Thromboembolism Flashcards
Venous thromboembolism
What is VTE?
Blood clot in vein which obstructs blood flow.
What is DVT?
-Deep vein thrombosis
-In legs or pelvis
-Unilateral localised pain +/or swelling
What is PE?
-Pulmonary embolism
-In lungs
-chest pain or SoB
Risk factors for thromboembolism?
- Surgery
- trauma
- significant immobility
- malignancy
- obesity
- pregnancy
- -hormonal therapy (COC/HRT)
which diagnositic test is done to test for VTE?
D-Dimer test
what are the two methods of prophylaxis for VTE?
Mechanical
Pharmacological
What is mechanical prophylaxis for VTE?
-graduated compression stockings wear till mobile
When do you start pharmacological prophylaxis for VTE?
-within 14hr of admission
-only use if risk factor for VTE outweighs risk of bleeding
How long is mechanical surgical prophylaxis for VTE used for?
all pt should continue until sufficiently mobile or discharged from hospital
Examples of pharmacologiccal surgical prophylaxis for VTE
-low molecular weight heparin (LMWH)
-unfractionated heparin (UH)
-fondaparinux sodium
when is LMWH suitable in prophylatic surgery
suitable in all types of general, orthopaedic and pregnancy surgeries
when is unfractionated heparin preferred in prophylatic surgery
in renal impairment as it has a low half life so if need to stop fluidity of blood quickly
when is fondaparinux sodium preferred in prophylatic surgery
lower limb immobilisation or pelvis fragility fractures
how long is pharmacological prophylaxis used for in surgery
- at least 7 days post surgery or until suf mobility
- 28DY after major cancer surgery in abdomen
- 30DY in spinal surgery
tx for elective hip replacement?
1) LMWH 10DY * 75mg aspirin 28DY
2) LMWH 28DY + stockings until discharge
3) rivaroxaban = common
tx for elective knee replacement?
1) 75mg aspirin 14DY
2)LMWH 14DY+ stockings until discharge
3)rivaroxaban
if pt has as high risk of VTE what should you give for prophylaxis and how long for?
-Mechanical until mobile
-Pharmacological for 7DY at least
what is the VTE prophylaxis in pregn?
1) LMWH during hosp admission
- prophylaxis until no risk of VTE or till discharge
what is VTE prophylaxis in pt who have given birth, miscarried or termination within 6 weeks
start LMWH 4-8hr after event and continue for min 7 days
tx of VTE in pregnancy
- LMWH
- Unfractionated heparin if high risk of haemorrhage
how long is additional mechanical prophylaxis if immobilised
until mobile or discharged
1st line tx if confirmed proximal DVT or PE
apixaban
rivaroxaban
2nd line tx if confirmed proximal DVT or PE
LMWH for 5DY then dabigatran or edoxaban
3rd line tx if confirmed proximal DVT or PE
LMWH + warfarin for 5DY till INR 2.0 for 2x readings then warfarin alone
What is the duration of distal DVT (calf) tx?
6 weeks
what is duration of proximal DVT/PE
3MT (3-6MT in active cancer)
what is duration of provoked DVT/PE
stop at 3MT if factors stopped
what is duration of unprovoked DVT/PE
3MT+
what is duration of recurrent DVT/PE
long term
When do you need to maintain and INR of 2.5 (+/-0.5)?
- VTEs
- AF
- cardioversion
- MI
- cardiomyopathy
When do you need to maintain and INR of 3.5
recurrent VTE or mechanical heart valves
What do you do in a major bleed?
stop warfarin + give IV vit K (phytomenadione) + dried prothrombin
What do you give if INR >8 and is minor bleed?
stop warfarin and give IV vit K
What do you give if INR >8 and no bleed?
stop warfarin and give oral vit K
What do you give if INR 5-8 and is minor bleed?
stop warfarin and give IV vit K
What do you give if INR 5-8 and no bleed?
withhold 1-2 doses of warfarin and restart when INR is <5
MHRA s/e warning of warfarin
skin necrosis and calciphylaxis (pale skin rash)
s/e of warfarin
- haemorrhage; prolonged bleed give vit K antidote
- pregn = avoid in 1st + 3rd trimester (use contraception
Interactions of warfarin
-vit k rich foods (reduce efficacy)
-pomegranate + cranberry juice (inc INR)
-miconazole (inc INR)
-CYP450 inhibitors/inducers (inc/dec conc of warfarin)
if it is minor procedure with low risk of bleeding what do you do (warfarin surgery)
only perform if INR less than 2.5 - restart warfarin within 24 hr of surgery
What do you do in (warfarin) procedures where there is severe risk of bleeding?
1) stop warfarin 3-5DYs before
2) vit K if INR is > or = to 1.5 the day before surgery
3) pt = high risk of thromb stop LMWH 24hr before + restart 48hr after
if it a emergency surgery do you do in regards with warfarin
if it can be delayed by 6-12hr give IV vit K if not then give IV vit k + dried prothrombin complex
What are the doses for apixaban?
10mg BD 7DY then 5mg BD
which DOACs are given after 5DYs of heparin?
edoxaban and dabigatran
What do all heparins do?
- avoid in heparin induced thrombocytopenia
- can cause hyperkalaemia
- haemorrhage tx protamine sulphate (unfractionated)
what do unfractionated heparins do?
- quick initation + elimiation ideal for high bleeding risk (monitor APTT)
- high risk of heparin induced thrombocytopenia
dose for rivaroxaban
15mg BD 3WK then 20mg OD
dose for dabigatran when 18-74yr
150mg BD
dose for dabigatran when 75-79yr
110-115mg BD
dose for dabigatran when 80yr+
110mg BD
dose for edoxaban
- 60mg OD
- if under 6kg then 30mg
