Acute Coronary Syndromes Part 2

Question 1

Antiplatelets

Answer 1

aspirin, P2Y12 inhibitors, GPIIb/IIIa inhibitors

Question 2

Aspirin

Answer 2

aspirin 162 mg to 325 mg immediately upon presentation (MONA)
aspirin 81 mg/d to 325 mg/d should be continued indefinitely: 81 mg is the preferred dose; no evidence higher doses are more effective, conflicting evidence if higher doses increase bleeding rate
take with food

Question 3

P2Y12 inhibitor

Answer 3

clopidogrel, ticagrelor, or prasugrel: Oral medications; Loading dose followed by maintenance dose in addition to aspirin; Dual antiplatelet therapy (DAPT) recommended for 12 months in STEMI or NSTEMI/UA; DAPT always ASA + P2Y12 inhibitor
cangrelor: IV option ($$); Platelet inhibition within 2 minutes; Use during PCI when patient did not receive loading dose P2Y12 inhibitor

Question 4

Clopidogrel dosing

Answer 4

loading dose: 300-600 mg
maintenance dose: 75 mg daily
600 mg loading dose results in greater, more rapid, and more reliable platelet inhibition compared with a 300 mg loading dose
600 mg loading dose preferred except when using fibronolytic: fibrinolytic + age > 75 = no loading dose; fibrinolytic + age </= 75 = 300 mg loading dose

Question 5

Ticagrelor dosing

Answer 5

loading dose: 180 mg
maintenance dose: 90 mg BID

Question 6

Prasugrel dosing

Answer 6

loading dose: 60 mg
maintenance dose: 10 mg daily

Question 7

Cangrelor dosing

Answer 7

30mcg/kg followed by 4mcg/kg/min x 2 hrs
maintenance dose: use an oral agent

Question 8

Clopidogrel

Answer 8

• Prodrug- converted to active metabolite by CYP 2C19
• Most common (may be due to insurance coverage)

Question 9

Ticagrelor effectiveness

Answer 9

• Greater inhibition of platelet aggregation than clopidogrel
• PLATO trial
• Clopidogrel vs ticagrelor
• Primary endpoint (death from vascular cause, MI, or stroke) decreased with ticagrelor
• Max dose of ASA is 81mg daily in combination with ticagrelor
• Side effects include dyspnea and ventricular pauses

Question 10

Prasugrel effectiveness

Answer 10

Prasugrel: Not recommended for ischemia guided strategy (ticagrelor/clopidogrel preferred)
Greater inhibition of platelet aggregation than clopidogrel post PCI: TRITON-TIMI 38 trial
- Clopidogrel vs prasugrel, Primary endpoint (CV death, non-fatal MI, or non-fatal stroke) decreased with prasugrel; Higher bleeding risk
Contraindicated in patients with history of TIA/stroke
Not recommended in in patients ≥75 years old, <60kg or high bleeding risk Maintenance dose of 5 mg MAY be used if deemed necessary

Question 11

Clopidogrel metabolism

Answer 11

prodrug
CYP2C19

Question 12

Prasugrel metabolism

Answer 12

prodrug
CYP3A4

Question 13

Ticagrelor metabolism

Answer 13

not a prodrug
CYP3A4

Question 14

NSTEMI/UA P2Y12 inhibitor use

Answer 14

ischemia guided therapy: clopidogrel or ticagrelor preferred
early invasive strategy (PCI): any could be used, preference for ticagrelor or prasugrel

Question 15

STEMI

Answer 15

fibrinolytic: clopidrogrel preferred
PCI: ticagrelor or prasugrel preferred

Question 16

Drug eluting stent (DES) or bare metal stent (BMS)

Answer 16

DES may not be preferred if patient is unable to tolerate or comply with a
prolonged course of DAPT. Why? -DES associated with higher rate of late stent thrombosis (up to 12 months)

Question 17

Aspirin patient counseling

Answer 17

need to take lifelong to prevent heart attack
take with food
risk of bleeding

Question 18

P2Y12 inhibitor patient counseling

Answer 18

take with ASA for one year to prevent heart attack
risk of bleeding
ticagrelor: take 12 hrs apart

Question 19

Signs and Symptoms of bleeding: minor

Answer 19

Bruising
Light nosebleeds
Bleeding gums when flossing

Question 20

Signs and Symptoms of Bleeding: Major

Answer 20

Blood in urine
Blood in stool (often dark and tarry)
Coughing up blood (looks like coffee grounds)
Cut that won’t stop bleeding after putting strong pressure on it for 10 minutes

Question 21

Coronary artery bypass graft

Answer 21

aspirin: Does not need to be held prior to CABG
P2Y12 inhibitors: Hold prior to elective CABG: Ticagrelor - 3 days; Clopidogrel - 5 days; Prasugrel – 7 days
* Hold for 24 hours prior to urgent CABG if possible

Question 22

GP IIb/IIIa Inhibitors

Answer 22

Abciximab, eptifibatide and tirofiban: Potent IV antiplatelets given IN ADDITION to ASA and P2Y12
inhibitor; Given at the time of PCI - No benefit to starting “upstream” before PCI; Expensive
Not used routinely: Case by case basis; Increased risk of bleeding when add a third antiplatelet; Majority of trials conducted before DAPT was standard of care

Question 23

GP IIb/IIIa Inhibitors - STEMI/NSTEMI

Answer 23

Consider on an individual basis at the time of PCI NSTEMI: high risk features such as positive troponin
STEMI: large thrombus burden
Inadequate P2Y12 inhibitor loading
“Bail out”
Use during procedure if thrombus develops or low blood after stenting

Question 24

GP IIb/IIIa Inhibitors - contraindications

Answer 24

Different for each agent. If you are going to recommend, check for contraindications
Examples?: Active bleeding; Any history of hemorrhagic stroke; Severe uncontrolled hypertension (SBP >180 or DBP >110); Major surgery within 6 weeks; Dialysis