Post-MI Care

Abbreviations

  • OAC – Oral anticoagulant (includes warfarin, NOACs, etc.)
  • DAPT – Dual anti-platelet therapy
  • PPI – Proton pump inhibitor
  • CCS – Canadian Cardiovascular Society
  • AHA – American Heart Association
  • CCS – Canadian Cardiovascular Society
  • ARB – Angiotensin receptor blocker
  • ACEi – ACE inhibitor
  • BB – Beta blocker
  • FFR – Fractional flow reserve

Pillars of post-MI care

  1. Determine need for further revascularization
  2. Optimize medical therapy
  3. Risk factor modification
  4. Cardiac rehab
  5. Arrange appropriate follow-up

Determine a need for further revascuarlization

  • If there are ongoing signs/symptoms of ischemia, further revascularization of potential flow-limiting non-culprit lesions can be considered.
  • Controversy has existed about “bystander” lesions found during a STEMI that are significant (either visually > 70% stenosis or by FFR). Latest trials recommend complete revascularization either during index PCI procedure or as a staged procedure. Decision is made with the interventional cardiologist.
  • Post-STEMI – Culprit-only PCI at time of STEMI and consider complete revascularization in 2-30 days based on visual assessment of stenosis and FFR

    COMPLETE Trial

    In patients with STEMI + multivessel coronary artery disease –>  complete revascularization superior to culprit-lesion-only PCI in reducing the risk of CV death or MI, as well as the risk of CV Death, MI, or ischemia-driven revascularization

    NEJM
    WJC
    (COMPLETE, PRAMI, CULPRIT favour complete revasc) 
  • Patients in shock – Culprit-only PCI at time of STEMI 

    CULPRIT-SHOCK Trial

    In patients with acute MI with multi-vessel CAD and cardiogenic shock culprit-only PCI is associated with 9.5% absolute reduction in the rate of death or renal replacement therapy at 30 days. This was driven primarily by a 7.3% absolute reduction in all-cause mortality with culprit-lesion only PCI.

    NEJM
    WJC
    (CULPRIT-SHOCK Trial)

Anti-Thrombotic Therapy

  • Patients should remain on dual antiplatelet therapy post-MI
  • ASA, ticagrelor, clopidogrel, and prasugrel all have mortality benefit post-MI
  •  Optimal duration:
    • STEMI or NSTEMI: At least 1 year
      CCS 2018 – Recommendations for duration of DAPT in patients who undergo elective PCI
      (CCS)
    • Elective PCI (Outpatient): At least 6mo
      CCS 2018 – Recommendations for duration of DAPT in patients with ACS (STEMI or NSTEACS) who undergo PCI
      (      CCS)
    • There is evidence to continue >1 year
    • At 1 year, weigh risks of bleeding vs. risk of ischemic events (See Table to the right)
    • Generally, if tolerating DAPT at 1 year post-MI, continue for up to 3 years with one of the following proven regimens:
      • ASA 81 mg daily + ticagrelor 60 mg BID (REDUCED DOSE) (PEGASUS-TIMI-54 Trial)
      • ASA 81 mg daily + clopidogrel 75 mg daily (DAPT Trial)
      • ASA 81 mg daily + prasugrel 10 mg daily (DAPT Trial) – not available in Canada
Bleeding Risk CCS 2018
Bleeding Risk CCS 2018
Thrombosis Risk CCS 2018
Thrombosis Risk CCS 2018

