Skip to content

ACS

Background

  • Completely or partially occluding thrombus on a disrupted atherothrombotic coronary plaque leading to myocardial ischemia
  • 30% mortality rate, half of which are pre-hospital
    • Decreased Cardiac Index, increased SVR, normal LVEDV
      • Acute or recent MI, CI is reduced due to myocardial dysfunction, SVR is increased to maintain organ perfusion
      • LVEDV remains relatively normal in the early phase before LV remodeling ± dilatation occurs in the following weeks

Types

  • ACS Includes: Unstable Angina, NSTEMI, STEMI
    • Unstable Angina: Angina w/o evidence of myocardial necrosis (normal troponin + normal EKG)
    • NSTEMI: Evidence of myocardial necrosis (elevated troponin) w/o ST segment elevation
    • 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

Unstable Angina

  • W/U: Troponins at 3-6 hours after symptoms onset, remeasure within 8-12
    • HEART Score in the ER
    • Risk Assessment (TIMI Risk Score)
      • For TIMI, baseline needs to be normal
        • ≥65, 3x (hypertension, DM, Dyslipidemia, FH, Smoking), >50% coronary stenosis, ST segment change, multiple episodes of angina in a day, increased troponin, aspirin in last week
          • Associated with increased number of all cause mortality, new or recurrent MI, or severe recurrent ischemia requiring revascularization
        • ≤2 = Low: Conservative w/medical therapy + stress tests within 48 hours
          • <10% 2 weeks risk for serious event
          • BB + Nitro + Statins + Heparin + Ticagrelor + Aspirin
        • 3-4 = Intermediate: Early PCI within 24hrs
          • Within 25-72 hours and TIMI 3 or 4 score (intermediate): Invasive assessment + consider cath
        • ≥5 = High: PCI within 2 hours
  • Management
    • Admission + Continuous Telemetry + O2 if needed
    • Unstable, HF, new MR, Recurrent CP, Ventricular Arrythmia: Immediate Coronary Angiography
    • Acute:
      • 1) 160-325mg Aspirin for all
      • 2) UFA w/bolus 60U/kg followed by infusion at 12U/kg/h or LMWH 1mg/kg
      • 3) P2Y12 receptor inhibitors (Clopidogrel, Prasugrel), ticagrelor if PCI
      • 4) BB if no contraindications
        • Reduces infarct size, lowers risk of reinfarction and early mortality
        • CI: Decompensated HF, Bradycardia
      • IV Nitroglycerin at 10mcg/min
        • Keep BP >100-110 mmHg
      • GP IIBIIIA if PCI (Epitifibatide, Tirofiban)
    • Long Term:
      • Antiplatelet, ACEI, or ARB
      • ACEI (Lisinopril)
      • Clopidogrel reduces MI incidence + ASA for 12 months
      • BBs (metoprolol, atenolol, propranolol)
      • BP control (CCBs)
      • Statins, Quit Smoking
      • Diet and Diabetes Control
      • Exercise

Acute Myocardial Infarction

  • Definition
    • The term acute myocardial infarction should be used when there is acute myocardial injury with clinical evidence of acute myocardial ischemia + detection of a rise and/or fall of cTn values with at least one value above the 99th percentile URL + least one of the following:
      • Symptoms of myocardial ischemia
      • New ischemic ECG changes
      • Development of pathological Q waves
      • Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality in a pattern consistent with an ischemic etiology
      • Identification of a coronary thrombus by angiography or autopsy (not for type 2 or 3 MIs)
    • Post-mortem demonstration of acute atherothrombosis in the artery supplying the infarcted myocardium meets criteria for type 1 MI
    • Evidence of an imbalance between myocardial oxygen supply and demand unrelated to acute atherothrombosis meets criteria for type 2 MI
    • Cardiac death in patients with symptoms suggestive of myocardial ischemia and presumed new ischemia ECG changes before cTn values become available or abnormal meets criteria for type 3 MI

