Warfarin & anticoagulation

Question 1

What is the purpose of anticoagulation and WHERE

Answer 1

Prevent thrombus in the slow moving venous circulation

DVT/PE

Question 2

What is the purpose of antiplatelets and WHERE

Answer 2

Prevent platelet aggregation and thrombus in the arterial circulation
(stroke)

Question 3

What is the difference between arterial and venous thrombi?

Answer 3

Venous - high fibrin, with platelets and RBC

Arterial - mainly platelets, low fibrin

Question 4

Mode of action of warfarin and duration to anticoagulant effect

Answer 4

vit k antagonism

48-72 hours

Question 5

How far from target INR is acceptable

Answer 5

0.5

Question 6

Target INR for AF/DVT etc

Answer 6

2.5

Question 7

Target INR for mechanical heart valves

Answer 7

depends on type of valve and pt factors

Question 8

When would you use target INR of 3.5

Answer 8

recurrent DVT/PE in pt already receiving anticoagulant with INR over 2

Question 9

Duration of anticoagulant treatment for

isolated calf DVT

Answer 9

6 weeks

Question 10

Duration of anticoagulant treatment for

VTE provoked by another factor - e.g. surgery

Answer 10

3 months

Question 11

Transient things that may provoke VTE (4)

Answer 11

surgery
COC
pregnancy
plastercast

Question 12

Duration of anticoagulant treatment for

unprovoked VTE

Answer 12

3 months at least

Question 13

Advice for major bleed on warfarin

Answer 13

stop warfarin
phytomenidione IV
give dried prothrombin complex or if no fresh frozen plasma

Question 14

Advice of INR over 8 and minor bleeding

Answer 14

stop warfarin
give phytomenidione IV
repeat if still too high after 24 hours

Question 15

After management of INR that is too high when should warfarin be reinitiated

Answer 15

INR

Question 16

Advice for INR over 8 and no bleeding

Answer 16

stop warfarin
give phytomenidione by mouth (unlicensed)
repeat if still too high after 24 hours

Question 17

advice for INR 5-8 and:

• minor bleeding
• no bleeding

Answer 17

-minor bleeding:
stop warfarin
give phytomenidione IV
-no bleeding
withhold 1-2 doses o f warfarin and reduce subsequent mantainance dose

Question 18

Adivce for bleeding at theraputic levels

Answer 18

investigate underlying cause e.g. renal or GI pathology

Question 19

How long before surgery should warfarin be stopped

when would we give phytomenidione day before before surgery

Answer 19

5 days

if the INR > 1.5 give phytomen day before

Question 20

when can we restart warfarin after surgery

Answer 20

evening of surgery or next day if all is well

Question 21

if someone is considered high risk for VTE before surgery how would we manage?
And who would be considered for this?

Answer 21

VTE in last 3 months, AF, previous TIA, heart valve

bridge with LMWH treatment dose, stop 24 hours before and start 28 hours after

Question 22

Is the risk of bleeding higher with asprin and warf or clop and warf

Answer 22

clop and warf

Question 23

what might be a day 1 dose of warfarin

Answer 23

5-10mg