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