Acute coronary syndrome—with ST-elevation (STEMI)

Investigations

• ECG
• Cardiac monitor
• Troponin
• CBC
• Urea & Creatinine
• Glucose
• Cholesterol
• CXR

Initial Management

• Attach ECG monitor
• IV access
• Aspirin: 300mg oral (if not already given);
• Ticagrelor: 180mg oral or prasugrel(60mg oral if no history of stroke/TIA and <75yrs) as newer alternatives to clopidogrel (300mg oral) as they have been shown to be superior in outcome studies.
• Morphine: 5–10mg IV (repeat after 5min if necessary).
• Give anti-emetic with the 1st dose of morphine:
  • Metoclopramide 10mg IV (1st line)
  • Cyclizine 50mg IV (2nd line).
• Glyceryl trinitrate (GTN): routine use now not recommended in the acute setting
  • Unless patient is hypertensive or in acute LVF.
  • Useful as anti-anginal in chronic/stable patients.
• Oxygen is recommended if patients are
  • SaO2 <95%
  • Breathless
  • Acute LVF
• Restore coronary perfusion in those presenting <12h after symptom onset
• Anticoagulation An injectable anticoagulant must be used in primary PCI
  • Bivalirudin is preferred, if not available use enoxaparin ± a glycoprotein (GP) IIb/IIIa blocker
• ß-blockers provide additional benefit when started early, e.g. bisoprolol 2.5mg orally once daily
  • Ensure no evidence of cardiogenic shock, heart failure, asthma/COPD, or heart block.
• In case of Right ventricular infarction
  • Treat hypotension and oliguria with fluids
  • Avoid nitrates and diuretics
  • Monitor BP assess early signs of pulmonary oedema
  • Intensive monitoring and inotropes may be useful in some patients

Reperfusion therapy

Look for Typical clinical symptoms of MI plus ECG criteria:

• ST elevation >1mm in ≥2 adjacent limb leads
• Or >2mm in ≥2 adjacent chest leads
• LBBB (unless known to have LBBB previously).
• Posterior changes: deep ST depression and tall R waves in leads V1 to V3.

Primary PCI

Should be offered to all patients presenting within 12h of symptom onset with a STEMI

If this is not possible, patients should receive thrombolysis and be transferred to a primary PCI center after the infusion for either rescue PCI (if residual ST elevation) or angiography (if successful).

Offer PCI beyond 12h if

• Evidence of ongoing ischemia
• Or in stable patients presenting after 12–24h may be appropriate—seek specialist advice.

Thrombolysis

Benefit reduces steadily from onset of pain, target time is less than 30min from admission

use >12h from symptom onset requires specialist advice.

Do not thrombolyse ST depression alone, T-wave inversion alone, or normal ECG.

• Tissue plasminogen activators e.g. tenecteplase as a single IV bolus.
• Contraindications
  • Previous intracranial hemorrhage
  • Ischemic stroke <6months
  • Cerebral malignancy or AVM
  • Recent major trauma/surgery/head injury (<3wks)
  • GI bleeding (<1 month)
  • Known bleeding disorder
  • Aortic dissection
  • Non-compressible punctures <24h, e.g. liver biopsy, lumbar puncture
• Relative CI
  • TIA <6 months
  • Anticoagulant therapy
  • Pregnancy/<1wk post partum
  • Refractory hypertension (>180mmHg/110mmHg)
  • Advanced liver disease
  • Infective endocarditis
  • Active peptic ulcer
  • Prolonged/traumatic resuscitation.

Patients with STEMI who do not receive reperfusion should be treated with fondaparinux, or enoxaparin/unfractionated heparin if not available.

Secondary Prevention

• Aspirin (75mg once daily) and a second antiplatelet agent (e.g. clopidogrel) for at least 12 months
• PPI (e.g. lansoprazole) for gastric protection
• Anticoagulant e.g. with fondaparinux, until discharge
• ß-blockers reduces myocardial oxygen demand
  • Start low and increase slowly, monitoring pulse and BP
  • If contraindicated, consider verapamil or diltiazem
• ACE-i in patients with LV dysfunction, hypertension, or diabetes
  • If not tolerated, consider ARB
  • Titrate up slowly, monitoring renal function
• High-dose statin, e.g. atorvastatin 80mg
• Eplerenone improves outcomes in MI patients with heart failure (ejection fraction <40%)
  • Do an echo to assess LV function