Cardio: Acute coronary syndrome (ACS)

How are ACS classified?

based on their ECG findings: Unstable angina, NSTEMI, STEMI

What is the main reason for distinction of ACS classifications?

to determine the need for acute reperfusion therapy

What determines if MI has occurred?

elevated biomarkers

What is myocardial ischemia?

- d/t not enough blood (athersclerosis, Vasospasm, Thrombosis, embolism).

- decreased oxygen, no death, reversible

- ischemia may come and go with angina or during stress

What will be seen on ECG with myocardial ischemia?

T-wave inversion

What troponin value will be seen with myocardial ischemia?

normal

What is myocardial injury?

- d/t no blood flow.

- prolonged decreased oxygen, damage, possibly reversible

What will be seen on ECG with myocardial injury?

ST elevation or depression

What troponin value will be seen with myocardial injury?

may be increased

What is myocardial infarct?

cell death, irreversible

What will be seen on ECG with myocardial infarct?

Q waves, persistent ST

What troponin value will be seen with myocardial infarct?

elevated

What is non-ST segment elevation ACS (NSTEACS) an umbrella term for?

any ACS which does not show ST segment elevation (unstable angina, NSTEMI)

What may EKG show with NSTEACS?

ST depression, T wave inversion, or normal

With NSTEACS what do troponin levels distinguish?

NSTEMI from unstable angina (UA)

What is the presentation of NSTEACS?

- Sx at rest or with exertion

- Typical: substernal CP with radiation to L shoulder, arm, jaw, neck

- Dyspnea, nausea, diaphoresis, syncope

- 1/3 may have no CP (older, female, diabetics)

What is unstable angina?

- type of ACS with ischemia but NO MI

- troponin normal

- no ST elevation on ECG

What is the patho of unstable angina?

1) Rupture of an unstable atherosclerotic plaque

2) platelet aggregation

3) partial thrombus, causing transient ischemia w/o infarction

What describes the chest pain seen with unstable angina?

- new in onset, considered unstable.

- cescendo angina

What is crescendo angina?

Unstable angina that is worsening in frequency, severity, or duration, even at rest

What is unstable angina measured against?

patient's usual pattern of stable angina

What is non-st segment MI (NSTEMI)?

- A form of acute coronary syndrome (ACS)

- Presents without ST elevation on ECG

- Positive troponin elevation

- Indicates myocardial infarction

What is NSTEMI type I?

Type of ACS caused by partial occlusion of a coronary artery.

What does NSTEMI type I result in?

subendocardial ischemia w/o ST-Segment elevation of ECG

What is the patho of NSTEMI type I?

- Rupture or erosion of an atherosclerotic plaque --> platelet aggregation --> thrombus formation

- Incomplete occlusion leads to ischemia, not transmural infarction.

What is seen on ECG with NSTEMI type I?

No ST elevation, may show ST depression or T wave inversion

What troponin value may be seen with NSTEMI type I?

elevated, indicating MI

What is the tx for NSTEMI type I?

standard ACS tx

What is NSTEMI type II?

Caused by imbalance between O2 supply and demand (mismatch). Not d/t primary plaque rupture

What is the etiology of NSTEMI type II?

- Severe anemia

- Sepsis

- Hypotension

- Tachycardia

- Respiratory failure

What may be seen on ECG with NSTEMI type II?

no ST-elevation, may show ST depression or T-wave inversion

What troponin level may be seen with NSTEMI type II?

modest rise in Troponin

What sx may be seen with NSTEMI type II?

may be silent in the presence of acute illness

What is the tx of NSTEMI type II?

Treat underlying cause, not just coronary perfusion.

What is the criteria for low risk NSTEACS?

- No recurrent chest pain

- Normal biomarkers

- Normal or unchanged ECG

- No high-risk features

What is the management approach for low risk NSTEACS?

Conservative strategy (stress testing and medical therapy)

What is the criteria for intermediate risk NSTEACS?

- Moderate angina symptoms

- Known CAD (≥50% stenosis)

- Age >70 years

- Mildly elevated biomarkers

- New or presumed new ST/T changes

- Diabetes, renal dysfunction, or reduced EF

What is the management approach for intermediate risk NSTEACS?

