dvt and pulmonary embolus - md connect · 2016. 4. 14. · overview • structure of deep and...
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DVT and Pulmonary Embolus
Dr Piers Blombery BSc(Biomed), MBBS (Hons), FRACP, FRCPA
Consultant Haematologist – Peter MacCallum Cancer Centre
Overview
• Structure of deep and superficial venous system of
upper and lower limb
• Venous thrombosis versus Arterial thrombosis
• Clinical features and consequences of DVT
• Clinical features and consequences of PE
Clinical case
• 56 year old woman with past history of hypertension and
gout presents with iron deficiency anaemia
• Gastroscopy/Colonoscopy performed – ulcerated lesion
in sigmoid colon
• Biopsied – colonic adenocarcinoma
• Undergoes anterior resection
• Very difficult venous access post-operatively due to
previous IVDU – required left femoral vein CVC
placement for fluid/antibiotics, etc
• D4 post-operative complains of a sore and swollen left
leg
The venous system
- low pressure
- variable anatomy
- high capacitance
- redundancy
UPPER LIMB VENOUS ANATOMY
Superficial Deep
LOWER LIMB VENOUS ANATOMY
Superficial Deep
LOWER LIMB VENOUS ANATOMY
“SUPERFICIAL
FEMORAL
VEIN”
The arterial system
- high pressure
- constant anatomy
- low capacitance
- limited redundancy
Virchow’s Triad
Venous thrombosis - Post-operative
- Prolonged immobility (e.g. ICU)
- Cast immobilisation
- Prolonged plane flight
Venous thrombosis - Post-operative
- Prolonged immobility (e.g. ICU)
- Cast immobilisation
- Prolonged plane flight
- Cancer
- Pregnancy/OCP
- Antiphospholipid
syndrome
- Genetic
predisposition
Venous thrombosis - Post-operative
- Prolonged immobility (e.g. ICU)
- Cast immobilisation
- Prolonged plane flight
- Cancer
- Pregnancy
- Antiphospholipid
syndrome
- Genetic
predisposition
- Intravenous
Cannula
- Trauma
Arterial Thrombosis
Ligation of artery
Genetic predisposition
Anti-phospholipid
syndrome
Atheroma
with plaque
rupture
Some terminology
• Deep venous thrombosis/DVT – a thrombosis occurring
anywhere in the deep venous system
• Common parlance – lower limb
• Pulmonary embolus – occlusion of pulmonary arterial
vasculature by any substance that has travelled from
elsewhere
• Common parlance – venous thromboembolism
Clinical features of lower limb DVT
• History
– Risk factors (immobilisation, Ca, FHx, etc)
– Swelling
– Calf pain
• Signs
– Lower limb erythema
– Lower limb pitting oedema
– Calf tenderness
– Venous gangrene (PCD)
Wells DVT score
Diagnosis of DVT
• Venous ultrasound of lower limb (or affected area)
Diagnosis of DVT
• Negative ultrasound doesn’t rule out DVT
• Repeat in a week if clinically suspicious
Diagnosis of DVT
• Venogram – not really performed in real life
• D-dimer
– Fibrinolysis product detectable in the circulation
Diagnosis of DVT
• D-dimer
– Highly sensitive
– Low specificity (any thrombosis, pregnancy, sepsis,
infection, etc..)
– Pre-test probability is crucial
Prevention of DVT
• Prevent hypercoagulability
– Post operative anticoagulation
– Treat cancer
• Prevent endothelial injury
– Treat cancer
• Prevent stasis
– Early mobilisation
– TED stockings
– Sequential calf compression
Post-operative DVT chemoprevention
• NO ASPIRIN
• Two major options
– Low molecular weight heparin (enoxaparin,
dalteparin)
– Oral Xa/Thrombin inhibitors (dabigatran, rivaroxaban,
apixaban, edoxaban)
Consequences of DVT
• Pulmonary embolus
• Embolus elsewhere
• Recurrent DVT
• Post-thrombotic syndrome (~50%)
– Chronic leg/arm swelling
– Chronic pain, aching, tingling, heaviness
– Venous insufficiency
– Venous Ulceration
Consequences of DVT
• Post thrombotic syndrome caused by
– Residual thrombus leading to venous hypertension
– Destruction of wall of vein and valves by thrombus
induced activation of inflammation and scarring
Treatment
• Prevention
• Anticoagulation
– Duration controversial and is highly dependent on
provoking cause
Clinical case
• 17 year old female presents with 1/7 history of sudden-
onset shortness of breath and right-sided chest pain.
• Denies any regular medications
• On examination SaO2 – 91% on RA, PR 130 sinus
tachycardia, BP 110/70, lungs clear, abdomen soft, no
lower limb swelling
Pulmonary Embolus – clinical features
• Signs
– Tachycardia, hypoxia
– Hypotension
– Signs of DVT
– Pleural Rub
• Symptoms
– Shortness of breath
– Pleuritic chest pain
– Central chest pain
– Syncope
Pulmonary Embolus
• Investigations
– CTPA or V/Q scan
– ECG (SIQIIITIII, sinus tachycardia)
– Arterial blood gases (hypoxia, hypocapnia, respiratory
alkalosis)
– D-dimer…
Pulmonary Embolus
CTPA
Other causes of hypoxia/chest pain
Sensitive
Specific Avoids intravenous contrast
V/Q
Wells PE score
Pulmonary Embolus - consequences
• Acute
– Death
– Cardiovascular collapse
– Hypoxia
– Pulmonary infarction
• Chronic
– Pulmonary hypertension
• Right sided heart failure
• Chronic hypoxia
Summary
• Venous thrombosis and arterial thrombosis are different
pathologically and clinically
• DVT in the leg followed by embolus to the lung is the
most common but not the only manifestation of VTE
• Virchows triad crucial for understanding causes and
preventative measures for DVT / PE
• No test is perfect for ruling in or out DVT/PE
• Significant morbidity / mortality from DVT/PE means it is
important regardless of your chosen specialty