NSTEMI

  • W/U: Troponins at 3-6 hours after symptoms onset, remeasure within 8-12 HEART Score in the ER
  • Treatment
    • Initial Stabilization
      • Aspirin: 325mg chewed immediately, 81mg QD
        • If no aspirin initially: 300mg followed by 75mg daily
        • If UA or NSTEMI: UFA: Bolus of 12-55 U/kg/min up to 60-70 U/kg/min maintained at 1.5-2.5x PTT for 2-5days
      • 0.4mg sublingual nitrogen ± 10 microg/min and increased by 5-10 microgram/min every 3-5 min until relief (200 usual max) for 12-24 hours
      • IV Metoprolol: 5mg IV Q5minx3, then 25-50mg Q6hrPO
        • OR IV Esmolol if COPD, Asthma
        • OR CCBs if BB CI and hypertensive
      • O2 if <90%, Aspirin, P2Y12 Inhibitor, Nitrates, BB, High-dose Statin, Anticoagulation
      • < 12 hours of symptom onset + PCI CI
        • Fibrinolysis
          • Higher rate of recurrent MI, Intracranial Hemorrhage, Mortality
      • NSTE-ACS + Low-Risk: Ischemia-Guided Strategy
        • Noninvasive stress testing prior to discharge
      • NSTE-ACS + High Risk (Refractory angina, HF, Arrythmia or Hemodynamic instability)
        • Urgent cath
    • Long-Term
      • ACEI if LVD, DM, Hypertension
      • Therapeutic ACEI + BB + LVEF ≤40 + (DM or HF): Eplerenone is beneficial

