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 is 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.

Surgical Intervention

Consider Coronary Angiography

  • In high-risk patients and medium-risk patients with angina, consider doing a coronary angiogram as part of further investigation of coronary artery status
  • Perform coronary angiogram if patient revascularization is a realistic option with intent to do percutaneous coronary intervention (PCI) or emergency coronary artery bypass graft (CABG)
  • Recommended in patients who have received fibrinolytic therapy and have the following:
    • Cardiogenic shock in patients <75 years old who are candidates for revascularization
    • Severe congestive heart failure (CHF) and/or pulmonary edema
    • Life-threatening ventricular arrhythmias
  • May be considered as part of an invasive strategy for risk assessment after fibrinolytic therapy or for patients not undergoing primary reperfusion therapy
  • Not recommended in patients who have received fibrinolytic therapy if further invasive management (PCI or CABG) is contraindicated or is against patient’s or designee’s wish

Percutaneous Coronary Intervention (PCI)

  • Appropriate use criteria for revascularization of culprit artery by primary PCI recommended by the American College of Cardiology (ACC), American Association for Thoracic Surgery (AATS), American Heart Association(AHA), American Society of Echocardiography (ASE), American Society of Nuclear Cardiology (ASNC), Society for Cardiovascular Angiography and Interventions (SCAI), Society of Cardiovascular Computed Tomography (SCCT), and the Society of Thoracic Surgeons (STS):
    • Patients with STEMI or MI with new LBBB whose onset of symptoms occurred within the past 12 hours
    • Onset of symptoms within the past 12-24 hours accompanied by severe acute heart failure, persistent ischemic symptoms, or hemodynamic/electrical instability
    • Stable patients with onset of symptoms within the past 12-24 hours without severe acute heart failure, persistent ischemic symptoms, or hemodynamic/electrical instability 
  • Primary PCI performed within 12 hours of symptom onset may help effectively secure and maintain patency of the coronary artery and may prevent some of the bleeding risks of fibrinolysis
  • Appropriate use criteria for immediate revascularization of ≥1 nonculprit arteries during the same procedure as primary PCI as recommended by the ACC, AATS, AHA, ASE, ASNC, SCAI, SCCT and STS:
    • Presence of cardiogenic shock after PCI of culprit artery and PCI of ≥1 additional vessels
    • In stable patients to be done immediately after primary PCI of culprit artery with ≥1 additional severe coronary artery stenoses
    • In stable patients to be done immediately after primary PCI of culprit artery with ≥1 additional intermediate (50-70%) coronary artery stenoses
  • Appropriate use criteria for revascularization of nonculprit arteries by PCI to be done during the same hospital stay for treatment of a culprit artery by PCI or fibrinolysis as recommended by the ACC, AATS, AHA, ASE,ASNC, SCAI, SCCT and STS:
    • Spontaneous or easily provoked ischemic symptoms with ≥1 additional severe coronary artery stenoses
    • Asymptomatic but positive for ischemia during non-invasive diagnostics and with ≥1 additional severe stenoses
    • Asymptomatic patients with ≥1 additional severe coronary artery stenoses
    • Asymptomatic patients with ≥1 additional intermediate coronary artery stenoses
    • Asymptomatic patients with ≥1 additional intermediate stenoses and fractional flow reserve of ≤0.80
  • Preferred when it can be performed in an experienced center within 90 minutes on hospital arrival (“door to balloon” time within 90 minutes)
    • Only hospitals that have an established interventional cardiology program should use primary PCI as a routine treatment in patients with signs and symptoms of AMI 
  • May be an option for patients with contraindications to thrombolytic therapy
    • Administer within 12 hours of symptom onset
  • May be performed in cases of recurrent myocardial infarction (MI), moderate to severe myocardial ischemia during recovery from STEMI, hemodynamic instability after thrombolytic therapy
  • Routine thrombus aspiration prior to primary PCI is not recommended
  • Primary PCI may be performed on non-culprit arteries if the patient is at intermediate to high risk for STEMI on pre-discharge noninvasive tests or if spontaneous ischemia is present

Drug-eluting stents (DES) Percutaneous Coronary Intervention

  • Reduces the risk of repeated target vessel revascularization compared with BMS
  • There is an increased risk of stent thrombosis with premature discontinuation of dual antiplatelet therapy (DAPT)

Bare-metal stents (BMS) Percutaneous Coronary Intervention

  • Used in patients with high risk of bleeding, inability to comply with 1 year of DAPT, or anticipated invasive or surgical procedures in the following year

Rescue Percutaneous Coronary Intervention

  • PCI within 12 hours after failed thrombolytic therapy in patients with continuing or recurrent myocardial ischemia and hemodynamic instability
  • For patients with STEMI who have received thrombolytic therapy but with persistent ST-segment elevation (<50% resolution 90 minutes after treatment initiation), rescue PCI is preferred over repeat thrombolytic therapy or no additional reperfusion therapy
    • Appropriate use criteria for PCI after fibrinolysis as recommended by the ACC, AATS, AHA, ASE, ASNC,SCAI, SCCT and STS:
      • Presence of perfusion failure following fibrinolysis
      • Hemodynamically stable patients who are asymptomatic after fibrinolysis and with PCI performed 3-24 hours after fibrinolysis
      • Hemodynamically stable patients who are asymptomatic after fibrinolysis and with PCI performed >24 hours after onset of ST-segment elevation myocardial infarction
    • If possible, procedure should be done within 2 hours of identifying the lack in resolution of ST-segment elevation
  • Transfer for PCI of patients that shows signs of failed reperfusion with fibrinolysis

Pharmacoinvasive Percutaneous Coronary Intervention

  • Pharmacological reperfusion strategy done using fibrinolytic therapy with back-up rescue PCI done and immediate angiography in a PCI-capable health facility

Coronary Artery Bypass Graft (CABG) Surgery

  • Very limited use in the acute phase of STEMI other than for cardiogenic shock
  • Appropriate use criteria for revascularization of nonculprit arteries by CABG (to be done during the same hospital stay for treatment of a culprit artery by PCI or fibrinolysis) recommended by the ACC, AATS, AHA,ASE, ASNC, SCAI, SCCT and STS:
    • Spontaneous or easily provoked ischemic symptoms with ≥1 additional severe coronary artery stenoses
    • Asymptomatic but positive for ischemia during non-invasive diagnostics and with ≥1 additional severe stenoses
    • Asymptomatic patients with ≥1 additional severe coronary artery stenoses
    • Asymptomatic patients with ≥1 additional intermediate coronary artery stenoses
    • Asymptomatic patients with ≥1 additional intermediate stenoses and fractional flow reserve of ≤0.80
  • May be considered in the following:
    • Failed PCI with persistent pain or hemodynamic instability in patients with coronary anatomy suitable for surgery
    • Coronary occlusion not suitable for PCI 
    • At time of surgical repair of mechanical complications (eg ventricular rupture, acute mitral regurgitation or ventricular septal defect)
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