Pulmonary%20Thromboembolic%20Disease

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Pulmonary Thromboembolic Disease

• By
• Ahmed Mansour, MSc, PhD

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Definition

• PE is a clinically significant obstruction of
  part or all of the pulmonary vascular tree
  (usually caused by migrating thrombus from a
  distant siteDVT).
• VTE PE DVT

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Natural History

• Death within 1 h 11.
• Survival gt 1 h 89
• Diagnosis made ttt started 29
• Survive 92
• Death 8
• Diagnosis not made 71
• Survive 70
• Death 30

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Source of Emboli

• Lower extremit (80-95) especially if popliteal
  or above.
• Pelvic veins in cases of...
• Upper extremity...
• Right ventricle, more hemodynamic instability and
  increased mortality.
• Other materials...

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Presisposing Factors

• Wirchows triad.
• Acquired risk factors
• Inherited thrombophilias
• 1- Factor V Leiden mutation (APC resistance)
• 2- Prothrombin gene mutation
• 3- Deficienecy of antithrombin III, protein C,
  protein S.

Minor 1- Cardiovascular 2- HRT, contraceptives 3- Others obesity, nephrotic syndrome, Major 1- Surgery 2- Obstetrics 3- Malignancy 4- LL problems 5- Immobility 6- Previous VTE
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Pathophysiology

• Factors determining the outcome
• 1- Size and location of emboli
• 2- Coexisiting cardiopulmonary diseases
• 3- Secondary humoral mediator release and
  vascular hypoxic responses
• 4- Resolution rate of emboli

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Haemodynamic consequences of acute PE

• 1- PAP rises.
• 2- RV after-load increases.
• 3- RV failure if gt 50 of pulmonary vascular bed
  is obstructed
• 4- LV filling is reducedhypotension.
• 5- Increased RA pressure may lead to
  intraccardiac shunt through a patent foramen
  ovale.

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Gas-Exchange Abnormalities

• Hypoxemia
• 1- Re-direction of blood flow to other parts of
  pulmonary vascular bed (V/Q mismatch)
• 2- Increased alveolar dead space due to
  atelectasis and bronchiolar constriction.
• Hypocapnea due to hyperventilation

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Clinical features of acute PE

• 1- Pulmonary infarction and hemoptysis
  pleuritic pain (60)
• Acute pleuretic chest pain and hemoptysis
• O/E local signs e.g. pleural rub
• ABGs and ECG are usually normal
• 2- Isolated dyspnea (25)
• Acute SOB in presence of a risk facto for VTE
• O/E patient is hemodynamically stable
• ABGs show hypoxemia, CTPA central thrombus
• 3- Circulatory collapse, poor reserve (10)
• Usually in elderly patients with cardiopulmonary
  diseases
• Rapid decompensation even with small PE
• O/E features of the underlying diseases.
• 4- Circulatory collapse in a previously well
  patient (1)
• Acute chest pain (RV angina), hemodynamic
  instability due to massive PE
• O/E RV failure...
• ECG changes, echocardiography shows RV failure

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Clinical features of chronic PE

• Insidious onset over weeks to months due to
  recurrent showers of small emboli.
• Dyspnea and tachypnea are the commonest features
  (90).
• Should be considered in the DD of
• Unexplained SOB
• RVF
• New AF
• Pleural effusion
• Collapse

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Examination

• 1- May be normal
• 2- Vital signs
• tachypnea, tachycardia (may be AF), low grade
  fever.
• 3- Heart
• Signs of pulmonary hypertension (loud splitted
  S2)
• Signs of RV failure (raised JVP, low COP with
  systemic hypotension, tricuspid gallop)
• 4- Chest the affected side may show
• Inspection reduced movement
• Palpation diminished expansion
• Percussion dullness in case of pleural effusion
• Auscultation pleural rub (Pulmonary infarction )
  or diminished intensity of breath sounds (pleural
  effusion)
• 5- Lower limbs
• Signs of DVT.

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Diagnosis of Acute PE

• Pre-test clinical probability scoring
• e.g. BTS scoring system
• a- Clinical features consistent with PE
• 1- Absence of other reasonable clinical
  explanation
• 2- Presence of a major risk factor
• High probability a12
• Intermediate probability a either 1 or 2
• Low probability a only

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Diagnosis of Acute PE

• D-dimer
• A fibrinolysis product generated in many clinical
  situations e.g...
• Indicated in
• 1- Low/intermediate clinical probability
• 2- Acute cases only
• 3- Outpatient cases only
• Sensitive (small no. Of false negatives) but not
  specific (large no. Of false positives).
• Interpretation of the results
• Normal level negative test, elevated level
  positive test
• A negative test is valid to exclude PE in cases
  with low/intermediate clinical probability. A
  positive test does not cofirm PE but rather
  further imaging is required

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Investigations

• 1- ECG
• 2- CXR
• 3- ABGs
• 4- D-dimer
• 5- Troponin and natriuretic peptides
• 5- CTPA
• 6- Ventilation/perfusion lung scan
• 7- Others

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ECG

• Sinus tachycardia
• AF
• RBBB
• RV starin
• Less commonly S1Q3T3

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CXR

• Small pleural effusion
• Raised hemi-diaphragm
• Collapse
• Infiltrate

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ABGs

• May be normal
• Hypoxemia and hypocapnea
• Increased A-a oxygen gradient

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Troponin and natriuretic peptides

• Indicate RVD
• Raised troponin predicts poor prognosis

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CTPA

• The gold standard investigation
• Highly sensitive (multi-detector scanners)
• More sensitive for central emboli
• More helpful for patients with abnormal CXR
• Negative CTPA
• In those with low/intermediate clinical
  probability PE is unlikely.
• In those with high clinical probablity further
  investigations are required.

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V/Q scan

• Mostly replaced by CTPA
• Still helpful in
• Patients with normal CXR
• Patients in whom CTPA is not safe e.g...
• Results

Clinical significance Scan probability Clinical probability
No PE Normal ???
PE excluded Low Low/intermediate
PE diagnosed High High
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Other imaging techniques

• Echocardiography
• Leg U/S
• CT venography
• Transthoracic U/S
• Conventional pulmonary angiography

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Management of acute massive PE

• 1- 100 O2
• 2- IV access, baseline clotting screen, ECG
• 3- Analgesia
• 4- Management of cardiogenic shock
• 5- IV heparin
• Unfractionated vs LMWH
• Loading, maintenance
• APTT
• 6- Investigations to confirm PE?
• 7- Thrombolysis for massive PE causing
  hemodynamic instablity
• 8- Embolectomy in patients with a
  contraindication for anticoagulants or
  thrombolytics
• 9- Oral anticoagulants
• Outpatient
• INR
• For how long?
• 10- IVC filter for patients with
• A contraindication for anticoagulants
• Massive PE after survival
• Reccurrent VTE despite adequate anticoagulation

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Thank you