patients should be counseled about cholesterol-lowering diet recommendations 
  • Please see Dyslipidemia disease management chart for further information

Blood Pressure Control

  • In addition to lifestyle interventions including increased physical activity, weight loss and decreased salt intake, pharmacotherapy should be initiated to obtain optimal blood pressure control
  • Please see Hypertension disease management chart for further information

Glucose Control

  • Target fasting blood glucose and glycosylated hemoglobin levels should be individualized
  • Please see Diabetes Mellitus disease management chart for further information

Influenza Vaccination

  • Patients with cardiovascular disease should have an annual influenza vaccination
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