Thromboembolism Flashcards
What are the two types of thromboelbolism
Lung and extremities (legs)
What are the symptoms of thromboembolism
SOB
Hot to touch
Painful
Usually unilateral (one leg)
Coughing
What is a VTE
A blood clot in the vein and obstructs blood flow
DVT- legs or pelvis- unilateral localised pain or swelling
PE- lungs- chest pain or SOB
What are the risk factors of VTE
Surgery
Trauma
Significant immobility
Malignancy
Obesity
Pregnancy
Hormonal therapy (COC or HRT)
What tests need to be done to conform a VTE
D-dimer test
What are the 2 methods of thromboembolism prophylaxis
Mechanical- graduated compression stockings
-wear until the patient is sufficiently mobile
Pharmacological- anticoagulants
-start within 14 hours of admission
-patients with risk factors for bleeding should only receive pharmacological prophylaxis’s when their risk of VTE outweighs the risk of bleeding
What is the treatment protocol for VTE in surgery
Mechanical prophylaxis
Prophylaxis should continue until the patient is sufficiently mobile or discharged from hospital
Pharmacological prophylaxis
Considered when the risk of VTE outweighs the risk of bleeding
A low molecular weight heparin is suitable in all types of general and orthopaedic surgery
-unfractionated heparin is preferred in renal impairment
- fondaparinux sodium for patients with lower limb immobilisation or pelvis fragility fractures
- continue for at least 7 days post surgery or until sufficient mobility has been re-established
— 28 days after major cancer surgery in the abdomen
— 30 days in spinal surgery
What is the treatment protocol for VTE in surgery continued
In elective hip replacement either:
- low molecular weight heparin for 10 days and then 75mg aspirin for 28 days
-LMWH for 28 days + stockings on discharge
-Rivaroxaban
Elective knee replacement either
- 75mg aspirin for 14 days
-LMWH for 14 days and stockings until discharge
-rivoraxaban
General medical patients with a high risk of VTE should be given pharmacological prophylaxis for at least 7 days or mechanical prophylaxis until mobile
What is the treatment protocol for VTE in pregnancy
If risk of VTE that outweighs the risk of bleeding
- LMWH during hospital admission
Pregnant women: prophylaxis until no risk of VTE or until patient is discharged
- some who have given birth, had a miscarriage or termination of pregnancy during the past 6 weeks - start LMWH 4-8 hours after the event - continue for a minimum of 7 days
Additional mechanical prophylaxis if immobilised- until sufficiently mobile or discharged from hospital
Treatment of VTE: LMWH, unfractionated if patient is at high risk of haemorrhage
Give unfractionated if need quick response as it has a short half life
What is the treatment for VTE
If you have conformed DVT or PE: apixaban or rivaroxaban
If unsuitable offer:
- LWMH for at least 5 days followed by dabigatran or edoxaban
-LMWH + warfarin for at least 5 days or until the INR is at least 2.0 for 2 consecutive readings followed by warfarin alone
What is the duration of treatment for VTE
Distal DVT (calf) : 6 weeks
Proximal DVT /PE: at least 3 months (3-6 months for those with active cancer)
Provoked DVT/PE: stop at 3 months if the provoking factor has been resolved
Unprovoked DVT/PE: 3 months+
Recurrent DVT/PE: long term
What are the monitoring requirements of warfarin
Maintain INR of 2.5: VTEs, AF, cardioversion, MI, Cardiomyopathy
Maintain INR of 3.5: VTEs or mechanical heart valves
Major bleed: stop warfarin- IV phytomenadione (vitamin K) and dried prothrombin
INR > 8, minor bleed: stop warfarin - IV phytomenadione
INR >8 , no bleed: stop warfarin and oral phytomenadione
INR 5-8, minor bleed: stop warfarin and IV phytomenadione
INR 5-8, no bleed: withhold 1-2 doses of warfarin
Restart warfarin when INR is <5
INR should be monitored every 1-2 days in early treatment and then every 12 weeks
What is the correlation between blood and INR
The higher the INR the runnier your blood is
What is the MHRA warning about warfarin
Skin necrosis and calciphylaxis
-painful skin rash
What are the side effects of warfarin
-Haemorrhage: prolonged bleeding
Vitamin k1antidote
Pregnancy: avoid in the first and third trimester
-use contraception
What are the interactions of warfarin
Vitamin k rich foods: avoid major changed in diet with leafy greens
-reduce efficacy of warfarin
Pomegranate and cranberry juice
-increases patients INR
Miconazole (OTC daktarin oral gel)
-increases patient INR
CYP450 enzyme inhibitors and inducers
-increases or decreases warfarin concentration
What is the protocol of warfarin and surgery
Minor procedures with low risk of bleeding:
Performed with an INR of less then 2.5
Restart warfarin within 24 hours of procedure
Procedure where there is a risk of severe bleeding
Stop warfarin 3-5 days before
Give vitamin k if INR is >1.5the day before the surgery
Patients at high risk of thromboembolism: bridge with LMWH- stop LMWH 24 hours before surgery- restart LMWH 48 hours after
Emergency surgery:
If can be delayed by 6-12 hours : IV vitamin k
If can’t be delayed by 6-12 hours : IV vitamin k + dried prothrombin complex
What are DOACs direct oral anticoagulants
They are newer generation anticoagulants which requires no monitoring:
-apixaban
-dabigatran
-edoxaban
-rivaroxaban
What are the dose of DOACs
Apixaban: 10mg BD for 7 days- 5mg BD
Rivaroxaban: 15mg BD for 3 weeks- 20mg OD
-should be taken with food
Dabigatran:150mg BD aged 18-74, 100-150 BD aged 75-79, 110mg BD for aged 80+
Only start once patient has had 5 days of LMWH
Edoxaban: 60mg OD 30mgOD if patient weighs under 61kg
Only start once patient has had 5 days of LMWH
These are the strengths for the TREATMENT of thromboembolism only
Parental anticoagulants- Heparins vs LMWH
All heparins:
-avoid in heparin induced thrombocytopenia
Can cause hyperkalaemia- not to be given with NSAIDs and ACE-i and other drugs that cause hyperkalemia
Haemorrhage- treat with protamine sulphate ( used for unfractionated heparins)
Heparins unfractionated
- quick initiation and elimination- ideal in high bleeding risk (monitor APTT)- short half life
Higher risk of heparin induced thrombocytopenia than LMWH
-preferred in renal impairment
LMWH:
Preferred in pregnancy
What is the MHRA warning in DOACs
Dose adjustment of DOACs in patients with renal impairment
