ACS - NSTE

    .

    All this is based on 2014 AHA/ACC Guidelines for NSTE-ACS

    Introduction

    • Two types:
      • Unstable Angina - Coronary ischemia that is not severe or long enough to elevate the troponin. 
      • NSTEMI - Coronary occlusion leading to ischemia that causes a troponin rise (rise and fall of troponin).  However, occlusion is not usually complete, hence ST elevation is not seen
    • Key is to stratify patients based on likelihood of ACS and adverse events to:
      • Decide on need of hospitalization
      • Assist in treatment selection
    • Two Key Questions:
      • What is the likelihood of ACS?
      • What is the likelihood of adverse clinical outcome?

    Diagnosis

    Troponins

    • Cardiac troponin should be obtained on presentation and within 3-6 hours (3 = TnT, 6 = TnI)
      • If first two are negative, can draw >6 hours after symptom onset.
    • CK IS NOT HELPFUL! (No longer recommended - Class III) if contemporary troponin is used. 
    • Reasonable to remeasure troponin once on day 3 or day 4 in pts with MI as index of infarct size and dynamics of necrosis.
      • Use of BNP may be reasonable for prognostic information

     

    Ischemic Pain

    • Nitroglycerin 0.4mg/spray 1 spray every 5 min up to 3 doses --> then consider IV nitro
    • Consider IV nitro for patients with:
      • 1. Ongoing ischemic chest pain
      • 2. HF
      • 3. Hypertension
    • Morphine can be considered if on maximally tolerated anti-ischemic medications. 
    • DO NOT use NSAIDs (increased MACE)
    • DO NOT use nitrates if within 24hrs of sildenafil or vardenafil or 48hrs of tadalafil

     

    Management

    • ALL patients with NSTE-ACS require inpatient management (relieve experience, MI, death)
    • Bedrest or chair recommended
    • Treatment should include:
      • Antiplatelet
      • Anticoagulation
      • Anti-anginal therapy

    Risk Assessment

    • TIMI (Thrombolysis in Myocardial Infarction) risk scoreScreen Shot 2017-07-13 at 10.45.39 PM.png
    • PURSUIT (Platelet Gp IIb/IIIa in UA) risk score
    • GRACE (Global Registry of Acute coronary Events) Risk Score
    • NCDR-ACTION

     

    • ALL these scores predict outcomes in ED with undifferentiated "pain"
      • "pain" = pain, discomfort, pressure, squeezing

     

     

     

     

     

     

     

     

     

     

    Anti-Thrombotic Therapy

    • ASA 162mg + 81mg/day for ALL patients with NSTE-ACS (Class I)
      • If allergic to ASA, give Clopidogrel load + maint. 
    • Clopidogrel OR Ticagrelor should be given in addition to ASA up to 12mo (Class I) CURE Trial
      • Clopidogrel 300mg or 600mg load then 75mg daily
      • Ticagrelor 180mg load then 90mg BID
    • Prasugrel NOT recommended upfront for NSTE-ACS:
      • Benefit driven by MI risk reduction & stent thrombosis (but +++ bleeding)
      • Pts with hx of cerebrovascular events, > 75, or <60kg. 
    • Gp IIb/IIIa can be considered if: (Grade IIB)  (eptifibatide or tirofiban)
      • 1. Patients on DAPT
      • 2. Intermediate/High Risk Features (Positive Troponin)
      • 3. Undergoing early invasive strategy
      • Based on EARLY-ACS Trial (early eptifibatide compared to post-angio not beneficial)

     

    Anticoagulation

    • Anticoagulation in addition to antiplatelet: (Class I)
    • Drug Dose Duration Notes

      Enoxaparin

      1mg/kg SC q12h

      (30mg load has been

      used)

      - Until DC

      or
      - Until PCI

      Reduce to ONCE DAILY for CrCl < 30

      ESSENCE Trial (benefit up to 1yr)

      Bivalirudin 

      0.10 mg/kg load then

      0.25 mg/kg/hr

      - Until Angiography

      or PCI

      ONLY in pts managed with early invasive

      strategy

      ACUITY Trial (UFH/LMWH+GpIIbIIIa vs. 

