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 patients are important to identify acute myocardial infarction patients who will benefit from reperfusion therapy.
Ideally, patient diagnosed with myocardial infarction should begin treatment within 30 minutes of arrival to hospital.

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
  • Clopidogrel or Prasugrel
    • Should be given for at least 12 months in patients receiving a stent (bare-metal stent or drug-eluting stent) during percutaneous coronary intervention (PCI)
    • Duration of therapy may be extended beyond 15 months in patients undergoing drug-eluting stent placement
    • If the risk of bleeding outweighs benefit, earlier discontinuation of either Clopidogrel or Prasugrel should be considered
  • Ticagrelor
    • May be given for 12 months, in conjunction with Aspirin, to patients who underwent stent implantation to prevent thromboembolic events
  • 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

Anticoagulation (Oral)

  • Warfarin
    • Recommended in patients with persistent atrial fibrillation (A-fib)
    • 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

Beta-Blocker

  • Continue indefinitely in all post-MI patients unless contraindicated
  • Has been shown to reduce mortality from a reduction in sudden and non-sudden cardiac death

ACE Inhibitor

  • ACE inhibitors should be continued indefinitely in patients with LV dysfunction
  • 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 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 left ventricular dysfunction (LVEF <40%), HF in the acute event, or wall motion index of ≤1.2 have seen the greatest benefit

Angiotensin II Antagonist

  • 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

Calcium Antagonist

  • 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

Treat Hyperlipidemia

  • Patients should have their lipid profile checked within 24 hours of MI symptom onset
  • On discharge, patients should be counseled about cholesterol-lowering diet recommendations
  • All patients should be started with statins, if without contraindications, to achieve LDL cholesterol <100 mg/dL (2.5 mmol/L)
  • In high-risk patients, further reduction of LDL cholesterol to achieve <70 mg/dL (1.8 mmol/L) may be advised
  • Increased consumption of omega-3 fatty acids found in fish or in commercially available capsule preparation, at 1 g per day, should be encouraged for reduction of risk
  • Higher doses of omega-3 fatty acids may be needed for treatment of elevated triglycerides
  • See Dyslipidemia Disease Management Chart for details

Glucose Control

  • Target fasting blood glucose and glycosylated hemoglobin levels should be individualized

Influenza Vaccination

  • Patients with cardiovascular disease should have an annual influenza vaccination
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