VTE Flashcards
Venous thromboembolism
- formation of a blood clot in the vein + inflammation
- DVT: deep vein thrombosis (iliac, femoral)
- SVT: superficial vein
- PE: pulmonary embolism
Venous thrombus: Aetiology & PP
Virchow’s triad:
* Venous stasis: inactive muscles, dysfunctional veins, causing increased viscosity and microthrombi
* Damage to endothelium: releases clotting factors and activates platelets
* Hypercoagulability: increase in tissue activating factor, decrease in antithrombin and fibrinolysins
Leads to thrombus development
* Extrinsic system involves activation of tissue lipoprotein due to injury
* Intrinsic system involves activation of circulating plasma factors
* Factor X is activated to Xa, which converts prothrombin to thrombin
* Fibrin clot forms, and is normally lysed by fibronylysins
Risk factors for VT
Stasis: age, obesity, pregnancy, fractures, HF, long trips, varicose veins
Endothelial damage: abdominal surgery, IV meds, fractures, hx, catheters
Hypercoagulability: dehydration, elevated lipoprotein, hormone therapy, pregnancy, sepsis, smoking
Pulmonary embolism
- Blockage of pulmonary arteries by thrombus, fat, air or tumour that begins in the venous system
- Affects lower lobes due to higher blood flow
DVT manifestations
- Limb oedema most common
- Thrombus of iliac bifurcation, pelvic veins and VC cause bilateral oedema
- High partial obstruction mimics mild oedema seen in R-HF or fluid overload
- Obstruction in lower limb vein causes unilateral oedema
- Pain may occur, sometimes when flexing foot, or just general tenderness
- Warmth and erythema
- May be asymptomatic
PE manifestations
- Variable symptoms
- Dyspnoea, tachypnoea, cough, chest pain, haemoptysis, crackles
- Fever, tachy, syncope
- Pulmonary HTN
VTE diagnosis
Clinical prediction rules: Wells and Geneva scores
D-dimer levels: protein released to breakdown clots, if -ve (rule out), if +ve (radiological investigation)
LL US: to diagnose and exclude
CT pulmonary: if PE is suspected
Ventilation perfusion: rule out PE
VTE medication management
Proximal DVT & PE: 3 months of meds
Distal DVT: 6-12 weeks
- Direct oral anticoagulants (DOACs): no monitoring, no interactions, except pregnancy (use LMW hep)
- Oral factor Xa inhibitors (rivaroxaban): preferred as they don’t require parenteral anticoags
- PO Warfarin (monitored by INR)
- IV/SC hep (monitored by aPTT) & subcut LMWH (no monitoring)
[AVOID aspirin, less effective with same bleeding risk]
VTE monitoring
INR: clotting time by extrinsic pathway, used to monitor warfarin
aPTT: clotting time by intrinsic pathway, used to monitor heparin
Activated clotting time: same as above
Anti-factor Xa: monitors LMWH
Invasive management of VTE
Rapid removal of thrombus to relieve right ventricular pressure
* Systemic thrombolytics
* Catheter-directed thrombolysis
* Surgical thrombectomy
* IVC filter insertion to prevent PE in patients contraindicated to anticoags
Nursing problems
- Acute pain related to venous congestion, impaired venous return and inflammation
- Ineffective health maintenance related to knowledge deficit
- Risk for impaired skin integrity related to altered tissue perfusion
- Potensial for bleeding related to antigoagulant therapy
- Potential for PE related to immobility, dehydration, embolism of thrombus
Management of anticoag therapy
- Monitor vitals
- Assess urine and stool for blood
- Inspect skin
- Coag tests and platelet levels
- Signs and symptoms of bleeding
- Reposition patient
- Compression stockings
- Falls risk
DVT complications
- PE, with possible cardiac arrest
- Chronic venous insufficiency
- Varicose veins long term
