Acute Coronary Syndromes

Anna Berry

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

• Classic Angina: dyspnea on exertion, substernal, pressure or vice-like quality, improved with rest. Note that response nitroglycerin is no longer in the guidelines.
• Anginal Equivalents: nausea, weakness, epigastric pain (esp. in age > 65 y/o, women, diabetics)
• Change in patient’s baseline angina, especially onset at rest
• Physical Exam: sinus tachycardia, diaphoresis
• If large infarct, can present with symptoms of acute heart failure

Evaluation

• EKG: Compare to prior EKG and assess for
  • New ST elevations or ST depressions
  • T wave inversions: not specific but more concerning if deep (> 0.3mV)
  • Biphasic T waves and deep T wave inversions in leads V2 & V3 (Wellens’ sign [LAD])
• Cardiac biomarkers: troponin I is most sensitive for myocardial injury
• ACC/AHA guidelines recommend both EKG and trop q2-6 hours
  • Consider this if high suspicion for ACS despite normal initial markers
  • If negative x2, OK to stop trending
• Other labs: lipid panel, TSH, A1C

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 receptor blocker until discussed with cards fellow

NSTEMI

• Medical management followed by left-heart catheterization within 48 hours
• General: bedrest, telemetry, repeat EKG with recurrent chest pain, NPO at midnight
• Place cath case request (see “pre-catheterization” management below)

Anti-thrombotic therapy

Antiplatelet agents

• ASA 325 mg loading dose then 81 mg daily after
• Do not give P2Y12 receptor blocker until discussed with cardiology fellow
• Clopidogrel: prodrug that is metabolized to active form (can have undermetabolizers), irreversible inhibition
• Ticagrelor: reversible inhibitor
• Prasugrel: prodrug but more rapidly metabolized than clopidogrel with less variation, irreversible inhibition, do not use w/ age > 75 or weight < 60 kg
• Prasugrel and ticagrelor are superior to clopidogrel but have higher bleeding risk
• Cangrelor: IV, rarely used

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.
• Enoxaparin (LMWH) can be used but requires preserved renal function (CrCl > 30) and most interventionalists prefer heparin prior to LHC

Pre-Catheterization Care

• Ensure pt. is NPO at MN for planned cath
• Continue anticoagulation with heparin gtt
• Place cardiac catheterization request (must be in cardiology context). Can also call cath lab to ensure pt. is scheduled appropriately

Post-Catheterization Care Catheterization Documentation

• The most appropriate guidance for post-cath care is in the cardiac catheterization report
• VUMC: Epic Cardiac tab Cardiac Catheterization/Intervention Report
• VA: Note tab Post-Procedure note and Cardiac Catheterization note
• If there is a delay in filing the final report at VUMC: Review the Cardiac Catheterization Nursing Documentation which shows if stents were deployed

Post-Catheterization Heparin

• Medical management w/o intervention: stop heparin unless directed in report
• If indication for CABG (ex: Left main, proximal LAD), continue heparin gtt until surgery
• PCI placed: stop heparin and continue/start DAPT as directed by cardiology
• Other medical indication for anticoagulation (DVT/PE, atrial fibrillation): restart ~ six hours after catheterization

Cath Site Checks

• 6 - 8 hours post catheterization (typically can be signed out as 0000 cath check), only needed for femoral arterial access
• Look, listen, feel: evaluate for hematoma & pseudoaneurysm; call fellow if concerned
• Small amount of bruising and mild tenderness at the site is normal
• Listen above and below the site for a bruit; the area should be soft
• Hypotension after femoral access is concerning for RP bleed
  • STAT CBC, CT A/P & call the cardiology fellow
• Femoral oozing: Cardiology fellow, will need to hold pressure
• Radial oozing: instruct nurse to re-inflate the TR band and restart the clock on deflation

Post ACS Care

• Echo prior to discharge
• DAPT: Aspirin 81 mg daily and P2Y12 agent
• Beta blocker in all patients within 24 hours
• Metoprolol, carvedilol & bisoprolol have proven mortality benefit with reduced EF
• High intensity statin (ex: rosuvastatin 40 or atorvastatin 80). See outpatient lipids section
• ACEi/ARB if anterior STEMI
• Lifestyle Modification: weight loss, smoking cessation, diabetes control
• See heart failure section for management of HFrEF

ACS Complications

• VT/VF, sinus bradycardia, third-degree heart block, new VSD, LV perforation, acute mitral regurgitation, pericarditis and cardiogenic shock; More common with STEMI CCU post-cath

Additional Information

• Initiate treatment if there is true concern for ACS and bleeding risk acceptable, medications can always be discontinued
• TIMI score: >2 correlates with ↑ mortality, indicating a need for aggressive treatment
• ACC Guideline Clinical App is a useful resource with summaries of guideline-based recs