Invasive strategy (within 24–72 hours)

What is the criteria for high risk NSTEACS?

- Recurrent angina at rest or with minimal exertion

- Elevated troponin (positive biomarkers)

- Dynamic ECG changes (ST depression ≥0.5 mm or transient ST Elevation)

- Heart failure symptoms or EF <40%

- Hemodynamic instability

- Sustained VT

- PCI within past 6 months

- Prior CABG

- High-risk TIMI or GRACE score

What is the management approach for high risk NSTEACS?

Early invasive strategy (within 24 hours)

What should happen with medium or high risk NSTEACS patients?

should be hospitalized, maintained at bed rest or at very limited activity for the first 24 hours

What is the Grace score?

- Global Registry of Acute Coronary Events

- Assess the risk of in-hospital mortality for ACS

- It provides a prediction for 1-3 years.

- The score estimates the risk of death or death/myocardial infarction (MI) following an initial ACS.

- It can be calculated both at hospital admission and at discharge.

What is the TIMI risk score for UA/NSTEMI?

- Age > 65

- >3 CAD risk factors (HTN, hypercholesterolemia, diabetes, FMHx of CAD, current smoker)

- Known CAD (stenosis > 50%)

- ASA use in past 7 days

- Severe angina (> 2 episodes in 24 hours)

- EKG ST changes in > 0.5mm

- Positive cardiac marker

What is the TIMI risk score for STEMI?

- Age (65-74 = +2, > 75 = +3)

- Diabetes, HTN, or angina

- Systolic BP <100 mmHg

- HR >100

- Killip class II-IV

- Weight <67kg

- Anterior ST elevation or LBBB

- Time to tx >4 hours

What are the components of heart score for major cardiac events?

- History

- EKG

- Age

- Risk factors

- Initial troponin

What is the heart score for major cardiac events?

- Designed specifically for ED chest pain eval

- Quick and easy bedside calculation

- Helps identify patients safe for d/c

- Performs very well for predicting short-term MACE

What is the use of morphine for ACS treatment?

Pain relief and anxiety reduction (use cautiously)

What is the use of O2 for ACS treatment?

only if hypoxic (SPO2 <90%)

What is the use of nitrates for ACS treatment?

vasodilation to relieve chest pain

What is the use of aspirin for ACS treatment?

antiplatelet therapy to reduce clot formation

What is the use of beta-blockers for ACS treatment?

decreases HR and myocardial O2 demand

What is the use of ACE-I for ACS treatment?

reduces afterload and prevents ventricular remodeling

What is the use of statins for ACS treatment?

stabilizes plaques and lowers LDL cholesterol?

What is the use of heparin for ACS treatment?

Anticoagulation to prevent thrombus progression

What is the use of thienopyridines (clopidogrel) for ACS treatment?

P2Y12 inhibitor for dual antiplatelet therapy

What is the use of ACE/ARB for ACS treatment?

reduce remodeling and afterload

What is the use of Interventions (PCI/CABG) for ACS treatment?

Revascularization when indicated

What daily dose of clopidogrel is used?

75mg PO QD

What is the ACS/PCI loading dose for clopidogrel?

300-600mg

What is the MOA of clopidogrel?

prevents platelet aggregation

What is the use of clopidogrel?

- Alternative if aspirin allergy/intolerance

- Use with aspirin after PCI (DAPT)

What are ADE of clopidogrel?

- Bleeding

- Bruising

- Rare: TTP

CI of clopidogrel

Avoid routine use with omeprazole & esomeprazole

What is the MOA of ticagrelor?

- Reversible P2Y12 receptor inhibitor

- Prevents platelet aggregation and clot formation

- Faster onset and more potent than clopidogrel

What is the use of ticagrelor?

- Preferred P2Y12 inhibitor for ACS

- Used with aspirin after NSTEMI, STEMI, and PCI

- Reduces risk of MI, stroke, and cardiovascular death

What are the CI of ticagrelor? Which one is different than clodipregil

- Active bleeding

- Prior intracranial hemorrhage

- Severe hepatic impairment

What are the MC reasons patients are switched fro ticagrelor to clopidogrel?

