CAD & ACS

Acute Coronary Syndrome (ACS) includes

unstable angina (UA), NSTEMI, and STEMI.

Unstable angina (UA) vs NSTEMI troponin

UA is troponin negative; NSTEMI is troponin positive.

UA/NSTEMI ECG findings

ST depression, T-wave inversion, or nonspecific/no ECG changes.

STEMI ECG finding

ST-segment elevation, typically in 2 or more contiguous leads.

NSTEMI thrombus

Usually partially occlusive; platelet component is greater than fibrin.

STEMI thrombus

Usually completely occlusive; fibrin component is greater than platelets.

Vulnerable plaque

Thin fibrous cap and large lipid core; more susceptible to rupture.

Stable plaque

Thick fibrous cap and small lipid core.

ECG timing in suspected ACS

Obtain within 10 minutes of first medical contact.

Cardiac biomarker for ACS

Cardiac troponin (cTn).

MONA stands for

Morphine, Oxygen, Nitroglycerin, Aspirin.

Oxygen indication in ACS

Give if O2 saturation is less than 90% or patient is at high risk for hypoxia.

Aspirin initial ACS dose

162–325 mg PO once; chew and swallow non-enteric-coated aspirin.

Aspirin maintenance dose

81 mg PO daily indefinitely.

Nitroglycerin SL dose

0.4 mg SL/spray every 5 minutes for up to 3 doses.

Nitroglycerin contraindications

SBP <90, HR <50, RV infarction, or recent PDE-5 inhibitor use.

Nitroglycerin + sildenafil/vardenafil

Avoid nitroglycerin within 24 hours.

Nitroglycerin + tadalafil

Avoid nitroglycerin within 48 hours.

Nitroglycerin mortality benefit

No mortality benefit; primarily provides symptom relief.

DAPT

Aspirin plus a P2Y12 inhibitor.

P2Y12 inhibitors

Clopidogrel, prasugrel, ticagrelor, and cangrelor.

Clopidogrel brand name

Plavix.

Clopidogrel mechanism

Irreversibly inhibits ADP P2Y12 receptors and decreases platelet aggregation.

Clopidogrel metabolism & enzyme

Prodrug requiring CYP metabolism

CYP2C19 polymorphisms can reduce activation.

Clopidogrel NSTE-ACS/STEMI dose

300–600 mg loading dose, then 75 mg PO daily.

Clopidogrel before CABG

Discontinue 5 days before CABG if surgery can be delayed.

Prasugrel brand

Effient.

Prasugrel mechanism

Irreversibly inhibits platelet ADP P2Y12 receptors.

Prasugrel PCI dose

60 mg loading dose, then 10 mg daily if ≥60 kg.

Prasugrel dose if <60 kg

5 mg PO daily.

Prasugrel major contraindication

History of stroke or TIA.

Prasugrel before CABG

Discontinue 7 days before surgery.

Ticagrelor brand

Brilinta.

Ticagrelor mechanism

Direct, reversible P2Y12 inhibitor

not a prodrug.

Ticagrelor ACS dose

180 mg loading dose, then 90 mg PO twice daily.

Ticagrelor adverse effects

Dyspnea, bradycardia, and heart block.

Ticagrelor + aspirin

Use aspirin maintenance dose of 81 mg daily.

Ticagrelor before CABG

Discontinue 3–5 days before surgery.

Cangrelor brand

Kangreal.

Cangrelor route

IV

Anticoagulants used in ACS

UFH, enoxaparin, fondaparinux, and bivalirudin.

UFH mechanism

Enhances antithrombin activity, inhibiting factors Xa and IIa.

UFH anti-Xa:anti-IIa ratio

Approximately 1:1.

UFH NSTEMI/non-PCI STEMI dose

60 units/kg IV load, max 4,000; then 12 units/kg/hr, max 1,000/hr.

UFH monitoring

aPTT, bleeding, hemoglobin, hematocrit, and platelets.

UFH aPTT goal

1.5–2 times control or about 50–70 seconds.

UFH adverse effects

Bleeding and HIT.