      Bival+GpIIbIIIa vs. Bival Alone) 

      Bival nonInf to Heparin/GpIIbIIIa, and less bleeding

      Fondaparinux 2.5 mg SC daily

      - Until DC

      or

      - Until PCI

      IF PCI performed on fondaparinux

      additional anticoagulant (UFH or bivalirudin)

       is given due to high risk of catheter thrombosis

      - OASIS Trial

      UFH IV

      Load 60 IU/kg (max 4000)

      initial infusion 12 IU/kg/hr

      (max 1000 IU/h) 

      Target aPTT based on

        hospital targets

      - For 48hrs 

      or

      - Until PCI

       

    Post-Event

    Beta Blockers

    • Oral BB within 24hrs if do not have: (Class I)
      • 1. HF
      • 2. Low-Output State
      • 3. High risk of Cardiogenic Shock
      • 4. Other Contraindications (PR > 240ms, 2nd/3rd deg AVB without PPM, active asthma)
    • If pts have low EF --> the following BB are acceptable (Class I, Level C) (Proven to reduce mortality in pts with HF)
      • Metoprolol Succinate (Long-Acting)
      • Carvedilol
      • Bisoprolol
    • If BB contraindicated, re-evaluate in 24h
    • IF REDUCED EF:
      • keep BB (Class I)
    • IF NORMAL EF:
      • keep BB (Class IIa)

     

    Calcium Channel Blockers

    • Mostly for angina
    • If BB contraindicated --> Can use CCB (Non-DHP) (Verapamil, Diltiazem) EXCEPT:  (Class 1)
      • LV Dysfunction
      • Risk of Cardiogenic Shock
      • PR interval > 240ms
      • 2nd/3rd Deg AVB without PPM
    • CCB are 3rd LINE, (after nitrates and BB) for recurrent ischemia (ischemic symptoms) (Class 1)
    • Long-Acting CCB & Nitrates for pts with Coronary Spasm! (Class 1)
    • Nifedipine IR contraindicated in NSTE-ACS (Amlodipine and Felodipine were not studied)

     

    Statin

    • High-intensity statin for ALL patients (without contraindications) (Class I, Level A)
    • Reasonable to get fasting lipid profile within 24hrs (Class II, Lvl C)

     

    ACE Inhibitors

    • ALL patients post-MI who have:
      • 1. LVEF < 40%
      • 2. HTN
      • 3. DMII
      • 4. Stable CKD
    • ARBs for pts with HF or MI, with EF < 40%, if ACEi intolerant
    • Aldosterone Blockade for pts Post-MI AND [EF < 40%, DMII or HF]
      • NO renal dysfunction (creat > 2.5 (221) for men and > 2.0 (176) for women)
      • NO hyperkalemia

     


    To Cath or Not to Cath?

    • 3 Strategies Have been Proposed:
      • Strategy Description Rationale
        Early Invasive Angiography for all patients within 24hrs

        - rapid definitive evaluation

        - prevent complications (early revasc)

        - earlier discharge

        Delayed Invasive Angiography for all patients within 25-72hrs
        Ischemia Guided

        ONLY cath patients with:

        - Fail Medical Therapy (refractory angina, 

             rest angina)

        - Objective Evidence of Ischemia (dynamic ECG 
             changes, MIBI)

        - High prognostic Risk (High TIMI or GRACE scores)

        - Avoid routine costly 

            invasive procedures

         (unless they need them)

        - Risk stratification is done via

          non-invasive evaluation to detect

          "severe ischemia" at low levels of 

          stress, and promptly refer if indicated

        - Some patient's conditions stabilize

          during medical therapy and do not

          require cath

         

        URGENT 

        Angiography

        - For patients with:

            1. Hemodynamic Instability (cardiogenic shock)

            2. Rhythm Instability 

         
    • NOTE: ALL STRATEGIES require same anti-ischemic and anti-thrombotic therapy!!
    • The optimal timing is unknown
      • Most studies cathed after 12-72hrs when antithrombotic and anti-ischemic strategies intensified
      • There is a concept that revascularization may be safer once plaque is stabilized and meds are intensified
    • Many studies favour early invasive approach (one study showed 18% RRR of death or MI)
      • Trials: FRISC, ICTUS Trial, RITA
    • Traetment Algorithm AHA 2014.png

    • Summary:

      • It is reasonable to do early invasive (within 24hrs) over delayed invasive (25-72hrs) for stabilized pts NSTE-ACS (Class IIa)

        • For those not high/intermediate risk, a delayed invasive approach is reasonable (Class IIa, Lvl B)

      • Ischemia Guided strategy can be selected (if no serious comorbidities or contraindications to this) based on clinician and patient preference (Class IIB)

      • Early Invasive (cath + PCI) NOT RECOMMENDED FOR:

        • Extensive Comorbidities (hepatic, renal, pulmonary, cancer) if risk > benefits (Class III)

        • Acute chest pain + low likelihood of ACS AND troponin negative, esp women (Class III)

           
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