Haematology - DVT/PE Flashcards
What is the first step when DVT/PE is suspected?
WELLS-DVT Score
<=1: DVT unlikely
>=2: DVT likely
How do we proceed if WELLS Score for DVT is >=2?
Proceed to Compression Ultrasound to confirm position of DVT.
If distal DVT: Embolism unlikely. Watch and wait
If proximal DVT: Risk of embolism. Start anticoagulation
What are the choices for anticoagulation in DVT/VTET?
- Rivaroxaban 15mg BD for 21d –> 20mg daily till 90d
- Apixaban 10 mg BD for 7d –> 5 mg BD till 90d
- SC UFH or LMWH for first 5d –> Dabigatran 150mg BD or Edoxaban 60mg daily till 90d
- UFH + LMWH overlap w Warfarin for first 5d –> Warfarin monotherapy till 90d
How do we determine whether to extend VTET beyond 90d –> 180d?
Present risk factors for DVT - think of Virchow’s triad
1. Vascular injury
2. Hemostasis
3. Hypercoagulable states
Esp if non-modifiable e.g. protein C or S def.
Must also not hv high risk of bleeding
What are the risk factors for DVT/PE?
Thrombophilia:
- Protein C or S deficiency
- Pregnancy
- Factor V Leiden
- Hyperhomocysteinaemia
- Prothrombin gene variant
- Activated protein C resistance
- Surgery
- Sedentary lifestyle
- Low BP, HR
- Immobility
- Long haul flights
- Smoking
- Obesity
- OC w oestrogen
- Malignancy
- Polycythemia
- Infections & sepsis (hypercoag)
- Cellulitits
- Atherosclerosis
- Genetics
What are the signs and symptoms of DVT?
Signs
- Measurement of calves 10cm below tibial tuberosity - > 3cm diff bet two sids
- Dilated superficial veins (palpable cord)
- Homan’s sign (pain in back of knee when examiner dorsiflexes foot of affected leg)
Symptoms
- Unilateral lower limb oedema, pain, redness, warmth
What are the signs & symptoms for PE?
Signs
- Tachypnoea, tachycardia
- Diaphoresis
- Neck veins distended
- Massive PE: cyanotic, hypoxic, hypotensive, RV failure, systemic congestion, low LV preload, decreased CO, overt RV failure, circulatory collapse, shock
Symptoms
- SOB
- Chest pain, tightness
- Dyspnoea
- Palpitation
- Hemoptysis
- Massive PE: dizziness, lightheadedness
When do we use warfarin for DVT/PE?
Renal impairment - CrCL <30mL/min
When do we extend VTET? (Medical VTEP)
When unprovoked, chronic risk of DVT, low-mod bleeding risk. Extend to 91+ days
Rivarox: Optional decrease to 10mg daily after first 6mo (180d)
Apix: Optional decrease to 2.5 mg BD after first 6mo (180d)
What is the protocol of surgical VTEP?
Rivarox:
- Haemostasis achieved, start 6-10h post surgery
- 10 mg daily x2/52 or 5/52
- If medically ill 10mg daily for upt to 31-39d
Apix:
- Haemostasis achieved, start 12-24h post surgery
- 2.5 mg BD x 10-14d or 32-35d
Dabi:
- Haemostasis achieved, start within 1-4h post surgery
- 220 mg daily x 10d, 25-35d
- CrCl 30-50mL/min: Use w caution. 150mg same duration as above
Edox:
- 30 mg daily
What are the defining principles of extended therapy?
Once anticoag stopped, risk of VTE recurrence ~30%. Decreases w time if no provoking risk factor.
Recurrence risk >2x in unprovoked (vs transient provoked VTE)
For provximal DVT & PE, 3mo anticoag best option if transient and reversible risk factors were present.
What criteria is used when PE is suspected?
WELLS Criteria
<= 4.0 PE unlikely
>4.0 PE likely
When PE is likely (WELLS >4.0) how may we proceed?
Image w CT pulmonary angiogram (CTPA) to rule in PE
After ruling in PE, how do we proceed?
Determine the PE severity & risk
Haemodynamically unstable.
Clinical parameters of PE severity &/or comorbidity (PESI class III-V or sPESI>=1)
RV dysfn on TTE or CTPA
Elevated cardiac troponin
If DVT/PE is unlikely, how may we proceed?
Perform D-dimer.
If D-dimer -ve rule out DVT/PE.
If D-dimer +ve
- For suspected DVT: perform compression ultrasound
- For suspected PE: perform CTPA
