ACS

Acute Coronary Syndrome - Nick King

Background

  • Completely or partially occluding thrombus on a disrupted atherothrombotic coronary plaque leading to myocardial ischemia/infarction
  • STEMI: Elevated troponin & elevation in ST segment or new LBBB with symptoms
    • > 0.1 mV in at least 2 contiguous leads
    • Exception, in V2-V3:
        • > 0.2 mV in men older than 40 y/o 
        • > 0.25 in men younger than 40 y/o
        • > 0.15 mV in women  
  • NSTEMI: Evidence of myocardial necrosis (elevated troponin) w/o ST segment elevation
  • Unstable Angina: Angina without evidence of myocardial necrosis (normal troponin)
  • Other causes of myocardial injury: coronary spasm, embolism, imbalance of oxygen demand and supply 2/2 fever, tachycardia, hypo-/hypertension

 

Presentation

  • Angina or Anginal equivalents:  
    • Exertional dyspnea, nausea, weakness; and epigastric pain in women and diabetics 
  • Change in patients’ baseline angina, especially onset at rest
  • Physical Exam: sinus tachycardia, diaphoresis

 

Evaluation

  • EKG:
    • Compare to prior EKG and assess for
      • New ST elevations or ST depressions
      • T wave inversions: less specific but more concerning if deep (> 0.3mV)
      • Biphasic T waves and T wave inversions in leads V2 & V3 (Wellen’s sign [LAD])
  • Cardiac biomarkers: troponin I is most sensitive for myocardial injury
    • ACC/AHA guidelines recommend both EKG and trop q6 hours
      • Consider this if high suspicion for primary ACS, despite normal initial markers
    • If negative x2, stop checking
    • Can be negative initially; Troponin takes ~2-3 hours to become detectable with ischemia

 

Management

STEMI: 

  • STAT page Cardiology on call via Synergy (whether in VA or Vanderbilt)
  • ASAP: aspirin 325mg, heparin drip (high nomogram, with bolus)
  • Hold P2Y12 until discussed with Cards fellow, patient may instead be taken directly to cath lab and loaded with anti-platelet agent there (prasugrel or ticagrelor)
  • Additional therapy during hospital stay:
    • High Intensity statin therapy:  Early initiation of statin in ACS reduces risk of short- and long-term coronary events

 

NSTEMI:

  • Medical management with left-heart catheterization within 48 hours of presentation.
    • General: bedrest, telemetry, repeat EKG with recurrent chest pain, NPO at midnight
  • Anti-thrombotic therapy:
    • Antiplatelet agents:
      • ASA 325 mg loading dose then 81 mg daily after
      • P2Y12 receptor blocker (can give Plavix (600 mg x1 -> 75 mg daily)
    • Anti-coagulants: Unfractionated heparin drip
      • Type this in Epic and select “nursing managed” protocol for “ACS”
      • VA it can be found under the “Orders” tab along the left-hand column.
      • No adjustment needed for renal function
      • Enoxaparin (LMHW) can be used but requires preserved renal function and most interventionalists prefer heparin prior to LHC
      • Anticoagulation can be stopped after catheterization if patient has no obstructive CAD, undergoes PCI, or after 48 hours (pure medical management)
  • Additional therapy: Maximal statin therapy (atorvastatin 80 QD or rosuvastatin 40mg)

 

Post ACS Care:

  • DAPT: Aspirin 81 mg daily and P2Y12 agent (clopidogrel, ticagrelor, prasugrel)
    • P2Y12 agent determined by cardiology
  • Beta blocker in all patients within 24 hours
    • Metoprolol, carvedilol & bisoprolol have proven mortality benefit with reduced EF
  • TTE to assess EF
  • ACEi/ARB if anterior STEMI, LVEF <40%, or CHF
  • Aldo Antagonists if LVEF<40% with HF symptoms or DM
  • Lipid panel and A1c
  • High intensity statin, consider ezetimibe if LDL > 70
  • Lifestyle Modification: Weight loss, exercise, smoking cessation, in DM goal A1c < 7%
  • Outpatient Cardiology follow up

 

Additional Information:

  • Initiate treatment if there is true concern for ACS, medications can always be discontinued 
  • TIMI score: >2 correlates with ↑ mortality, indicating a need for aggressive treatment
  • Ticagrelor and prasugrel are superior for prevention of MI and stroke but have an increased bleeding risk, and will delay surgery (CABG) so defer to Cardiology to initiate
  • Complications:
    • VT/VF, sinus bradycardia, third-degree heart block, new VSD, LV perforation, acute mitral regurgitation, pericarditis and cardiogenic shock; More common with STEMI
    • STEMI is usually managed in CCU post-catherization