By
Ahmed Mansour, MSc, PhD

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

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

• 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...

• Wirchow ’ s triad.
• Acquired risk factors
Major:
1- Surgery
2- Obstetrics
3- Malignancy
4- LL problems
5- Immobility
Minor:
1- Cardiovascular
2- HRT, contraceptives
3- Others: obesity, nephrotic syndrome, …
6- Previous VTE
• Inherited thrombophilias
1- Factor V Leiden mutation (APC resistance)
2- Prothrombin gene mutation
3- Deficienecy of antithrombin III, protein C, protein S.

• 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

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

• 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

1- Pulmonary infarction and hemoptysis ± pleuritic pain (60%):
- Acute pleuretic chest pain and hemoptysis
- O/E: local signs e.g. pleura;l 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

• 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

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.

• 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: a+1+2
Intermediate probability: a+ either 1 or 2
Low probability: a only

• 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

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

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

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

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

• Indicate RVD
• Raised troponin predicts poor prognosis

• 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.

• Mostly replaced by CTPA
• Still helpful in:
- Patients with normal CXR
- Patients in whom CTPA is not safe e.g...
• Results:
Clinical probability
???
Low/intermediate
High
Scan probability
Normal
Low
High
Clinical significance
No PE
PE excluded
PE diagnosed

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

1100% O
2
2- IV access, baseline clotting screen, ECG
3- Analgesia
4- Management of cardiogenic shock
5- IV heparin:
– Unfractionated vs LMWH
– Loading, maintenance
– APTT
6Investigations 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?
10IVC filter for patients with :
A contraindication for anticoagulants
Massive PE after survival
Reccurrent VTE despite adequate anticoagulation