STEMI

  • General
  • Symptoms
    • Pale, sweaty, may be agitated or restless
    • Crushing, pressure like substernal chest pain, SOB, diaphoresis, and sometimes a history of exertional chest pain
    • Often radiates down the left arm or into the jaw
      • Aortic Dissection more likely if radiation to the back
    • If recurrent MI:
      • Dyspnea and wheezing
        • Indicate LV impairment and pulmonary edema
      • Bibasilar rales ± JVD
    • RVMI usually have hypotension, JVD, clear lungs (inferior MI MC)
      • If RVMI w/hypotension, low-normal JVD, then give IV saline Bolus for inadequate RV preload, avoid nitrates
  • Exam
    • Arrythmia, heart block, sinus tachycardia (Prior to BBs)
    • JVP
    • MR w/soft S1 and pansystolic murmur
    • VSD
    • Pericardial friction rub
    • Aortic dissection
  • Diagnosis: EKG + Trops
    • EKG
      • ST-elevation at the J-point in 2 contiguous leads with the cut point: ≥1mm in all leads other than V2-V3 where the following cut-points apply:
        • ≥2mm in men ≥40y
        • ≥2.5mm in men <40y
        • ≥1.5mm in women of any age
      • Depression
        • New horizontal or downsloping ST-depression ≥0.5mm in 2 continguous leads and/or T inversion ≥1mm in two contiguous leads with prominent R wave or R/S ratio >1.
          • 1mm in two or more contiguous limb or chest leads, 2mm elevation in leads V2/V3 in men or 1.5mm in women.
        • Posterior: 2mm in anterior V1-V4 with tall R waves often with ST-segment elevation in the inferior or lateral leads and ST elevation in posterior V7-V9
    • Myoglobin rises within 1h of onset, peak at 6h, normal in 1 day
    • CK-MB rises within 4-6h, peak at 1 day, normal in 2-3 days
    • Troponin rises within 2-6h, peaks 2 days, normal in 4-10 days
      • Good in both acute and recent Mis
      • Most sensitive and specific
  • Acute ST-Segment Myocardial Infarction (STEMI)
    • Anterior Wall STEMI
      • Heart Failure
        • Flash pulmonary edema
          • Loop Diuretic (Furosemide), relieves pulmonary edema by decreasing the cardiac preload
          • Venodilation, which further decreases the preload
          • Hypotension and AKI if normo/hypovolemic (aka be careful)
    • Inferior Wall STEMI (Inferior MI)
      • General
        • ST elevation in leads II, III, and aVF
        • Usually due to occlusion of the RCA > LCX
      • Transient Bradycardia or AV block
        • Treatment
          • Usually just Atropine
          • Temporary pacemaker possibly
      • Right Ventricular MI (RVMI)
        • 30-50% of Acute inferior wall Mis
          • Due to occlusion of the proximal RCA before the origin of the RV branches
        • Leads to impaired RV filling and often creates high sensitivity to intravascular volume depletion
          • Decreased preload and CO
          • Not observed in a pure LVMI
        • Clear lungs + Inferior wall MI indicate RVMI
        • Exam
          • Distended neck veins (JCD), clear lungs, tachycardia
          • Hypotension + low/normal JVP (≤3cm above the sternal angle) suggest Cardiogenic Shock
            • Due to inadequate RV preload
            • Bolus with Isotonic Saline to increase RV preload and improve CO
            • Avoid Beta blockers
            • Beta blockers contraindicated in bradycardia or cardiogenic shock
          • Hypotension in Right Ventricular MI with low-normal JVP
            • CVP = JVP + depth to right atrium (5cm)
              • 30-45 degrees, sternal angle
              • Normal CVP (6-8 cm H2O)
              • Elevated CVP (>8 cm H2O)
            • Indicates inadequate RV preload
            • IV saline bolus (avoid nitrates)
        • Diagnosis: V4 on R-sided EKG is 100% specific (V4-V6R)
        • Treatment
          • Initial IV Normal Saline Bolus
          • Vigorous fluid resuscitation
            • ± Dopamine/dobutamine if refractory
          • Manage Like an Acute STEMI after
          • Diuretics (volume depletion) and opiates (venous dilation) should be avoided or used in caution
          • Avoid Nitrates
            • Nitrates (venous dilation) will lead to profound hypotension due to decreased RV preload
  • Treatment
    • Goal: Decrease Cardiac Myocardial O2 and increase O2 delivery
    • ACC/AHA guideline update for the management of STEMI
    • General
      • To reduce morbidity and mortality
        • Aspirin + Clopidogrel, ticagrelor + BB + ACEI/ARB + Statins ± Aldosterone antagonists
      • ACEI: LV dysfunction, HF, EF ≤40%, Anterior wall infarction, diabetes
        • Give ACEI/ARB within 24h to limit Ventricular Remodeling (AT2 mediated), results in dilatation of the ventricle
        • SAVE: ACEI improve survival/morbidity/mortality in LV dysfunction after MI
      • If Pulmonary Edema w/o hypotension or hypovolemic: IV Furosemide
    • 1) Dual Antiplatelet Therapy (DAPT)
      • P2Y12s
        • PLATO: Ticagrelor > Clopidogrel in ACS including mortality
        • DAPT: Continuing Thienopyridine after 12 months decreased risk of In-stent thrombosis and MI at 18 months, increased risk of bleeding
        • WOEST: Bleeding w/AC + Plavix < Triple Therapy w/o change in MI/Stroke/MACE
        • COGENT: PPI with DAPT reduces GIB 87%, no CV event change
      • Acute Recommendations
        • Give chewable Aspirin (325mg) at presentation
        • P2Y12 Receptor Blocker (Clopidogrel, prasugrel, ticagrelor)
          • If PCI: Loading dose of Clopidogrel 600mg or Ticagrelor 180mg
