M5.4 Things 2 Know according to AI

What differentiates STEMI from NSTEMI and unstable angina?

STEMI is a complete coronary occlusion with elevated troponins; NSTEMI is partial occlusion with elevated troponins; unstable angina is partial occlusion with normal troponins.

What is the first treatment fork in ACS management?

STEMI patients go to the procedure pathway (PCI or fibrinolysis); NSTEMI/UA patients are risk-stratified for medical management or early invasive approach.

What is the aspirin loading and maintenance dose in ACS?

Load with 325 mg chewed; maintain 81 mg daily indefinitely.

For how long is DAPT recommended after PCI?

Dual antiplatelet therapy (aspirin + P2Y12 inhibitor) is recommended for at least 12 months after PCI.

Which P2Y12 inhibitors are generally preferred over clopidogrel?

Prasugrel and ticagrelor are generally preferred over clopidogrel.

What is the maximum daily aspirin dose allowed with ticagrelor?

Do not exceed 81 mg/day of aspirin with ticagrelor.

In which patients is prasugrel contraindicated?

Patients with a history of stroke or TIA.

Why might clopidogrel be less effective in some patients?

It is a prodrug requiring CYP2C19 activation; loss-of-function alleles (2, 3) reduce active metabolite formation and efficacy.

What is the genotype-guided approach for P2Y12 inhibitor selection?

Patients with CYP2C19 loss-of-function alleles should receive ticagrelor or prasugrel; those without can receive clopidogrel.

Which P2Y12 combination is recommended after fibrinolysis in STEMI?

Aspirin plus clopidogrel.

Which P2Y12 combination is recommended for medically managed NSTE-ACS?

Aspirin plus ticagrelor.

Which P2Y12 combination is recommended after CABG?

Aspirin plus clopidogrel (ticagrelor may be used based on newer data).

How should aspirin be timed if a patient must also take NSAIDs?

Take aspirin 60 minutes before or at least 8 hours after NSAIDs to preserve antiplatelet effect.

What is the mechanism of action of warfarin?

Inhibits VKORC1, preventing vitamin K recycling and reducing synthesis of functional clotting factors II, VII, IX, and X.

Which warfarin enantiomer is more potent?

The S-enantiomer is more potent than the R-enantiomer.

What is the mechanism of action of unfractionated heparin?

It bridges antithrombin III to both thrombin and factor Xa, inhibiting their activity.

How do LMWH and fondaparinux differ from UFH in mechanism?

They have greater selectivity for factor Xa inhibition; fondaparinux is a synthetic pentasaccharide that only inhibits Xa.

What is the mechanism of action of direct thrombin inhibitors?

They directly inhibit thrombin (factor IIa) without requiring antithrombin III; examples include argatroban and bivalirudin.

What is the mechanism of action of dabigatran?

Dabigatran is a direct thrombin (factor IIa) inhibitor.

What is the mechanism of action of apixaban and edoxaban?

They directly inhibit factor Xa.

What is the standard discharge medication bundle after ACS?

Aspirin + P2Y12 inhibitor, beta-blocker, high-intensity statin, ACEi/ARB, and an MRA if low ejection fraction.

Which glycoprotein IIb/IIIa inhibitors may be used at PCI?

Eptifibatide and tirofiban; less commonly used now due to potent P2Y12 inhibitors.

How does fondaparinux compare to heparin for anticoagulation?

Fondaparinux selectively inhibits factor Xa and has no direct thrombin inhibition; lower risk of HIT.

What is the clinical significance of CYP2C19 2 and 3 alleles?

They are loss-of-function alleles that decrease clopidogrel activation and reduce platelet inhibition.

What are the treatment options for NSTEMI vs STEMI?

NSTEMI: medical management or early invasive PCI; STEMI: immediate PCI or fibrinolysis if PCI unavailable within 120 minutes.

What is the role of fibrinolysis in STEMI management?

Used when PCI cannot be performed within 120 minutes; requires concomitant aspirin and clopidogrel therapy.

What key adverse interaction can occur between warfarin and antibiotics?

Certain antibiotics (e.g., TMP-SMX, macrolides) inhibit metabolism or reduce vitamin K production, increasing INR.

Which oral anticoagulant directly inhibits factor Xa and requires renal dose adjustment?

Apixaban or edoxaban; both require renal function assessment.

What are the key factors in selecting anticoagulant therapy for ACS?

Renal/hepatic function, bleeding risk, drug interactions, and whether PCI or fibrinolysis is planned.