DVT & PE Flashcards
Two types of clot
Arterial
Venous
Where do arterial thrombi originate?
In arteries and left heart chambers
How does arterial thrombosis occur?
Rupture of atherosclerotic plaque
Consequence of arterial thrombosis
Ischaemia and infarction
ACS, Ischaemic stroke, Limb claudication/ischaemia
What colour is an arterial thrombus and what are its components?
White
Platelets and fibrin
What is Virchow’s triad?
Stasis, Hypercoagulability, Endothelial injury
How does venous thrombosis occur?
Elements of virchows triads
Back pressure
DVT and PE
What colour is a venous thrombus and what are its components?
Red
RBC and fibrin
Factors leading to stasis in blood
Immobility
Long haul travel
Factors that contribute to endothelial dysfunction
Hypertension
Smoking
High cholesterol
Factors that cause endothelial damage
Indwelling venous catheters
Trauma
Surgery
3 states of acquired hypercoagulability
Pregnancy
Cancer
Sepsis
4 types of venous thromboembolism
Limb DVT
PE
Visceral venous thrombosis
Intramural
Risk factors for VTE
Surgery Obstetrics Lower limb fracture Varicose veins Malignancy Reduced mobility Previous VTE Cardiovascular history Oestrogens - OCP, HRT COPD Neurological disability Obesity
Signs and symptoms of DVT
Unilateral limb swelling Erythema Calf tenderness Hot to touch Prominent collateral veins Unilateral pitting oedema
Potential long term consequences of DVT
Post thrombotic syndrome
Damage to venous valves
- swelling, discomfort, pigmentation, ulceration
Diagnosis of DVT
Clinical assessment and pretest probability - Wells score
Blood test - D dimer if low Wells score
Imaging - Compression ultrasound if positive D-dimer/high pretest score
What is D-dimer?
Fibrin degradation product
High sensitivity but low specificity
What other indications will also exhibit levels of D-dimer?
Trauma Malignancy Sepsis Bleeding Recent surgery
Symptoms and signs of PE
Dyspnoea Pleuritic chest pain Haemoptysis Tachycardia Pleural rub
Signs of massive PE
Severe dyspnoea sudden onset Cyanosis Collapse Tachycardia Hypotension Raised JVP
Investigations for PE
Ventilation/perfusion V/Q scan
CT pulmonary angiogram
Long term consequence of PE
Pulmonary arterial hypertension
Aim of treatment in PE
Prevent clot extension
Prevent clot embolisation
Prevent current clot
Management of PE
Anticoagulants - unfractionated or LMWH (Cancer associated VTE), Warfarin, DOAC - rivaroxaban, apixaban (FIRST LINE)
Thrombolysis by alteplase reserved for massive PE
Prevention of venous thrombosis in hospital
Early mobility
Anticoagulants
Compression stockings
All patients assessed for risk on admission and reassessed within 24 hours of any clinical change
Inherited cause of hypercoagulability
Factor V leiden
Length of anticoagulant treatment following VTE
3 months if provoked
6 months if unprovoked - high risk may require lifelong
Differential for pulmonary embolism
Myocardial infarction
Aortic dissection
Signs of PE on ECG
Sinus tachycardia most commonly
S1Q3T3
RBBB
RV strain
