Haem

Question 1

Switching from DOAC to warfarin

Answer 1

• Start warfarin while patient is on DOAC
• Check INR 3-4 days after starting
• Continue DOAC until INR is 2 or above
• Recheck INR 2 days after stopping DOAC

Question 2

Switching from warfarin to DOAC

Answer 2

• Check INR
• Stop warfarin and start DOAC immediately if INR <2.5
• Stop warfarin and start DOAC next day if INR 2.5-3
• Repeat INR until <3 if INR >3

Question 3

Switching from warfarin to LMWH

Answer 3

• Stop warfarin
• Initiate LMWH if INR <2

Question 4

Vascular protection doses of DOAC

Answer 4

Rivaroxaban 2.5 mg BD +/- aspirin
This dosing range is excluded from the major exclusion criteria for r-TPA use

Question 5

Monitoring for LMWH

Answer 5

• Anti-Xa levels
• To be drawn after 3rd/4th dose (steady state)
• General goal: 0.6-1 units/mL for BD treatment

Question 6

DDI for P2Y12 inhibitors

Answer 6

Clopidogrel: 2C19/3A3/PGP substrate
Ticagrelor: 3A4/PGP substrate, 2C9 inducer

Question 7

Time to reach steady state for P2Y12 inhibitors

Answer 7

• Clopidogrel: 2 hours (600 mg LD), >6 hours (300 mg LD), 5-6 days otherwise
• Prasugrel: 1.5 hours (60 mg LD), 2-4 days otherwise
• Ticagrelor: 2 hours (180 mg LD), 2 days otherwise

Question 8

Holding P2Y12 inhibitors prior to surgery

Answer 8

• Clopidogrel: 5 days prior
• Ticagrelor: 3-5 days prior
• Prasugrel: 7 days prior

Question 9

CHA2DS2VASC score

Answer 9

Congestive HF
HTN
Age >75
DM
Stroke/TIA
Vascular disease
Age 65-74