DVT and PE Flashcards
Most common sites for DVT
- Calves
More proximal lower limb possible as well as rarely the upper limb
Pathophysiology of DVT
- Imbalance between prothrombotic factors and antithrombotic modulation
- VIRCHOWS TRIAD shows what can tip to a prothrombotic state:
low flow
prothrombotic state
vessel wall damage
Risk Factors for DVT:
High Risk:
- Major trauma
- Major surgery
Mod Risk:
- Malignancy
- Thrombophilia
- Prev. DVT
Low Risk:
- Increased age
- Obesity
- Pregnancy
- Varicose veins
Post-operative DVT risk:
High risk:
- Lower limb ortho surg.
- Abdo/pelvic surg. for malignancy
- Prev. VTE
- Known thrombophilia
Moderate:
- Age > 40yr
- Major Surg. for >30 min
- Additional RFs
Low:
- other
to note mod. and high risk require both mechanical and pharmacological prophylaxis
Mechanical thromboprophylaxis options:
- Early mobilization
- Elevation
- Elastic compre. stockings (class 0-1)
- Intermittent pneumatic compression
Pharmacological Thromboprophylaxis options:
Injectable Agents:
1. Heparin
- Inhibits factor Xa and II via ATIII binding
- needs lab monitoring if IV
2. LMWH
- Enoxeparin
- Inhibits Xa
- Predicatable (no need to monitor)
- Once daily dosing
Oral Agents: (more useful for pts requiring long term anti-coag.)
1. Vit. K antagonists
- Warfarin
- Inhibits factors II, VII, IX, X
- Unpredictable (need regular INRs)
- Need bridging with injectables
2. Direct acting oral anticoagulants
- Predictable (no monitoring)
- Direct Factor Xa inhibitors (Rivaroxaban)
- Direct Factor II inhibitor (Dabigatran)
Clinical Presentation of DVT
Classically:
- Unilat. Leg pain, swelling, tenderness
- Fever
- Dilated superficial veins
- Homans Test [pain in calf on passive stretch of calf]
But use DVT Wells Score! [2 points are more = DVT likely]
Investigations for DVT
D-Dimer
- Used as rule-out test in pts. with low Wells score
If either high Wells or D-Dimer then to make definitive Dx you need:
- Duplex USS = diagnostic test of choice
CT venogram useful for Prox. DVTs or IVC planning
Venography for intervention only
Prognosis of DVTs
- most DVTs will recanalize and resolve in 3 months
BUT are affected by: - pt. factors (Overweight, pregnancy)
- Thrombus factors (how extensive, prox. obstruction)
- Treatment factors
Management of DVT
Goals: prevent thrombus extension, prevent early recurrence and prevent complications
Early management of a DVT:
- Provoked & Isolated pop/tib DVT
- If no other DVT risk factors then treat with: Analgesia; early ambulation; compression stockings - All other cases
- Add pharmacological anticoagulation: Same drugs as for prophylaxis with higher dose. Duration usually about 3 months to lifelong depending on recurrence risk - Proximal (iliac vein) DVT
- Endovascular = catheter directed thrombolysis/ pharmacomechanical catheter directed thrombolysis
- vs open thrombectomy
Ongoing management of DVT:
Graduated compression stockings (Class II)
- these improve Sx
- Prevent complications
- use for a longer duration than Rx
Complications of a DVT
Early:
- Acute PE: high incidence but most asymptomatic, symptomatic PE increases DVT mortality by 18x
- Acutely threatened limb (extreme form of DVT resulting in ischaemia)
Late:
- Post-thrombotic syndrome: Great socioeconomic morbidity. RFs [Pt factors like vv & obesity, DVT factors like extent and recurrence, Treatment factors]
- Pulmonary HPT: Recent PE -> Pulm. HPT -> Cor pulmonale
Phlegmasia summary:
- Extreme form of lower limb DVT resulting in limb-threatening ischaemia
- Result from extensive proximal (iliac veins) DVTs
- Urgent surgical & thrombolytic therapy needed to save the limb
- 2 forms:
Phlegmasia alba dolens [white leg due to comprised arterial flow]
Phlegmasia cerulea dolens [blue leg due to cyanosis, thromb. of both deep and superficial venous systems]
Central Vein filters summary
Used to prevent LARGE PEs not as Rx for DVT
- Place in IVC for lower limb DVTs or SVC for UL
Indications: ineffective or contraindicated anticoagulation