Twice-daily dosing and dyspnea

what dose of heparin is used for ACS tx?

60 U/kg IV bolus (max 4,000 U), then 12 U/kg/hr infusion (max 1,000 U)

What is the MOA of heparin (Unfractionated Heparin-UFH)?

Enhances antithrombin III to inhibit thrombin (IIa) and Factor Xa, preventing clot propagation

What is the use of heparin (Unfractionated Heparin-UFH)?

- Anticoagulant of choice for NSTEMI and PCI

- Used with DAPT in ACS to reduce ischemic events

- Preferred when PCI is planned due to rapid reversibility

What are ADE of heparin (Unfractionated Heparin-UFH)?

- Bleeding

- Thrombocytopenia

- Heparin-induced thrombocytopenia (HIT)

What is the antidote of heparin (Unfractionated Heparin-UFH)?

Protamine sulfate

What is the treatment approach of UA/NSTEMI once discharged home?

- Beta Blocker

- DAPT x 12 months

- ACE/ARB

- high intensity statin

- Cardiac rehab

What is the DAPT tx after ACS if ACS and no intervention?

DAPT x 12 months

What is the DAPT tx after ACS if PCI with bare metal stent (BMS-rare)?

DAPT x 12 mo

What is the DAPT tx after ACS if PCI with drug eluding stent (DES)?

- DAPT x 6 months stable ischemic heart disease

- DAPT x 12 months for ACS

What is a STEMI?

ST elevation myocardial infarction, emergency!!!

What is the MC cause of a STEMI?

occlusive coronary thrombus at site of a preexisting atherosclerotic plaque

What are potential other causes of a STEMI?

prolonged vasospasm, inadequate blood flow, emboli, coronary dissection, cocaine, coronary vasculitis

What type of dx is a STEMI?

visual, do not wait on labs

What is the typical presentation of a STEMI?

- sx depend on size and location of infarct

- chest pain/presssure often worsening from prior angina, occuring at rest or with minimal exertion

What is early death in STEMI patients MC due to?

VT/VF

When do STEMI sx mc occur (time of day)?

early morning

What are associated sx of STEMI?

diaphoresis, weakness, fatigue, N/V, syncope, SOB, abdominal pain

What population will have atypical presentation with a STEMI (approx 1/3 of pt present without chest pain)?

older adults, diabetics, women

What are the EKG findings of a STEMI?

- ST elevation in 2+ contigious leads

- reciprocal ST depression

- pathologic Q waves may develop later

When should an ECG for a suspected STEMI be obtained and interpreted?

within 10 min of arrival

What does a STEMI require immediately?

reperfusion therapy (PCI preferred)

What is the describes dx of a STEMI?

clinical sx consistent with ACS PLUS persistent ST elevation on EKG

How are ischemic changes with chest pain + new LBBB evaluated?

evaluate with sgarbossa criteria

What is the time frame from door to doc with a STEMI?

<10 min

What is the initial approach for a suspected STEMI?

- O2 if <90%

- EKG within 10 min of arrival

- door to doc within 10 min

- IV x 2

- labs

- CXR

- MONA-BASH/THROMBINS2

- PCI or fibrinolytics

Why is a CXR ordered for a suspected STEMI?

r/o aortic dissection, may show HF/congestion, or be normal

What is the timeframe for PCI with a suspected STEMI?

within 90 min

What is the timeframe for fibrinolytics with a suspected STEMI?

within 30min

When are fibrinolytics used over PCI?

use if PCI cannot be performed within 120 min of first medical contact.

When do fibrinolytics have greatest benefit?

within 12 hours of sx onset

What is the preferred fibrinolytic agent?

tenecteplase (TNK)

What P2Y12 inhibitor can be used with fibrinolytics?

only clopidogrel

What is the adjunctive therapy alongside fibrinolytics with a suspected STEMI?

- aspirin 162-325 mg

- clopidogrel

- heparin or enoxaprin