          • If Fibrinolytics: Clopidogrel 300mg; 75mg if >75y/o
        • PPI if on DAPT and high-risk for bleeding (previous bleed, PUD, active H. Pylori, Age >65)
          • Decreases risk of UGIB
          • Avoid Omeprazole if on Strong CYP2C19 (Plavix), use Protonix/Dexlansoprazole
            • Does not affect prasugrel or ticagrelor
      • Duration Recommendations
        • DAPT for minimum of 6-12 months after BMS/DES Placement
        • DAPT for 6 months if no stent w/ACS
        • DAPT for ≥12 months for drug-eluting stent in ACS
          • Clopidogrel or Ticagrelor
          • Restart ASA after cessation of P2Y12
          • Premature discontinuation is the strongest predictor of stent thrombosis within 1st 12 months
        • DAPT > 1 year if: high risk for recurrence, depressed LV function, Saphenous vein graft stenting, diabetic
          • In whom the risk < benefit for up to 36m
          • May use DAPT bleeding risk score
          • Clopidogrel if hx of upper gi bleed
        • DAPT for minimum of 4 weeks in select patients after BMS
          • Use in pts with high bleeding risk
        • Continue DAPT for a total of 30 months if possible (Low bleeding risk)
        • Continue Aspirin Indefinitely
        • CAD + PAD
          • COMPASS Trial: Aspirin 100mg + Xarelto 2.5mg BID improves MACE
        • PCI
        • Perioperative Management
          • Elective Surgery: Defer Surgery until after minimum DAPT duration
            • Urgent Surgery: Continue P2Y12 receptor blacker or hold for shortest duration possible
            • Continue aspirin unless high risk of severe surgical bleeding
            • Reduces rate of early graft occlusion and overall CV morbidity and mortality in CABG, continue
            • Hold P2Y12 inhibitors for 5-7 days prior to CABG
            • Increased risk of significant bleeding with increased requirements for blood transfusion and possible re-op
    • 2) Beta-blockers (BBs) if Hypertensive/ongoing (Metoprolol)
    • 3) O2 for arterial saturation <90% (SaO2 <95%, breathless, or HF)
    • 4) IV Opioids to relieve pain if needed
    • 5) Anticoagulation
      • If PCI: UFH, Enoxaparin, or Bivalirudin
        • ± Glycoprotein IIb/IIa inhibitor to UFH
        • Determine Need for ongoing anticoagulation after
          • Low risk: Stop IV UFH after cath
            • Low VTE risk: SCDs
            • Intermediate/High VTE risk: Give lovenox 6hr after stopping drip
          • Intermediate Risk: May continue IV UFH
            • If Fibrinolytics: UFH, Enoxaparin, Fondaparinux
              • For 48h up to 8 days
    • 6) Sublingual Nitrates > Morphine
      • Nitrates: 3 x 0.4mg tablets, IV afterward
        • CI: Sildenafil within 24-48 hours, Shock, RV infarction
      • Morphine Sulfate: 2-4mg IV at 5-15min intervals
      • No nitro if hypotension, RV infarct, severe AS
    • 7) High dose Statins ASAP after stabilization (Atorvastatin 80mg)
      • PROVE-IT: Significantly reduced CVD events following MI with High-dose Lipitor vs. Pravastatin
      • Want LDL < 70 1 month after
    • 8) Prompt reperfusion with PCI or Alteplase (fibrinolytics)
      • Early Invasive Strategy
      • Give IV UFH/Bivalirudin
        • Abciximab
      • PCI > Fibrinolysis (Alteplase, not for NSTEMI or Unstable)
      • Ideal first medical contact to PCI ≤90mins or ≤30mins for fibrinolytics
      • Avoid Milrinone and Dobutamine in Acute STEMI
        • Increases mortality in cardiogenic shock, may cause hypotension
        • Use Norepinephrine if hypotensive
    • Reperfusion:
      • Percutaneous Transluminal Coronary Angioplasty (PTCA)
      • Thrombolysis (If PTCA not available within 120min)
    • TIMI Grade
      • Used to quantitatively evaluate coronary blood flow
      • 0 = complete occlusion
      • 1 = faint coronary flow
      • 2 = delayed or sluggish but complete flow
      • 3 = normal flow
    • Initiate Reperfusion Therapy (Fibrinolysis/PCI) < 12 hours of symptom onset and within 90 minutes of medical contact (120 if transporting)
      • Percutaneous Coronary Intervention (PCI)
        • PCI = Angioplasty + Stent
    • < 12 hours of symptom onset + PCI CI or > 12 hours of symptom onset
      • Thrombolysis
      • No PCI: Fibrinolytics within 30 mins of arrival
        • Absolute CI to fibrinolytics:
          • Ischemic stroke within 3 months, Intracranial Hemorrhage ever
        • Relative CI:
          • Ischemic stroke >3 months, SBP > 180, elevated INR on warfarin
            • Can still get FT
        • Better if used within 12 hours, best within 60-70 minutes
        • DAPT for at least 14 days up to 1 year
    • Aldosterone antagonist if:
      • NYHA II-IV HF & EF ≤35%
      • On ACEI/BB, EF ≤40% and symptomatic HF or DM
        • Therapeutic ACEI + BB + LVEF ≤40 + (DM or HF): Eplerenone is beneficial
          • Improves mortality and morbidity
          • Avoid if Cr <30, Hyperkalemia
    • On Discharge:
      • Cardiac Rehabilitation for those with PCI
    • Eval for ICD if reduced EF after 40 days or 3 months after revascularization on optimal medical therapy
      • MADIT-II: ICD improves survival in pts with prior MI and severe LV dysfunction
    • Non-Culprit lesions
      • 50% of STEMI have obstructive lesions remote form the area of infarction
        • Consider revascularization
      • Treat within 4-6 weeks if stable STEMI or low-complexity MCVD