Interruption of antiplatelet therapy

  • Reasons to consider early interruption (<1 year) of therapy in patients with a stent:
    • High-risk of bleeding
    • Elective non-cardiac surgery
    • Semi-urgent non-cardiac surgery
    • CABG (urgent or elective)
  • Continue ASA monotherapy through surgery if possible
  • Early interruption increases risk of stent thrombosis
  • Resume DAPT post-op once “deemed safe by the surgeon” (CCS 2018)
CCS 2018 Antiplatelet Guidelines
Interruption of antiplatelet therapy
  • Minimum treatment duration: (i.e. delay elective surgery if possible)
    • Drug-eluting stents: 3 months
      • Semi-urgent non-cardiac surgery: 1 month (i.e. cancer surgery)
    • Bare-metal stents: 1 month
  • CABG (special case):
    • Continue ASA peri-operatively (operate on ASA)
    • Ticagrelor and clopidogrel: interrupt at least 48-72hrs pre-CABG (ideally 5 days)
    • Prasugrel: interrupt at least 5 days pre-CABG (ideally 7 days)
    • Urgent cases: try to wait at least 24hrs (sometimes wait not possible)
  • Overall, weigh risks of bleeding and thrombosis.  Include others in the decision (surgeon, cardiologist, attending physician)

Switching antiplatelet therapy (CCS 2018)

    • Do not switch unless compelling reason to do so (stent thrombosis, bleeding, side effects, etc.)
    • Clopidogrel → Ticagrelor (load 180 mg + 90 mg BID regardless of last dose)
    • Ticagrelor → Clopidogrel (load 600 mg at time of next ticag dose) (OPTI-CROSS Trial)
    • Do not load when switching from prasugrel (see CCS 2018 guideline)
      • Clopidogrel → Prasugrel (load 60 mg + 10 mg daily regardless of last dose)
      • Prasugrel → Ticagrelor (do not load, give 90 mg BID at time of next dose)
      • Ticagrelor → Prasugrel (load 60 mg + 10 mg daily at time of next dose)
      • Prasugrel → Clopidogrel (do not load, give 75 mg at time of next dose)

ACS in patient with atrial fibrillation

Atrial fibrillation ACS or high-risk PCI:

  • ASA + clopidogrel + reduced-dose OAC (aka “triple therapy”)
    • ASA can be discontinued from 1 day after PCI to 6 months. (In clinical trials, clinicians converted triple therapy to dual therapy after 1-3 weeks. Interventionalist will generally dictate duration.)
    • Once ASA discontinued, patient continues on clopidogrel + OAC (aka “dual therapy”)
  • NOTE: The dose of OAC depends on whether it is used for triple or dual therapy (see below).
  • OACs regimens tested in triple therapy:
    • Rivaroxaban 2.5 mg BID + ASA + clopidogrel
    • Warfarin (target INR 2.0-2.5) + ASA + clopidogrel
    • Apixaban 5 mg BID + ASA + clopidogrel
  • OACs tested in dual therapy:
    • Rivaroxaban 15 mg daily + clopidogrel (PIONEER)
      (Rivaroxaban 10 mg in renal dysfunction)
    • Dabigatran 150 mg BID + clopidogrel (RE-DUAL trial)
      (Dabigatran 110 mg BID = lower bleeding, trend towards ischemic events)
    • Apixaban 5 mg BID + clopidogrel (AUGUSTUS Trial) 
      *use low-dose apixaban 2.5 mg BID if 2 of: age < 80, weight < 60 kg, creatinine > 133 umol/L
  • Notes:
    • Use PPI with triple therapy.
    • Clopidogrel is safest in combination with OAC (dual or triple therapy). Less data with ticagrelor.
    • Routine triple therapy is not recommended for prevention of LV thrombus in anterior MI (CCS 2018 guideline).
    • All above reflects chronic management post-ACS/stenting. However, patients actively treated for acute coronary syndromes should still be treated with DAPT and IV/SC anticoagulation, which has proven benefit in acute coronary syndromes. OAC is often held in these situations, and restarted once need for IV/SC anticoagulation resolves.

