Management of Pulmonary Embolism in Emergency Department

Dr A. BaraiMBBS, MRCS Ed, MSc

Registrar in Emergency Medicine

Topics• Introduction

• Diagnostic approach

• Treatment options

• Special circumstances: Pregnant patient

• Prevention

Introduction• Pulmonary embolism (PE) is a medical emergency

where pulmonary artery or its branches are blocked with embolic substances most commonly blood clots

• Most cases are not life threatening.

• Incidence: 600,000/year in USA

• Mortality rate: 50,000 to 200,000/yr in US

Types of PE• Massive PE: Acute PE with obstructive shock or SBP

<90 mmHg

• Sub-massive PE: Acute PE without systemic hypotension (SBP ≥90 mm Hg) but with either RV dysfunction or myocardial necrosis

• Non-massive or low risk PE: None of the above severe features.

Pathophysiology

Deep vein thrombosis from large vein commonly above the knee → Inferior vena cava → Right atrium → Right ventricle → Pulmonary artery → PE

Ventilation perfusion mismatch → Hypoxemia

↓Venous return → Right heart failure → Shock

Diagnosis• Risk stratification

• Clinical examination

• Bed side tests

• Laboratory tests

• Imaging techniques

Risk factors• Alteration of blood flow:

– Prolonged immobilisation, – Obesity, – Pregnancy, – Cancer

• Factors in blood vessel wall: – Surgery, – Catheterisation.– Trauma

• Hypercoagulable states: – Estrogen containing OCP, – Genetic thrombophilia (Factor V Leiden deficiency, Protein C and

Protein S deficiency, antithrombin deficiency etc.), – Acquired thrombophilia (antiphospholipid syndrome, nephrotic

syndrome, paroxysmal nocturnal hemoglobinuria)

Risk stratification• Clinical judgement

• Wells score for PE

• Modified Geneva score for PE

Wells score for PE

Modified Geneva score for PE

Clinical Presentation: Symptoms• Chest pain: Sharp, pleuritic in nature, no radiation,

aggravated by coughing and deep breath

• Haemoptysis

• Shortness of breath

• Collapse

• Palpitations

• Sudden death: 15% of sudden death due to PE

Clinical Presentation: Signs• Dyspnoea, cyanosis, pale

• Tachypnea

• Tachycardia

• Hypoxia

• Hypotension

• Pulmonary hypertension

Chest examination• May be normal

• Friction rub

• Features of pleural effusion

• Raised JVP

Investigations• Bed side tests: ECG, ABG

• Blood tests: D-dimer, FBC, Troponin, UEC

• Imaging techniques: Ultrasound/ Doppler scan, Chest xray, CTPA, V/Q scan, Echocardiogram

ABG findings in PE

• pH= ↑ • PaO2= ↓• PaCO2= ↓• HCO3= Normal• Aa gradient= Large

Aa gradient= PAO2- PaO2

Chest xray• Mostly normal findings

• Done to exclude other pathology

• Plural effusion

• Specific signs:- Hampton’s hump- Westermark sign

Hampton’s hump

Westermark sign

ECG findings in PE• Normal sinus rhythm

• Sinus tachycardia

• Tall peaked T waves in V1- V4

• S1Q3T3 pattern: Not specific. Can be seen in any Cor pulmonale syndrome

• RBBB

S1Q3T3 pattern ECG

D-dimer in PE• D-dimer is a type of Fibrin degradation product

• Can be raised due to a number of reasons

• Negative D-dimer rules out PE/DVT in 98% cases

• False positive D-dimer: infection, pregnancy, renal failure, post-operative

Echocardiogram in PE

CTPAIndications:

- Suspected PE

Contra-indications:- Renal failure- Pregnancy- Allergy to radio-contrast

Procedure:- Radioactive iodine administered IV- CT scan performed

Ventilation-perfusion scanIndications:

- Renal failure- Pregnancy

Procedure:- Ventilation scan with Xenon inhalation- Perfusion scan with Tc99m labelled radioactive dye infusion- Scan V/Q- Result: unmatched V/Q