Complications

  • Prognostic
    • The higher LVEF post MI, the better the prognosis
  • Post MI
    • Sexual activity: 2 weeks if healthy, 6 weeks if not
      • ED and decreased satisfaction are common, PDE-5s if not on nitrates
  • Pericardial Effusion
    • Stop all AC unless Afib or LV thrombus
  • Post-PCI
    • Reperfusion leading to contraction band necrosis from calcium influx
  • 3 Major Mechanical Complications
    • MR due to Papillary muscle rupture
    • LV free wall rupture
    • Ventricular septal rupture
  • 0-4 Hours
    • Microscopic/Gross: None
    • Complications:
      • Arrhythmia
        • Bradycardia
        • AV Block
      • Fatal Arrhythmia
        • Ventricular Extrasystole
          • Electrical instability, risk of VF if R on T
          • Most common fatal
        • Immediate (<10mins): Acute ischemia predisposes to reentrant arrythmias
          • Ventricular Fibrillation is the MCC of SCD during acute MI
        • Delayed (10-60mins): Abnormal automaticity leads to arrythmias
      • Cardiogenic Shock
        • Severe SOB, chest pain, decreased CO, increased PCWP (indicates cardiac), causes pulmonary edema
      • Congestive Heart Failure
        • Inefficient pumping of the LV, decreased EF
  • 4-24 hours
    • Microscopic: Coagulative necrosis, Edema, Wavy Fibers, Contraction bands
    • Gross: Dark Discoloration
    • Complications:
      • Fatal Arrythmia
      • Reperfusion injury
        • Return of oxygen and inflammatory cells can cause reperfusion injury
      • Right Ventricular Failure (Acute)
        • RCA involvement
        • Symptoms
          • Hypotension and clear lungs
          • Kussmaul sign
        • Echocardiogram: Hypokinetic RV
  • 1-3 days then 4-7 days (1 week)
    • Microscopic:
      • First Neutrophils (inflammation)
      • Then Macrophages (cleanup)
    • Gross: Yellow Pallor
    • Complications:
      • Acute Peri-infarct Pericarditis (PIP)
        • 1-3 days after an MI – diffuse ST-segment elevation
          • Causes collagen deposition and increases risk of Ventricular free wall rupture
          • More common in pts unable to be re-perfused
        • Symptoms
          • Pericardial friction rub with or without pleuritic chest pain with radiation to the shoulder
          • Clear lungs, improves when leaning forward
        • Treatment
          • Self-limiting
          • Increase aspirin to 650-1000mg TID
          • Colchicine ± Opioids if poor control
          • D/C AC if no Afib/LV Thrombus with pericardial effusion
          • No NSAIDS/No Steroids
      • Papillary Muscle Rupture (Acute to 3-5 days)
        • RCA or Dominant LCX
        • Symptoms
          • Soft new holosystolic or early systolic murmur (MR at apex), 50% may have silent MR
            • No thrill
            • Hyperdynamic precordium
          • Acute inferior MI leading to acute mitral regurgitation and pulmonary edema
            • Excessive diastolic volume overload which leads to elevated LV EDP, LV filling pressure
            • Posteromedial Papillary muscle rupture
            • LHF symptoms but no RHF symptoms
          • Acute, severe pulmonary edema
          • Hypotension, dyspnea, tachypnea
          • 50% have silent MR
        • Diagnosis: TTE or TEE
      • Interventricular Septal Rupture (Acute to 3-5 days)
        • LAD – Apical Septal Rupture
        • RCA – Basal Septal Rupture
        • Symptoms
          • Shock and chest pain, cardiogenic shock, palpable thrill
          • Harsh new holosystolic murmur at the left sternal border (Thrill, step up O2 from RA to RV)
          • Biventricular Failure
            • Causes a VSD, More RHF (JVD) > LHF
            • Step-up O2 between RA and RV, Left to right shunt at the level of the ventricle (pulmonary edema, JVD)
        • Diagnosis: TTE
        • Treatment
          • Prompt surgical repair
      • Ventricular Free Wall Rupture (50% by 5 days up to 2 weeks)
        • LAD involved
          • LV leak into pericardial space due to macrophages phagocytosing infarcted tissue
          • Due to hemopericardium, typically leads to cardiac tamponade
        • Majority are after transmural Anterior MI (<1% overall)
        • Symptoms
          • Sudden onset chest pain w/ profound shock, JVD
            • Acute Severe hypotension
            • Distant heart sounds
          • Syncope w/rapid loss of pulses (PEA)
        • Diagnosis
          • Pericardial effusion with Cardiac tamponade on Echo
        • Treatment
          • Early Surgical Repair
      • Pseudoaneurysm
        • Gradual rupture later sealed off by pericardium

  • 1 month

    • Microscopic: Fibrosis
    • Gross: None ± White Scarring
    • Complications:
      • Left Ventricular Aneurysm (5 days to 3 months)
        • LAD involvement
        • Scar Tissue deposition following transmural MI
        • Aneurysm leads to LV enlargement
        • Thin and dyskinetic myocardial wall
        • Symptoms
          • Subacute CHF (HF and angina) and Persistent ST elevation/Deep q waves with systolic MR murmur, Stroke, ventricular arrythmia
        • Increased risk of mural thrombus due to slow blood flow
        • Echo: Thin and dyskinetic myocardial wall
      • Dressler Syndrome (Post-MI Pericarditis)
      • Hemorrhagic Pericardial Effusion
      • Depression
        • 20% of post-MI patients
        • Sertraline and Escitalopram
        • CI: Citalopram, paroxetine
  • Months to years
    • In-stent Restenosis

Other Resources