Enoxaparin brand

Lovenox.

Enoxaparin mechanism

Enhances antithrombin with greater inhibition of Xa than IIa.

Enoxaparin anti-Xa:anti-IIa ratio

4:1

Enoxaparin STEMI + fibrinolytic age ≤75

30 mg IV bolus, then 1 mg/kg SC q12h beginning 15 minutes later.

Enoxaparin STEMI + fibrinolytic age >75

No IV bolus; 0.75 mg/kg SC every 12 hours.

Fondaparinux brand

Arixtra.

Fondaparinux ACS dose

2.5 mg SC once daily.

Fondaparinux renal contraindication

CrCl <30 mL/min.

Fondaparinux and PCI

Do not use alone for primary PCI; concomitant UFH is required.

Bivalirudin indication

Used in NSTEMI or STEMI patients undergoing PCI.

Bivalirudin PCI dose

0.75 mg/kg IV bolus followed by 1.75 mg/kg/hr infusion.

Bivalirudin clinical pearl

Useful in patients with HIT or high bleeding risk.

Bivalirudin CrCl <30

Reduce infusion to 1 mg/kg/hr.

GP IIb/IIIa inhibitors

Tirofiban, eptifibatide, and abciximab.

GP IIb/IIIa mechanism

Block the final common pathway of platelet aggregation.

GP IIb/IIIa current role

Selected PCI patients with large thrombus burden or rescue/bailout therapy.

Fibrinolytic indication

Eligible STEMI presenting within 12 hours of symptom onset.

Fibrinolytics in NSTEMI/UA

Not used for NSTEMI or unstable angina.

Preferred fibrin-specific fibrinolytics

Tenecteplase, reteplase, and alteplase.

STAR

Streptokinase, Tenecteplase, Alteplase, Reteplase.

Preferred STEMI reperfusion strategy

Primary PCI when it can be performed in a timely manner.

Beta blocker timing

Start within the first 24 hours after ACS if no contraindications.

ACS beta blockers

Metoprolol, carvedilol, or bisoprolol.

Beta blocker contraindications

HF/low output, shock risk, AV block, severe reactive airway disease, SBP <90, or HR <60.

Beta blocker target HR

Approximately 50–60 beats/min.

ACE inhibitor indication

LVEF <40%, pulmonary edema/HF, hypertension, or diabetes.

ACE inhibitor benefit

Reduces afterload, LV remodeling, mortality, reinfarction, and development of HF.

Lisinopril monitoring

BP, potassium, BUN, and serum creatinine.

ARB indication

Use when an ACE inhibitor is indicated but not tolerated.

Verapamil/diltiazem role

Alternative when BB contraindicated or ischemia recurs despite maximal NTG/BB therapy.

Verapamil/diltiazem mortality benefit

None

Aldosterone antagonist indication

EF ≤40% plus symptomatic HF or DM while receiving ACE-I and beta blocker.

Aldosterone antagonists

Spironolactone or eplerenone.

Aldosterone antagonist monitoring

BP, potassium, and serum creatinine.

High-intensity statin indication

Recommended for all ACS patients without contraindications.

High-intensity atorvastatin dose

40–80 mg PO daily.

High-intensity rosuvastatin dose

20–40 mg PO daily.

LDL >70 despite maximal statin

Add a nonstatin lipid-lowering agent.

Major ACS complication groups

Pump failure, electrical arrhythmias, and recurrent ischemia/reinfarction.

Pump failure complications

Heart failure and cardiogenic shock.

Electrical ACS complications

AF/flutter, ventricular arrhythmias, sudden cardiac death, and AV block.

ACS discharge aspirin

Aspirin 81 mg PO daily.

ACS discharge statin

High-intensity statin indefinitely regardless of baseline LDL.

ACS discharge nitroglycerin

Nitroglycerin 0.4 mg SL for chest pain.

ACS discharge medications

Beta blocker, ACE-I/ARB when indicated, statin, ASA, P2Y12 inhibitor, SL NTG ± aldosterone antagonist.