Pulmonary angiogram• Gold standard test for PE

• Not practised due to the side effects and high mortality

• Procedure:– Catheter inserted to right ventricle– Radio opaque dye injected– Imaging technique used to identify the clot

Treatment options• Symptomatic treatment:

– ABCD approach– Oxygen– Analgesia

• Anticoagulation:– IV Heparin– S/C LMWH eg Enoxaparine, Dalteparine– Oral Warfarin

• IVC filter: If there is contra-indications for anti-coagulation

• Thrombolysis: tPA eg Alteplase, Tenectaplase

• Surgical procedures: Pulmonary embolectomy

Treatment options

• Massive PE: Thrombolysis/embolectomy

• Sub-massive PE: Strongly consider thrombolysis/embolectomy but need to balance risk of bleeding

• Non-massive PE: Anticoagulation

Thrombolysis• Indications:

– Massive PE– Sub-massive PE where risk of bleeding low

• Contraindications:– Bleeding, recent stroke, HI, current GI bleeding, bleeding

PUD, surgery within 7 day, prolonged CPR

• Drugs:– Alteplase 100mg IV: 15mg IV stat followed by 85mg over

2 hours– Followed by Heparin infusion

Anticoagulation• IV Heparin:

– 80 units/kg bolus followed by – 18 units/kg infusion

• Monitor APTT 60-90 sec

• Side effects: – HITS (Heparin induced thrombocytopenia syndrome):

paradoxical hypercoagulable state leads to clots– Bleeding

AnticoagulationLow molecular weight Heparin (LMWH)

Enoxaprin (Clexane): S/C- 1.5mg/kg/24 hours Or 1mg/kg/12 hours- 1 mg/kg/24 hours in renal impairment

Duration: 6 to 9 months

Side effect: Low HITS

Anticoagulation• Vitamin K antagonist

• Warfarin: – 5mg PO initial dose– Check regular INR 2-3

• Side effects:– Bleeding– Unusual bruises– Headache

IVC filter

Indications:- DVT with massive pulmonary embolus- Recurrent PE not treatable with anticoagulation- Absolute contra-indications for anti-coagulation- Trauma patients

PE in Pregnancy• All three components of Virchow’s triad are affected during

pregnancy

• D-dimer has high negative predictive value. False positive result is common

• V/Q scan is preferred technique

• CTPA can be done if VQ is inconclusive

• Preferred treatment option: LMWH

• Warfarin is contraindicated

Prevention of PE• Control of obesity

• Stop smoking

• Stockings

• Heparin: 5000 units/day IV

• Enoxaprin: 40 mg/day S/C

And finally…

PE is often over-diagnosed;

PE is often under-diagnosed;

The over- or under-diagnosis of PE results in increased cost, morbidity, mortality and medico-legal risks.

References• Agnelli G, Becattini C. Acute pulmonary embolism. N Engl J Med. 2010 Jul 15;363(3):266-74. doi:

10.1056/NEJMra0907731. Epub 2010 Jun 30

• Bourjeily G, Paidas M, Khalil H, et al. Pulmonary embolism in pregnancy.Lancet. 2010;375:500-512

• Hofman, M. S.; Beauregard, J. -M.; Barber, T. W. et al.(2011). 68Ga PET/CT Ventilation-Perfusion Imaging for Pulmonary Embolism: A Pilot Study with Comparison to Conventional Scintigraphy. Journal of Nuclear Medicine 52 (10): 1513–1519.

• Jaff MR, et al. Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientific statement from the American Heart Association. Circulation. 2011 Apr 26;123(16):1788-830. doi: 10.1161/CIR.0b013e318214914f. Epub 2011 Mar 21. Erratum in: Circulation. 2012 Mar 20;125(11):e495. Circulation. 2012 Aug 14;126(7):e104.

• Mattu, A. PE in pregnancy: A complicated diagnosis. Medscape. August 9, 2010 (Online) URL: http://www.medscape.com/viewarticle/726318

• Pulmonary embolism. Life in the fast lane. (Online). http://lifeinthefastlane.com/education/ccc/pulmonary-embolism/

Thank you!

drbarai@gmail.com