Adjunctive Therapy

  • Beta Blockers

    • Indications: Start within 24 hours of ACS diagnosis (unless contraindication), continue for at least 3 years [Class I]
    • Benefits: Reduce ischemia, re-infarction, arrhythmias, mortality.
      • Acutely in MI: Benefits controversial, more benefit in chronic post-MI care
      • Trials: TIMI-2B Study, BHAT (mortality benefit), COMMIT (no benefit), (N Engl J Med. 1983; 308:614–8)
    • Options/Doses:
      • If no LV dysfunction (post-MI prevention): Metoprolol 12.5 mg BID, atenolol 12.5-25 mg OD, benefit extrapolated to bisoprolol 2.5 mg OD
      • If LV dysfunction: Bisoprolol 2.5 mg daily, carvedilol 3.125 mg BID, metoprolol 12.5 mg BID
      • If contraindicated: Re-evaluate in 24 hours
    • Contraindications: (if contraindicated, re-evaluate in 24hrs)
      • Acute heart failure (risk of precipitating cardiogenic shock)
      • Evidence of low-output state / cardiogenic shock
      • AV block: 3rd/2nd degree, PR interval > 240ms
      • Severe asthma/COPD

  • ACE Inhibitors

    (use ARB if ACEi-intolerant)

    • Indications: Proven benefit in post-ACS patients with ANY of: EF < 40%, HTN, DMII, or CKD [Class I], but benefit extrapolated to all ACS within 24hrs [Class IIB]
      • Trials: SAVE, AIRE, HOPE
    • Options/Doses:
      • Ramipril 2.5-5 mg OD (titrate to 10 daily – AIRE study)
      • Perindopril 2 mg OD (titrate to 8 mg – PREAMI study)
      • Enalapril (CONSENSUS II – no benefit) 

  • Mineralocorticoid Receptor Antagonists (MRA)

    • Indications:
      • Need all of: On max dose ACEi, BB, and post-MI + EF ≤ 40% + (HF symptoms or DMII) [Class I]
        • CCS 2017 HF Guideline: “MRA for patients with acute MI with EF < 40% and HF or with acute MI and an EF < 30% alone in the presence of diabetes”
      • Trial: EPHESUS
    • Options/Doses:
      • Eplerenone 25 mg daily (titrate up to 50 mg daily)
    • Contraindications (for post-MI indication):
      • Creatinine > 221 (men), > 176 (women)
      • K+ > 5.0
  • Calcium channel blockers (diltiazem/verapamil)
    • 2nd line to beta blockers (if ongoing ischemia), reduce re-infarction
    • Negative inotropes → contraindicated in LV dysfunction
    • Indicated for coronary artery spasm

  • High-Intensity Statins

    • Indications: All ACS patients [Class I]
    • Benefits: Reduces recurrent MI, CV mortality, need for revascularization, and stroke
      • Trials: PROVE IT-TIMI 22, MIRACL, TNT (high dose)
    • Options/Doses:
      • Atorvastatin 40-80 mg
      • Rosuvastatin 20-40 mg
      • Pravastatin and simvastatin are not high-intensity statins.
  • ESC 2017 STEMI recommendations for post-MI care
    2017 ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation
  • NOTES:
    • NSAIDs contraindicated post-MI (increases risk of MACE)
    • All admitted NSTEMI patients need 24 hours of rhythm monitoring (or until revascularization), and only select UA patients 

Cardiac Rehab

  • Cardiac rehab for all ACS patients
    • Benefits:
      • Risk factor modification:
        • Lipid profile improves
        • More effective smoking cessation
        • Improves glycemic control in diabetes
      • Improves symptoms
        • Improves functional capacity (improves O2 delivery and reduces utilization)
        • Improves mortality by 20% post-MI (especially after PCI and CABG)
      • Psychological
        • Improves self-confidence and anxiety/depression (patients feel healthy after coronary events, more likely to return to work/exercise)
    • Complications:
      • Ventricular fibrillation, myocardial infarction, sudden death (but risk is low, attributed to poor surveillance

Counselling

  • Medication adherence
  • Follow-up plan 
  • Smoking cessation (counselling should be initiated in hospital and followed up at 3 months as outpatient)
  • Dietary advice
  • Physical activity

Driving

Further Reading

  • Primary Author: Dr. Pavel Antiperovitch (MD, FRCPC, Cardiology Fellow)
  • Author/Reviewer: Dr. Atul Jaidka (MD, FRCPC, Cardiology Fellow)
  • Staff Reviewer: Pending
  • Copy Editor: Perri Deacon (medical student)
  • Last Updated: March 22, 2020