Pumonary embolism/Venous Thromboembolism

Question 1

Risk factors for VTE

Answer 1

• Note up to 10% patients with unprovoked PE are diagnosed with cancer in the year after the VTE diagnosis

Question 2

Notes on recurrence rates of VTE

Answer 2

**Predictors of recurrence
**Unprovoked
Non-surgical provoking factor
PE and proximal DVT vs distal DVT
Prior VTE
Male sex
Antithrombin, protein C or S deficiency (Factor V Leidin or prothrombin heterozygosity has little effect)

Question 3

Notes on clinical prediction rules for VTE

Answer 3

• Most validated = Well’s and Geneva - must be used with D dimer testing. Designed for outpatient or ED department assessment - not applicable to hospitalised patients
• PERC - only applicable to patients younger than 50 years of age when estimated rate of PE is low (<15%)
• **Features of PERC
  ** Age < 50 years, hemoptysis, recent surgery, active malignancy, prior VTE, oestrogen use, arterial O2 < 94%, heart rate >100bpm, unilateral leg swelling

**Well’s score
<=2 = DVT/PE unlikely

Question 4

Diagnostic algorithm for DVT

Answer 4

Question 5

Diagnostic algorithm for PE

Answer 5

Question 6

Notes on imaging to confirm PE in pregnancy

Answer 6

Thrombosis and Haemostasis Society of Australia say V/Q scan, Eileen Bass says CTPA

Question 7

Notes on treatment of VTE

Answer 7

• DOACs and warfarin equally effective - DOACs preferred, no monitoring
• If choosing dabigatran - need to use parenteral anticoagulation for 5 days
• Can’t use DOACs in pregnancy or breastfeeding

Question 8

Notes on treatment duration of treatment

Answer 8

• Distal DVT - consider 6-12 weeks
• Everything else at least 3 months treatment. Consider prolonged course if unprovoked.
• Continuning therapy in these cases, reduces risk of recurrence by 80% but there is an increased risk of bleeding
• Can consider low intensity anticoagulation in those on prolonged courses e.g. apixaban 2.5mg BD as efficacious as 5mg BD for prevention VTE beyond 6 months (same for rivaroxaban 10mg vs 20mg)

Question 9

Notes on HERDOO2 score

Answer 9

Identifies women who may be able to safely stop anticoagultation after completeing a course of 3-6 months for unprovoked VTE

Question 10

Role of DOACs in cancer associated VTE

Answer 10

• Use rivaroxaban or apixaban, not dabigatran
• 3 months after “all clear” - can stop anticoagulation

Question 11

Notes on VTE rescurrence despite anticoagulation

Answer 11

• Review compliance, drug drug interaction
• If on hepatin - ?antithrombin deficiency
• Low INR - ?carbamazepine therapy/phenytoin, rifampicin, post amiodarone, increased vitamin K intake
• ?Rivaroxaban not taken with food, CYP3A4 inducers, obese